how far can a comet stretch?
550092
Many millioms of miles.
442669
A comet is made up of rock, dust and ices that freeze as the comet moves away from the sun. When it gets closer to the sun the ices and rock will burn due to solar radiation. A comet does not always have a tail!
418460
They can bounce light off and measure it, but I don't think they've done that with the distant planets.  Redshift only works with huge distances like distant stars that are hundreds or millions of light years away.\n\nThink of the hundreds (and thousands) of years that humans have been keeping track of the movements of the planets.  Mathematicians can use these records to determine how far away from the sun these planets must be in order to move the way they do in the sky,  after all this is how they figured out that they all move around the sun instead of the earth.\n\nOnce you know roughly how far away these planets are from the sun and how far the earth is from the sun, you can determine the range of distances from the earth.  Sometimes the planets can be in line with us between them and the sun and be close.  Sometimes they are on the complete opposite side of the sun and are at their most distant.\n\nNow, of course, we have satellites that have gone around every planet and it's easy to figure out how long signals take to get to them and back.  But we knew the distances already or else the satellites would never have gotten there.
993967
several large asteroids have earth-crossing orbits, but we know of no asteroids that will come close to us at this time.  Odds are, if an asteroid that was 1 mile across or bigger coming at us soon, we wouldn't know it at all in advance.  We're working on finding them all and getting their orbits mapped.
36124
Just a few feet as long as you are looking at a smooth horizon like the ocean. Line up the edge of a flat table with the horizon and you will see the earth bending bulging above the table edge center.\n\nYou can also watch a boat sail straight away and disappear over the horizon. You may need to use binoculars!\n\nHere's another method you can use to show the curvature of the earth:
63833
50 feet or about 2-3 seconds
460102
Depends on the size of the comet, many just disintegrate on the atmosphere. A really big one could create:\nShift in the orbit, heat from the explosion, smoke and dust from the explosion covering the Sun. Earthquakes and volcanic eruptions from shift in magnetic field due to orbit shift. Basically extinction of many forms of life, possibly even human.
786773
Their distance from the Sun
1042534
"Near close approach around 4h44m UT July 3, this 600-meter/yard diameter asteroid\n\n Passes only 268,873 miles from the Earth, only  1.1 times the distance to the moon away.\n\nPeaking at  visual magnitude 11.1 four hours later, users of telescopes of 6 inches (15cm)  \n\nor larger can enjoy observing a  rare celestial  treat.  At time of close approach, 2004 XP14\n\n races along at 8.323 degrees per hour, or a mean lunar diameter every four minutes!\n\nSuch a rapid speed results in direct motion becoming visible, second by second. Just \n\nas naked eye Earth satellites are seen crossing the sky, 2004 XP14 will both amaze and\n\nchallenge the observer, both visually and those taking images."\n\nFrom www.lpl.arizona.edu\n\nHope it helps.
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.)
571553
good question. depends on how far away it is. if the horizon is flat and you can see 10 miles away then it would be like a circle with a 20 mile radius...becuase it goes all the way around you...get it?
38307
how far you can stretch your tax refund.
918837
In theory there is no upper bound except those imposed by real-world engineering constraints.\n\nThe Russians popped an underground event in Siberia that was a bit over 50 megatons.  It *moved* the entire  Siberian techtonic plate something like a centimeter and they decided that was probably as big as they needed to test ☺\n\nSay you detonated something in the 10 megaton range at an altitude of about 5 miles.  Pretty much everything within about a 3 mile radius of 'ground zero' is going to be, literally, vaporized.  In fact, the top 30 or 40 feet of ground zero is going to be vaporized, leaving a sort of round 'dish' shaped depression a mile or so across in the ground.  Inside this radius, the 'dish' will be coated with a 'slag' formed as melted soil and rock cools.  Depending on the minerals in the area, some of these slags are quite colerful and would make excellent souvenirs.  (Just avoid the ones that glow in the dark ☺)  Everything out to about 10 miles or so will be knocked flat and/or incinerated (total destruction on the surface) by the heat and shock wave.  The structural damage begins to fall off after that, but significant damage to structures would still occur at ranges of 20 or more miles.  People directly exposed to the event would be killed (instantly) by the radiation at distances of up to about 10 miles.  After that, survival probabilities would increase logarithmically out to about 30 to 35 miles.  Life expectency (which would be zero out to ranges up to about 10 miles)  would go up along a logarithmic curve out to a range of about 100 miles or so, at which point the mean expected lifetime (post event) would be about the same as it was before the event.  One exception would be optical effects.  Anyone looking in the general direction of the event would probably be blinded out to a range of 30 to 40 miles.\n\n\nDoug
713331
It's sounds like pretty average conditions though I don't know what upper comet means but you neglected to mention is there was snow. There has to be a nice thick layer of snow to ride.
34602
ALthough the exact distance at which the Earth's atmosphere (the 'sky') loses influence is debated, the atmosphere does end, so yes there is a limit to the sky.  As for space, space is most likely finite in size, but since it is expanding at such great speed, relative to someone in a spaceship, space would appear unlimited.
1169146
At least 12 feet.\nI could be wrong though.
1151814
Yes but only to the person observing from one comet the speed of one is only relitive to the still space it occupies , but yes compared to the other it would appeare to go faster than the speed of light.