Yes, in other words, tonight and tomorrow night are the maximum event rates for the Geminids, the meteor shower that originates from the direction of the constellation Gemini. From Gary Kronk’s site, I borrowed this diagram that shows roughly where to look:
So as you can see, you’re popping out to look in a Easterly direction, more or less, and after about 9:00pm you should get some results. There’s some more information here at this site.
You’ll recall from a number of earlier posts on meteor showers that I’ve mentioned that they are caused by the Earth passing through the debris field of a comet. The Geminids are somewhat different. Well, yes and no. They are actually passing through the debris field of a local object, called 3200 Phaethon, which has a highly elliptical orbit around the sun. It was discovered as late as 1983 by Green and Davies. This fellow is a bit like an asteroid and a bit like a comet. People still debate this. It could be a former comet that somehow got captured and remains local now, or not. Its debris field could have been created by collision with another body, such as another asteroid. You can find out more at this SkyTonight site, and more about Phaethon at this Wikipedia site.
Well, enjoy the view. I’ll be popping out later tonight with a glass of Caol Ila to keep me warm against the chill of December. Tonight and tomorrow nights are the peak activity nights, but there should be viewable comets on other nights to come for a few more days. Let me know if you see any!
-cvj
astromcnaught: I’m a fan of Fred Whipple too, but he didn’t discover Phaethon.
A rather nice single malt from Islay. Less well known than some of the others you hear about, but no lesser a drink, to be sure.
-cvj
what is Caol Ila?
WOW! This mixed asteroid/comet object is vaguely reminiscent of a sphinx journeying across the sky. Phaethon is a rare gem in the Solar System, which travels like a comet, yet looks like an asteroid. Since its surface is rocky–instead of icy–Phaethon lacks a tail. Interestingly, Phaethon was the first asteroid/comet object to be linked to a meteor shower: the Geminid meteor shower.
By the way, Clifford, it’s refreshing to see a high-energy physicist such as yourself post on low-energy physics. Otherwise, I’d spend more time at the Bad Astronomer’s site getting my daily fill of astronomy.;) Oh sure, quantum gravity at the Planck scale is incredibly intense and mind-bending. On the flipside though, classical mechanics of the night’s sky is wonderfully relaxing and just plain fun.:)
Have a most enjoyable evening!
Cynthia
No…. considerable light pollution in the direction I needed to look. Will try again tonight. Maybe go into the hills nearby, if I get the chance.
-cvj
http://www.imo.net/live/geminids2006/ indicates a ZHR of around 95, slightly less than usual it seems.
The Gemininds are my favourite shower of the year: they have about the highest rates and consist of medium speed meteors such that one can have a good look at each event. The radiant also rises early so there is no need to stay up late, or get up in the wee small hours.
Did you see any Clifford? It was cloudy here in the UK (again, dabnabit) and still is. I reckon, using my inbuilt mental graphing ability, that I’ll be 756 years old before i stop being disappointed at missing good meteor showers, lol.
Finally, Amara, I’m a huge fan of Whipple. He did tremendous work on meteors and the interplanetary medium in the 50’s. Especially interesting are the papers produced reducing the observations of his specially commissioned Baker super-schmidt cameras (f.0.65/0.85 12 inch things !!)
It’s easy to ask questions when one of the co-discoverers is a colleague and a friend. The discovery of 3200 Phaethon occurred in 1983 while Green (PhD student working on his thesis) and Davies (postdoc) found it in rejected IRAS data. Any communication between the RAL ground-station (where they were pouring over IRAS printouts) and observatories (for confirmation observations) was usually telexed, but in this case, from their paper discovery, they personally telephoned Kowal at the Palomar 48 inch Schmidt to ask to observe it. Kowal did, the asteroid was present, and they found it. Fred Whipple’s contribution in the story was to ‘link’ the object from its listing in the Minor Planet database to the Germinid meteor stream. In addition to this nice story, Green also told me that the thermal properties of Phaethon don’t indicate cometary origin, either. He said that thermal modelling to fit the IR photometry [Green et al., MNRAS 214, 29p-36p, 1985] implies a rocky surface.
P.S. It seems that Jenniskens attributed the discovery to Fred Whipple, while the IAU minor planets recorded the discovery to Green and Davies ?? Maybe they are all co-discoverers? Should my referee have caught this? I don’t know what is going on, but I will ask some questions…
A quote from : Jenniskens, P., “Meteor Showers from Broken Comets” (2007), from the volume: Krueger, H. and Graps, A. editors, “Dust in Planetary Systems” (Workshop, September 26-30 2005, Kauai, Hawaii), ESA Publications, SP-643 in press, February 2007.
(My coeditor and I are working on getting the above conference proceedings electronically searchable and freely downloadable from an ESA website in a couple months.)
“In 1983, Fred Whipple discovered a minor planet 3200 Phaethon among the very short-period (P ~ 1.59 yr.) and unusually small perihelion distance (q = 0.14 AU) meteoroid stream responsible for the Geminid shower [3]. Due to the uncommon orbit, the probability of this good an association by chance is only about 1 in 2 million, depending on the actual number of objects in this still sparsely sampled population. However, the reflectance properties of the minor planet (taxonomic type B) made the nature of this object as an extinct comet nucleus uncertain. The small perihelion distance heated the surface to above 700 K and sintered the Geminid meteoroids enough to change their morphology. It has since been shown that the Geminids appear to have been created close to perihelion, more typical of comet ejection than asteroidal collisions”
and in the conclusions near the end, we read:
“Many ecliptic meteoroid streams have now associated inactive minor bodies that are still in very similar orbits. This implies that discrete fragmentation through the spill-off of boulders, loss of cometesimals, or catastrophic disruption is a common phenomenon among the population of dormant comet nuclei in the inner solar system. It is, in fact, their main mass-loss mechanism.”
Peter Jenniskens has newly published book on the topic, as well.