Is the universe eternal with no beginning; or is it like all other life forms with a beginning and an end?

It’s eternal. Whatever there was, was the universe….and whatever will exist in the future is another version of the universe. “Nothing” doesn’t exist in this context.

A universe may have a beginning, but depending on how it is defined likely has no end.

^^In the same way, life on earth has no end whereas everything is re-purposed in one form or another (the cycle of life). We just haven’t discovered, as yet, exactly how the Universe began.

When you say “the” universe I assume you’re speaking of the one we inhabit.

“End” can be thought of at least two ways. End as in expiration or end as in outer limit.

Expiration: The universe becomes so diffuse in it’s expansion that time itself has nothing left it can influence.

Outer limit: The “edge” of the universe is not only expanding, it is accelerating. But here we still have two definitions. The edge of the universe we can actually see “live” (limited by the speed of light) and the outer remainder that we can see some of as the universe’s expansion catches up with light from extremely distant and fast objects.

Odder still it seems the universe has the capability of expanding into itself.

The Big Bang Theory posits there was a beginning, approximately 13,800,000,008 years ago. (The 8 years is because the age was published in the NY Times in 2008, and we know that is The Newspaper of Record on all important matters.)

No beginning, no end. It always was and always will be with no boundaries in any direction. I believe there may have been countless “Big Bangs” since time is like the universe.

No one can say with any certainty that the universe will or will not eventually end. What we call the universe may be a bubble in a larger universe.

If we accept that the universe is everything that is, was, and will be, then it how can it not be eternal.

The fabric of the universe is space time. The universe is eternal because it contains all the time there is. There was no time before it and there can be no time after it.

I’m a little behind on the layman explanations of the latest theories, but from what I understood, scientists have been able to look farther and farther out (so farther back in time)—and the farthest they can ever get in any direction is 13.8 billion years ago—hence that dating of the universe—and the universe looks quite different that far back in time… things are less differentiated, more compressed, hotter, etc… even if the big bang theory gets overturned, even if the “universe” itself has existed without a beginning, I would presume we’ve got some particular epoch or era (or whatever you call a time period of at least 13.8 by) that had a beginning or transition-into of some sort, and probably (when the stars all burn out, etc., etc.,) will have an end…

I’ve never been able to believe in eternality or infinity. Even in mathematics, infinity always seemed more like a concept than a thing to me—a way of saying “and it’s still going, past what we can see or measure or even comprehend”—but I’ve never been able to believe it literally means “forever.” I can conceptualize a big bang that started the universe as we know it (with our matter, our physics)—a universe that is expanding and will expire in one way or another (there are several theories on that end as well.) I can conceptualize a spatial arena of “nothingness” that lacks our (four) dimensions until something carves and stretches them into being. Alternatively, I can conceptualize “it’s still going”—a universe that just keeps going, with different “epochs,” and we’re just a part of the current one, and we can’t comprehend the beginning or the end… I can even conceptualize a universe that has no boundaries whatever, just keeps going forever, but I don’t really believe that last conceptualization. I still believe there’s a beginning and end, and I still believe our universe is spatially finite, (though expanding in size and age continuously). Maybe that’s a limitation of my psyche, but there it is. For whatever reason, I can believe in the eternity of nothingness. Just not the eternity of matter—and the universe to me is only the matter.

“All other life forms” Is the universe a life form ?
I think most scientific points of view consider the universe a phenomenon with particles and laws of physics, but not a life form.