How long can comets last?

Answer 1

There is no one answer for this question. It would depend on its original mass and composition, and how close its orbit brings it to the Sun, or to Jupiter, and how long the orbit is.

The greater the initial mass, the more passes by the Sun the comet can survive. Each pass close to the Sun boils off a significant amount of ice and dust; eventually, there would be nothing left.

Many comets collide with other bodies such as planets. In 1994, the comet Shoemaker-Levy 9 broke apart and crashed into Jupiter. We know that at least five times in Earth's past, massive impacts have caused global devastation; one such impact 65 million years ago killed off the dinosaurs. We don't know if that was an asteroid or a comet.

The farther out its orbit goes, the longer the comet can survive. It freezes more solidly, gets a chance to accrete some additional mass.

Scientists believe that Halley's Comet, for example, may last for 10 million years.

Answer 2

Comets can vary in how long they last, with some lasting only a few years and others taking thousands of years to complete their orbits. When a comet gets too close to the Sun, it can break apart or vaporize, shortening its lifespan. Ultimately, the lifespan of a comet depends on its size, composition, and orbit around the Sun.

Answer 3

as far as i am aware, typically it can be between 20,000 years and 200,000 years.

for a great book about the comet that is returning to earth very soon, read millennium mysterium.