Starship Asterisk*

Great explanation of the apparent motion being the sum of the meteor's motion and the Earth's. I had such a wonderful time observing the Geminid meteor shower this year! I really feel like I saw almost a meteor a minute here only about 40 miles outside of NYC.

[float=right][img3="[b][color=#0000FF]Meteors appear to radiate from a particular point in the sky for the same reason snow does in the headlights of a moving car. Earth is a “fast car” moving into a [falling] cloud of meteoroids. The ones directly in front of us – closest to the radiant – make very short streaks, while those farther off to the side make longer streaks. Both meteor debris and snow flakes are really moving parallel to one another. They only appear to converge like the familiar illusion of train tracks meeting in the distance. Photo: Bob King[/color][/b]"]http://astrobob.areavoices.com/files/2012/12/Snow-radiantS-400x266.jpg[/img3]

[img3="[b][color=#0000FF]NASA’s all-sky meteor camera network recorded 56 Geminids last night and triangulated their positions to create this diagram showing the orbit of each meteor. The thick yellow band corresponds nicely with the orbit of the asteroid Phaethon, the source of the Geminids. The other loops are random meteors. I’ve included the position of the Earth. Credit: NASA/MSFC[/color][/b]"]http://astrobob.areavoices.com/files/2012/12/Geminids-2012-orbital-diagram-bill-cooke-nasa1-1024x668.jpg[/img3][/float][quote="Lordcat Darkstar"][quote="Gawil"]

How come the all the meteor traces seem to have a common spot? I don't get the geometry about it since it the same for traces both to the left and to the right.[/quote]
As the earth orbits the sun it passes through the trail of debris left behind by a comet.
Right now the earth is headed toward Gemini so that is where the radiant is. At least that is how I understand it.[/quote]
Actually, Earth is more [b][u]headed towards the constellation Leo[/u][/b] but the asteroid [url=http://en.wikipedia.org/wiki/3200_Phaethon]3200 Phaethon[/url] (aphelion ~ 2.4 AU) has left a trail of particles that bombards us from an anti-solar direction such that [b][u]the combined velocity of the Geminids minus the velocity of Earth [/u][/b] appears to come from the general direction of Castor.
[quote=" http://astrobob.areavoices.com/2012/12/13/geminid-shower-heats-up-tips-on-meteor-photography/"]

Geminid shower heats up; tips on meteor photography
by AstroBob, December 13, 2012

Don’t forget the potential new shower expected earlier in the evening from Comet Wirtanen. THOSE meteors will appear to radiate from the dim constellation Pisces below the Great Square of Pegasus. Up to 30 slow-moving meteors per hour might be visible from dark skies. Look toward the south early in the evening as soon as it gets dark. There have already been a few early sightings of bright, slow meteors from the vicinity.

Meteors from either shower can appear anywhere in the sky, but you’ll know which is which if you follow their paths back to the radiant, the point in the sky from they appear to originate. At mid-evening, Geminids will trace back to the east; those from Comet Wirtanen to the south and west. No matter where you point the camera meteors will fly by, however the further away from the radiant you are, the longer the meteor trails will be. I usually include the radiant off to one side or frame a catchy composition with showy stars like those in Orion. Including brilliant Jupiter along with the neighboring star clusters of the Pleiades and Hyades might be another scenic angle.>>[/quote]

[quote="Gawil"]Hi all!
How come the all the meteor traces seem to have a common spot? I don't get the geometry about it since it the same for traces both to the left and to the right.
Thanks for the site btw, it's great![/quote]

See if this article helps
[url=http://www.skyandtelescope.com/about/pressreleases/Geminid-Meteor-Shower-December-13-14-182064841.html][size=120][b][i]Geminid Meteor Shower Coming on December 13–14[/i][/b][/size][/url]
Sky & Telescope | Alan MacRobert | 2012 Dec 05

[img3="[i]The Geminids will radiate from Gemini, shown here at its highest point above the southwestern sky around 2am on December 14th. [b](Courtesy: Sky & Telescope)[/b][/i]"]http://media.skyandtelescope.com/images/GEMINIDSforPrint.jpg[/img3][hr][/hr]
The graphic shows much toward answering your question but the article is interesting too

[b][i] http://asterisk.apod.com/viewtopic.php?t=30347 [/i][/b]

[quote="Gawil"]Hi all!
How come the all the meteor traces seem to have a common spot? I don't get the geometry about it since it the same for traces both to the left and to the right.
Thanks for the site btw, it's great![/quote]
As the earth orbits the sun it passes through the trail of debris left behind by a comet. Right now the earth is headed toward Gemini so that is where the radiant is. At least that is how I understand it.

[quote="Gawil"]Hi all!
How come the all the meteor traces seem to have a common spot? I don't get the geometry about it since it the same for traces both to the left and to the right.
Thanks for the site btw, it's great![/quote]


Because that is where they come out of the sky and they get their name from the constellation they appear to come out of. Geminid Meteor Shower, in this case. From the Constellation, Gemini.

:---[===] *

"Chewy, prepare for the jump to light speed."

:---[===] *

Hi all!
How come the all the meteor traces seem to have a common spot? I don't get the geometry about it since it the same for traces both to the left and to the right.
Thanks for the site btw, it's great!

[url=http://apod.nasa.gov/apod/ap121215.html][img]http://apod.nasa.gov/apod/calendar/S_121215.jpg[/img] [size=150]When Gemini Sends Stars to Paranal[/size][/url]

[b] Explanation: [/b] From a radiant point in the constellation of the Twins, the [url=http://asterisk.apod.com/viewtopic.php?f=29&t=30347&p=189419]annual Geminid meteor shower[/url] rained down on planet Earth this week. Recorded near the shower's peak in the early hours of December 14, [url=http://www.astrosurf.com/sguisard/Pagim/Paranal-Geminids.html]this skyscape captures[/url] Gemini's lovely shooting stars in a careful composite of 30 exposures, each 20 seconds long, from the dark of the Chilean Atacama Desert over ESO's [url=http://apod.nasa.gov/apod/ap110811.html]Paranal Observatory[/url]. In the foreground Paranal's four [url=http://apod.nasa.gov/apod/ap111228.html]Very Large Telescopes[/url], four [url=http://apod.nasa.gov/apod/ap120421.html]Auxillary Telescopes[/url], and the [url=http://apod.nasa.gov/apod/ap110630.html]VLT Survey telescope[/url] are all open and observing. The skies above are shared with bright Jupiter (left), Orion, (top left), and the faint light of the Milky Way. Dust swept up from the orbit of [url=http://arxiv.org/abs/1112.5220]active asteroid[/url] [url=http://arxiv.org/abs/1009.2710]3200 Phaethon[/url], Gemini's meteors enter the atmosphere traveling at about 22 kilometers per second.

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