Anonymous
Anonymous asked in Science & MathematicsPhysics · 1 month ago

# How do scientists know the universe will end?

There are multiple theories on how it will end, the big rip, heat death, etc.

How do they know this though? I've always been told humans cannot possibly comprehend the universe and on the time scale of trillions of years these theories make no sense.

Even if they project these events from axiomatic things like math, there are plenty of things out there that don't play by the rules of math or physics (e.g. black holes) and those of both man made anyway.

Update:

I see what you're saying, but I never brought up religion or questioned the scientific method itself.

I'm just a bit confused at the know it all mentality that seems to be coming from a lot of people I talk to.

### 11 Answers

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• 1 month ago

Peter Gore Seer,

The Start And The Stop, Revers The Argument,Stop And Start,It Makes No Sense,

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• 1 month ago

there are many theories by which scientist can calculate.

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• goring
Lv 6
1 month ago

There is approx one trillion galaxies in the observable physical universe. Galaxies are just group of stars.When one star gives up another star lights up.

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• 1 month ago

Everyone is making this into a deep philosophical thing.

The "end" of the universe is generally "the point in which life can no longer exist" and is calculated statistically and using logical conclusions. It can be divided into 2 cause and effect logical conclusions.

1) Certain conditions are required for stars to form, at a certain point, entropy (everything gets more spread out) will cause these conditions to no longer exist

Thus: Eventually, the universe will no longer have the ability to make stars

A simple way to put it:

Stars are made of matter, of which there is a finite amount

Thus: eventually, the atoms will be too far apart to form a star

2) Stars have a finite life span and every star will eventually die

Thus: Once no new stars form, the number of stars will decrease until there are eventually zero.

How is there a date for all of this?

There... really isn't. Using statistical trends, we can determine an approximate number of years until this occurs. It is in the trillions to quadrillions of years. Much longer than we can even imagine, many times longer than the universe has currently existed

The true "end of the universe" will likely come with proton decay. We know protons decay and the approximate rate at which they do so, and as such, we can conclude around the time where atoms will no longer be able to form... Which is in ~10^100 years.

How do we know when the universe began:

This one is really easy. Light. Light is, as far as we are aware, the fastest thing in the universe. We can see light as far away as 13.8 billion light years. Light travels one light year in a year. As such, we can approximate that the universe has existed for 13.8 billion light years as, if it existed for 13.7 billion light years, we wouldn't be able to see what we do as the light could not have traveled from there to here. If it existed for 13.9 billion years, we would be able to see more.

Of course, this is an approximation as there are a number of factors we can't account for, such as if the big bang exceeded the speed of light.

Overall, its pretty sound science, but is subject to change if we learn anything new. Though, don't expect the lifespan of the universe to increase, it'll likely only decrease as we learn more. The age of the universe will only increase as we learn more by the same token. We understand and comprehend the universe, just what we assume to be a very small chunk of it. We can determine when the chunks we understand will cease to exist, and thus, when the universe will "end"

Also, black holes play by the rules of physics, as do quantum physics... just a different set of rules. You can't apply Newtonian physics to quantum particles or visa versa, they play by a different set of rules. Black hole are a mystery in many respects, but we understand how they work and act and form. It is determinable by mathematics and physics.

Hope this helps

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• A.J.
Lv 7
1 month ago

They can speculate on theories, some of which have better scientific basis. The exact method of the beginning and end of the universe is purely academic. There is little application meaning. There is far more evidence about the end of the Earth and Sun and our projected motion of Milky Way intersecting into the next galaxy.

You can look up about the cooling of the Earth's core and its effects. And you can look up star stages for what the Sun becomes and how it affects the Earth.

For other catastrophic events, try the Yellowstone supervolcano, solar ejection striking the Earth, and an errant meteor strike.

The Earth with human life will not exist forever.

It is one of several reasons I lost belief in any religion.

It makes time seem more precious.

If human life on Earth is gone, what happens to the universe as a whole after that won't have anyone that cares about it.

• Andrew Smith
Lv 7
1 month agoReport

But the religion does not solely view the universe in terms of humans alone.  Perhaps God is smarter than us humans and can realize when he made a bad mistake.  Get rid of us and try again with something else.

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• Anonymous
1 month ago

They are called theories.

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• 1 month ago

Nobody knows what will happen to the universe in trillions of years. There may be laws of nature we haven't discovered yet.

Those end of universe stories are extrapolations of what our current theories predict. But no one (that has scientific education) says any of those ideas will actually happen.

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• Damien
Lv 5
1 month ago

Its all theories, guesses, although u do seem to be confused, they have mentioned how the earth will end case theyve seen other galaxies getting wiped out through telescopes, but they have never said how the universe will end cause that is just impossible for them to figure out since they are sitting here on earth and cant see to the end of the universe.

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• 1 month ago

Scientists don't "know" the universe will end.

In fact, it's not even clear that "ending" is even a meaningful term to apply to the universe.

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• Brian
Lv 7
1 month ago

Maybe. But at least their theories are grounded in science, and have some sort of rationality to them.

Unlike all of the End Timers on YA.

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