Comets & their appearance?
826997
As the comet approaches the sun in it radically elliptical orbit, its tail seems to trail behind it.  As it approaches the low point of its orbit, the tail appears to be at nearly a right angle to its the tangent of it orbit.  As the comet continues around to the long out bound side of its elliptical orbit, the tail proceeds it.  The tail is in fact the out-gassing of the evaporating meteorite which is pushed away from the sun by the solar wind; so the tail lies nearly on a radial line out from the sun.  While the comet is nearer the sun, the tail should become thicker, because the greater amount of light and heat from the sun will cause gas to evaporate more quickly than when the comet is farther out from the sun.
508585
There have been many systems identified, some with multiple planets and a few with asteroid belts. The problem is that they are mostly discovered by measuring the minute movements of the star caused by gravitational influences of nearby orbiting objects, so most of the discoveries to date have been systems with relatively large planets (many times larger than our Jupiter) and quite close to the star so that the movement is more easily detected. Recently however, there have been more sensitive sensor arrays which have been able to resolve more "normal" configurations using sophisticated imagery, so there is hope for discoveries of systems more similar to our own in the near future. In any event, given the tremendous distances involved, the resolution of optical telescopes available in the foreseeable future would pretty much preclude any traditional photograph of such a system if it were to be found. There have been some rather blurry computer images generated from these other imaging systems, but I'd hardly call them photographs. Try monitoring <space.com>
176404
Its period is 76 years on average. I varies because of its gravitational interaction with the other planets. Its orbit takes if from just inside earths orbit out to just beyond Neptune. Lots of worlds to influence its orbit in between. \n\nHalley´s is considered a short-period comet despite the 76 year period. It is its interaction with other gravitational sources that has trapped it in its short period. Most comets originate from the Oort cloud some 50000 AUs from the sun. They appear and disappear for 1 to 30 million years! They are thus called long-period comets. Comet Halley would have begun its "career" as a long-period comet.
251640
"Quickie Questions - Other Solar System Stuff - Asteroids / Meteors / Meteroids / Comets"\nhttp://www.windows.ucar.edu/tour/link=/kids_space/qss_ast.html&edu=high\n\n"Meteoroids are smaller fragments of rock broken off of asteroids or dust released from a comet’s tail.\n...\nShooting stars, or meteors, are caused when a meteoroid enters the atmosphere. (When the meteroid enters the atmosphere, it becomes a meteor.)"
935624
The evolution of a comet. We did that last year to show how a comet becomes an asteroid. We used dry ice, dirt, dark corn syrup. It was fun. And we had live demonstration and lots of pictures. This link has a comet recipe: http://www.noao.edu/education/crecipe.html\n\nHere's another site that you can look for ideas: http://www.spartechsoftware.com/reeko/MoreExperimentsSortCategory.htm
1090033
There is actually a comet passing by Earth this month.  To calculate where the comet will be visible go to\nhttp://ssd.jpl.nasa.gov/horizons.cgi#top\n\nType in information for comet 73P
715943
Here's the Wikipedia entry for that comet.  What you are looking for seems to be on the right of the page:\n\nhttp://en.wikipedia.org/wiki/Great_Comet_of_1811\n\n(Sorry about that first incorrect website.  Good luck.)
420776
a comet is a ball of rock and ice that orbits the sun on a large elliptical orbit.  THey usually are not in the normal orbital plane of the planets so we only see them once in a while. So if the planets go around and around like on a plate, comets go on an angle like a plate on a 75 degree angle.  And instead of the sun being close to the center of the plate, with comets, the sun is much closer to the edge of the plate.\n\nSome planets take far longer than 76 years to orbit (pluto, neptune, etc...) so their orbits are even larger.  But they are more regular, comet's orbits are more stretched out so they get closer to the sun.
596093
Yes I have seen them all of my life...Just to name a few that I have been witness to ..A huge rectangle object that could take an entire football field to land. A silver disc right above me in the middle of the afternoon as I sit on the lake in my boat fishing..then it shot up and gone with instant speed..speed we do NOT have...an orange sphere...silver balls....a backwards c shape object we followed for 45 min...an elongated diamond that shone an intense spotlight on me before it shot up into the night ...then the very most recent was last month.\nIt was a windy night and not really that nice out, no rain just not nice. I decided to go to grab a bag of blankets from the RV that's parked down by the lake. I headed out from the cabin and was half way there when I looked at my watch and it was 12:01 am Sunday May 7th. I then went inside to grab my bag of blankets. I was in there for maybe 15  seconds and I then stepped outside and was facing west and there, right in front of me was a elongated diamond light sitting in the western sky. It was the size of the moon. If you imagine the moon being shaped to that description of an elongated diamond it was similar to the one I had witnessed last August here, but there was a dark circle in the middle of it. I stopped in my tracks as it took my breath away.\n\nIt was very clear, very visible and so very out of place. it was approx. 1/4 mile away and 300 - 400 meters up. I stared at it for about 4 or 5 seconds, suddenly there was a bright flash that lasted about 3 seconds. I quickly thought maybe it's a meteor or something burning up in the atmosphere, due to the intensity of the light, but I realized as it went back to it's original intensity, again that was not the case. As I already knew deep inside me and the fact the object wasn't moving. It sat there for another few seconds then it started upwards and towards the west and in an instant it was as small as a tiny star. I then followed it as it turned south for a second and shot up straight into space. Yes they are real..I have seen them all of my life
120286
a meteor/comet or self destruction
830457
Hi, I answered this question earlier. I'm going to cut and paste it for you.\n--\nMost sightings happen at night. People see strange lights or shapes in the sky.\nMine happened in broad daylight. Crystal clear blue sky. About noon. No sun in my eyes. An object appeared in the sky directly in front of me. It was traveling parallel to the ground. It wasn't zipping along at lightning fast speed. It was fairly slow. About airplane speed. \nIt wasn't more than a half mile away. Fairly low in the sky.\nI could see every detail. The color. It was a semi-shiny or brushed metallic almost burnt looking. Very hard to explain. All one color. No markings. No lights. I could see the intricate patterns of the body. I wont ever describe them. I'm not planting any seeds. When I hear an identical description then I'll know it was real. You see this was 25 years ago. To this day nobody has matched the description. Not even close. I watched it for a few seconds. I was in amazement. It simply vanished. \n--\nPsst, don't take me wrong. I'm not discounting your sighting at all. Just because it was at night doesn't mean you didn't see it. I totally believe you. Look at my story. People tell me I imagined it. What do they know anyway!\n.
957877
Meteors can vaporize and break apart, thus "explode".  That is probably what you saw.
823944
The basic method is to observe its position over several nights.  The subsequent motion of the comet against the background stars is then fitted to a curve that describes the orbit.  The difficulty with this method is that a elliptical orbit can resemble a parabolic or hyperbolic orbit at certain sections of the orbit.  In the early days of astronomical observations, this closeness made it difficult to determine if a comet was in a closed, periodic orbit or whether it would be on an escape path from the Solar System.
124650
It is pretty hard for me to say..no they are not real...\nI have seen several things both day and night..A huge object perhaps the size of a football field..it was very massive and overwhelming..I have have witnessed a silver disc object above me in mid afternoon..that shot straight up into the sky with instant speed. Speed that we dont have here. An elongated diamond light at night that turned out to have the intensity of a very bright spotlight...then dimmed again..and shot off up into the sky..with incredible speed ..Orange glowing spheres in early evening...backwards "c" shaped object in the daylight...the list goes on..but..Yeah..I have seen many...I cannot believe other than..We are NOT alone
134289
There are several things. Right now comet Pojmanski is visible in the morning sky. Also Mercury is visble. In a month the Lyrid metershower will peak. Events like these are constantly posted on www.spaceweather.com
427235
Dust particles and ionized gas from the comet.  The dust and gas each form their own distinct tail.
556709
The scientist in charge of this project were taking extra care with picture preparation. Go to the site and you will see that around May 17th I think we can start looking for the particles from space.\nSee link below for Stardust at Home