38 votes
Accepted

Why didn't the Big Bang produce heavier elements?

I think that your thought process is flawed in that you assume that by drastically increasing the temperature you are guaranteed to get heavy elements. As odd as this may sound, this isn't the case (...
zephyr's user avatar
  • 15k
11 votes
Accepted

Portion of universe visible if gathering image from inflationary epoch

tl;dr: Your field of view would cover roughly one square centimeter of the sky at that time, and you would observe roughly 50 billionths of the observable Universe. You can't really… With photons, ...
pela's user avatar
  • 38.2k
10 votes
Accepted

Why is the Cosmic Microwave Background evidence of a hotter, denser early Universe?

By request: Beyond the fact that the cosmic microwave background (CMB) is a direct prediction of the big bang model, there is the question of how you would produce it in any other way. It is ...
ProfRob's user avatar
  • 152k
7 votes
Accepted

Is it possible to get a glimpse of the Big Bang through gravitation waves?

Gravitational waves from the big bang may be "heard" but not by LIGO. The waves emitted at or around the inflationary epoch of the big bang are expected to be at much lower frequencies (milli-Hz or ...
ProfRob's user avatar
  • 152k
6 votes

What would the night sky have looked like 12.9 billion years ago when galaxies first started to form?

As @Gerald stated in his excellent answer, the Hubble XDF photo might describe the night sky - many irregular, blue galaxies. As the redshift at 12.9 billion light years is about $z=6.5$, the universe ...
WarpPrime's user avatar
  • 6,653
6 votes

What existed before the big bang

We don't have theories that can describe the big bang (or whatever happened) properly so we can't say anything definite about the big bang itself, let alone if/what was before it. We would need (at a ...
StephenG - Help Ukraine's user avatar
6 votes
Accepted

How could lithium burning take place in a quasi-star?

Lithium, along with Hydrogen and Helium, was one of the 3 elements created in the Big Bang. Thus, it should exist to some part in any star that hasn't burnt all of it out, and as mentioned, it's not ...
PearsonArtPhoto's user avatar
6 votes
Accepted

How does science knows what is the early universe?

I assume you're referring to the recent press release about the quasar J043947.08+163415.7, observed recently using Hubble. The paper about the observations details how the authors measured the ...
HDE 226868's user avatar
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6 votes
Accepted

Why is the CMB's redshift so high?

Well during those periods we can assume universe is matter dominated. Thus, we can write $a(t) \propto t^{2/3}$. By also using $1+z = a^{-1}$, we can write. $$\frac{1+z_{\rm CMB}}{1 + z_{\rm HD1}} = \...
seVenVo1d's user avatar
  • 576
6 votes
Accepted

Can we observe the same very old object more than once?

We can't, because the universe isn't curved enough to allow light to travel far enough since the big bang If the universe was more highly curved, this might be possible. And the objects that appeared &...
James K's user avatar
  • 121k
5 votes
Accepted

Does the CMB pattern evolve in a human lifetime?

In principle yes, in practice no. As seen in the temperature power spectrum below, the Planck satellite detects power (i.e. "a signal") even on the smallest probed scales, which is a few arcminutes. ...
pela's user avatar
  • 38.2k
5 votes
Accepted

What is the meaning tiny bundle of energy smaller than an atom

What the video is clumsily alluding to is that the universe was very much smaller than it is today. However, if the universe is infinite, then it was still infinite at all times in the past. All one ...
ProfRob's user avatar
  • 152k
5 votes
Accepted

Why is the Cosmic Microwave Background at the same distance no matter the direction we look?

The CMB is visible at a distance of 13.8 billion light years in all directions from Earth, leading scientists to determine that this is the true age of the Universe. This is wrong in a few ways. ...
benrg's user avatar
  • 3,852
5 votes

Do black holes "store" ancient light?

Infalling objects pass right through the event horizon. They don't freeze there. The vicinity of the event horizon is locally just like any other part of spacetime. If a light-emitting or light-...
benrg's user avatar
  • 3,852
4 votes

Expanding universe

The very first stars were probably, massive, ultraluminous, and very short-lived. So if they were formed 400 million years after the big bang, then they would have ceased to exist only a few million ...
ProfRob's user avatar
  • 152k
4 votes

Expanding universe

Yes, and indeed it did. For some stars. Some first stars were close to us, some were far away. The light from the ones that were very far away has yet to reach us, while the light from the ones that ...
pela's user avatar
  • 38.2k
4 votes

Why do we presume that the universe has always expanded?

We can, after making some approximations, trace the movements and locations of the matter in the universe back in time, using the laws of physics (mainly general relativity). At the moment we see a ...
Steve Linton's user avatar
  • 10.3k
3 votes

Characteristics of the first planets in the Universe?

Our knowledge of planet formation processes comes from theoretical work and is supported by observations. I'm going to give it my take based on that. On the lower mass end of the planet distribution, ...
AtmosphericPrisonEscape's user avatar
3 votes
Accepted

Question about expansion of space time

Your question is one that bothered cosmologists for a long time, how do you get clumps of matter out of a smooth initial condition, in the time allowed? It was long understood that a perfectly smooth ...
Ken G's user avatar
  • 5,320
3 votes

How does science knows what is the early universe?

To answer the question "how does science knows what is early and what is late?" in simple terms: We know that the Universe is expanding. Because of this, the light from things further away from us ...
Chappo Hasn't Forgotten's user avatar
3 votes

What is the probability that we are the first ever intelligent life in the whole universe?

We know that intelligent life exists on one planet. We do not fully understand the processes by which life (a) starts and (b) becomes intelligent. Therefore, the probability of these things happening ...
ProfRob's user avatar
  • 152k
3 votes

How could lithium burning take place in a quasi-star?

If present, lithium is burned at lower temperatures than hydrogen (protium), although at higher temperatures than deuterium. See Why does lithium fuse at lower temperatures than hydrogen? The ...
ProfRob's user avatar
  • 152k
3 votes

Cosmic Microwave Background Map

Above I have plotted few Planck's radiation contribution: The violet is due to CMBR, Green is due to Milky way Galaxy, and Blue is due to contribution from both. One way to resolve out CMBR is by ...
Kartik Chhajed's user avatar
3 votes
Accepted

What was the size of the universe around 400 million years after the Big Bang?

There are two issues: what counts as "the size of the universe", and how to rescale this. The second issue is easier. If you have something at distance $d_1$ at time $t_1$ it will be at ...
Anders Sandberg's user avatar
3 votes

Is there any correlation between the Cosmic Microwave Background (CMB) and the distribution of distant galaxies?

CMB fluctuations The CMB fluctuations are often analyzed through their power spectrum $P(k)$, which is a measure of the extent to which it is "clumpy" on a given scale $\ell$, with ...
pela's user avatar
  • 38.2k
3 votes

Are features in the CMB correlated with features in the SDSS map of the most distant galaxies?

There shouldn't be any correlation. The CMB light that we see is from a spherical region in the early universe. Its homogeneity strongly suggests that the interior of the sphere was just as ...
benrg's user avatar
  • 3,852
3 votes

If Looking Into Space is Like Looking Back in Time, Why is it the Same in Every Direction?

Assuming, as you seem to do, that there is an edge of the universe, what if we were very far from the edge, so that the part we can observe (the observable universe) is a very small circle inside the ...
Prallax's user avatar
  • 4,431
3 votes

If Looking Into Space is Like Looking Back in Time, Why is it the Same in Every Direction?

If Earth was located in an unprivileged spot, anywhere but the center of the Universe, then some of the space around us should go "farther back" than others. This is not the case, at least ...
David Hammen's user avatar

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