Though not all are unhappy, This Troper knows several elderly people who out-lived all their local friends, and live on the opposite side of the world of their old friends. Unfortunately, that you're gonna die eventually doesn't necessarily mean that you go out with your friends.

If you assume the theories of universal entropy and the big crunch are true, then millions of years floating in completely empty space, eternally suffocating, only to to be eventually crushed into a singularity sound like a very hard price to be for a (relatively) short amount of extra time doing things you enjoy. But you also have forever to get used to it.

That's if you're lucky. If there's no Big Crunch, all you get is an eternally expanding universe. By the time all protons have evaporated in ten thousand million million million million million million years' time, you might be getting a bit bored.

One advantage to being immortal if the eternally expanding universe is true is that according to one wacky theory that given enough time, say a googol (that's 1x10^100) years of waiting and the now vast empty universe might humor us immortals and spit up another big bang. So we immortals get to live a universal lifetime all over again...

The universe will (might, could) only do that if it's ''empty'' -- no massive particles. Floating immortal astronauts would screw that all up.

On the other hand, immortality will likely break the second law of thermodynamics. If you try to starve yourself, where does the energy come from to keep you functional?

Zero-point energy.

Besides being impossible to harvest, it's a fairly small amount of energy.

This is the most serious argument for "no afterlife" too. However, people with opposite views are quick to point out that the big bang itself screws with rules of thermodynamics ( a universe appearing in a setting where the opposite - stuff falling apart and energy dispersing, is the norm)

Also, only if you assume that the afterlife is a physical life '''in the same physical universe''' as this one! If it's wholly other, then talk about entropy and the eventual death of '''this''' universe is irrelevant.

Only if you assume a closed system. We can only speculate what existed before the initial expansion, but that the expansion itself occurred is based on very solid evidence and observation.

There is only one universe by definition. The only question is how accurate our understanding of the laws of physics is.

This prospect is discussed in the book "The Last Five Minutes," where it is postulated that if a conscious entity were able to become an Ascended Energy Being, said consciousness would be able to skew its own sense of time before the inevitable end and enjoy a virtual immortality. If you can't, you're screwed, because a physical body would be destroyed long before the end, no matter what kind of longevity you've got.

Unfortunately, there's a certain minimum amount of entropy required to erase a bit of memory. Eventually, you'd run out of useful energy.

This troper thought up another plan. All you have to do is build a machine that traverses dimensions, and go to a dimension that isn't so close to dying.

...Assuming that alternate dimensions even exist.

Why would it matter which way you face?

It is reasonable to expect that, unless an immortal being has severe memory problems, it will become {{Sufficiently Advanced| Alien}} long before the end of the universe, and would be able to make its own. Or at least go back in time to stay in a living universe.

I had a lengthy discussion on this subject with my roommate a while ago. I think that perfect immortality would be awesome for a few years, but then...I would soon grow distant and lose my grip on reality. My roommate, on the other hand, is already half AxeCrazy, so he'd do all the crazy stunts you could think of: he'd join the FightClub, do some stunt work, go skydiving and other extreme sports, all that. And in 500 years or so when he's had his fun? He would learn. He would attempt to AscendToAHigherPlaneOfExistence by becoming the most supremely knowledgeable person on the planet.

Seriously, this wouldn't be too much of a problem for me. Do you know how many degrees I could get? Seriously, with the ever expanding sphere of human knowledge, I don't think we'll run out of stuff to learn about.

Oh, you will. There's only 26^1000000 different books that can be written in one thousand pages with one thousand letters to the page. Heck, there's only (10^80)! ways to arrange all the particles of the universe. You'd run out at an infinitesimal fraction of your lifespan.

In the planning of this troper's fiction, this trope usually is why immortality (even with eternal youth) is a curse for some slight to a GodOfEvil or sufficiently powerful EldritchAbomination, or possibly on the offspring of such a person. Said person, if good-aligned, usually dates back to Dark Age Viking era or some such a period, or if evil, may date back even further, to Egypt, Sumeria or (depending on the setting having those myths in the background) even ''Atlantis''. The evil immortals usually wish to TakeOverTheWorld using ancient magic and forgotten science, using a few tricks to disguise themselves or go unnoticed with their followers both immortal and mortal - whereas good immortals usually are either trying to stop the evil immortals and perhaps seek a get-out clause for their immortality in doing so...at least, that's the story this troper is planning someday...

In the stories this troper is writing, one of the characters, a dragon goddess makes a deal with Death to live forever. Realizing this trope, she adds an escape clause, suicide. What she didn't know at the time was that, because of her title and the way the spirits work, she can't kill herself. This wouldn't be so bad if her mate didn't die and she didn't have an unfortunate habit of befriending humans. Even before gaining immortality she fell into a MayflyDecemberRomance issue with a human she met when she was eighteen, who was the same age as her. Since dragons age slower than humans, she's more or less a toddler or a young child while he's nearly an adult, preventing it from ever becoming more than a friendship. He lives long enough to see her lay her first clutch of eggs then passes away quietly as they take one last flight together. She'll spend the rest of eternity wishing they had met after she had stopped being a 'small(age wise) dragon.'