Want to hear the latest news about space or science? A few times each year, author Jeffrey Bennett sends an e-mail with such things as summaries of major new developments in science or information on sky events that you can observe for yourself. Aimed primarily at the general public, the news letter also sometimes includes questions that teachers at any level (including college) might want to use in class.

To subscribe to future e-mails: send an e-mail to subscribe-spacenews_bennett@lists.awl.com. Put the word "subscribe" (without the quotes) in the body of an otherwise blank message (remember to leave off your signature lines as well).

You can read past news e-mails below; here's the list and quick links:

03/07/07: Super (Bowl) Misconceptions, Part 2: Global Warming

02/05/07: Super (Bowl) Misconceptions, Part 1: Gravity on the Moon

01/09/07: Look for the comet! Plus Mars, Titan, and more.

09/01/06: Pluto Redefined, and more

04/24/06: Astronomy Day, Enceladus, New Horizons, more

10/16/05: Max Day at DMNS, Mars, Gamma Ray Bursts, NASA Moon plans, more

08/09/05: Who ordered the extra pizza?, and more space news

07/04/05: Cometary Fireworks

06/24/05: Sunset Planets

05/01/05: Hubble, Mars, July 4 crash, Physics Year, Eclipse Trip, Astronomy
Workshops, School visits

01/14/05: Titan Success!

01/12/05: The Sirens of Titan; Comet, asteroid missions

12/03/04: Upcoming sky events; mission update; Max

10/25/04: lunar eclipse, Cassini at Titan, Max update

08/11/04: Perseid meteor shower

06/08/04: Transit of Venus

05/03/04: lunar eclipse, bright Venus, Venus transit, and more

03/27/04: Planet viewing tonight; science updates on Mars, Saturn, and Pluto

03/07/07: Super (Bowl) Misconceptions, Part 2: Global Warming

Note: This longer e-mail, enhanced with graphics, is posted here.

02/05/07: Super (Bowl) Misconceptions, Part 1: Gravity on the Moon

Dear Friends,
Did you watch the Super Bowl yesterday? If so, you might have seen a great example of science illiteracy in America, taking the form of a Fedex commercial. Brace yourself, as it's pretty appalling... And in case you are wondering why I've titled this e-mail "Part 1," it's because I plan to follow up (hopefully in the next few days) with Part 2 on an even more appalling example of scientific illiteracy from this weekend's news...
Best wishes,
Jeff

Super (Bowl) Misconceptions, Part 1: Gravity on the Moon

GRAVITY ON THE MOON. Early in the game, Fedex broadcast an ad about the first office on the Moon; in case you didn't see it, Fedex is apparently so proud of this ad that they've posted the video at http://football.fedex.com. They should not be so proud, as they have contributed to a major scientific misconception: the common but incorrect belief that there is "no gravity on the Moon." In fact, if you look carefully, you'll see that Fedex did even worse than make it look like there's no gravity on the Moon: They actually made gravity different in different situations! For example:

• At the beginning, we see people on a tour of the Moon office; these people are bounding up and down, which is somewhat realistic. However...
• ...seconds later, we see a guy taking a drink in the Moon office, and his liquid is floating, so at this point the implication is that people are affected by the Moon's gravity but liquids are not...
• ...but seconds after that, we see other people (and a dog!) floating around inside the office, so gravity must depend on the individual...
• ...then we head outside, where astronauts are walking around, and they are walking just like they would on Earth! So gravity outside must be stronger than gravity inside...
• ...and then one of the astronauts gets a small push, and floats off into space - where he is improbably struck by some sort of meteor, which is all the more amazing since the Moon lacks an atmosphere and therefore a meteor could not burn up as shown.

A less egregious form of this misconception about gravity is actually quite common. For example, when I do my Max Goes to the Moon talks at elementary schools, I show the kids the Apollo scene on p. 12-13 and ask why the flag stays up. By far the most common initial answer is that "there is no gravity on the Moon." (Even some of the teachers think this is the answer.)

To help the students understand why this answer is incorrect, I then ask them to look closely at the Apollo picture and figure out whether or not there is gravity on the Moon. They quickly realize that the fact that the astronauts and the spacecraft are on the surface and not floating away means that there IS gravity on the Moon. They are then ready to understand the real answer - the flag was held up by a horizontal rod along the top - and, hopefully, will never again believe the "no gravity on the Moon" misconception.

Teachers, I encourage you to use this same example to help dispel the Moon gravity misconception among your own students. It will work for almost all elementary students, and most students of all ages. Of course, there will always be some people who prefer to deny reality (more on that in the forthcoming Part 2 e-mail); for a humorous if sad commentary on this issue, scroll down and read the "heavy boots" piece that I have pasted below the questions.

Questions/Discussion Topics for Class:

1. (Math question.) The average price of air time for Super Bowl ads this year was reported to be $2.6 million; note that this is air time only, and does not include the cost of producing the ad. Since Fedex placed this ad early in the game, their cost for the broadcast was probably around $3 million. Suppose they had spent 0.1% of this amount to hire a scientist to make sure their science was right. How much would it have cost them? (Answer: 0.1% of $3 million is $3,000; they would have had no difficulty finding a scientist to help them out at that price.)
2. Given that they could so easily have gotten the science correct, we can only assume that they made a deliberate choice not to do so. Why might they have made this choice? (Answer: Beats me; perhaps they thought their way was funnier, and that the American public is too scientifically ignorant to notice.)
3. Read the "heavy boots" piece below. Why can't "heavy boots" explain how the astronauts walked on the Moon? (Answer: It's wrong on numerous levels, but the most obvious is that if there's no gravity, then everything would be weightless, including "heavy" boots.)
4. Another common misconception is that "there is no gravity in space." To dispel this one, first ask your students why astronauts are weightless in the Space Shuttle and Space Station. You'll probably get the "no gravity in space" answer. Then ask them why the Moon orbits the Earth, or why Earth orbits the Sun. If they are past about fourth or fifth grade, they'll almost certainly know that it's because of gravity --- thereby proving that there IS gravity in space. In case you are wondering, the real reason that astronauts are weightless in orbit is that they are in free-fall, in essence always "falling around" Earth as they orbit. In fact, you are weightless anytime you are in free-fall, which is why you can do the same types flips and twists when diving off a diving board or jumping on a trampoline as the astronauts can do in orbit. The only difference is that in orbit, the free-fall lasts much longer. (For a more detailed explanation, please see Section 4.1 of my textbooks The Cosmic Perspective or The Essential Cosmic Perspective.)

PS to Elementary teachers and Parents: To show how pervasive this misconception is, I offer the cautionary note that even one of my favorite series of children's books messed this one up. In "Midnight on the Moon" - #8 of the generally outstanding Magic Tree House series - Jack and Annie arrive at a future Moon base, put on space suits and go outside. All fine, except: They don't realize the gravity is reduced and start bounding around until they go outside! Apparently, like Fedex, the author thought that gravity would be different inside and outside on the Moon. Nope...

HEAVY BOOTS: SCIENCE EDUCATION IN AMERICA
Now, as promised above, here is the piece about "heavy boots". I do not know the original source, though I found it quoted with "Reprinted from Astronet, Issue 11." If anyone knows who wrote it originally, please let me know.

About 6-7 years ago, I was in a philosophy class at the University of Wisconsin, Madison (good science/engineering school) and the teaching assistant was explaining Descartes. He was trying to show how things don't always happen the way we think they will and explained that, while a pen always falls when you drop it on Earth, it would just float away if you let go of it on the Moon.

My jaw dropped a little. I blurted "What?!" Looking around the room, I saw that only my friend Mark and one other student looked confused by the TA's statement. The other 17 people just looked at me like "What's your problem?"

"But a pen would fall if you dropped it on the Moon, just more slowly." I protested.

"No it wouldn't." the TA explained calmly, "because you're too far away from the Earth's gravity."

Think. Think. Aha! "You saw the APOLLO astronauts walking around on the Moon, didn't you?'' I countered, "why didn't they float away?" "Because they were wearing heavy boots.'' he responded, as if this made perfect sense (remember, this is a Philosophy TA who's had plenty of logic classes).

By then I realized that we were each living in totally different worlds, and did not speak each others language, so I gave up. As we left the room, my friend Mark was raging. "My God! How can all those people be so stupid?"

I tried to be understanding. "Mark, they knew this stuff at one time, but it's not part of their basic view of the world, so they've forgotten it. Most people could probably make the same mistake." To prove my point, we went back to our dorm room and began randomly selecting names from the campus phone book. We called about 30 people and asked each this question:

If you're standing on the Moon holding a pen, and you let go, will it a) float away, b) float where it is, or c) fall to the ground?

About 47 percent got this question correct. Of the ones who got it wrong, we asked the obvious follow-up question:

You've seen films of the APOLLO astronauts walking around on the Moon, why didn't they fall off?

About 20 percent of the people changed their answer to the first question when they heard this one! But the most amazing part was that about half of them confidently answered, "Because they were wearing heavy boots."

I say, science education must be at an all time peak!!!

01/09/07: Look for the comet! Plus Mars, Titan, and more.

Dear Friends,
Much to astronomers' surprise, a faint comet -- Comet McNaught -- discovered a few months ago is rapidly brightening, and I'm now told that it is easily visible with binoculars and possibly even to the naked eye in early evening and pre-dawn skies if your observing conditions are favorable. The observing is best from father north, so Canadians and Europeans (who generally live at higher latitudes than the U.S.) have a better shot at it than most of us in the U.S. Still, I plan to look for it over the next few days, and I encourage you to do so also. If you find it, please send me an e-mail reply to let me know what you saw.

To find the comet, look:

• 15 to 30 minutes after sunset: near the horizon, west-southwest
• 15 to 30 minutes before sunrise: near the horizon, east-southeast

More details and pictures of Comet McNaught:

• Astronomy Picture of the Day for Tuesday, January 9: http://antwrp.gsfc.nasa.gov/apod/ap070109.html
• Space.com article at: http://www.space.com/spacewatch/070104_comet_mcnaught.html
• Sky and Telescope article at: http://skytonight.com/observing/home/5118926.html

Now, since it's been so long since I've sent out one of these news e-mails, three more items too exciting to wait on any longer:

1. Evidence of a recent water flow on Mars. Although the low atmospheric pressure makes liquid water unstable on the surface of Mars -- meaning any liquid water would rapidly freeze or evaporate --- it is possible that liquid water might occasionally be released from beneath the surface or might form as surface ice melts and then flow for a few minutes before it freezes or evaporates. A few years ago, orbital images of Mars revealed the presence of gullies on many crater walls, presumably formed by this type of flowing water. Because blowing sand should erase gullies in thousands to millions of years, their existence indicated "recent" water flows --- but "recent" still might have meant millions of years ago. Now, however, comparisons of the same craters show new gullies in just the past couple years, indicating that the water flows are an ongoing process. Because water is considered so important to life, the ongoing existence of water flows at least marginally increases the likelihood that we will someday discover life on Mars. You can see the comparison images at http://antwrp.gsfc.nasa.gov/apod/ap061212.html.
2. Methane lakes on Titan. Saturn's moon Titan is far too cold for liquid water, but temperatures are just about right for liquid methane. Last summer, new images from the Cassini spacecraft (which is orbiting Saturn and often passing close to Titan) appeared to show lake-like features. Further analysis of the images makes a very strong case that at least 75 lakes exist in just one relatively small region near Titan's north pole. For more details, see the article from January 4 New York Times at http://www.nytimes.com/2007/01/04/science/space/04titan.html.
3. New Horizons approaching Jupiter. Just about a year ago (Jan. 19), I had the good fortune to see the launch of the New Horizons spacecraft, bound for Pluto. The fastest spacecraft ever launched, it is already approaching Jupiter, where it will get a further boost in speed next month as it uses Jupiter's gravity to "sling-shot" it toward Pluto. Its cameras should also capture some great images of Jupiter as it goes by. Keep up with New Horizons at its web site: http://pluto.jhuapl.edu.

See below if you are wondering why I've been too busy to send out many of these e-mails, and otherwise that's all for now. Also, please see my revamped web site: http://www.jeffreybennett.com.

Best wishes for the new year!
Jeff

JEFF'S LATEST BOOKS UPDATE

New for Spring 2007 classes:

1. The Essential Cosmic Perspective, Fourth Edition: Fully updated (including the latest on Pluto's planetary status), with more than a dozen spectacular new 2-page spreads, and now accompanied by access to our Mastering Astronomy web site.
2. The Cosmic Perspective, Fourth Edition Media Update: The fourth edition first came out a year ago, but we have updated the book to discuss Pluto's planetary status, and also updated the Mastering Astronomy web site.
3. Life in the Universe, Second Edition: Fully updated, this text is designed to make it easy for you to teach an introductory astrobiology class at either the college or senior high school levels.
   
   Coming Soon:
   
4. Using and Understanding Mathematics, Fourth Edition: Fully updated, with new units on personal finance and congressional redistricting. It is now at the printer, and will be available in February.
5. Max Goes to the Ice Age: Third grader Logan Weinman wrote and illustrated this story, which won a writing contest in Summit County Colorado. I thought it was so good that I added some science content and we are putting it out as a new Big Kid Science book. Available in July.
6. Statistical Reasoning for Everyday Life, Third Edition: We're hard at work on it right now, and it will publish in the fall.
7. Max Goes to Jupiter: We're just getting started on it, and hope to have it out for Spring 2008.

09/01/06: Pluto Redefined, and more

Dear Friends,

A quick update on things going on in space. In this e-mail:

1. Thoughts on Pluto
2. Dark Matter Still Dark
3. Lunar Impact
4. Max books donation update

Best wishes,
Jeff

1. Thoughts on Pluto. Many of you have been asking me what I think of the new definitions that demote Pluto and create a new category of "dwarf planets" that includes Pluto, the object still nicknamed Xena, the asteroid Ceres, and perhaps dozens of other objects to be named later. My short answer: Scientifically, it's long been clear that Pluto is in a different category than the other 8 planets. Semantically, whether that means it's a regular planet, one of a whole new group of regular planets, a dwarf planet that is not a regular planet, a "large Kuiper belt comet" (my personal favorite for Pluto), or anything else is just, well, semantics. For my longer answer, please see my article posted at http://www.space.com/searchforlife/seti_pluto_060831.html.
   Questions for class:
   • How is Pluto different from the 8 now-official planets? (Answer: It differs in orbit (more elongated ellipse and more tilted to ecliptic), it is much lower in mass, and it differs in composition (ice/rock, unlike either the rocky terrestrial planets or gaseous jovian planets).)
   • What is "Xena," and in what way did it spur the current debate? (Answer: See my posting at http://www.space.com/searchforlife/seti_pluto_060831.html.)
   • What do YOU think of the new definitions? Defend your opinions.

2. Dark Matter Still Dark. Most of the matter in the universe seems to be "dark" -- by which astronomers mean that we can detect its gravitational influence but cannot see any light coming from the matter. The leading hypothesis holds that most of this dark matter is made of subatomic particles that do not emit or absorb light. However, some physicists have proposed that dark matter doesn't really exist, and instead the observed effects tell us that our current theory of gravity (Einstein's general theory of relativity) is not quite correct. A very cool new set of results from Hubble -- posted at http://hubblesite.org/newscenter/newsdesk/archive/releases/2006/39/ --- greatly strengthens the case for the existence of dark matter, and appears to rule out the alternate theories of gravity that have been proposed. A triumph for Einstein, but the dark matter is still quite dark both in visibility and in the fact that we still have little idea of exactly what it is. For more discussion, please see Mystery #2 in my book On the Cosmic Horizon or Chapter 22 in The Cosmic Perspective.
   Questions for class:
   • Read the news release on the Hubble web site. How were the data collected? What does the image show? (Answer: data were based on measurements of gravitational lensing caused by the galaxy cluster. Note that the image shows the inferred dark matter distribution based on these measurements; it does NOT show any type of light emission.)

3. Lunar Impact: The European SMART-1 spacecraft will execute a planned crash into the Moon tomorrow. Read about it and find out how to observe it at http://science.nasa.gov/headlines/y2006/30aug_smart1.htm.

4. Max books donation update. This fall, I am donating another 5,000 copies of Max Goes to Mars. About 3,200 copies have been claimed so far, and will be going to, among others, the entire states of Mississippi, Michigan, and Rhode Island, a large part of Kentucky, the Atlanta metro area, and Indian reservations in New Mexico and Arizona. I'm still looking for districts to receive the remaining 1,800 copies. So if you know some that might be interested, FIRST read my program guidelines at http://www.jeffreybennett.com/MaxMarsDonate.htm, and then contact me. Thanks.

04/24/06: Astronomy Day, Enceladus, New Horizons, more

1. Boulder/Denver-area folks: This Saturday (4/29) is CU Astronomy Day, with lots of free activities for kids and families, including demonstrations, talks, solar observing (weather permitting), and much more. Starts at noon at Fiske Planetarium; more information at http://cosmos.colorado.edu/sbo/public/special.html. As part of the event, I'll be doing a reading of Max Goes to Mars in the planetarium theater at 2pm.

2. Life on Enceladus? The Cassini mission at Saturn (http://saturn.jpl.nasa.gov) has been spectacular since its start, but perhaps nothing has been quite so surprising as its recent findings at the moon Enceladus. This relatively small moon is spraying out fountains of ice crystals, and may contain liquid water or a colder liquid water/ammonia mixture inside it. Liquid water makes scientists think about the possibility of life... Personally, I think life on Enceladus is unlikely, but the mere raising of the possibility suggests that there might be many more homes for life than we had imagined even quite recently. For example, if Enceladus could have life, why not Triton, or some of the moons of Uranus, or...? Clearly, it's an issue worthy of further study.
   
   Questions for class:
   • How big is Enceladus? (Answer: At about 500 km in diameter, it is barely 1/7 the diameter of our Moon.)
   • How can such a small moon be warm enough for liquids in its interior? (Answer: Scientists are still investigating this question, but we know that Enceladus is subject to tidal heating, and presumably that is the answer.)
   • When is NASA planning a follow-up mission to investigate Titan and Enceladus further? (Answer: Sadly, there are no such plans at this time.)

3. New Horizons en route to Pluto. I had the good fortune to attend the spectacular launch of New Horizons on January 19. Now, barely 3 months later, it has already crossed the orbit of Mars. It will pass Jupiter next year, and reach Pluto in 2015. More info and great launch photos at http://pluto.jhuapl.edu.
   
   Questions for class:
   • What is the Kuiper belt, and what makes us think that Pluto is a member? (Answer: The Kuiper belt is a "reservoir" of icy objects out beyond the orbit of Neptune; Pluto shares many traits with other Kuiper belt objects.)
   • Is Pluto the largest member of the Kuiper belt? (Answer: No; a slightly larger one was discovered last July; others may yet be found.)
   • How many moons does Pluto have? (Answer: Two small ones were discovered just last summer, making a total of 3; the largest of the 3, Charon, was discovered in 1978.)

4. Mars Reconnaissance Orbiter (MRO) in Mars Orbit. MRO reached Mars orbit about a month ago. It is now in the period during which it skims the martian atmosphere at the low point of each orbit, thereby shedding orbital energy ("aerobraking") that helps circularize its orbit. It has already returned some spectacular pictures, and will begin full operations toward the end of this year. More info at http://marsprogram.jpl.nasa.gov/mro.
   
   Questions to ask in class:
   • How many spacecraft are now operating at Mars? (Answer: 6: Two rovers on the surface, Spirit and Opportunity; Mars Global Surveyor, Mars Odyssey, Mars Express, and MRO.)
   • What is the point of the aerobraking to alter MRO's orbit? (Answer: The trajectory from Earth to Mars would send a spacecraft on a single flyby. To obtain any orbit of Mars, a spacecraft must slow down --- and the lower the orbit (which is desirable for closer-up observations), the more it must slow. It can slow either by firing its engines (in reverse) or by shedding energy to friction with the atmosphere. The former requires carrying more fuel, which raises the spacecraft weight and hence its launch costs. The latter is "free," since it just relies on the martian atmosphere.)

5. Meanwhile, at Venus... The European Venus Express mission is now in orbit of Venus, and promises our best-ever views of our nearest planetary neighbor. More info at http://sci.esa.int/venusexpress.
   
   Questions for class:
   • Venus is on average closer to Earth than Mars. Why, then, do we think about sending people to Mars before sending people to Venus? (Answer: Venus is way, way, way too hot.)
   • Why is Venus so hot? (Answer: An extreme greenhouse effect, caused by having almost 200,000 times as much carbon dioxide in its atmosphere as is present in Earth's atmosphere.)
   • Why should Venus give us a scare? (Answer: Earth is in little danger of becoming like Venus for the next few billion years, but Venus certainly stands as proof that global warming can get out of hand.)

6. Speaking of global warming... The ice core data showing past carbon dioxide concentrations has recently been extended to go back 650,000 years; lots of articles reporting on this, but here's a good one from New Scientist: http://www.newscientist.com/article.ns?id=dn8369. The big news is that the data show that the current carbon dioxide concentration is significantly higher than Earth has experienced during the past 650,000 years. Now that's a reason to be concerned...
   
   Questions for class:
   • Is this proof that global warming is a serious problem? (Answer: No, but it sure makes you think.)
   • Is global warming responsible for the recent upsurge in hurricanes? (Answer: No one really knows, and making a direct connection to short-term events is nearly impossible. Nevertheless, global warming basically means increased energy in Earth's atmosphere, which would be expected to mean more and more severe storms. So no proof --- but the upsurge is consistent with what we might expect.)

7. Max Goes to Mars School Donation Program -- Preliminary Info on Round 2. I am tentatively planning to donate another 5,000 copies of Max Goes to Mars to schools around the nation; first round info is at http://www.jeffreybennett.com/MaxMarsDonate.htm. I'm still working out the logistics, but it will probably involve my shipping books only to large districts or groups of districts, because it is too difficult for me to send the books out in small batches. If you know a school system that might be interested, please let me know and start the process of the initial contacts.

All for now!
Jeff

10/16/05: Max Day at DMNS, Mars, Gamma Ray Bursts, NASA Moon plans, more

1. Halloween Mars: Mars comes closest in its orbit to Earth, and hence reaches a peak in brightness in our sky, about every 26 months. That time is coming up right around Halloween, so it will be especially easy to spot when you are out trick-or-treating. In fact, you can already see Mars quite easily. Mars is rising in the southeast not too long after it gets dark, reaching its highest point to the south (on the meridian) near midnight, and then setting in the southwest. It's bright and red-orange in color, so you can't miss it. For more details, see http://science.nasa.gov/headlines/y2005/22sep_doublemars.htm.
   
   Questions to ask in class:
   • Why does this unusually bright Mars reach its highest point in the sky around midnight? (Answer: For Mars to be at its closest to Earth, it must be on the direct opposite side of Earth from the Sun [called "opposition"], so it is 180° away from the Sun in our sky, which puts it on the meridian at midnight.)
   • Mars is also now in the middle of what is called its "retrograde loop." What is this, and why is Mars in the middle of the loop now? (Answer: If you don't already understand this, try the demonstration that is shown at the end of Max Goes to Mars or in my astronomy text, chapter 2. You'll see that opposition always occurs in the middle of the retrograde loop.)
   • Why are spacecraft to Mars launched about 26 months apart, and what mission was launched most recently? (The "launch windows" must be timed for when Mars is coming closest to Earth, which as above is every 26 months. The Mars Reconnaissance Orbiter was launched on August 12 and is currently en route to Mars; read about it at http://marsprogram.jpl.nasa.gov/mro.)

2. Gamma Ray Burst Mystery Solved? Gamma ray bursts may be the most powerful explosions that ever occur in the cosmos, but until recently we had little idea of their origin. In fact, I chose them as Mystery #5 in On the Cosmic Horizon, my book on the top 10 mysteries in astronomy. Part of the mystery seemed to be solved a couple years ago, as strong evidence pointed to explosions of very massive stars - sometimes called hypernovae to distinguish them from other supernovae - as their sources. However, gamma ray bursts come in two distinct types, and the second type, "short" burst that last just seconds, still had no known source. Well, you may have read recent news reports claiming that the mystery is now solved, and that the sources of the short bursts are exotic collisions between two neutron stars or a neutron star and a black hole. So can we cross this mystery off the list?

   Not so fast...Unless I'm missing something in the new results, here's the thought process: To date, scientists have thought of only two viable ideas about how gamma ray might be produced: the hypernovae and the collisions of neutron stars or black holes. The new results rule out hypernovae for the short bursts so, voila, we're left with collisions as the mechanism. It sounds reasonable, but one of the great lessons of astronomy in the past century has been that we should never underestimate the capacity of nature to think of something before we do. Just because we have ruled out the hypernovae does not mean we can automatically rule in the collisions. The mystery MIGHT be solved, but we'll need a lot more data before I'll scratch it off my list...

   • Class project: The two missions that are giving us the greatest insight into gamma ray bursts at the moment are called Swift (http://www.swift.psu.edu) and HETE (http://space.mit.edu/HETE) . Go to their web sites to learn more about the missions, about gamma ray bursts, and about the current status of the attempt to unravel the mystery.

3. Get Ready for Pluto: New Horizons launch in January. Pluto may recently have been demoted from the ninth to the tenth spot in size for objects orbiting the Sun, but it's still a fascinating place that we'd like to learn a lot more about. The first spacecraft to Pluto is now just about ready for launch: the New Horizons mission, developed by Alan Stern and other colleagues here in Boulder, is scheduled for launch from the Kennedy Space Center on January 11. It will then take about a decade to reach Pluto. Read about this exciting mission at http://pluto.jhuapl.edu.
   
   Questions for class:
   • How many planets are there in our solar system? (Answer: trick question! The answer is unclear, especially since July's announcement of "Planet X"; see my prior posting from Aug. 9; direct link to archive is http://www.jeffreybennett.com/news_space.html.)
   • What is Pluto made of, and how does it resemble a comet? (Answer: rock and ice; it's composition is nearly identical to that of many comets, and it differs primarily in being unusually large for a comet.)
   • Go to the New Horizons web site and learn more about the mission. When will it reach Pluto? What other objects will it visit? What are its scientific goals?

4. 100 Years of E = mc². Einstein published his famous equation in September 1905, which means we've now known it for a century. Few equations have had such a direct and obvious impact on world history. It explains how the Sun generates energy, and has led to the nuclear age. Physicist Brian Green, author of The Fabric of the Cosmos (highly recommended!), wrote a great article about the famous equation for the New York Times op-ed page, Friday, Sept. 30, 2005. The link is http://select.nytimes.com/gst/abstract.html?res=F70F13FD38540C738FDDA00894DD404482, though it's only free if you are a subscriber. (Users of my textbooks can also get access through the Research Navigator on the text web site.) And if you really want to understand Einstein's theory and the equation, read Chapter S2 in the full version of The Cosmic Perspective.

5. Op-ed: NASA's New Moon Shot - Where's the Inspiration? If you've read my children's books or my op-ed from the Denver Post (click the article title on http://www.jeffreybennett.com/news_space.html), you might think I'd be jumping up and down at NASA's newly announced plans to return to the Moon in 13 years. I have not studied the plan in any detail, so I'm reacting mainly to newspaper accounts, but here's my initial reaction: While it looks like a technically sound and relatively inexpensive way of returning to the Moon, it seems to be missing the key ingredient of INSPIRATION. Where's the base with people from all nations, so that children around the world can look up at the Moon and say "people just like me are there right now, and if we can work together up there, surely we can work together down here too." Where's the great observatories that will make astounding new discoveries? Where's the University of the Moon, to which children from around the world will work for admission? How will ordinary people get there, so they can share the experience of seeing our world as a "pale blue dot"? The plan simply says we'll get there, and worry about the other stuff later. Moreover, the fact that is an almost entirely American plan, rather than an international plan, undercuts the critical importance of space exploration as a global endeavor. As is already evident from the many newspaper editorials saying "been there, done that," the new plan sounds too much like what we did more than 36 years ago. I'm glad to see some type of plan, but this one is going to need a lot of work before it will convince anyone that it is worth the money it will cost.

6. Book update:
   • Max Goes to Mars: is now in bookstores everywhere. Special thanks to all of you who helped with my Max Goes to Schools donation program (http://www.jeffreybennett.com/MaxMarsDonate.htm), which has successfully placed the new book in more than 5,000 elementary schools across the country, and the first book (Max Goes to the Moon) in more than 3,000 schools. (Please note: EVERY public elementary school in Colorado should have received both books in the past week or two; if you know of a school that did not, please let me know.)

   All for now!
   Jeff

   ---

   8/9/05: Who ordered the extra pizza?, and more space news

   Welcome to the latest installment of my space science e-mail. A lot has been happening in astronomy lately --- enough to keep textbook writers like myself scrambling to keep up with it! I don't have enough time right now to cover all of it in one e-mail, so some news items will have to wait until a future e-mail. Here's what I have for this time:

   1. Who ordered the extra pizza? The discovery of an"Planet X."
   2. Mars Reconnaissance Orbiter launch tomorrow!
   3. Perseid meteor shower peaks early morning August 12.
   4. Mars will NOT be super bright on Aug. 27.
   5. What next for the Shuttle? My editorial opinion...
   6. Max Goes to Schools: Update on my 5,000 book donation program.

   Read on below...

   1. Who ordered the extra pizza? You've probably heard the mnemonic for remembering the order of the planets that goes "My very excellent mother just sent us nine pizzas." Well, as you may have read, someone ordered another pizza! On July 29, astronomers announced the discovery of an icy object in our outer solar system that is as big as or slightly bigger than Pluto; NASA Science News has a report on the discovery. For the moment, the object is being referred to as "Planet X," though it is likely to get an official name soon. What does this discovery mean? Here are a few key points:

   • The discovery was NOT a big surprise. We've known for more than a decade that Pluto is one of many relatively large, icy objects --- essentially large comets --- that orbit the Sun beyond Neptune, in a region of our solar system called the Kuiper (pronounced koy-per) Belt. Until this new discovery, Pluto was the largest known object in the Kuiper Belt, but many objects that are fairly close in size to Pluto have been discovered in recent years. It seemed only a matter of time before we found another object as large as Pluto, and now it has happened. Even today, less than about half the Kuiper Belt has been carefully searched with telescopes, so it is possible that other Pluto-size objects remain to be discovered.
   • The discovery will force astronomers to confront the question of whether Pluto should count as a planet. We've known for several decades that Pluto is quite different in character from the other 8 planets. Besides being the most distant planet with the most unusual orbit around the Sun, it is much smaller than any of the other planets --- its mass is only about 0.2% that of Earth. Moreover, Pluto's composition of ice and rock makes it much more similar to the thousands of known comets than to the other eight planets. Some people have therefore argued that Pluto should be demoted from "planet" to "large comet" (or "large Kuiper belt object"). Others have argued that other large objects found in the Kuiper belt (or elsewhere in our solar system) should be promoted to being planets as well. The status quo has been to say that Pluto retains its planetary designation due to the fact that we've been calling it a planet since its discovery in 1930, while the other large Kuiper belt objects are just considered large comets. The new discovery disrupts this status quo, because it would be very strange to say that Pluto is a planet but an even larger object is not. Thus....
   • The number of planets in our solar system is no longer clear --- but it is NOT NINE! With the new discovery, we face at least 3 options in counting planets: (1) If we decide that objects like Pluto are too small to be planets, then the new object is also too small because it is so close in size to Pluto. Then there are 8 planets in our solar system. (2) If we decide that Pluto represents the minimum size cutoff, then the new object also makes it, and there are 10 planets in our solar system --- and it's possible that other Pluto-size objects still remain to be discovered; (3) Or we could decide that the minimum size cutoff is somewhat smaller than Pluto, in which case the number of known planets in our solar system could be 12, 15, 20, or many other numbers, depending on exactly where we place the cutoff.

   Questions/activities for class:

   • Compare the planets to scale: Build scale models of Earth, Jupiter, and Pluto so that you can see how they compare in size. Data you'll need: Jupiter's diameter is 11.2 times that of Earth; Pluto's diameter is 0.18 times that of Earth.
   • How many planets are in our solar system? Discuss the various options for counting planets, and form an opinion about how we should answer this question.
   • Name Planet X: The official name of the new object will be decided by the International Astronomical Union. But in the meantime, suggest your own name for the new planet.
   • Web search: Kuiper belt objects. Use the web to find out about other large Kuiper belt objects discovered in recent years. Make a list of the 5 largest after Pluto, and their estimated sizes.
   • Research: Size estimates. As you learn about Kuiper belt objects, you'll see that their sizes are usually given as rough estimates rather than more exact values. Find out why.

   
   2. Mars Reconnaissance Orbiter (MRO) scheduled for launch. NASA's next mission to Mars, an orbiter that should give us much better global views of the surface than ever before, is tentatively scheduled for launch TOMORROW (Aug. 10). Read more at the mission's home page.
   Questions for class:

   • By studying the MRO web site, make a list of the key capabilities of MRO that exceed those of prior Mars orbiters.
   • What are the major things that scientists hope to learn about Mars from MRO?
   • What other spacecraft are currently studying Mars? (Answer: 3 other orbiters --- Mars Global Surveyor, Mars Odyssey, and Mars Express --- plus the two rovers, Spirit and Opportunity, on the ground.)

   3. Perseid meteor shower peaks early morning August 12. The annual Perseid meteor shower is well worth watching. As usual for meteor showers, the best time to watch is before dawn --- say, between 2 am and 5 am. Any dark site will do -- you just need a clear view of the sky. No equipment needed; in fact, it's best to use your naked eye and as much peripheral vision as possible, so you can catch meteors in all directions. More info on this year's shower here. Be sure to note that the MORNING of Aug. 12 means you need to set your alarm on the NIGHT of Aug. 11.

   4. Mars will NOT be super bright on Aug. 27. Perhaps you've seen the e-mails circulating that claim that Mars will be super bright on Aug. 27. Sounds cool, but it's just NOT TRUE. Read more about this "Mars hoax" here.
   Questions for class:

   • When will Mars really be at its brightest this year? (Answer: Oct. 30).
   • Why will Mars be at its brightest at that time? (Answer: That is when it is closest to Earth as both planets orbit the Sun. Propaganda: My new children's book, Max Goes to Mars, has an end-of-book activity that will help you understand the appearance of Mars in our night sky.)
   • At its brightest, how will Mars compare in brightness to the full moon? (Answer: you can calculate if you wish, but the key point is that it is WAY dimmer than the full moon, and also much smaller in angular size.)

   5. What next for the Shuttle? Hey, it's my e-mail, so I'll editorialize if I want to... We're all very relieved at the successful landing of the Space Shuttle Discovery this morning. It is truly an amazing spacecraft, and NASA should be commended for its safe launch and return --- but the Shuttle program is also more than 20 years old and built with even older technology. With Shuttles now grounded again while NASA seeks to solve more safety problems, it's a good time to ask what should be next for the Shuttle. I have a fairly strong personal opinion on this question, based on the following key points:

   • I'm a huge supporter of NASA's Moon/Mars initiative (see the article I wrote), but the current NASA budget is not large enough to do the initiative justice.
   • The Shuttle and Station consume the bulk of NASA's current budget.
   • One way or other, the Shuttle is going to be "retired" within the next few years anyway.
   • The Station has been scaled down so much from early visions that it is capable of doing very little useful science of any kind.
   • Aside from completing the Station, the only remaining important mission for the Shuttle would be the repair of the Hubble Space Telescope --- but I'd wager that the cost of fixing/upgrading the Shuttle for such a flight will turn out to be greater than the cost of building and launching an entirely new space telescope.

   The obvious conclusion, at least in my opinion: Cancel the Shuttle and Station programs now, and redirect the money into the Moon/Mars initiative. Divert a small portion of the money to quickly building and launching a replacement for Hubble. The only potential downsides that I've heard to this plan are that it could affect Shuttle-related jobs and might anger our international partners working on the Space Station, but both complaints seem unfounded: As long as the money goes to new space initiatives, jobs will be changed but not lost, and it's hard for me to believe that our partners wouldn't actually PREFER to redirect their efforts toward the Moon and Mars rather than low-Earth orbit.

   6. Max Goes to Schools update. As you are probably aware from prior e-mails, I am donating 5,000 copies of Max Goes to Mars to public school libraries around the nation; click here for info about the program. As of today, all but about 600 of the 5,000 copies have been claimed by various school districts, so if you are still looking into this for your district, please hurry. If you're waiting for the new book: It has been printed and will be in our distributor's warehouse by the end of the month. The books for schools should arrive in September, and it should arrive in bookstores by October 1.

   All for now!
   Jeff

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   7/4/05: Cometary Fireworks

   Dear Friends,

   How fast can you run a 10K? Last night, NASA's Deep Impact mission was "running" slightly more than 10 kilometers toward Comet Tempel 1 every single second. And then it crashed into the comet, just as planned, igniting what was almost certainly the biggest July 4 fireworks display in the solar system.

   Some "fast" facts:

   • With some quick math, you'll realize that the spacecraft's impact speed of 10.2 km/s is equivalent to almost 37,000 km/hr, or about 23,000 mi/hr. That means it covered a distance nearly equivalent to that from Earth to the Moon during the last 10 hours of its approach.
   • If I've done my own quick math right, the impact released energy nearly equivalent to that of detonating 10 tons of TNT. (fyi, I base my calculation on the 370-kg spacecraft's kinetic energy of about 2x10^10 joules, all presumably converted to light and heat upon impact.)
   • See the impact movie (taken by the spacecraft that hit the comet as it made its final approach).
   • For more general info, photos, and updates on science results, see the Deep Impact web site.
   • There was also a great article about the rationale for the mission in yesterday's New York Times (July 3, 2005, op-ed page), written by my friend Dave Grinspoon...
     

   Happy July 4 to all!
   Jeff

   ---

   6/24/05: Sunset Planets

   Dear Friends:
   A great and easy skywatching opportunity this weekend: Shortly after sunset each evening, the planets Mercury, Venus, and Saturn will appear VERY close together in the sky --- on Saturday evening, they'll be so close that you could cover them all with your thumb at arm's length, and then they'll be even closer on Sunday and Monday evenings. The planets will be easy to spot if you look in the right place; the keys to finding them are: (1) look very soon after sunset, while the sky is still aglow with twilight, because the planets will set below the horizon by the time it is very dark; (2) Look to the west, since the planets will be following close behind the Sun. You can get more details from this NASA Science News article.

   Also, while I have your attention: Thanks to so many of you for responding to my offer of 5,000 free copies of Max Goes to Mars for elementary schools. If you are still looking into the offer, please hurry --- about 3,700 of the 5,000 books are already spoken for, with firm commitments for books to go to every public elementary school in Colorado, New York City, Houston, Ann Arbor, St. Paul, New Orleans, Sonoma County, Tucson, Nacogdoches TX, and more...
   Thanks!
   Jeff

   ---

   5/1/05: Hubble, Mars, July 4 crash, Physics Year, Eclipse Trip, Astronomy
   Workshops, School visits

   1. SAVING HUBBLE: Since my last e-mail, Mike Griffin has been appointed and confirmed by Congress as the new Administrator of NASA. I don't know him personally, but from everything I've read he seems like an outstanding choice who might really be able to get NASA out of its current doldrums. As readers of these e-mails know, I strongly support the Moon/Mars Initiative, but the initiative should not be done at the expense of the one shining light in NASA right now -- its science programs. So it is great to see someone at the head of NASA who seems to share these beliefs. The first concrete evidence of the new attitude is already before us: Griffin has directed the Agency to begin planning for a possible servicing mission to the Hubble Space Telescope. As you may know, the previous Administrator cancelled all future plans for servicing of Hubble by the Space Shuttle, which basically would have doomed the telescope to no more than 2 or 3 more years of operational life. With servicing, Hubble could continue its great scientific achievements for many more years --- hopefully at least until the successor observatory, the James Webb Telescope, is launched into orbit. The servicing mission is by no means a sure thing yet, but the fact that it's back on the table is very good news indeed. For more info, see the Space.com article at http://www.space.com/news/050429_hubble_griffin.html.

   Questions you might want to ask your students in class:

   • The Hubble Space Telescope orbits Earth at an altitude less than about 600 kilometers (360 miles). Does its altitude give it any advantage over ground-based telescopes? (Answer: No -- this altitude is small even compared to the size of Earth [diameter 12,750 km] and completely negligible compared to the distances to planets or stars.)
   • So why can Hubble get clearer pictures than ground-based observatories? (Answer: it is above most of Earth's atmosphere, and the atmosphere distorts starlight. E.g., the familiar "twinkling" of stars is caused by air motion in the atmosphere -- this motion causes slight shifts in the direction of starlight that our eyes interpret as twinkling but that show up as blurring in telescopic photos. Above the atmosphere, stars don't twinkle, so sharper photos are possible.)
   • Some ground-based telescopes can now obtain visible-light images that rival Hubble's by using a new technology known as adaptive optics; in essence, this technology tracks the atmospheric motion that causes twinkling and then moves part of the telescope in a way that exactly cancels the blurring effects of the motion. If this technology can be used more extensively by ground-based telescopes, will it make Hubble obsolete? (Answer: No --- the key words in the question are "visible light." Hubble also observes forms of infrared and ultraviolet light that do not penetrate Earth's atmosphere and hence cannot be observed from the ground at all. Thus, even if ground-based telescopes match Hubble's visible-light capabilities, it will remain the world's most powerful telescope for much of the infrared and ultraviolet portions of the light spectrum.)

   2. DUST DEVIL ON MARS. The Mars rovers Spirit and Opportunity continue to go strong a year past their original projected lifetimes. Check out this mini-movie of a dust devil on Mars, recently recorded by the Spirit rover: http://antwrp.gsfc.nasa.gov/apod/ap050426.html. Is that cool, or what? Fyi, dust devils occur when sunlight warms the ground enough to heat the air right above it, and the hot air begins to swirl as it rises upward. The swirling air can carry loose sand or soil, which is why dust devils on Earth are easiest to see over desert sands or dry farmland.

   Questions you might want to ask your students in class:

   • Have you ever seen a dust devil on Earth? How does it compare to what you see in the dust devil on Mars? (Answer: This is a discussion question.)
   • Some people confuse dust devils and tornadoes. Visually, what are the main differences between them? (Answer: a tornado comes down from the sky, while a dust devil rises up from the ground. Tornadoes are also far stronger and larger than dust devils.)

   3. NASA READY FOR JULY 4 FIREWORKS IN SPACE! On July 4, NASA's Deep Impact spacecraft will slam head-on into a comet (Comet Tempel 1). The impact is expected to gouge out a big crater and send ice and other debris flying out into space. Only one part of the spacecraft will actually crash into the comet; the rest will fly past safely (hopefully) and record the fireworks, sending the data back to Earth by radio for scientific analysis. Learn more and follow the ongoing mission at: http://www.nasa.gov/mission_pages/deepimpact/main/index.html.

   Questions you might want to ask your students in class:

   • What is a comet? (Answer: a chunk of ice, mixed with dust or rock, that orbits the Sun. Comets are thought to be leftover chunks of material from the era of planet formation in our solar system, which means they formed about 4.5 billion years ago.)
   • My write-up above uses the term "fireworks." Will there really be any fire when the spacecraft crashes into the comet? (Answer: No. Fire is due to chemical combustion with oxygen, so the lack of air/oxygen in space means there cannot be a fire [unless it is INSIDE a spacecraft that contains air]. My use of "fireworks" is poetic license here...)

   4. WORLD YEAR OF PHYSICS. Did you know that the United Nations designated 2005 as "World Year of Physics"? The designation commemorates the 100th Anniversary of Einstein's "miracle year," when he published the theory of relativity, effectively proved the existence of atoms and molecules, and demonstrated the particle nature of light. What did all this mean? Well, in brief, Einstein's publications of 1905 redefined human understanding of space, time, matter, and energy... Read more and learn about events in your area at http://www.physics2005.org/. There's also a great article about Einstein at NASA science news: http://science.nasa.gov/headlines/y2005/23mar_spacealien.htm.

   5. TOTAL SOLAR ECLIPSE TRIP, 2006 - WOW! My friend Doug Duncan, director of the University of Colorado's Fiske Planetarium, has put together a truly fantastic trip to see the total solar eclipse of 2006. The trip is an 11-day cruise through the Mediterranean, at a price that can't be beat. In fact, my entire family will be going on the trip -- hope you can join us! Here's Doug's trip description:

   "Have you dreamed about seeing the pyramids, ancient temples, the city of Pompeii: frozen in time by the volcano Vesuvius 2000 years ago? Have you heard that a total eclipse of the sun is one of the most spectacular sights you can ever see? People scream, shout, and cry from the eerie sight of the moon covering the sun, with pink flames and silver streamers stretching across the sky. This special 11 day cruise combines all these wonders of the world. Led by Fiske Planetarium Director and former National Public Radio commentator Dr. Doug Duncan, you’ll hear fascinating talks by the country’s best speakers on astronomy and the classical world. Bring your kids and grandkids: the cruise offers a special children’s program staffed by some of the country’s best and most fun science teachers. A beautiful Costa Cruise ship is entirely chartered for this occasion, so prices are remarkably low: $1600 - $2600 per person. Children are only $759 (up to 2 in your cabin).  For more details see http://casa.colorado.edu/~dduncan/eclipse. To To book or ask additional questions: 1-800-338-9051. This trip may sell out by summertime, so please doesn’t delay if you are interested."

   6. WORKSHOPS FOR ASTRONOMY TEACHERS. Do you teach astronomy at the high school or college level? My friends Tim Slater and Ed Prather have put together an outstanding set of NASA and NSF sponsored workshops for astronomy teachers. The first one has already taken place in Seattle, but more are upcoming: May 7-8 in New York City; May 21-22 in New Orleans; May 28-29 in Minneapolis; June 20-24 in Kona, Hawaii (I think I'd choose that one!); July 6-8 in Bozeman; and August 4-6 in Salt Lake City. For more information, go to http://astronomy101.jpl.nasa.gov.

   7. SCHOOL VISITS FOR FALL. My second book for children, Max Goes to Mars, is done and getting ready to go to the printer. Books will be available by fall, which means I will be available for school visits and other public programs. My fall schedule is already starting to fill up, so please let me know if you are interested in a visit to your school or other venue. See my web site for details about my current programs for Max Goes to the Moon; the Mars program will be similar but geared toward the new book...

   ---

   1/14/05: Titan Success!
   
   My apologies for violating my usual rule of sending e-mails only on rare occasions, but this is just too exciting for anyone to miss: The Huygens probe landed successfully on Titan this morning!
   Check out the "raw images" already posted at http://www.esa.int/SPECIALS/Cassini-Huygens/index.html. Scientists are only just beginning to try to understand what we are seeing, and better pictures will be available soon as image processing techniques are applied. Nevertheless...

   1. The surface photo shows what appears to be chunks of ice strewn around (remember that the temperature is 300 degrees below zero Fahrenheit). If you're not sufficiently impressed, remember that you are looking at the surface of a world that is nearly a billion miles away.
   2. Even more intriguing, look at the photo taken during descent. To get a sense of what you are looking at, imagine you are looking at the surface from a high-flying airplane. What does it look like to you? Sure looks to me like river/creek beds and possibly a lake over on the right.. I can hardly wait to hear what the experts say...

   What to watch for in coming days and weeks: The Huygens probe had a short battery life, so all the data has been collected and transmitted. Now it's a matter of processing all the data and interpreting it. The probe's couple hours of operation on Titan will probably keep many scientists busy for years to come...

   Jeff

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   1/12/05 The Sirens of Titan; comet, asteroid missions

   1. THE SIRENS OF TITAN: Don't miss this one: I'd suggest clicking right now on http://saturn.jpl.nasa.gov/home/index.cfm  to see the countdown to our first landing on the surface of a world in the outer solar system. That's right --- the Huygens probe arrives at Titan on Friday morning. If all goes well, it will collect data during its descent and send back pictures of the surface for up to about a half-hour before its batteries run out. Watch the data come in on the web on Friday morning starting at about 7am PST, 8am MST, 9am CST, 10am EST; many universities and science centers will have special live programs as well. For those who may have forgotten why Titan is so exciting, here's a few facts repeated from one of my prior e-mails:

   • Although it is a "moon" because it orbits the planet Saturn, Titan is bigger than the planets Mercury and Pluto. In fact, it's the 10th largest object in our solar system (after the Sun, the other 7 planets, and Jupiter's moon Ganymede).
   • Titan is the only moon in the solar system with a substantial atmosphere, and this atmosphere shares two interesting characteristics with Earth's atmosphere: A similar atmospheric pressure (Titan's surface pressure is only about 50% more than Earth's) and a composition of mostly nitrogen (Earth's atmosphere is 77% nitrogen and Titan's is 90% nitrogen). Of course, there are also two important differences: (1) the rest of Earth's atmosphere is mostly oxygen, while the rest of Titan's atmosphere is argon, methane, ethane, and other hydrogen compounds; (2) Titan is extremely cold, with a surface temperature of nearly 300 degrees below zero (Fahrenheit).
   • While the temperature is far too low for liquid water, there's good reason to think that Titan may have lakes or oceans of liquid methane and ethane, and perhaps even methane/ethane rain or snow.
   • And the possibility of these cold liquids raises at least some small potential for life: Although all life on Earth requires liquid water, it's at least marginally possible that other liquids could support life. (Some sort of liquid is generally deemed necessary for life in order to transport chemicals from one place to another.) Don't get overly hopeful: water has several chemical advantages over other liquids that make it seem far more suitable than other liquids as a molecule for life. Still, I won't be completely blown away if we discover little cold-liquid critters on Titan.
   • Finally, Titan has literary and art connections: (1) The title of this e-mail (The Sirens of Titan) is the title of an entertaining 1959 novel by Kurt Vonnegut. (2) It is also the title of a very cool song by Al Stewart, which he based on the Vonnegut novel. (3) And Titan is the destination of choice in the 1997 movie Gattaca, which I enjoyed a lot.

   Questions you might want to ask your students in class:

   • Make a prediction: What do you think Huygens will find on Titan? Explain why you think your prediction is reasonable. (Answer: obviously a subjective question, but here's my admittedly unlikely prediction: The surface photos will show something that does not move, but looks enough like certain Earth-based organisms that we'll be left wondering if there is actually life on Titan.)

   
   2. BOUND FOR A COMET: This just in... Today, NASA successfully launched the Deep Impact mission, which will fire a projectile into the heart of a comet in July. For the latest, see the Deep Impact web site at http://deepimpact.umd.edu/.

   Questions you might want to ask your students in class:

   • What is a comet? (Answer: a chunk of ice and rock, though not necessarily packed solid, that orbits the Sun. Comets are thought to be leftovers from the formation of our solar system.)
   • Could the projectile from Deep Impact destroy the comet? (Answer: Highly unlikely. Use the Deep Impact web site to contrast the size of the comet with the size of the spacecraft, and you'll see why.

   3. BOUND FOR AN ASTEROID: There's another mission that I myself just learned about --- it's garnered very little publicity but is potentially VERY exciting. The Japanese spacecraft Hayabusa is en route to an asteroid, where it will fire a projection to blast asteroid chunks from the surface, and then collect these to return to Earth. Even more fun: It will deploy a small robot to land on the surface and hop around! This is so cool that I wish I could tell you more. If anyone has any additional info about this mission, please let me know. I found some info at http://www.jaxa.jp/missions/projects/sat/exploration/muses_c/index_e.html.

   
   4. SEE A COMET FOR YOURSELF: There's a comet visible in the sky right now. Comet Machholz is not particularly bright, but beautiful through a telescope. See the photo at http://antwrp.gsfc.nasa.gov/apod/ap050105.html and the NASA science news article http://science.nasa.gov/headlines/y2005/05jan_machholz.htm.

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   12/3/04: Upcoming sky events; mission update; Max
   

   1. MOON/JUPITER ECLIPSE FOR EARLY EASTERN RISERS: For those of you in the Eastern U.S., the Moon will eclipse (pass in front of) Jupiter shortly before dawn on Dec. 7; for exact times at different locations, see http://science.nasa.gov/headlines/y2004/29nov_moonjupiter.htm. Elsewhere, Jupiter and the Moon will still appear quite close together as a beautiful pair....

   Questions you might want to ask your students in class:

   • Why is this eclipse visible only to people in some locations and not in others? (Answer: The Moon is close enough to Earth that observers in different locations see it in slightly different positions against the background sky of more distant planets and stars; that is, the Moon exhibits a noticeable parallax as seen from different points on Earth' surface.)
   • Suppose a spacecraft photographed Jupiter during the time that we see the Moon eclipsing Jupiter in our sky. Would we see the Moon's shadow on Jupiter? (Answer: No --- while the Moon does indeed cast a shadow (the shadow that falls on Earth during a solar eclipse), the shadow extends only a few hundred thousand kilometers in space --- far short of the distance to Jupiter.)

   2. GEMINID METEOR SHOWER: No matter where you live, you may want to stay up late or get up early for this year's Geminid meteor shower, which should be the best meteor shower we've had all year. The shower will peak on the night of Dec. 13/14. You can see it starting around about 10pm local time (anywhere) on Monday Dec. 13, and it should peak around 2am on Tuesday morning. Thus, for the best viewing, set your alarm for about 1:30 am before you go to bed on Monday Dec. 13. Details at http://skyandtelescope.com/observing/objects/meteors/article_802_1.asp.

   Questions you might want to ask your students in class:

   • Meteors are sometimes called "shooting stars." Do they actually have anything to do with the stars we see in the sky? (Answer: No. Meteors are created by particles of dust burning up in Earth's atmosphere, which means they are right here on our own planet --- unrelated to stars, which are very far away.)

   3. MARS/SATURN MISSION UPDATE: The Mars rovers and the Cassini spacecraft at Saturn continue to produce amazing results. The best part is the photos. So keep looking at the Mars rover web site (http://marsrovers.jpl.nasa.gov) and the Cassini web site (http://saturn.jpl.nasa.gov). And stay tuned for two exciting events at Saturn's moon Titan: (1) The next close flyby of Titan by Cassini on Dec. 13; (2) Scheduled release of the Huygens probe on Christmas Day, en route to land on Titan on Jan. 14. See the web site for news on these events.

   4. SWIFT IN ORBIT: Many people think the Hubble Space Telescope is the only telescope in space, but in fact there are many more. The latest addition to our fleet of space observatories is Swift, launched on Nov. 20. Swift is designed to explore the mystery of gamma ray bursts. (For those of you who have my book "On the Cosmic Horizon," this is Mystery #5 on my Top 10 list.) While we have learned much about these bursts in the past few years, much still remains mysterious. For more information, see the Swift web site at http://swift.gsfc.nasa.gov.

   MAX'S GIFT: For those of you who have followed the story of our dog Max, inspiration for and star of Max Goes to the Moon (and the forthcoming Max Goes to Mars): As you may recall, Max had surgery for bone cancer last May. The surgery was successful and he had a great summer and fall - swimming, hiking, running, and enjoying time with all of us. Unfortunately, his cancer returned fast and furious, and with great sadness we had to put him to sleep on Nov. 13. We all miss him a lot, but we are thankful for 9 1/2 great years and especially for our five "bonus" months after the surgery. In addition, Max apparently left us a parting gift. On the same day that Max returned to our home in an urn, Max Goes to the Moon won the 2004 Colorado Book Award for Best Children's Book (books published in 2003). We feel very honored, especially given the competition: The other 3 finalists included a book that had already won a Newberry Honor this year and a book by a past Newberry winner. Thank you, Max...

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   10/25/04: lunar eclipse, Cassini at Titan, Max update
   
   Welcome back to school! Here's the first of this academic year's space science updates, with information about Wednesday's total lunar eclipse and tomorrow's Cassini flyby of Titan.
   Best wishes,
   Jeff
   
   1. TOTAL LUNAR ECLIPSE: Don't miss this Wednesday night's (Oct. 27) total eclipse of the Moon --- it will be 2 1/2 years until the next total lunar eclipse. The eclipse will be visible throughout the United States, the rest of the Americas, and Europe. Totality will last more than an hour, starting at: 7:23pm Pacific time, 8:23 Mountain time, 9:23 Central time, 10:23 Eastern time, and so on. (For those of you in Europe, that makes the eclipse early Thursday morning.) Complete data for the eclipse is available at http://sunearth.gsfc.nasa.gov/eclipse/LEmono/TLE2004Oct28/TLE2004Oct28.html.

   Questions you might want to ask your students in class:

   • Wednesday night is not only the eclipse but it is also a full moon. Is this a coincidence or not? (Answer: not -- a lunar eclipse can occur only when Earth's shadow falls on the Moon, which means the Moon and Sun must be on directly opposite sides of the Earth, which is the condition for full moon. Thus, a lunar eclipse can happen only at full moon. Similarly, a solar eclipse can happen only at new moon.)

   
   2. CASSINI AT TITAN: Be among the first people on your planet to find out what Titan looks like! Cassini will make its first close flyby of Titan tomorrow night (Oct. 26); more info and live webcast at http://saturn.jpl.nasa.gov. Why should you care about Titan? Here's a few reasons:

   • Although it is a "moon" because it orbits the planet Saturn, Titan is bigger than the planets Mercury and Pluto. In fact, it's the 10th largest object in our solar system (after the Sun, the other 7 planets, and Jupiter's moon Ganymede).
   • Titan is the only moon in the solar system with a substantial atmosphere, and this atmosphere shares two interesting characteristics with Earth's atmosphere: A similar atmospheric pressure (Titan's surface pressure is only about 50% more than Earth's) and a composition of mostly nitrogen (Earth's atmosphere is 77% nitrogen and Titan's is 90% nitrogen). Of course, there are also two important differences: (1) the rest of Earth's atmosphere is mostly oxygen, while the rest of Titan's atmosphere is argon, methane, ethane, and other hydrogen compounds; (2) Titan is extremely cold, with a surface temperature of nearly 300 degrees below zero (Fahrenheit).
   • While the temperature is far too low for liquid water, there's good reason to think that Titan may have lakes or oceans of liquid methane and ethane, and perhaps even methane/ethane rain or snow.
   • And the possibility of these cold liquids raises at least some small potential for life: Although all life on Earth requires liquid water, it's at least marginally possible that other liquids could support life. (Some sort of liquid is generally deemed necessary for life in order to transport chemicals from one place to another.) Don't get overly hopeful: water has several chemical advantages over other liquids that make it seem far more suitable than other liquids as a molecule for life. Still, I won't be completely blown away if we discover little cold-liquid critters on Titan.

   Tomorrow's flyby will take Cassini within about 750 miles of Titan's surface, which means it will be only about 3 times as high above Titan as the Space Station is above Earth. In fact, Cassini will actually pass through Titan's thin upper atmosphere. Instruments will study the atmosphere, while cameras will give us our best-ever views of Titan and radar will be used to map the surface. With luck, we'll get a definitive answer to the question of lakes or oceans on Titan. Then, in January, a probe (called Huygens) will descend to Titan's surface --- that's when you should be watching for the cold-liquid creatures staring into the probe's cameras...

   Questions you might want to ask your students in class:

   • With its thick atmosphere, Titan is not much like our own Moon at all. So why do we call it a "moon"? (Answer:we define a "moon" as a body that orbits a planet, while a planet orbits the Sun. So Titan is a moon because it orbits Saturn.)
   • Why is Titan so cold? (Answer: look at its distance from the Sun...)
   • For those with some chemistry background: Why is water considered a better molecule for life than other liquids? (Answer: 3 advantages of water are: (1) liquid at higher temperature which means higher chemical reaction rates; (2) water is a polar molecule, which allows the formation of hydrogen bonds and affects how other molecules dissolve or don't dissolve in water; (3) water expands when it freezes, so that ice floats and thereby can insulate liquid water lying under frozen ice.)
     
     MAX UPDATE
     Thanks to all of you who have sent your good wishes for our dog Max, star of my children's book Max Goes to the Moon. Good news: his bone cancer is now in remission, following surgery to remove the tumor last May and treatment over the summer. Our local newspaper recently published an article about Max and me.

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   8/11/04: Perseid meteor shower
   
   Dear Friends,

   Tonight and tomorrow morning are the best times to watch the annual Perseid meteor shower, which is expected to be quite good this year. Simple watching instructions: you need an unobstructed view of the sky, so that you can watch a large part of the sky with your peripheral vision and thereby "catch" the flashes of meteors, which typically last just a few seconds. A dark site out in the country helps, but you'll see some meteors anywhere you have a clear sky and can see stars. Best times to view:

   • second best time is tonight (Wed., Aug. 11): for the first couple hours after sunset.
   • BEST time to view is before dawn tomorrow am (Thursday, Aug. 12): get up around 3 or 4 am, and just watch the sky for awhile...

   For a great article about what makes the meteor shower, see NASA science news at this link:
   http://science.nasa.gov/headlines/y2004/09aug_horseflies.htm?list146819 .Good luck!

   Jeff

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   6/8/04: Transit of Venus

   Dear Friends,

   A short e-mail this time: This morning's transit of Venus produced many beautiful images that will undoubtedly appear on the web over the coming days. For the moment, I recommend taking a look at a slide show that the New York Times has just posted on its web site. Go to http://www.nytimes.com/ (you may need to register, but it is free). If you check there today, you'll see a heading for "The Transit of Venus" near the upper-right of the page; click on the link "Slide Show: A World Event." (After today you may need to search the NYT web site to find the slide show.) It's a great set of photos --- my favorite is the one with fishermen and a pelican in Daytona Beach --- and shows how all the world does indeed to share some common interest in science and our remarkable universe.

   Best wishes,
   Jeff

   PS. Some of you have asked for an update on Max, my family's dog who is featured in my children's book Max Goes to the Moon: Max is 9 years old and was recently diagnosed with bone cancer. Two weeks ago he had surgery to remove the tumor from his shoulder. He is now undergoing chemo treatments. As with any cancer, the prognosis is uncertain. Statistically he has a 50% chance of survival for 1 year, 30% of survival for 2 years or more. Of course, age 9 is already getting up there for a large dog like a Rottweiler. We can only hope to have as much time as possible with him, and we thank you for all your good wishes.

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   5/3/04: lunar eclipse, bright Venus, Venus transit, and more

   Dear Friends,
   Here is the next in my occasional series of space science updates, with info today on the May 4 lunar eclipse, observing Venus, the Venus transit, and the latest NASA space science missions. instructions for subscribing or unsubscribing can be found at the end of the message.
   Best wishes,
   Jeff

   1. LUNAR ECLIPSE MAY 4: There is a total eclipse of the Moon tomorrow night (May 4). Those of you in Europe, Africa, and Australia can watch it. It will not be visible in North America, but you can still watch it on the web at http://www.xs4all.nl/~carlkop/eclipsmaan/leclips2004.html.
   
   2. VENUS AT ITS BRIGHTEST THIS WEEK: Venus has been incredibly bright in our skies for more than a month now, but is only just now reaching its peak brightness. Be sure to have a look at Venus in the evening skies this week --- just look to the west after sunset, and you can't miss it if the sky is clear. NASA science news has posted a great article about why Venus is so bright right now, and how it is often mistaken for a UFO.

   Questions you might want to ask your students in class:

   • Venus is very bright right now in part because it is at a point in its orbit where it is fairly close to Earth. However, once it reaches the point where it is CLOSEST to Earth, we will not be able to see it at all in our sky. Why not? (Answer: At its closest, Venus lies between the Sun and us, and therefore it is completely obscured by the light of the Sun in our daytime sky. In addition, even if we could see it at this time, we'd be looking only at its night side ("new Venus").)
   • Look at Venus through a pair of binoculars (be sure to hold them steady on a tripod). You'll notice that we do not see a "full Venus," but rather see a phase of Venus much like a phase of the Moon. What phase do you see for Venus right now? (Answer: crescent.)
   • Do we ever see a full Venus? Why or why not? (Answer: No. Venus is "full" when it is on the other side of the Sun from us --- which means that we cannot see it because it is in the same place in our sky as our Sun and therefore drowned out by the light of the Sun.)
   • The Moon is much brighter when it is gibbous (almost full) than when it is a crescent, but Venus is the opposite: brighter when it is a crescent than when it is gibbous. Why? (Answer: If you draw a diagram showing where Venus's phases occur in its orbit [as seen from Earth], you'll see that Venus is much farther away from us and hence dimmer when it is gibbous than when it is a crescent. In contrast, the distance to the Moon does not depend on its phase, so it is brighter when a larger portion of its visible face is sunlit. Note: NASA has a nice applet explaining the phases of Venus.

   
   3. TRANSIT OF VENUS. As Venus continues along its orbit, in a few weeks it will reach the point where it lies between the Sun and Earth. This year, however, something special is going to happen at this point. The plane of Venus's orbit around the Sun is not quite perfectly aligned with the plane of Earth's orbit around the Sun (the ecliptic plane). As a result, when Venus passes between us and the Sun, it usually passes a little above or below the Sun in our sky. About twice a century, however, Venus passes right across the face of the Sun in what we call a transit. The last transit of Venus occurred in 1882, some 122 years ago, and careful observations of it helped astronomers pin down the true scale of the solar system. The next transit of Venus is coming up on June 8. Lots of great information about the transit, including how to observe it either yourself or on the web, can be found at http://www.vt-2004.org/index.html. (For a quick primer, check out their teacher's guide.)

   Questions for class:

   • Suppose that Venus DID orbit the Sun in the same plane as Earth. How often would we have transits in that case? (Answer: every time Venus passes between the Sun and Earth in its orbit, which is about every 19 months).
   • What is Venus's phase during a transit? (Answer: new.)

   4. PUTTING EINSTEIN TO THE TEST. On April 20, 2004 NASA launched a new satellite dedicated to testing Einstein's general theory of relativity with unprecedented precision. The satellite, named "Gravity Probe B" (also the winner of this year's award for "most creative satellite name --- NOT") is in some sense the longest running NASA mission ever, since work on its development began more than 40 years ago. The long lag in getting to launch had to do largely with the extreme technological requirements of testing very subtle effects predicted by Einstein's theory. The lag also led to the mission becoming embroiled in controversy, as some scientists argued that the effects it was designed to test have already been tested and confirmed in other ways by now, and therefore that this additional test was not worth the huge expense of a space mission. The controversy is moot at this point, since the satellite is now in space. Read more about its mission.

   5. KEEPING UP WITH MARS AND SATURN. The two rovers Spirit and Opportunity both continue to roam the red planet, while Cassini gets closer and closer to entering orbit of Saturn this July. Keep up with the Mars rovers at http://marsrovers.nasa.gov/home/index.html. See the latest Saturn images at http://ciclops.lpl.arizona.edu/.

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   3/27/04: Planet viewing tonight; science updates on Mars, Saturn, and Pluto

   Dear Friends,

   Welcome to the new "listserv" for my space science news e-mails.

   1. All five naked-eye planets (Mercury, Venus, Mars, Jupiter, Saturn) are visible in the early evening right now. Don't miss it -- go out just after the Sun drops below the horizon, and watch as the sky darkens. You'll first see Venus in the west, then Jupiter over toward the east. As the sky darkens, you'll be able to see the other planets. For details on exactly where to look, along with sky maps, go to http://science.nasa.gov/headlines/y2004/19mar_planets.htm?list146819. Be sure to notice that the 5 planets all fall on nearly the same line (or segment of circle) across the sky --- demonstrating that all the planets orbit the Sun in approximately the same plane.

   For those of you teaching classes, here's a few questions to ask your students:

   • What makes Venus so bright? (Answer: combination of being relatively close to Earth and the fact that it is completely covered by very reflective clouds.)
   • Why is Jupiter brighter than Mars, even though Mars is much closer to Earth? (Answer: combination of its much larger size and its much more reflective clouds; fyi, Jupiter radius is about 20 times that of Mars, which means the area of its visible disk is 20^2 = 400 times as large as that of Mars.)
   • How can you be sure that the bright object toward the east is Jupiter rather than Venus? (Answer: Because Venus is closer to the Sun than Earth, it must always appear fairly close to the Sun in the sky. Thus, when Venus is visible in the evening, it must be in the west near where the Sun set. When Venus is visible in the pre-dawn sky, it must be in the east near where the Sun will rise.)
   • Of the five planets you see, which one is the most difficult to see in general, and why? (Answer: Mercury. Because it is the innermost planet, it is never far from the Sun in the sky. Thus it is usually above the horizon only in the daytime, when the bright sky drowns out its light. We can see it only when it happens to be in an orbital position where it appears far enough from the Sun for us to see it for a short time after sunset (as is the case right now) or before dawn.)
   • [for fun:] What object in the sky is far and away the most commonly reported "UFO"? (Answer: Venus is reported frequently as a UFO by people who don't realize what they are looking at.)

   2. Mars update: The Spirit and Opportunity rovers are still both operating, and have proven to be tremendous successes. They have gathered important new evidence supporting the idea that water has flowed and pooled on Mars in the distant past (probably more than 3 billion years ago). I'll try to write up a more detailed summary in coming months; meanwhile, here's recent NASA article about the rover discoveries.

   3. Saturn like you've never seen it before: The Cassini spacecraft has been traveling through space for nearly seven years en route to Saturn. It is now nearly there, and will enter Saturn orbit on July 1. It is already returning spectacular photos of Saturn. See them at http://ciclops.lpl.arizona.edu/.

   4. Is Pluto a planet? Ask Sedna! ... Poor little Pluto has had its planetary status under attack for the past couple decades. When it was first discovered in 1930, astronomers guessed that Pluto was large like other planets of the outer solar system. Over the subsequent decades, however, more refined estimates kept making Pluto smaller. A definitive measurement of Pluto's size (mass) became possible in 1978, when astronomers discovered that it has a moon, named Charon. Because a planet and moon tug on each other gravitationally, careful observations of Charon's orbit around Pluto allowed astronomers to determine the masses of both objects. Pluto turns out to be far less massive than any of the other 8 planets --- less than 4% the mass of the next smallest planet, Mercury (and only 0.2% the mass of Earth). It is also made mostly of ice, unlike any of the other planets but quite like the objects we call comets. Moreover, Pluto's region of the solar system is thought to be populated by thousands of other icy comets make up what we call the Kuiper belt. This suggested that Pluto is really a large Kuiper belt comet rather than a true "planet."

   Astronomers began detecting Kuiper belt comets in the 1990s. A couple weeks ago, the latest attack on Pluto's planetary status came with the discovery of an object named Sedna, which is now the largest known comet --- except for Pluto. (There's some debate over whether Sedna is a member of the Kuiper belt or an interloper from the even more distant Oort cloud of comets; see http://science.nasa.gov/headlines/y2004/16mar_sedna.htm.) So should Pluto still be considered a planet? If Pluto had not been accidentally discovered in 1930 and its discovery were made today, it's likely that we would consider it the largest known Kuiper belt comet rather than a planet. However, historical accidents count for something, so for now many astronomers think that Pluto should keep its planetary status for historical reasons. After all, the "My Very Excellent Mother Just Sent Us Nine Pizzas" mnemonic won't work too well without Pluto... On the more serious side, some astronomers have proposed a definition in which a planet is any object orbiting the Sun that is large enough to be spherical in shape. Under this defintion, Pluto is clearly a planet, as is the largest asteroid (Ceres) and several other ojects in our solar system. [Late update: as of late 2004, astronomers are questioning the initial size and mass estimates of Sedna and several other recently discovered Kuiper belt objects; they may be smaller than initially thought.]

   For those teaching classes, consider using the following discussion question:

   • Most of the comets of the Kuiper belt probably remain undiscovered. Suppose we someday discover a Kuiper belt comet that is larger than Pluto. How would this affect the debate over Pluto's planetary status? What if we found a dozen other objects larger than Pluto? (Discussion points: If we call Pluto a planet, wouldn't we be obligated to call any larger object a planet as well? If we found one such object, would we make it the ninth planet and Pluto the "tenth planet"? If we found a dozen such objects, would it make sense to say that our solar system has 20+ planets? And why draw the line at Pluto? Would we then count Sedna or other objects as planets? How should we define the term "planet"? Under the proposed spherical size definition above, our solar system already had more than 9 planets. Is this OK or a problem?)

   
   All for now!
   Best wishes,
   Jeffrey Bennett