Universe expanding Definition and 46 Threads

Hi, I'm aware of the measured recession of the galaxies in our universe and the universe expansion itself cannot be understood as an "ordinary" velocity/speed (for instance in the FRW solutions of Einstein's equations). Can you kindly help me clarify this topic ? Thank you.

I was wondering if someone could answer my question. I know I may be dumb but I don't really understand why our universe has a limited capacity for mass. If I remember correctly black holes occur when concentration of mass causes a hole in spacetime. I don't really understand I guess how space...

As we know universe is everything having every matter and energy. From the observation using Hubble's law it was said that the galaxies are moving away from the Earth which means the universe is expanding. If it is everything then what is it expanding into. Is there some outer edge that it can...

The universe seems to be expanding since the farther away an object is, the faster it is moving. However, because of the finite speed of light, the farther away we look in distance, the further back in time we look. Does that mean that galaxies were moving faster in the past and are now slowing...

How can the universe keep on expanding if it's infinite? Expanding metal, like a cube of aluminium, has a surface area which forms a border for the matter contained inside. So the universe must have a border for the matter it contains.

Is it expanding from the edges? Or from the center?

Normally when one is asked what is the universe expanding into, the answer is its not expanding into anything. Space itself can expand. However In the context of eternal inflation, our universe is a bubble in a sea of inflating space. And hence assuming eternal inflation is right, does the...

hello there, I am totally into all astrophysics. so I want to know, how fast is the known universe at the most outer edge moving? or in other words, how fast is the most outer edge expanding away from earth. - and what's the rate of acceleration? I mean even if, as I understand it, the space...

Could anyone please guide me how to do these problems?

Neutrinos were flavor eigenstates at the time of their decoupling from baryonic matter. Since they were not pure mass eigenstates, how do you take this fact into account if you try to study how they evolved as the universe expanded? Could we determine if the heaviest neutrino could be non...

I can not find a paper on this, but is it possible that the universe is expanding faster than expected? https://www.sciencedaily.com/releases/2017/01/170126132624.htm Because galaxies do not create perfectly spherical distortions in the fabric of space and the lensing galaxies and quasars are...

Once again I am reading and trying to understand more about the different theories of the beginning of time/space. I don't know why I never thought about this, but they say that galaxies are moving further and further away. One day we will not be able to see them because they moved so far. My...

http://www.ox.ac.uk/news/science-blog/universe-expanding-accelerating-rate-%E2%80%93-or-it Now, a team of scientists led by Professor Subir Sarkar of Oxford University's Department of Physics has cast doubt on this standard cosmological concept. Making use of a vastly increased data set – a...

If space is expanding wouldn't that violate the first law of thermodynamics

Here they use information gathered form Cepheids, are these parallax measurements accurate? From science daily. Date: June 2, 2016 Source: Space Telescope Science Institute (STScI) Summary: Hubble Space Telescope astronomers have discovered that the universe is expanding 5-9%...

If you measure the red-shift of a star 10 million light years away, you measure the velocity of the star 10 million years ago when the stars were traveling faster (if we are willing to accept that the expansion of the universe is slowing down). This not such an outrageous idea since firstly it...

Well I'm just a high school student but I'm very passionate about Astronomy. I usually ask myself that into WHAT is our Universe is expanding if the expanison theory is true ! I'll be waiting for responses..

I know this question is quite odd as we're still researching on this, but is the universe speeding up, aka, accelerating? Or is the speed constant? Or is it slowing down? Thoughts? (PS - I don't know what the prefixes B I A means, I have chosen a random A, please consider if it's wrong, am...

then where light transmits to in the universe? Does that mean the universe expanding speed is at least light-speed? Because we know light is energy, it is part of our universe. As if it is like this, the universe expands endless and will become cold and dark. It sounds impossible to me

I am looking for reliable information about the functional dependence of the diameter ##d(t)## of the visible universe on the time ##t## since the big bang singularity, based on the different hypotheses currently deemed competitive.

If temperature of universe is cooling then why universe is expanding.

We all know the concept of the universe expanding. Would it be possible that the universe is not expanding at all, but the spacetime between objects is increasing? My question comes from the idea that spacetime is changed due to the presence of gravitational objects and the idea that gravity is...

Hi, I joined this forum because I love learning new things about our universe and I often have questions like the one I'm about to ask. Also I would like to state that I haven't taken any physics classes so terms and advanced talk will be beyond me however, because I am so interested in...

I have been looking around people are talking about the universe expanding. By geometry we are able to figure out that the universe is infinite. The question is, if the universe is infinite than how can be expanding?

we all know the that the universe is exapnding. But where it is expanding?

Hey i am new to the forum but i have done some studying and I am trying to wrap my head around something but I am not sure if I am quite getting it i was hoping if someone could direct me to some reading or books, and so here it is, i was recently explained to that as the universe is expanding...

Due to the doppler effect, when the source of the sound is moving away from the observer, the sound waves are spread out. Light waves also hace this effect and when a star or galaxy is moving away from us, we see the light wth a slight reddish tint. So my quesion is, does the expansion of the...

Hey all, Just to make it clear I am in no way a scientist or physicist but a mere space enthusiast. Yesterday I noticed when I was making some lunch that oil in my frying pan starts to ''run away'' from the center of pan towards outer side when heat gets just a little bit higher, since pan is...

ok, here it goes: this afternoon, wandering on wikipedia I stumbled across a 3D projection of a rotating tesseract I spent some time looking at it, then i started thinking about the universe. a bit of context: I've always been passionate for astronomy. I like to read about other planets and...

a)since universe is expanding is today's 1 meter different from tomorrow's 1m? b)since distant between any 2 points is increasing is the universe expanding into 4th dimension?

can anyone tell me why is the universe expanding faster and faster and not slower and slower or moving at a constant speed ,if a bomb explodes everything close to it accelerates away then slows down as time moves on ,in the void of space i would think things would just carry on expanding not...

I was wondering because of my personal theories what others thought of the universe expansion. please help

so, many shows on tv today that keep suggesting our universe is expanding. is it really? 1. if you can say "it is expanding" doesn't that imply you 1st have to know how big it is now, then make a observation (measurement)? so if the universe is already infinite in size how can anyone say its...

gravity pulls two galaxies. Andromeda and Milky Way are going to collide in few billion years. this seems to show that everything in the universe is moving close to each other i.e. contracting. but, since the universe was formed, it has been expanding due to dark energy. how do you explain this...

Redshift measurements show the universe is expanding, and the rate of expansion has been accelerating since 5 (is that the correct number?) billion years ago. It occurred to me that instead of space expanding (a concept with a few unresolved problems such as what is dark energy?), the same...

Hi I understand that the universe is expanding due to hubble's constant and the proof that this can show that the universe is expanding, i just would like to know what physicists suggest the universe is expanding into? Thanks

When it is referred that the Universe is expanding/accelerating outward, do they mean to say that space is expanding or that matter is accelerating outward through space?

can anybody explain this to joe public?

I was thinking of an idea in my head about a week ago, but it would need the rate of the expansion of the universe to increase over time (this is different from it just expanding at a constant rate). Today, i was reading about dark matter and it had stated that it might be the reason why the...

I read it is possible for the universe to be expanding faster than the speed of light. What would be the implications of this?

What allows the universe to expand faster than the speed of light? What force will slow it down, causing it to start contracting on itself?

I know the Observable Universe (OU) is Expanding, and I think this is (by now) beyond dispute. However, there is no evidence at all to show that every part of the Universe is expanding. Perhaps the Universe as a Whole (UAW) is not expanding at all. What if it was contracting? What if...

I know it's been proven beyond all doubt that the universe is expanding but one thing is bugging me. Why isn't the Earth (and the other planets for that matter) moving away from the sun due to this expansion? Maybe this is a daft question but I can't think of an answer. Can somebody please explain?

First, a quick note to explain why this question is being posted in the "Beyond the Standard Model" forum, as opposed to the relativity forum. Many studies of relativity discuss the expansion of our universe, but I haven't seen many which explicitly target the question of what our universe is...

I'm trying hard to find a decent explanation for someone that an expanding universe doesn't mean that galaxies get stretched out and made bigger; that the planets won't get further away from the sun; that we don't grow bigger etc. I've googled and searched about but a decent explanation of...

I may be out of touch, but I don't think I've ever read it for sure so what are your theories on this? I mean the big bang theory may provide the inertia to expand but why at an accelerated rate? What force is being added if any to accelerate this expansion and where does it come from?