0
votes
2answers
92 views

How does measuring redshift make us conclude that rate universe expansion is accelerating?

The universe is expanding in all directions. We can detect this by the redshift of electromagnetic radiation from other galaxies. We detect a larger redshift in galaxies which are further away, and ...
0
votes
0answers
33 views

Is Dark Energy Pushing Us Or Pulling Us? [duplicate]

This may seem silly, but how do they know that the effects we are seeing from dark energy, (which we only assume must be there due to observed acceleration), are not from gravity pulling us out from ...
4
votes
1answer
33 views

Open Big Bang-less universe?

This came up in discussion around a class I'm taking. For a Universe with $\Lambda$ and matter contributions to energy density (and implicitly curvature, but no radiation), can you have a universe ...
1
vote
1answer
24 views

Does the rate of expansion of the universe exceed the rate at which the local group is being pulled toward the Great Attractor?

I understand that the expansion rate of the universe driven dark energy exceeds the rate at which the local group is being pulled toward The Great Attractor (Hydra-Centaurus Supercluster). Does this ...
0
votes
2answers
62 views

How does “space” expand? [duplicate]

According to Big Bang theory and The Red shift theory "space" is "expanding". Keeping this notion of "space" as physically something in and of itself(space -time did not exist before The Big Bang); ...
5
votes
2answers
305 views

Light takes too long to get here

When looking at the night sky, we see lots of stars. Several places tell you that the light of those stars has traveled to many light years to reach Earth and there may be others where light has not ...
0
votes
0answers
117 views

If nothing can travel faster than the speed of light, how can there be parts of the universe we can't see? [duplicate]

Assuming we originated from a single infinitely dense point in space time in the big bang, how can there be parts of the universe that we can't see as the light has not reached us yet, if nothing can ...
3
votes
1answer
106 views

Many times speed of light [duplicate]

http://www.huffingtonpost.com/2014/03/24/theory-of-everything-big-bang-discovery_n_5019126.html What does "many times speed of light" really mean in this context? For a layman it's easy to draw wrong ...
0
votes
2answers
54 views

Direction of expansion of the universe

From what I understand the expansion of the universe has no "center". If we're flying through space away from the "center of the big bang", there's basically no way to tell. Every two given points in ...
-1
votes
1answer
128 views

Can we have a static point in the universe? [closed]

Big bang theory states that the universe began from a single point (which we may consider as a central frame of reference for the objects in the Universe). In 1929, Edwin Hubble confirmed that the ...
-3
votes
4answers
244 views

Was Einstein wrong when he said nothing can go faster than the speed of light? [duplicate]

If the universe is constantly expanding faster than the speed of light, how could Einstein be right?
0
votes
0answers
24 views

How is the scale factor from the FLRW equation used with Volume?

I'm trying to put a spreadsheet together that shows the co-moving volume of the universe from the time soon after the Big Bang through the present and then as predicted into the future. I am pretty ...
1
vote
1answer
55 views

Acceleration of the Expansion of Universe

Is the acceleration of the expansion of the universe (AEU) uniform in direction? Meaning that if a particular direction in the sky is chosen and the AEU is measured and then other directions are ...
1
vote
2answers
114 views

How can space expand?

How can space expand when it is only a perception of the separation between at least 2 objects. Isn't saying "space expands" implying it has properties?
-1
votes
2answers
64 views

A way to determine the exact location of the Big Bang?

See What is our location relative to the Big Bang?, which contains the following: The conclusion is that the Big Bang happened everywhere, all at once. Phys.SE users Ali and WernerCD reached this ...
2
votes
1answer
69 views

If we were able to double the mass of the ordinary matter in the universe it will recollapse?

What will happen if we suppose to be able to add mass at the universe? For example doubling the mass of the ordinary matter?
0
votes
3answers
121 views

Space and the size of infinity [duplicate]

If you could build a spaceship and keep travelling in one direction, what would finally happen? One answer is that you would never ever reach the end. But this sounds purely platonic space and comes ...
3
votes
1answer
240 views

What is the universe 'expanding' into? [duplicate]

We say the universe is expanding, and by expanding we mean the distance between objects gets larger over time. We call that "Metric Expansion of the Universe". So far so good. I kind of get the idea ...
1
vote
2answers
60 views

Expanding universe and the peculiar velocity

Hubble's law states that the universe is expanding with a velocity equals Hubble's constant*distance from earth. But, recent findings show that the Andromeda galaxy is actually blueshifting towards us ...
3
votes
3answers
147 views

Faster than light galaxies/clusters?

A few years ago in an astronomy course, we calculated some (transverse?) velocity of a moving object and got super luminal results. The answer was apparent and not physical velocity of the object. ...
2
votes
2answers
108 views

Is it possible to detect if everyting in the Universe is changing size?

This may be a trivial question, but I cannot find a good answer to it. What would happen if the size of everything in the Universe is multiplied by some constant factor at the same time, let's say ...
1
vote
1answer
58 views

Speed of light's relation with the expansion of the universe [duplicate]

If nothing can travel at the speed of light and light cannot escape the universe, then the rate of expansion of the universe should be equal to the speed of light, why it is not?
-1
votes
3answers
144 views

Can the Cosmological Constant explain an accelerated expansion?

From what I've learned so far, it appears that all models that attempt to explain the expansion of the universe are either based on Lambda-CDM or quintessence. The former support a big bang with ...
2
votes
1answer
88 views

What is the equation for the scale factor of the universe, a(t), for the best fit of data to the $\Lambda CDM$ Model of Cosmology?

Ideally I like a single formula or multiple formulas for different time ranges that would cover the time from the end of inflation through 100+ billion years after the big bang using the $\Lambda ...
1
vote
1answer
137 views

Equation for Hubble Value as a function of time

I am trying to write the equation for the situation where the Hubble parameter $H$ would be changing over time. In other words, it would represent an accelerated expansion of the Universe. That is, ...
-1
votes
1answer
93 views

If the universe can expand at a speed faster than that of light, why don't we feel the effect? [closed]

the universe, as I have read, is capable of inflating at a speed faster than that of light! How is that even possible if we don't feel the effect? or does it affect us?
1
vote
1answer
116 views

Metric expansion of space - past, present and future

Scientists say that out universe is expanding faster and faster. This was detected via the red-shift effect. Farther galaxies are moving from us faster than those that are more closely. But how can ...
4
votes
1answer
282 views

Is there a center of the Universe if the Universe is finite?

Ok, let me make myself clear. I saw all the other questions related to the question, but none of them actually asks the question the way I would put it and therefore no one answers it the way I want ...
1
vote
4answers
227 views

The universe is expanding but why the galaxies have no motion?

It is said that the universe is expanding and the galaxies are moving apart. I understand that the space between every two galaxies is increasing. Doesn't this seem to imply that the galaxies will ...
8
votes
8answers
395 views

As the universe ages, will we see more stars or less?

After a very long time will we see more stars (due to the fact that more light is get to us) or less stars (as the universe expends and light have to pass larger distance)? In general, can stellar ...
0
votes
2answers
134 views

Big Bang, What is wrong with such thinking? [closed]

Also if I think the Expanding of Universe like this: At the Start : The Amount of Matter and Anti-Matter is equal and they annihilate and all we had is Large Amount of energy. But some 'X' Thing, ...
4
votes
1answer
279 views

Is “A Brief History of Time” still up to date?

I have recently found my copy of Hawkings' A Brief History of Time which I have never finished. This time I'm determined to read it all the way through. However, the book is now almost 25 years old. ...
1
vote
2answers
152 views

Does the black hole only increase?

I don't understand this: The more mass a Black Hole has, the more gravity it create! The more gravity it has, the more mass it can get! With this lines, someday, all the universe will be a black ...
1
vote
3answers
96 views

What happened to high temperatures in the universe?

We know that after the big bang the temperature was about 10^32 K. But now the average temperature of the universe is about 4 K. What happened to the temperature at that time? Where did it go?
0
votes
2answers
149 views

What is the universe expanding into? [duplicate]

Due to curiosity, it made me wonder what is outside of the universe, is it a new chemical or just empty space? But empty space have protons appearing and disappearing in it, it basically still has ...
0
votes
1answer
88 views

Why does a doppler red shift prove expansion?

My question boils down to this. If the Universe was contracting the stars closer to the center would move faster to the middle than stars that were further away from the center. That would also ...
2
votes
3answers
572 views

Scale factor and age of the universe

Why is the cosmological scale factor (expansion rate of the universe) not simply the time $t$, i.e. the age of the universe?
1
vote
1answer
150 views

What exactly is expanding when they say universe is expanding? [duplicate]

We know that universe is expanding and galaxies are moving away from each other. Does this mean the galaxies are also expanding in itself and therefore I guess growing larger in volume? Depending on ...
-1
votes
0answers
92 views

Are we travelling at a speed close to the light speed? [duplicate]

This is a question which has been puzzling me quite a while. There was a news report saying that the farthest galaxy spotted so far is at 13.3 billion light-years away, and it is said that the galaxy ...
9
votes
3answers
861 views

According to Hubble's Law, how can the expansion of the Universe be accelerating?

Scientists today think the expansion of the universe is accelerating. According to Hubble's law, objects further away are moving faster than objects closer to us. The further away an object is, the ...
0
votes
1answer
508 views

Is time slowing down and disappearing from the universe instead of the expansion of universe? [duplicate]

Are we fooled into thinking that expansion of the universe is accelerating, when in fact, time itself is slowing? Or if dark energy does exist?
2
votes
4answers
872 views

Is there anything physically infinite?

I can't think of a single thing that could be infinite. Because the universe is expanding, isn't it? But there is an ever-changing barrier, so why could there be anything infinite, both ...
1
vote
2answers
125 views

Is it possible that universe might not be speeding up expansion?

I'm not sure but I was thinking of galaxies shrinking with time while still moving apart from each other at almost a constant speed or less (i.e: uniform/slightly decelerating expansion). This may ...
1
vote
2answers
93 views

If everything in existence were increasing in size at some rate, would we be able to detect it?

Would our eyes observe any changes? What about electronic measurement devices?
1
vote
2answers
106 views

Could the outer structure of the Universe be made from Antimatter?

Cern recently stated that antimatter may be repelled by matter, much like the opposite effect of Gravity. So is it possible that antimatter is actually repelled to the edges of the Universe to create ...
0
votes
3answers
148 views

Acceleration in the rate of expanansion of the universe due to weakening gravity?

Could the acceleration in the rate of expansion of the universe be due to the weakening of gravitational forces, as the distance between objects continues to increase?
0
votes
1answer
52 views

Is dark matter expanding the universe, and creating the structures within it?

If dark matter repelled other dark matter, as well as regular matter(atomic or celestial), and regular matter were repelled by other regular matter "less" than by the dark matter, would not this ...
0
votes
3answers
215 views

Cosmological redshift interpretation

Can the cosmological redshift be interpreted as atomic frequencies increasing by the scale factor as the Universe expands? This explanation seems closer to the truth than the popular idea that a ...
12
votes
3answers
883 views

Can space expand with unlimited speed?

At the beginning, right after the Big Bang, the universe was the size of a coin. One millionth of a second after the universe was the size of the Solar System (acording to ...
3
votes
3answers
362 views

Looking out into the universe means looking back in time - how does that work?

This is a question that has been gnawing on me for many years now. Back a long time ago, as I recall in reference to a scene in a popular science show on TV, I was asked the following. The claim is ...