Go out, look up, see the Geminids

Posted By Pamela on Dec 10, 2007 | 13 comments

The other night, while driving home, I saw the constellation Orion looming large over the horizon. This leaning ancient warrior was fighting off Taurus the Bull as he does every winter from here in the Northern Hemisphere. The return of this particular set of stars to my home commute can only mean 2 things, 1) I stayed on campus far too late (which wasn’t the case) or 2) it’s almost the end of the semester (which was the case). For me, the end of the semester marks several coincident things that I need to pay attention to. The first is final’s week (next Monday through Friday), the second is my Birthday (Wednesday) and the third is the Geminids meteor shower ( now through about December 17, peaking December 13-14. (see here for free chart creation tools – you don’t really need though, these meteors shower the entire sky with their light. Just go outside anytime after dark and look up for a few minutes)

While having my birthday and finals align themselves has been a fairly constant source of annoyance, having my Birthday and a meteor shower align is kind of cool. (Of course, that whole “finals week” thing makes it often hard to actually enjoy them, but what’s life without dichotomy?)

The Geminids are consistently one of the more active meteor showers. This may be due to the 1.5 year period of the parent object, 3200 Phaethon. This strange object refreshes the meteor stream every other year, keeping the source of the storm fresh. This year — TODAY, Dec 10 — this object actually passes within 47 lunar distances of Earth, making for a particularly fresh storm.

Most meteor showers come from comets, but Phaethon looks a lot like an asteroid. We think we have some understanding of the mystery involved. It’s thought Phaethon is a former comet ran out of surface volatiles – the pockets of material that can turn into gas and produce a tail. It has also built up a thick crust of interplanetary dust grains – bits and pieces of left over stuff from the solar system’s creation, knocked off of asteroids, planets and other objects during collisions, or spewed into space by particularly spectacular volcanoes. This combination means that Pantheon is in many ways the equivalent of a snowball rolled around in dirt until it looks like a mud ball. As that mud ball rolls around the sun, it leaves behind a trail of dirt, ice, and other stuff that is aligned just right for the Earth to smack into them once a year.

Meteor showers are really nothing more than the Earth smacking through a column of dust and ice left behind by some comet or comet like object. When these objects hit our atmosphere, like bugs hitting a windshield, they give off tremendous amounts off light as they burn up in the atmosphere. A lot of scientists encourage people to go out and report their observations (although I have to admit I can’t find anywhere to report this shower online – anyone know anywhere?) so that we can get better measurements of the paths of the parent object. As the Earth passes through this years tail and the tail from 1.5 years again and from 3 years ago, etc, etc, we get separate peaks in the number of meteors we see each hour. It takes a whole globe of people looking up to measure where our atmosphere is hitting how many objects per hour. Imagine driving down the road with a clean wind shield and crossing a stream of gnats. You can measure the distribution of the gnat stream by counting how many dead gnats you end up with on different parts of your wind shield.

In general, just like the gnats won’t harm your windshield, the its and pieces of comet-like-thing that cause the meteor shower won’t harm the Earth. That said, there is a probability that someday in the future we will cross the comet instead of the comet’s stream. There is no concern for anytime in the next several 1000 years for any of the known objects, but …. there is a neat possible history of a possible past collision between the Earth and a fragment of Comet Enke (the parent of the Taurid Meteor Shower) that may (may may may – the data is week) have aided in the end of the bronze era.

So, you’re safe today. 3200 Phaethon is a little bit close (and landed on the Potentially Hazardous Asteroid List (scroll down)) but no possible harm will actually come. Instead, go out, look up, and catch yourself a look at a falling star falling comet dust.


  1. I’ve been anticipating this shower. Orion is also the first ever constellation I recognized despite my vision. It’s a good thing that this shower is a worldwide shower, unlike Perseids.

  2. I share your frustration with your birthday falling in the exam period.

    Now I’m in college and have exames in january I won’t have that πŸ™‚

    downsite I won’t have much of a fun x-mas holiday though due to the exames looming behind them.

    I just wish it would be less cloudy this week but things look grim.

    ~ Jorge

  3. Happy Birthday! I have long enjoyed your podcasts and blog and greatly admire your work ethic, your passion for astronomy, and your desire to share it with the rest of us. Best wishes for a truly happy birthday.

  4. I’ll second that:
    Happy Birthday to you,
    Happy Birthday to you!
    Happy Birthday dear Pammie,
    Happy Birthday to you!

    When you said:
    “While having my birthday and finals align themselves has been a fairly constant source of announce, having my Birthday and a meteor shower align is kind of cool.”
    Did you mean “source of annoyance” instead of “announce”? I’m confused…

    Now -I- want a meteor shower for -MY- brithday! πŸ˜†

  5. Opps – Yes that was a typo Richard. Spell check just can’t catch it when my brain flings out the wrong word. Fixed.

  6. I feel awkward for forgetting to say this: Happy Birthday! Sorry for that.

  7. Being constantly annoyed by the alignment of your birthday and finals is a typical Ophiuchan thing to say πŸ˜‰ Only joking. Happy Birthday for tomorrow.

  8. I’m hoping the sky clears enough for me to see the show (it was drizzling on my commute home here in Atlanta).

    Hoping you have/had a spectacular, cosmic birthday, and also that you ‘ace’ all your finals.

  9. Hi Pam, thanks for the post. I’m living in Japan at GMT +9, and I’m having a bear of a time figuring out if I’m going to be able to see this shower tonight. I’m 14 hours ahead of everyone in EST, any thoughts from you or anyone else on what my chances are? All the info I’m finding is for North American viewing. Many thanks in advance.

  10. So, are you saying that if Patheon impacts Earth, it will be finals week? πŸ™‚ Happy Birthday!!

  11. I went out last night, but I did not see anything. The clouds started moving in and probably blocked most of it. On the way back in the car, I think I saw 1 fly by. Tonight it is overcast. No chance to see anything here. Perhaps it will be better tomorrow. We need the rain though with our drought. I can’t complain when we get any rain at all. James

  12. Excuse my ignorance… I’ve never seen this beauty in person, where would be the best place for me to see the shower? Is Big Bear, ca. a good place?

  13. Anywhere dark is good πŸ™‚ Big Bear is a great site! Definitely try and get out there if you can.


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