I think this is physics based(?), but I thought of this question during my summer chemistry course, so I wasn’t sure of the flair.
In: Physics
Energy should stay the same, even as the universe expand, things just get colder, eventually causing the heat death of the universe
I don’t think these two concepts really play nice together. The first law does require the system to be constant, because energy depends on your reference point. For everyone on Earth it’s stationary in space and Earth’s kinetic energy would be zero. Look at Earth from the sun and it would be moving very fast, I’m gonna guess it like 40,000 m/s something, suddenly the Earth has a lot of kinetic energy.
Look at the sun from the Milky Way’s center and suddenly the sun is moving at like 200 km/s something and the Earth would be moving at speeds up to 240 km/s, a insane amount of kinetic energy.
Has the kinetic energy of the Earth changed? Yes it went from none, to a lot, to a ton. However, your system also changed and those numbers are in no way comparable. The easiest way of getting out of answering this question would be that if the system is expanding, your system isn’t constant. (Energy is being added in the form of dark energy).
Physicists really hate this question though, it’s always been a pain in the ass for them. This is because thermodynamics is built on quantum mechanics and in quantum in nature. The universe mostly just functions with gravity. Quantum and gravity don’t play nice together. A working theory of Quantum Gravity is what physicist have been trying to find for the past 50 years and so far they’ve been very unsuccessful.
This is an excellent question with a surprisingly deep answer.
The short version is, the total energy in an expanding universe **is not constant**. For instance, when light from a distant galaxy is redshifted to lower energy wavelengths by traveling through the expanding universe, that energy doesn’t go anywhere, its just *gone*.
This can seem a little startling, Conservation of Energy is held up as one of the unbreakable laws of physics, but it actually comes from an even deeper relationship that most people have never heard of.
In the 1920s mathematician [Emmy Noether](https://en.wikipedia.org/wiki/Emmy_Noether) was interested in *why* the various conservation laws that scientists had discovered would be true. She managed to prove that any system–including the universe–that has a certain type of symmetry would have a resulting conserved quantity, and showed how to calculate one from the other.
In the case of energy, the symmetry is called “Time Translation Symmetry”, which just means that the laws of physics work the same no matter *when* you perform an experiment; today, last week, 20 million years in the future, whenever.
However, on *Cosmic* timescales of billions of years, this isn’t true. The universe used to be hot and dense, a soup of high energy particles blinking in and out of existence, and now its cold, dark, and mostly empty. You can experimentally determine *when* you are just by looking around. This means that Time Translation Symmetry is broken on very long timescales, as long as the age of the universe, and so on those same timescales energy isn’t exactly conserved.
This doesn’t show up in day to day life because our lives are too short for this to have any effect, but its real. Don’t get your hopes up for a perpetual motion machine or anything like that though.
That’s an easy one, ironically. The total energy of the universe is 0. In physics terms, we say the universe is flat. They mean the same thing.
It seems strange, considering that matter, radiation, and dark energy all contribute to positive energy terms. Worse yet, the amount of energy in our visible universe due to dark energy is increasing! However, gravitational potential is negative, and exactly balances with all the positive energy terms. Even as the total amount of dark energy increases, the negative potential of gravity gets larger as well.
The other thing to remember is that the energy of a CLOSED system is constant. But the universe is not necessarily a closed system.
That is a question that will probably win you a Nobel Prize if you can answer it. The reality is that nobody knows.
What you’re talking about is exactly the thing referred to as “dark energy.” The vacuum energy of the universe is, indeed, constant and the source of that energy is dark energy – “dark” here meaning “unknown”.
Side note: dark *matter* was originally called “dark” because scientists initially thought it was normal matter that is literally too dark to be seen on telescopes at the time, but that theory has been ruled out. Since then, “dark” in that context has taken on a new meaning which is “unknown” or “not understood” or “doesn’t interact with normal matter probably.” Dark matter and dark energy are not related (probably), they just share a similar name.
Dark energy might be the *cause* of the expansion. It could be that some constant source of energy is pumping energy into our universe, which causes its expansion the way blowing air into a balloon causes it to expand. Or, dark energy could just be a consequence of it – some property of spacetime causes vacuum energy to be constant, so as the universe expands dark energy is created by some unknown process or drawn in from some source outside of the universe – like how drawing a syringe pulls liquid into it.
It should also be noted that dark energy isn’t usable in any way. Energy only does work when it goes from places where there is more of it to places where there is less of it. The vacuum energy despite not being zero is still the least concentrated that energy can be, like the ocean being the lowest point that rivers flow too. So although dark energy means the energy of the vacuum remains constant the universe will still eventually run out of energy that *does* anything. Dark energy isn’t reversing entropy, in other words.
From my understanding this law only applies to closed systems. Given that we know we don’t know everything about the totality of our universes energy system, dark matter and dark energy being two examples, we cannot evaluate wether or not it adheres to this principle of nature.
I could be way off on this one but an analogy that may make sense would be a water balloon?
so the universe has a constant amount of energy right but let’s say some how all of it (a gallon of water for example) was squeezed down into the size of a pea then let go… the gallon of water forced into a pea size would obviously expand very quickly and make the water balloon expand with it but ultimately the amount of energy (the water) would stay the same. as it gets stretched it becomes calmer and more relaxed as the pressures are released but instead of happening instantly it takes trillions of years if not more to happen.
i would like to hear from anyone else that knows more on subject if this is a correct way of thinking.
The answer that makes sense for me is that it’s not that things are moving farther apart, it’s that space itself is expanding. It’s like you have an object that’s a meter long, space stretches so that the object appears 2 meters long, but the mass doesn’t change
The non-uniform expansion of the universe is evidence against the notion of an isotropic Big Bang. Dark energy makes the notion of a Big Bang superfluous.
[Black holes banish matter into cosmic voids](http://www.spacedaily.com/reports/Black_holes_banish_matter_into_cosmic_voids_999.html)
>Some of the matter falling towards the [supermassive black] holes is converted into energy. This energy is delivered to the surrounding gas, and leads to large outflows of matter, which stretch for hundreds of thousands of light years from the black holes, reaching far beyond the extent of their host galaxies.
Our visible universe is in the outflow of our universe’s hypermassive black hole. As ordinary matter falls toward the hypermassive black hole it evaporates into dark matter. It is the dark matter outflow which pushes the galaxy clusters, causing them to move outward and away from us. The dark matter outflow is dark energy.
The galaxy clusters which have been pushed for longer than we have are accelerating outward and away from us. We are accelerating outward and away from the galaxy clusters which have been pushed for less time than we have. From our perspective most of the galaxy clusters are accelerating away from us.
Dark energy is the dark matter outflow associated with our universe’s hypermassive black hole.
You toss a bunch of ping pong balls into a fast flowing stream. As long as the stream is flowing faster than the ping pong balls the ping pong balls are going to accelerate. As the ping pong balls empty into a lake, again, as long as the stream is flowing faster than the ping pong balls, the ping pong balls are going to continue to accelerate as they move outward and away from one another.
In the analogy, the fast flowing stream emptying into the lake is dark energy, the water is dark matter and the ping pong balls are the galaxy clusters. The ping pong balls displace the water. The water pushing back and exerting pressure toward the ping pong balls is gravity.
[Dark flow](https://en.wikipedia.org/wiki/Dark_flow) is the outflow along the pole of the hypermassive black hole, concentrated along the axis.
[Cosmic Void “Pushes” Milky Way](http://www.skyandtelescope.com/astronomy-news/cosmic-void-pushes-milky-way-3001201723/)
>Astronomers have discovered a giant cosmic void that explains why our Local Group of galaxies is moving through the universe as fast as it is.
The void is where the dark matter is able to flow through unimpeded, pushing the Milky Way.
[The universe may have been born spinning, according to new findings on the symmetry of the cosmos](https://phys.org/news/2011-07-universe-born-symmetry-cosmos.html)
>If the universe was born rotating, like a spinning basketball, Longo said, it would have a preferred axis, and galaxies would have retained that initial motion.
Is the universe still spinning?
“It could be,” Longo said. “I think this result suggests that it is.”
The universe has a preferred axis of rotation because we are in the outflow of the hypermassive black hole.
[Astronomers discover mysterious alignment of black holes](https://www.sciencedaily.com/releases/2016/04/160411130033.htm)
>Since these black holes don’t know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe
The reason for the alignment is due to the galaxies being in the outflow of the hypermassive black hole.
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