Page 1 of 2 12 LastLast
Results 1 to 30 of 42

Thread: 'Shooting star' question...

  1. #1
    Join Date
    Jun 2004
    Posts
    39

    'Shooting star' question...

    Hello everyone...

    First, for the record, I was posting on this BB a year ago at the height of the PX2003 non-event. I was posting under the user name 'Jerod S.' However, it's been a while and my previous account seems to be deactivated. Tried to get a new password a couple weeks back (as I'd long since spaced the old one) but didn't have any luck getting that to cooperate with me. Since I hate to complain to webmasters 'cause they have enough to worry about, I've simply registered anew under a variation on my previous user name. Sorry about the confusion this creates (if any) -and hopefully I won't be kicked off the board outright for it...

    Now, the item I really wanted to post about!

    I was outside at 11:30 PM on what is now last night and happened to catch what is probably *the* coolest 'shooting star' I've ever seen. Everything I've seen before has resembled a star in terms of the coloration. But this one clearly had a green tint to it. Not only that, but it appeared in the sky for roughly 5-6 seconds as opposed to the usual 1-3 seconds. (All times are rough estimates on my part...)

    Two questions:

    1) Does the elemental composition of 'shooting star' burning up in the atmosphere effect the color that we see? (Obviously the green color mentioned above threw me off, hence the question.)

    2) I've heard (correct me if I'm wrong) that most of the 'shooting stars' we see are somewhere between the size of a grain of sand and the average grape -or thereabouts. Would I be correct in guessing the one I saw last night hung around a bit longer 'cause it was a little larger and therefore took a little longer to burn up in the atmosphere?

    I realize this isn't a terribly exciting thread, but...just curious as to why I saw what I saw last night. I'm pretty certain it wasn't Venus, a UFO or an undigested bit of ham, for the record...

  2. #2
    Join Date
    Sep 2003
    Posts
    182
    ok im not an authority but your probably right in assuming the size was a bit larger because of how long it lasted. As to what the size of most shooting stars are vs the one you saw, I thinking that shooting stars are larger than grains of sand or even grapes as to how much larger ? shrug

    and concerning the color of light you saw; could be due to the materials that made up that particular shooting star, could be due to atmospheric conditions. Dunno.

  3. #3
    Join Date
    Mar 2004
    Posts
    285
    Green ones are rare, but happen. There was a spectacular green one a few years back.

    It is indeed based on composition, density, size, speed, and to some extent, atmospheric condition.

  4. #4
    Join Date
    Feb 2004
    Posts
    1,885
    I've seen a green one too, a couple years ago. What burns green? Somebody told me copper but I don't know.

  5. #5
    Join Date
    Mar 2004
    Posts
    5,653
    Quote Originally Posted by jt-3d
    I've seen a green one too, a couple years ago. What burns green? Somebody told me copper but I don't know.
    Copper is the classic, though Barium also burns green.

  6. #6
    Join Date
    Nov 2003
    Posts
    83
    Fireballs are always fantastic to watch. I've stayed up many nights during the annual meteor showers hoping for a few good fireballs (usually to be disappointed). Congrats on seeing this one.

  7. #7
    Join Date
    Oct 2001
    Posts
    1,575
    IIRC the light you see is from the ionization of the atmosphere ahead of the meteor, not from the meteor itself. They all look white to me so colorization must be from some other factor. If you were to see any of the material ablating from the object it would be in the form of smoke astern of the object.

    Regarding size: It does matter. No, No, No, I'm not going there! :-? The big ones tend to last longer as they enter the atmosphere BUT, that is dependent on the material from which it is made. A bigger carbinasious condrite will burn up quicker than a smaller nickle-iron. There are other factors, angle of entry, differential velocity, etc.

  8. #8
    Join Date
    Oct 2001
    Posts
    7,816
    1) Does the elemental composition of 'shooting star' burning up in the atmosphere effect the color that we see? (Obviously the green color mentioned above threw me off, hence the question.)
    Although most meteors are white, I've seen several yellow ones, a few red ones, a couple of blue ones and yes one very bright and brilliant green one! To answer your question, yes composition does play a part in determining the color of the meteor. Copper and barium have been mentioned. Oxygen (from the atmosphere) might also contribute.

    2) I've heard (correct me if I'm wrong) that most of the 'shooting stars' we see are somewhere between the size of a grain of sand and the average grape -or thereabouts.
    The faintest meteors are more on the order of the size of a particle of cigarette smoke! "Grain of sand" would be typical of a run of the mill meteor. A meteoroid the size of a grape would produce a spectacular fireball!
    Would I be correct in guessing the one I saw last night hung around a bit longer 'cause it was a little larger and therefore took a little longer to burn up in the atmosphere?
    The time that a meteor is visible is more a function of geometry (how steeply it enters the atmosphere) and its speed. The speed of a meteor varies from 11 Km/sec (Earth's escape velocity) to over 100 Km/sec.

  9. #9
    Join Date
    Jun 2004
    Posts
    39
    Thank you to all of you who replied to my inquiry.

    I can't begin to guess about atmospheric conditions when I saw the shooting star in question. The closest to that I can offer is that it was clear outside. Not overcast, no blatantly visible high clouds in the vicinity where Mr. Green came down. I realize that's almost (and may outright be) a seperate issue from atmospheric conditions, but...

    It was just rather cool. In my three decades on planet Earth I've only ever seen the white, very brief variety. Had a few instances where I could actually hear the thing burn up. Also cool, but mildly unnerving. Began awaiting the impact on my left temple or something. :roll:

  10. #10
    Join Date
    May 2002
    Posts
    5,527
    I'm pretty sure Russ is right here. The color is the result of ionizing particles in the atmosphere. The altitude of the burn is what changes the colors. If the meteor is coming in at an steep angle or more parallel to the horizon, it affects the rate of accumulating friction and subsequently the altitude you see the flash.

    Single meteors can come in at any angle. Meteor showers are affected as the Earth turns and moves along its orbit. Sometimes we are catching up to the dust trail and sometimes it is catching up to us. Sometimes we are turning into a dust trail so meteors are coming over the horizon and sometimes they are coming in directly overhead.

    A larger rock will make it further into the atmosphere. There it is hitting way more air molecules thus way more friction. That's when you get a fireball. And if it makes it all the way to a point where the friction causes the meteor to explode, you get daylight for a few seconds like we had in WA the other night. People's 24 hour cameras recorded not just a little light, but you could actually see distant mountain ranges.

    Too bad I was asleep. Oh well.

    Anyway, some meteors leave trails of greenish colored smoke. It has to include some of the meteor. I'm not sure if stony meteors or iron meteors leave different smoke colors. The vast majority of meteorites that reach the ground are stony, despite the fact that most of the ones that are found are iron. So the majority of meteors are stone though there are several varieties. Anyway, back to the topic, its the atmosphere not the meteor that provides the color.

  11. #11
    Join Date
    Jun 2004
    Posts
    11
    I saw a big yellow fireball last year that left a yellow trail. So the altitude affects the color? What's the color order, highest to lowest, anyone know?

  12. #12
    Join Date
    Oct 2001
    Posts
    29,142
    Composition does matter

    The composition of the meteoroid plays an important part in the observed colors of a meteor, with certain elements displaying signature colors when vaporized. For example, sodium produces a bright yellow color, nickel shows as green, and magnesium as blue-white. The velocity of the meteor also plays an important role, since a higher level of kinetic energy will excite the atoms to a higher degree. Slow meteors are often reported as red or orange, while fast meteors frequently have a blue color. Due to the nearly identical composition and velocity of meteors belonging to a particular shower, several showers are known for their characteristically colored meteors.
    Everything I need to know I learned through Googling.

  13. #13
    Join Date
    Jun 2002
    Posts
    4,813
    Considering how long it lasted (you said 5-6 seconds), maybe it was a re-entering satellite that you saw? In Oklahoma I once saw what I thought was a fireball very low in the northern sky for several seconds. The paper the next day reported that a Soviet communication satellite had re-entered over Nebraska causing phone calls to police departments all over Kansas and Nebraska.

  14. #14
    Join Date
    Feb 2002
    Posts
    387
    I have seen green streaks in the sky. None of them lasted 5 - 6 seconds. They were all like 2 or 3 seconds max.

  15. #15
    Join Date
    Oct 2001
    Posts
    7,816
    August 10, 1972 - Daylight fireball caught on film. 26 seconds of film after first being noticed!

    http://www.maa.agleia.de/Comet/Other/1972.html

  16. #16
    Join Date
    Apr 2004
    Posts
    26
    Ooo, wow, green meteor!? Cool. I still have yet to see one... even during a shower. , Tho i did see a nice orange-yellow fireball a few years back that lasted quite a while. \/ went almost the entire length of the sky, tho i cant confirm that as by the time i looked up she was already burning up.

  17. #17
    Join Date
    Dec 2003
    Posts
    2,384
    Quote Originally Posted by Kaptain K
    August 10, 1972
    The fireball over the Grand Tetons!

  18. #18
    Join Date
    Oct 2001
    Posts
    29,142
    Quote Originally Posted by SiriMurthy
    I have seen green streaks in the sky. None of them lasted 5 - 6 seconds. They were all like 2 or 3 seconds max.
    I saw a bright green fireball once.
    Everything I need to know I learned through Googling.

  19. #19
    Join Date
    Sep 2002
    Posts
    770
    Quote Originally Posted by ToSeek
    Quote Originally Posted by SiriMurthy
    I have seen green streaks in the sky. None of them lasted 5 - 6 seconds. They were all like 2 or 3 seconds max.
    I saw a bright green fireball once.
    Yeah, me too. Didn't last but 2-3 seconds probably though. I didn't realize that green was unusual, I thought it was the norm. It's about the only one I ever remember seeing. Well, no. Once I saw one come down, seemed to level out a bit (maybe even head back up slightly), then head back down again. Dunno if it skipped on the atmosphere or what. It wasn't an airplane, though. Way too fast for that. I do know that it didn't look nearly as big or spectacular as the other fireball I saw.

  20. #20
    Hi!
    I'm in the South of England, UK and have just seen a green shooting star! It was awesome! lasted about 5 seconds, was really bright and was heading towards London, lol.

    I thought it was weird so searched on google to find out why it was green and found this thread..

    Very informative, thanks!

    It was real bright though, at first I thought it was a firework or a flare, but it was too high, went too far and too fast to be either.

    Before it disappeared it got much slower and probably 4 times as bright than when it was going faster.


    Amazing!

    Stu

  21. #21
    Join Date
    Feb 2004
    Posts
    413
    Quote Originally Posted by S Raynor
    Hi!
    I'm in the South of England, UK and have just seen a green shooting star! It was awesome! lasted about 5 seconds, was really bright and was heading towards London, lol.

    I thought it was weird so searched on google to find out why it was green and found this thread..

    Very informative, thanks!

    It was real bright though, at first I thought it was a firework or a flare, but it was too high, went too far and too fast to be either.

    Before it disappeared it got much slower and probably 4 times as bright than when it was going faster.


    Amazing!

    Stu
    Yippee, I wasn't seeing things! I saw this and thought it might be a firework too. But I decided to tell the British Astronomical Association about it, because they collect information about these things: http://www.britastro.org/meteor/obs_fireballs.html

    If anyone else saw this, you might want to contact the BAA's meteor section (email address is here: http://www.britastro.org/info/meteor.html) so that they can collate the reports. Maybe, if lots of accurate reports come in, they can work out where it would have landed and find a meteorite!

    For your info, here's the report I sent in:
    Dear Mr Bone,

    I think I might have seen a bright green meteor near Oxford.

    I was walking North-West over Magdalen Bridge [Lat: 51:45:04N (51.751)
    : Lon: 1:14:45W (-1.2459)] at about 10:40pm when I saw it on my right
    (to the North-East). It was bright green, and split into about three
    pieces as it fell. I only saw it briefly (for about half a second)
    before it faded. I saw it falling at a steep angle, and from my
    viewpoint it was heading North West. It was lowish in the sky (but I
    can't guess the angle I'm afraid), and I have no idea of the distance.

    I'm not sure what it was - it is possible that I only saw a firework.
    However, all three pieces were falling on the same path (i.e. not like
    a firework shower) and I heard no noise. It was moving relatively
    slowly (relative to normal meteors, but much faster than a plane).

    I don't want to send you off on some wild goose chase, but I thought
    it worth contacting you just in case other people reported it too - so
    that you might be able to triangulate the position of any surviving
    fragments.

    Thank you,

  22. #22
    Quote Originally Posted by PhantomWolf
    Copper is the classic, though Barium also burns green.
    Both copper and barium should be quite rare in interplanetary space. Copper was chosen to smack comet Temple 1 simply because the copper atomic absorbtion lines could be subtracted out to reveal the composition of the asteroid--and copper is cheaper than even rarer metals such as gold or platinum.

    Aluminum burns bright white. What colors do silicon and sulfur burn?

  23. #23
    Join Date
    Sep 2005
    Posts
    1,293
    Atomic Oxygen burns green and may be a reaction with the atmosphere of either the temperature of the fireball or its actual chemical composition

  24. #24
    Join Date
    Jan 2006
    Posts
    25

    same in green.. green-red, that is

    Ive had a similar experience last year in summer. We were setting up our little telescope on a hill outside town near the Alps mountains.

    I had never seen sizeable shooting stars of any color before. Even though I had always had a latent interest into astronomy as a science, I had just recently gotten into "practical astronomy" / star gazing because my wife had given me that telescope as a birthday gift.

    Just when we were shooting north with the telescope to get it aligned, we saw a very bright green shooting star (in the West/NW). It seemed to last forever, I would immediately have guessed 5 or more seconds, but in retrospect it was really probably only one or two seconds, it was just that it was so spectacular that it seemed to last very long at that time.

    Now here comes the tricky part.

    It was distinctly green...a rich, beautiful green... but towards the end, when it was near the horizon, this was replaced by red. In the end it was red. Not just faint or greenish red but red in the same way that SOS sea signal candles burn off a bright red.
    I was very happy that my wife saw it too because I would have thought I was seeing things.

    It was so bright and intense that instinctly I waited for a loud impact noise. It was just that it appeared so big and powerful and near. Nonsense, of course, but in that moment I was instinctly preparing for a loud bang.
    Of course there was no impact or other noise at all.

    I would like to hear what your take on this is.

    sincerely,
    z.


    p.s.: btw, I havent seen any more sizeable shooting stars of any kind ever since, I am also especially unlucky at catching those meteor showers.

  25. #25
    Join Date
    Feb 2011
    Posts
    4

    Your not the only one

    Never really had an interest in stars or astronomy untill last night.

    12:21am looked up as I was discarding some water onto the lawn, less than a kilometer from the house a bright green light desended at a 45 degree angle. Saw it for all of 3 to 4 seconds. Can't have been a plane as it would have impacted due to its speed, angle and distance from the ground (wasn't the typical movement of an aircraft). First thoughts were it's some sort of falling star? but a bright green one!!!

    Glad I found this blog, now believe it was a falling meteroite after reading your posts.

    Spent two hours the next day driving around the countryside looking for a possible crater/reminants/anything as it was large and very low when I lost eye contact with it as I have trees surrounding the house.

    After no success come to believe must have finished burning up or desended into the estuary.

    Certainly some sight, shame I live in a rural area as hard to say others would have seen it. But no halo effect, no tail, just like a fast moving bright circular light.

    Warkworth, New Zealand

  26. #26
    Join Date
    Sep 2003
    Location
    The beautiful north coast (Ohio)
    Posts
    39,403
    Hi Eyes Open, welcome to BAUT. I've only seen a green one once, nice "catch". And though it was bright, it might not actually have made it to the ground, or might be very tiny. Meteors are a lot smaller than people think. The typical ones during a meteor shower are the size of grains of sand.
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  27. #27
    Join Date
    Jun 2005
    Posts
    8,909
    I've also only seen a green meteor once, and it was a big fireball. I think maybe that the small ones appear white because I don't see them long or well enough to be able to make out the color correctly.
    As above, so below

  28. #28
    Join Date
    Jun 2004
    Posts
    6,011
    Welcome... Yes, last night right across most of New Zealand it was a perfect night for astronomy. I did spend just five hours observing and had my back to your object.. ( saw nothing at 12.21am...) I was recording images of 47 tuc.
    From your description I can only say that a green bright fast moving object is not so rare.. By that I comment to have seen three over a number of years... small, metallic, entry and burn. If you did not hear it or a sonic BOOM... chances are it did not get below 35,000 ft., and yes. Most objects re entering and been seen are no bigger than a marble...or grains of sand.

  29. #29
    Join Date
    Jun 2007
    Posts
    182
    I wonder if speed and temperature has a role in color
    I know iron/steel will start dull orange go to red yellow and finally white hot as it is heated
    maybe blue or green are ever higher temperature

    I have seen a very very bright green fireball over the lights of the orange bowl at a game
    and a blue one against the ocean sky

  30. #30
    Join Date
    Jun 2003
    Posts
    7,980
    As Fr Wayne noted above, the most likely cause of the green colour is atmospheric oxygen. In an aurora oxygen glows a nice mid-green: the green colour in many meteors seems to have a similar origin.

    Combustion of copper or other metals is unlikely to be the cause of the commonest green coloured meteors, but might sometimes be significant.

Similar Threads

  1. How Big Was the shooting star I saw
    By wiggy in forum Space/Astronomy Questions and Answers
    Replies: 2
    Last Post: 2011-Jun-27, 10:00 AM
  2. Shooting Star
    By Z28Jerry in forum Astrophotography
    Replies: 3
    Last Post: 2007-Jan-05, 03:03 AM
  3. shooting star
    By Star_Scream in forum Astronomy
    Replies: 5
    Last Post: 2006-Dec-14, 02:40 PM
  4. I saw a shooting star!
    By ObiWan377 in forum Astronomy
    Replies: 7
    Last Post: 2004-Feb-19, 06:05 AM
  5. Shooting Star over NJ?
    By ObiWan377 in forum Astronomy
    Replies: 3
    Last Post: 2003-Aug-20, 06:11 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
here
The forum is sponsored in-part by: