Have you all been watching the evening sky for the beautiful views of Venus and Jupiter? They are currently the two brightest “stars” in the evening sky in the west, with Venus the brighter of the two. If you haven’t been watching, check them out soon. Meanwhile, this will be a short update, primarily so you can mark your calendars for two exciting events this spring:
1. Annular solar Eclipse in the U.S. — May 20
2. Transit of Venus — June 5
In addition, anyone in the Boulder/Denver area is invited to the World Premiere of the Max Goes to the Moon planetarium show:
When: Friday, March 16, 7pm.
Where: Fiske Planetarium, University of Colorado, Boulder
The Evening:Price: Tax deductible donation to Fiske, suggested $25 per person
For Reservations: contact the planetarium by phone (303-492-5002) or e-mail firstname.lastname@example.org. Space is limited to the theatre capacity, so please book your reservation soon.
Future showings: After the premiere, the show will play on a regular schedule at Fiske, starting Saturday March 17 at 2pm. Astronaut Drew will likely attend the first matinee as well.
Other Locations: The show will be available to planetariums everywhere starting this summer; if you have a local planetarium, please encourage them to contact Fiske (or me) to learn about how to get the show.
P.S. As always, I welcome responses, so don’t be afraid to comment; I’ll do my best to respond.
PS. If you haven’t seen them, I hope you’ll check out my latest books for children (The Wizard Who Saved the World) and for adults (Math for Life); if you like them, please spread the word.
1. Annular Solar Eclipse in the U.S. — May 20
If you live in the western United States, don’t miss the upcoming annular solar eclipse in the late afternoon of May 20. To understand the treat you are in for, note that solar eclipses come in three basic types:
- a partial solar eclipse is one in which the Moon passes partly in front of the Sun from your location, so that you see a “bite” taken out of the Sun.
- a total solar eclipse is one in which the Moon completely blocks the Sun, so that it becomes dark in the daytime
- an annular solar eclipse is somewhat like a total solar eclipse, in that the Moon passes directly in front of the Sun. However, it occurs at a time when the Moon is farther away from us in its elliptical orbit, so that it is not quite large enough to fully block the Sun. We therefore see the Sun as a “ring of fire” surrounding the disk of the Moon.
Although an annular solar eclipse is not as spectacular as a total solar eclipse, it is still a rare treat and worth seeing. Read this NASA Science News article for more details and a pretty photo.
Where you can see the annular eclipse: The eclipse path begins over Southern China and Hong Kong, passes over much of Japan (Tokyo is nearly on center line), then goes mostly over the ocean until it comes to the U.S. in northern California (Eureka, Redding), continuing over central Nevada (Reno, just misses Las Vegas) and southern Utah (St. George) and northern Arizona (Grand Canyon), moves on over New Mexico, including Albuquerque on center line and Santa Fe, before finally coming to an end at sunset near Lubbock TX. Click here for a full map of the eclipse path.
Where you can see a partial eclipse: If you miss the annular eclipse path but are not too far from it, you’ll still get a great partial solar eclipse.
Equipment Needed: You MUST NOT look directly at the Sun at any time during a partial or annular eclipse. The best way to view the eclipse is by purchasing an inexpensive pair of eclipse glasses. They are available in many places, including this online store. If you want to take photos or view in more sophisticated ways, check out this introduction to Sun watching from Fiske Planetarium director Doug Duncan.
For Classroom Discussion:
- Why does the Moon’s orbital distance from Earth vary? (Answer: orbits are elliptical, not circular, and therefore the Moon’s distance from Earth varies over the course of each orbit. [And recall that the Moon takes approximately a month — think “moonth” — for each orbit.])
- How does the Moon’s orbital distance affect its apparent (angular) size in the sky? (Answer: The actual Moon, of course, always stays the same size. Therefore, just as a quarter appears smaller as you move it farther from your eyes, the Moon appears smaller when it is farther from Earth.)
- What is the difference between an annular and total solar eclipse? (Answer: Earth’s orbital distance from the Sun varies much less (by percentage) than the Moon’s distance from Earth. So we can think of the Sun as staying about the same angular size in our sky. A total eclipse can occur when the Moon is relatively close to Earth in its orbit, so that its angular size is large enough to cover the Sun. An annular eclipse occurs when the Moon is farther away, so that its angular size is not quite large enough to fully block the Sun.)
2. Transit of Venus — June 5
If you watch Venus in the evening sky, over the next couple of months you will see it get closer and closer to the setting Sun. It will eventually disappear from view because of the bright sunlight. Then, on June 5 (June 6 in Europe, Asia, Africa), Venus will pass directly in front of the Sun — which is an event called a transit. This is a very rare event. Due to the details of the orbits of Earth and Venus around the Sun, Venus transits occur in pairs separated by more than a century, with the two transits of a pair coming about 8 years apart. We are between the two transits of the only pair that will occur in our lifetimes. The first of this pair occurred on June 8, 2004. The second is the one coming up on June 5/6. After this one, the next transit of Venus will not occur until the year 2117! So if you’d like to see one, don’t miss out in June…
Where you can see it: Most of the world’s population will be able to see this transit, including the entire continental United States and most of Europe, northern Africa, the Middle East, and southern Asia. See this NASA site for the full map and more details.
Equipment needed: Although you can use eclipse glasses to look at the Sun, the dot of Venus will be so small that you won’t be able to see it without more sophisticated cameras or telescopes. Doug Duncan’s page has info about viewing the transit. Many observatories, planetariums, and science museums will be providing viewing opportunities, so check local listings. It will also surely be viewable live on the Web, though I don’t yet have a link to recommend.
For Classroom Discussion: The transit of Venus was historically very important to our learning of the actual distance scale of the solar system. Today, however, we have more sophisticated techniques for measuring distances. The main scientific importance of the transit today is less in the transit of Venus itself than in the general idea of transits — watching for subtle changes in a star’s brightness as a planet passes in front of it turns out to be one of our best methods for discovering planets in other solar systems, and is the method employed by the Kepler mission.
All for now…