Is there a reason for the amount of stuff that there is in the universe? All the matter and energy?

Assuming the universe is finite, why couldn't there be a universe comprised of just enough energy and matter to make say, a handful of atoms? Or 10x the amount of stuff that exists, even accounting for what's beyond the observable parts?

If the universe is finite, then what do you think are the implications of the quantity? Like even if some energy was converted into matter and vice versa, the total sum must be there.

Previously I made this graph in Desmos which you can adjust the inputs to get parameterized solutions to the Friedmann equations for conventional mixes of matter, radiation and a cosmological constant:

https://www.desmos.com/calculator/jcbuq6jdap

Since then I've done a version that gives a broader range of solutions, that can demonstrate alternative models for dark energy.:

https://www.desmos.com/calculator/0obfzuky2x

In addition to parameters for radiation, matter and a cosmological constant, there are 3 components with the CPL w0wa parameterization of the equation of state (NB setting w_a to zero gives a perfect fluid with equation of state w_0)

Its presentation isn't as good as the first one and particularly I haven't done much to fix the mirroring of solutions where H_0 goes to zero at some point or points. This can be fixed by hand for a particular solution, or the mirroring can just be turned off.

The LCDM model is the purple dotted line and the default parameters for the green line shows a simple alternative model to the LCDM with time-varying dark energy.

The observable universe is 46.5 billion light years and we simply can’t see past that, but surely something, likely more galaxies are past our own observation range.

Surely advances in technology will increase are observation range or is there a specific, cosmic, hard limit to our viewing range for a reason?

Another thought, but as the universe grows older, will that in itself, increase our own viewing range?

Just before I start, i really don't know whether that's the correct subreddit for this post, so if you think it is inappropriate here, tell me in the comments.
Also, I am very new in cosmology and astronomy, therefore the whole theory may be bullshit, and for that tell me as well in the comments.

Yesterday, while i was reading "Brief Answers to the Big Questions" by Stephen Hawking, some weird theory came to my mind, about the origin of the universe and what was before that.
In the first chapter "Is there God?", he mentions that before the Big Bang happened, there was no time, no space and certainly nothing. (He also mentions the theory of negative and positive energy and how it adds up to zero.)

From what we know, black holes also have no time, however they do have a lot of mass and positive energy*. They have so much mass, that it curves the light, and if light or pretty much anything gets in them, it cannot come out.

My theory comes here, that universes are contained inside different black holes, and ours as well.
And that's the reason they contain so much mass. Also that's the reason why we cannot se before the Big Bang, because we were in a black hole.
In the beginning, it is said that the expansion of the universe was faster than the speed of light, meaning mass can travel faster than the speed of light. How did that happen? Could it be that our universe came out of a black hole and started expanding beyond?

I imagined it, like a sine wave. At the beginning, it's going vertical and after that it reaches a solid top, after that it compresses and enters a state of black hole and continues in the same cycle.
(However, I think this thing about the sine wave, is bullshit but felt sharing it)

I will say it again, i am very new in this thing, so please be easy with me :D
I really want to hear, what you think of this theory and if anyone thought of it, I will be more than grateful to learn about it.

* I am using the words "energy" and "mass" with a similar meaning, because of Einstein's E=mc^2

I don’t have a strong physics background so bear with me please this question is gonna be dumb but I gotta ask it for my sanity.

Does gravitational lensing only occur only on a large scale or can it be seen (or calculated) on a smaller scale too? My reasoning is that since everything with mass warps spacetime, even on an atomic level a single atom should have some effect on the direction of light. (Right?)

Imagine a vacuum with a single atom of some arbitrary mass and some light approaching the atom tangentially without being absorbed. Since the atom has mass it technically warps spacetime to some degree even if it’s considered negligible. If that’s true then the change in direction of this light should be extremely small but not 0, right?

Essentially is there a minimum mass required in order to actually start “bending” the light? I’ve always assumed there wasn’t from what I’ve been able to pick up. Do we ignore this because it’s so unbelievably small it doesn’t matter or because it doesn’t actually happen on a small scale at all?

The speed of light is amazingly fast. You can circle the Earth 7.5 times in one second at that speed. The distance to the moon is 1.3 seconds. The distance to our own Sun takes 8 minutes and 17 seconds. At that intense speed, imagine travelling through space for one hour… how much distance you would cover. Then imagine one day. One month. A year. This helps us to understand and visualize the great vastness of space, the endless and eternal void.

The average distance between stars are light years apart. The nearest star to us, is 4.3 light years away. If you zoom in on a galaxy, you will see thousands upon thousands, millions of stars. Just knowing that the average distance between each point of light is light years apart is mind boggling… staggering.

Watching high resolution simulation videos of zooming through and in on a galaxy really helps put things in perspective. You will fly through endless waves of thousands of stars, as if they are sand. It will help you realize that galaxies are much bigger than you can even imagine.

I will say, if the entire Universe were the size of our galaxy alone, I would still be immensely impressed by its size. However, as it turns out, there are thousands upon thousands, millions, billions of galaxies in the Universe. All of immense size, all separated by the massive void and emptiness of space…

People ask, “Are we alone?” Of course not. Our Universe is beyond massive, filled with endless possibilities for life… A better question is.. “I wonder what life on other planets is like?” Perhaps more like us than we think. Planets with extraterrestrial animals, dinosaurs, or even human forms much like us. And of course intelligent life, all with cities and technology, probably much like our own.

People ask, “Why haven’t we been visited?” For one thing, you have to appreciate the massive distances in space… It would take thousands of years for any one to reach here. If we are being visited, it is more likely to be Artificial Intelligence, rather than any life forms. As well, we cannot ignore the experiences and evidence of UFOs on our planet. It is not a big mystery anymore… these things are real. Perhaps they don’t truly want us to know, due to the effect it would have on us on a global scale. However, one thing is certain… our Universe is filled with endless opportunities for life.

It is best to be imaginative open minded when it comes to other species in the Universe. To think of us as being alone is primitive. Once one can appreciate the immense size of the Universe, the possibilities are endless.

I hear about new stars being formed from the remnants of dying stars all the time, but do we have any idea what the average number of stars that is? Let's use a star that's 10 solar masses as an example.

It occurred to me that the common definition of the universe (ie. everything) doesn't answer this: As light energy travels in every direction, the universe would necessarily expand, assuming light qualifies as something that can exist only in the universe.

I'm not trying to stir a pot about definitions or semantics. If light has been emitting at its nominal speed since the fog lifted, would it resemble the rate of expansion we observe now?

Hey, I'm a student doing post-graduation and my area of interest is in cosmology. Unfortunately, my institute doesn't have professors who are into theoretical physics/cosmology and I've been trying to get a proper lead for the thesis. I've been wanting to work on either Hubble tension or Dark Energy-Hubble constant relation. Need guidance with what's the best I can do here? Any leads regarding how to do the right literature review(tho i've gone through some papers already) and collect data from the web for same. Is it realistic to derive data from DESI and be able to work on it?
Any help would be appreciated. Thank you.

Let's say humanity has the opportunity to send a mission anywhere in the universe to study and/or explore.

You can imagine different reasons for that: the limited resources on Earth allow for only one mission of this scale, or perhaps due to time dilation, humanity can only plan a single mission that we know will return before the end of our species.

Whatever the reason, the task of finding the most interesting place has been given to you. Where would you send the mission, and what makes that place so interesting for you ?

question in title. if dark energy is supposedly dynamic and this is continued to be demonstrated with future DESI findings, what implications does it have on the fate of the universe and our current cosmological understanding? does it undermine the probability of heat death?

I don't understand how the Hubble diagrams of SN1a imply that the universe is expanding at an accelerated rate.

Let me explain my reasoning:

1 - From the Hubble diagrams we deduce that the supernovae are further away than they should be if the rate of expansion of the universe had always been the same as it is now.

2 - This means that they have traveled further than they could have if their recession velocity had always been the same.

3 - Since they have traveled further than expected, we deduce that their recession velocity was greater in the past than it is now.

4 - Therefore their recession velocity has decreased over time, that is, the universe has expanded more and more slowly: the expansion has decelerated.

What am I getting wrong?

Ah yes, let me just grab my Cosmology for Dummies manual and turn to the chapter on "Mysterious, Unseen Forces That Laugh at Our Attempts to Understand Them." Dark energy isn't pushing, Karen, it's expanding the very fabric of space itself. But sure, let's compare it to blowing up a balloon because that totally captures the terrifying existential complexity. 🚀💀

Is energy conserved? We demand it be conserved locally, but what about on cosmological scales? If the universe is expanding, where is energy loss due to redshift “going”/ how is it transferred? Is it transferred?

Estou lendo bastante sobre a morte térmica do universo e gostaria de entender mais sobre isso. Gostaria de dar um foque filosófico também a questão… Pelo que li, no futuro, com o universo em expansão chegará um momento que até as mínimas partículas serão separadas, estrelas ja não vão mais existir, nem buracos negros, etc etc

Existe alguma forma, mesmo que teórica, ou fantasiosa, dos humanos do futuro adiarem isso? Ou mesmo remediarem? Sei la, mantendo estrelas vivas sei la, ou criando estrelas em laboratório nao sei.

Eu tô com uma crise existencial. Tipo, pra que tudo vai existir mesmo sem ter ninguém ali pra viver? O universo inteiro viverá sem vida nem nada um vazio total?

hey! I’m very interested in cosmology and everything that relates to it. I was dreaming of being an astronaut as a kid but then due to personal family circumstances I gave up that dream and interest completely. as a result I know literally nothing more than the basics about the universe. are there any good resources, documentaries, books, posts that I should look into to get some insight? what do you recommend?

Hello all. I truly hope that this question is not completely idiotic,.

Today, I learned about gravastars...which isn't great because I've spent the last 30 years unsuccessfully trying to wrap my brain around black holes.

From what I understand, gravastars only exist in theory as a third result of a collapsing star.

From what I understand (in a very simplistic way), a gravastar is a bubble full of extremely dense nothing.

I completely do not understand that. Is there any way that anyone can explain to me (like I'm five) how "nothing" can be dense?

Thank you very much for your help.

edit Thank you everyone. The universe is amazing. It is up to greater minds than mine to try to comprehend it...and I'm always rooting for those greater minds.

I always go back to this:

"There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.

There is another theory which states that this has already happened." -Douglas Adams, The Restaurant at the End of the Universe

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Black holes seem to be detectable only when they are gobbling up surrounding matter. Is it possible that there are a large number of small isolated black holes. If so, could they be detected by transient deflections of light from background stars.