Is it possible for one to live eternally?

There is still so much we don't know, but I doubt eternal life will ever work out. I know people are expected to live longer once we find more cures to stuff and more technology, but living FOREVER... The world is going to end at some point. Even if we did put someone's brain into like a robot or something, it'll still die. But hey, nothing is impossible until we really prove it!

I don't know why anyone whose lived on earth more than a year would want to stay here forever. Why prolong the suffering? Sure there's lots of beauty in life too but even that is passing and ethereal. The Bible is filled with images of heaven and describes in a very limited way the joys that are to come after this life if we've lived well. I believe in the mortal body which will die and decay but houses temporarily the soul which is eternal.

I agree

Immortal beings already exist. They are called "trees". Technically trees do no die because of age, although trees can get weaker over time, although I must note it depend per tree breed. Oaks in particular are known to last forever if the conditions are right. Some Holy Oaks that believers of Wotan prayed to still live today. Since the Wotan religion was driven out by Christianity approx 2000 years ago, that tells us something, eh? What is important to note is that "immortal" is not the same as "invincible", the two terms are often mixed up since gods are usually both, and some entities encountered in mythology and fantasy stories are both.

There are also a few constraints. Human memory for starters cannot be infinite... Someday it must reach its limit and how are you gonna live on then? And a lot of scientists say that even the universe as a whole must come to an end eventually, although there is no full consensus on that one yet.

Of course. Do you want to live forever? To quote Q (not THE Q) from Star Trek Voyager in the episode "Death Wish": "They haven't spoken to each other for 6 billion years. And why should they? Everything there is to be said, has been said".

In theory anything is possible, but what is realistic?

Maybe, but who would would want it anyways?