Where Did comets come from initially?

Comets are believed to have two sources. Long-period comets (those which take more than 200 years to complete an orbit around the Sun) originate from the Oort Cloud. Short-period comets (those which take less than 200 years to complete an orbit around the Sun) originate from the Kuiper Belt.

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How long do comets stay in the sky?

Comets are primitive bodies that formed at the same time as the Sun and planets about 4.6 billion years ago. But once they come close enough to be seen, comets begin to fall apart and they must eventually vanish from sight, often in less than a million years after first sighting. Thereof, why do comets get a tail? Comets leave long beautiful tails when they come close to the sun. But when it approaches the sun, the heat evaporates the comet's gases, causing it to emit dust and microparticles (electrons and ions). These materials form a tail whose flow is affected by the sun's radiation pressure.

You can also ask what happens when a comet hits earth?

The energy of the impact will vaporize the asteroid and a large amount of the Earth's crust, creating a crater more than one hundred kilometers across, throwing all that rock into the air. Some of this debris will be going so fast that it will fly right out of the Earth's atmosphere and go into orbit around the Earth. Accordingly, why do comets glow? A comet's tail is made from the volatile materials inside the comet vaporising, which carries dust and gas out with them. This detritus reflects sunlight, leaving it glowing.