2007-11-16 09:38:19 · 7 answers · asked by christine2550@sbcglobal.net 2 in Science & Mathematics ➔ Astronomy & Space
Comets are about 50% water ice. When comets get close enough to the sun, they begin to heat up and stuff vaporizes and flies off the surface, creating a cloud (called a coma) and also a tail.
Since earth passes through cometary debris several times a year (creating the regular meteor showers we see) and since some of the stuff probably makes it to the ground before burning up in our atmosphere, I'd say it's likely that, yes, it could possibly still happen.
We've actually gone TO a comet, grabbed stuff, and brought it back. NASA launched a craft called "Stardust" back in 1999 to grab up some debris from the comet Wild-2 and bring it back to Earth. Once they got the stuff back and analyzed it they found all sorts of neat things, like the "stardust" grains they expected, and also some silicate crystals they didn't expect.
I'm anxious to see other people's input on this. It's an interesting question.
2007-11-16 10:14:58 · answer #1 · answered by kyeri y 4 · 0⤊ 0⤋
Yes, but not every day... None every year... They would come in with an average of one each 100 millions years. Last time a big comet came, it killed the dinosaurs.
(Have you ever read the Bible? See the Apocalypses... It looks like a description of a comets rain!)
2007-11-16 10:11:22 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Nothing like the good old days of the accretion. However photographs have shown that earth is constantly being showered by mini-comets. How much of that material ever finds its way down to the surface isn't known.
2007-11-16 09:44:35 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Comets probably brought about 20% of the water that is on Earth today, not all of it. The rest (the other 80%)came and comes from vulcanism. Most people have no idea how "wet" lava is, whatever its chemical composition may be.
2016-05-23 10:58:14 · answer #4 · answered by ? 3 · 0⤊ 0⤋
There is no evidence that they are. Louis Frank of the University of Iowa actively promoted this idea in the 1990s, but he eventually dropped it. There was no supporting evidence, and the photographic evidence he thought he had turned out to be camera noise.
2007-11-16 10:15:20 · answer #5 · answered by injanier 7 · 0⤊ 0⤋
No. The amount of water on Earth now is the same as the amount there was when the dinosaurs were alive and well.
2007-11-16 12:18:03 · answer #6 · answered by Anonymous · 0⤊ 0⤋
i never knew it was
2007-11-16 09:46:04 · answer #7 · answered by 10 out of 10 4 · 0⤊ 0⤋