Well, where do comets come from then??? Why do we still have comets around if they only last 100,000 years or less? When did they form? Just 100,000 years ago and if so, how? Will there be anymore comets when these ones burn up? Or do Oort Clouds really exist?
Comets are leftovers from the formation of the solar system.
And
yes, the Oort Cloud exists. It's been directly observed. Same with the Kuiper Belt. We've detected quite a few objects out there.
Not all comets get burned up by the Sun - most of them are still sitting out in the Oort Cloud, too far from direct sunlight for anything to happen. But there are a lot of objects out there - as they move around in their individual orbits, occasionally they interact with each other gravitationally. This sometimes results in a comet's orbit getting changed, which sometimes brings it closer to the Sun, and we get a nice view.
There's no magic limit of 100,000 years on a comet's life. Their existence depends on their initial size and how much direct sunlight they get, and what they run into (remember Shoemaker-Levy, when it got caught by Jupiter's gravitational pull?).
Where in the world are you getting your info, Flyer? Did you read some report about an
individual comet that's only expected to last another 100,000 years and think that meant
all comets had some sort of shelf life?
™ Version 4.2