There is, at present, no evidence that any life forms have arrived on Earth from comets. As well as we can determine, all life on Earth is related to all other terrestrial life; the DNA is all similar enough that we know we're all related.
When we get to the stars, and IF we find other life forms, we may be able to examine the structure of those life forms. IF it turns out that alien life is related to terrestrial life, THEN we may have some evidence to support the hypothesis of "panspermia", which suggests that interstellar space may be teeming with cosmic spores of life.
Halley's Comet.
The comet Hale- Bopp, dicovred by alan hale and thomas Bopp, came close to the earth in 1997.This happenend eleven years after Halley's comet came around.
Halley's Comet.
The name of the comet seen in 1986 is Halley's Comet. You can see it every 75-76 years, and is the only short period comet that is clearly visible to the naked eye from earth, and thus the only naked-eye comet that might appear twice in a human lifetime.
Hale-Bopp
Probably several times. It is assumed that a third of Earth water came from comets and it was a comet that hit the Earth 65 million years ago and caused the dinosaur extinction.
Alan Hale and Thomas Bopp discovered Comet Hale-Bopp (C/1995 O1), which came close to the planet in 1997, in 1995.
The sun is the largest out of the three and then the earth and then a comet.
As of May 20, 2014 the next comet that will be coming by the Earth is Comet Faye at the end of May 2014. In June 2014, Comet Brooks 2 will be passing the Earth.
comet sandy
The name of the comet that will pass Earth on August 15, 2011, is the comet Honda.
We don't currently know when a comet will hit planet Earth.