2
votes
1answer
27 views

Experimental evidence for the relic neutrinos

What are the experimental (indirect) evidence for the cosmic neutrino background? Where can I read more about this? The discussion on the wikipedia page about the C$\nu$B seems to me to be more ...
3
votes
1answer
37 views

Qualtitative explanation for the link between low magnitude of high z supernova and accelerated expansion

Is there any explanation on a qualitative level why we can see in the observed magnitude vs. redshift z plot that the universe is expanding accelerated? See for example here: ...
0
votes
1answer
39 views

Could the universe be a series of Big Bangs? [closed]

Imagine an eruption of energy/mass $E$ from a singularity $O$, as in a Big Bang. After the energy/mass $E$ is all at more than a distance $d$ from $O$, is it for some value of $d$ possible that there ...
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 ...
3
votes
1answer
128 views

The first $10^{-35}$ seconds [closed]

I am a rank amateur, so please forgive me if the answer to this is well-known. The following quote can in a weekly update for an EdX course I am following in astrophysics: "And what a week it's ...
3
votes
1answer
72 views

When did the first carbon atom in the Universe come into existence?

I am a chemist with a passion for astrophysics and particle physics, and one of the most marvellous things I have learned in my life is the process of stellar nucleosynthesis. It saddens me how my ...
4
votes
1answer
111 views

How does the Cosmic Microwave Background give us information about the Big Bang?

I was reading about CMB after this new breakthrough last week and I could not figure this out. The CMB did not exist before the epoch of Last Scattering. They were just photons which were formed at ...
2
votes
1answer
95 views

Immediately after the Big Bang, was the universe in a state of extremely low or extremely high entropy?

Phase space theory suggests that the largest course-graining region, $p$, in a phase space, $P$, is the point in the phase space with the highest entropy. As such, it is in thermal equilibrium with ...
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 ...
21
votes
2answers
1k views

The age of the universe

Many times I have read statements like, "the age of the universe is 14 billion years" . For example this wikipedia page Big Bang. Now, my question is, which observers' are these time intervals? ...
-3
votes
3answers
155 views

What is the scientific view of creation? [closed]

Can space be created or destroyed? Is space conserved? I am not asking for matter,energy and time. Its just a question about conservation of space PS: I am asking for what was there before big bang. ...
3
votes
0answers
20 views

Connection between BAO und CMB Spectrum

I have a problem understanding the connection between the accoustic peaks in the CMB spectrum and the baryon oscillation picture. On the one hand it is stated, that the odd accoustic peaks (1,3,5..) ...
0
votes
2answers
220 views

Did the singularity really existed in the begining of the universe?

I read in Hawking's brief history of time the following: The final result was a joint paper by Penrose and myself in 1970, which at last proved that there must have been a big bang ...
-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?
3
votes
2answers
43 views

Approximation of the energy for low $T$ in the early universe

In Perkins `Particle Physics', to compute the baryon-antibaryon-ratio, he uses that for $Mc^2\gg kT$: $$E= Mc^2 + \frac{p^2c^2}{2m}.$$ I realize that the approximation comes from $E^2=M^2c^4 + p^2c^2$ ...
-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 ...
0
votes
2answers
100 views

How could mass exist before Big Bang?

I heard that before Big Bang the temperatures were so high that mass and energy constantly converted to each other. After big bang the temperature became less and the conversion stopped that is what ...
1
vote
1answer
66 views

Is this a possible big-bang scenario? [closed]

Assume an universe with a single black hole that contains all the universe's mass and then let's wait for quite some time. What happens if by Heisenberg's uncertainty principle a virtual ...
2
votes
1answer
84 views

How to reconcile these two principles?

Quantum mechanics says that the entropy of an unobserved system remains constant. As such, the apparent growth of entropy is a subjective illusion. If we consider the wave function of the universe, ...
1
vote
1answer
57 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
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, ...
0
votes
3answers
563 views

Whats left at the center of the Universe after Big bang?

If you consider big bang. According to that What's left at the center of universe where the Big bang occured?
2
votes
2answers
111 views

Could there have been two “Big Bangs”?

A couple of years ago, I remember seeing a documentary on the big bang theory. The theory presented was that to explain the cosmic microwave background radiation, there needed to have been two big ...
1
vote
2answers
203 views

Bathroom photons from the edge at the universe [duplicate]

I was looking through my bathroom window this night and I was wondering if any of the photons my retina is hit with are from 13 (40) billion light years away ?! I was looking through it a few ...
5
votes
1answer
118 views

Charge neutrality of the Universe: evidences and theories

I've always wondered why the number of protons in the Universe exactly matches the number of electrons. They are such different particles with totally different cross sections. So, first of all, is ...
10
votes
1answer
88 views

Do primordial background neutrinos orbit in dark matter halos?

According to Wikipedia, neutrinos separated from other matter seconds after the Big Bang and formed a separate background radiation field which now fills space at a temperature ~2 K. Supposing ...
0
votes
0answers
41 views

Calculate age of the Universe at 7 billion and 28 billion years old [duplicate]

If $1 / H_0 $ is about 14 billion years, then what happened when the universe was half its current age? Is the empirically determined $H_0$ supposed to have been twice its current value? And when ...
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. ...
0
votes
2answers
67 views

Red Shift and Light Speed

I read several questions/answers about red shift on this web site, but there is something I still don't understand. Why is red-shift considered to be the effect of expanding space-time, why it could ...
-4
votes
1answer
120 views

Does the big bang violate the conservation of energy? [duplicate]

It is a fact that a thing is existing now because it had already been created. So why don't we take this to account to redefine law of conservation of energy.
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 ...
1
vote
1answer
170 views

How far away is Cosmic Background Radiation? [duplicate]

I've been reading about Cosmic Background Radiation (CMBR) lately. My understanding so far is that this is the "Noise"/"Flash" from the big bang. Assuming that information is correct, how far away ...
10
votes
1answer
957 views

What could explain the measurements that the Methuselah star is older than the universe?

So there has been talk in the news of a star named Methuselah that is "older than the universe". Moreover, this star happens to belong to our very own Milky Way. The article mentions that Methuselah ...
1
vote
3answers
380 views

Entropy and Big Bang aren't mutually exclusible? [closed]

There are some principles in entropy im having trouble understanding. If Entropy requires that the energy in the universe must always been constant, shouldnt in theory 'Heat Death' have occurred since ...
4
votes
1answer
453 views

Additional merits to Wetterich's “Universe without expansion” compared to standard cosmological redshift interpretation?

A recent news item in Nature promotes Wetterich's preprint "A Universe without expansion". All sounds very exciting but hard to judge for non-experts. As I understand from the Nature's article, the ...
4
votes
3answers
101 views

Hydrogen cloud at the universe's beginning?

What prevented all of the hydrogen at the universe's start from coalescing into one gigantic star?
4
votes
1answer
119 views

Why is there a line in the middle of the Planck full sky map?

Why there is a straight line (or perhaps a flat surface) in the middle of the Planck full sky map? and zoom (it makes it seem that the big bang was a collision between two unknown surfaces)
-1
votes
1answer
119 views

Why is the Big Bang the biggest explosion in the universe?

What makes the big bang the biggest explosion in the universe? Why even should such an explosion ever happens? Through what process and how does this amount of energy get released as a big bang? Are ...
0
votes
2answers
74 views

Spread and direction of the cosmic background radiation

Something I can never understand is that where the cosmic background radiation spreads? If I know well, the cosmic background radiation is actually the light of the Big Bang. If it happened exactly ...
4
votes
0answers
62 views

Why didn't a black hole form right after the Big Bang? [duplicate]

Why didn't a black hole form right after the Big Bang and the universe contract towards a singularity?
0
votes
1answer
78 views

The Univere's mass-energy and uncertainty [duplicate]

A virtual creation with total mass-energy = $E$ is allowed as long as that virtual creation doesn’t last longer than $E/h$. Can the uncertainty principle also be used to estimate the mass-energy in ...
1
vote
1answer
120 views

Assuming space is infinite can our observable universe be an island amongst an archipelego?

According to recent measurements our observable universe is roughly 93 billion light years in diameter; also it appears (according to WMAP measurements) that spacetime is flat. Supposing space is ...
3
votes
2answers
273 views

Excluding big bang itself, does spacetime have a boundary?

My understanding of big bang cosmology and General Relativity is that both matter and spacetime emerged together (I'm not considering time zero where there was a singularity). Does this mean that ...
0
votes
1answer
1k views

Did space and time exist before the Big Bang? [duplicate]

I accept the Big Bang theory. What I can't understand is how there can be a where or when to the Big Bang if space time did not exist prior to it. Did space and time exist prior to the Big Bang?
3
votes
1answer
115 views

How fast did hydrogen atoms travel when they were first formed in the early universe?

I can't seem to find any data on this, is it a known value?