Dear Friends:
In difficult times, it’s nice to have some positive news, and there has been quite a bit in Earth and Space Science. Here are just a few news items that I think you’ll enjoy:
Bipartisan student leadership on climate change: Student leaders across the U.S. have released a fantastic statement of support for the kind of carbon tax and dividend plan long advocated by the Citizen’s Climate Lobby. No matter what your politics, I hope you will get behind this brilliant pathway to a better future. We cannot afford to wait any longer.
➔ I will be doing my “Global Warming Demystified” talk (which includes a short portion on the tax and dividend plan) online for the Aquarium of the Pacific on August 11, 7pm Pacific time. Watch live at this link.
Three missions to Mars successfully launched! NASA’s Perseverance rover successfully launched on July 30, joining two other missions launched days earlier: China’s Tianwen-1 (translates as “questions to heaven”) and the UAE’s Hope Mars Mission. I recommend this great NYT article to learn more about Perseverance.
Great Sky Viewing Opportunities. With warm summer nights, it’s a great time to go out and do some stargazaing, especially to take advantage of these two opportunities:
- Comet NEOWISE is fading but still visible with binoculars, especially if you go to a dark site. If you haven’t seen it yet, check it out! See my prior post for details on how to find it.
- The annual Perseid meteor shower will peak Aug. 11 to 13. You can find full details about this year’s shower in this Earthsky article, but scroll down and you’ll see a quick Q&A to get you started.
Ready for use by Middle School Teachers this Fall: Our free, online curriculum for middle school Earth & Space Science. Please check it out and share it with all the teachers you know. And please e-mail me with your comments and feedback about the site.
Best,
Jeff
Comet and Meteor Shower Q&A:
Q: How do I watch a meteor shower? Easy! All you need is a clear sky and a place to sit back or, better, lie down — because you’ll want to watch for at least 15 minutes or more to have a good chance of catching at least a few meteors in the act. Remember that “shower” is a bit of an overstatement; even in the best meteor showers, you’ll be lucky to see a meteor every couple of minutes. So be patient, and try to keep a wide view of the sky, since you may catch some meteors with your peripheral vision.
Q: Does it help to have binoculars for a meteor shower? No. Meteors flash by too quickly and appear all over the sky, so there’s no time to point your binoculars at one. Note: But if you also want to see Comet NEOWISE, then you’ll need binoculars for that.
Q: Do I need to drive to a darker site? You’ll see more meteors at a darker site, but as long as you can see at least some stars, you are likely to catch at least some meteors.
Q: Is it better to get up before dawn to watch? In general, meteor showers peak in the early morning, but during a good shower like the Perseids, you’ll see plenty in the evening as well. Going out later at night is generally better. Note, however, that for the 2020 Perseids, the Moon will be rising around midnight, and since the Moon brightens the sky, you may actually get better views this year in the late evening than in the early morning.
Q: What exactly is a “meteor”? A meteor is the flash of light that we see as a particle of space dust or small space pebble/rock enters our atmosphere and burns up. That is, what we see as a meteor is the trail of light from the burn-up, not the particle itself. The particles burn up because they are entering the atmosphere at extremely high speed (up to about 250,000 km/hr, which is about 150,000 mi/hr). If the particle is large enough (a pebble or small rock), it may make an especially bright meteor sometimes called a “fireball,” and may even explode at the end as what is called a “bolide.” Very, very rarely, a space rock is large enough that it does not completely disintegrate in the atmosphere, and in that case pieces of it will hit the ground to make what we call “meteorites.”
Q: What’s the difference between a meteor and a “shooting star”? No difference. Meteors are sometimes called “shooting stars” because they kind of look like stars shooting across the sky. However, as above, meteors are flashes of light in our own atmosphere, so they are very different from stars.
Q: What’s the difference between a comet and a meteor? People often confuse the two, but comets and meteors are quite different:
- As above, a meteor is a flash of light in our own atmosphere, created as a piece of space dust or a small space pebble/rock burns up. Hence, meteors are visible for only a few seconds as they dart across the sky.
- Comets are in space, orbiting the Sun. This means that even the ones that come close enough for us to see are still typically tens to hundreds of millions of kilometers from Earth. As a result, their motion relative to the stars is fairly slow, so that on a single night, you may not notice this motion at all; the comet will simply rise and set with the stars. In other words, even though comet photos may make it look like they are racing across the sky, they aren’t; you’ll simply see a comet with its long tail sitting in one spot among the stars in the sky.
- Note: Despite these differences, there is a deep connection between comets and meteors: Most of the particles that enter our atmosphere to become meteors were actually shed by comets. That is, meteors are created by comet dust, and therefore we tend to get more of them — a meteor shower — at times of year when our orbit crosses the orbit of a comet that has shed lots of dust.