When will the Hailey's Comet finally "burn out"?

Question

As far as I know, comets "melt" when they come near the sun (isn't that why they have "tails" like a meteor?). So... Wondering if anybody here knows when that big thing'll finally disappear.

Answer 1

A comets composition is made up of a solid rocky core, with several icy layers (frozen water, methane, ammonia, and carbon dioxide) which is encased with a dark outer crust.

Halley's Comet had a period of approximately 75-76 years.  The vast majority of it's orbit it is keeping it's icy layers, for it is far too distant from the sun to be stripped of this.  

Although it is possible a time will come when Halley's comet will be depleted of it's icy layers, this will take several hundreds of thousands of revolutions around the sun... and most likely the sun will become a red giant before this ever happens...  and when the sun swells that size,  (in about 5 bilion years) Halley's orbit will either have to be adjusted, ir it will crash into the sun, long before it becomes just a peice of rock devoid of it's frozen gasses.  This doesn't mean it won't become a much fainter comet in the future, but all comets have a lot of irregularities in their appearance, and the truth is, we just don't have a complete understanding of their behavior just yet.

I also think you have a misunderstanding of meteors, but I'm not sure from your question about that.  You do have a legitimate (yet crude) understanding of what makes the comet's tail though...  as it approaches the sun, these ice layers get forced back by solar winds and radiation, which is why a comets tail ALWAYS points away from the sun.