All Questions
Tagged with observable-universe observational-astronomy
24
questions
5
votes
1
answer
799
views
Is there any way to detect the three-dimensional distribution of baryonic gas in our Universe?
As the title suggests, can the current observational techniques detect the 3D large-scale distribution of the baryonic gas, rather than just the gas within groups or clusters?
- 451
0
votes
1
answer
50
views
Formula for rate of expansion of the universe vs distance?
How does the distance $r$ scale with the expansion of the universe?For example if $r_{o}$ is the distance between us and a galaxy and $V(r_{o})$ is the rate of expansion of the universe at that ...
- 21
1
vote
0
answers
42
views
Has any astronomer/physicist used geometry and trigonometry to calculate where the center of the universe is? [duplicate]
Since we are pretty sure that the universe is expanding at a steady and accelerating rate wouldn’t it be possible to simultaneously observe 4 points (galaxies) that are all, as closely as we can tell, ...
- 21
1
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0
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75
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What Parts of the Observable Universe have we Observed?
Everyone talks about how big the observable universe is, all of the complexity, etc... But what parts of the observable universe have we actually seen? What Parts are hidden in relative shadows? Is ...
- 309
5
votes
1
answer
402
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Does "Angular Diameter Turnaround Point" solve the Great Wall Problem?
According to Wikipedia,
The Hercules–Corona Borealis Great Wall is the largest known structure in the observable universe, measuring approximately 10 billion light-years in length.
But since it's ...
8
votes
1
answer
228
views
How is observable matter distributed in the universe?
The observable matter in the universe is distributed and arranged into various structures, including black holes, stars, nebulae, and the much more diffuse regions of the inter-stellar and inter-...
- 558
0
votes
1
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145
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If the ratio of actual total mass to critical mass (Ω) in the universe is only about 0.3, why do cosmologists believe it is flat, as far as we see?
What about astronomical observations makes scientists believe our universe is flat, at least as far as they can tell? Despite the critical Friedmann density being less than one, plus the existence of ...
- 5,307
2
votes
1
answer
450
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Why would a quantity like the 'Hubble contrast' be squared, then have its square root taken?
From Sabine Hossenfelder's recent video, New Evidence AGAINST Standard Cosmology:
And her source....
Figure 2. The variation with increasing void radius of the variance of the Hubble parameter, the ...
- 5,307
4
votes
1
answer
106
views
Eccentricity of Exoplanets
The field of astrobiology specifically discovering other planets that revolve around the sun-like star (also known as Exoplanets) has risen since 1990, but certain orbits of exoplanets are observed to ...
- 311
6
votes
2
answers
882
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Is the age of the Universe really 13.8 billion years?
Ok, I know this has been asked by a lot of people, but my reason for asking this question is a bit different. Please read further.
I was watching a video by Fermilab (Start at 6:30, at 8:30 he ...
- 189
0
votes
1
answer
88
views
Computing the over-density of Lyman-alpha emitters
Let's assume that I have observations of $N$ galaxies in a projected area $A$, within a redshift range $\Delta z = z_{max} - z_{min}$. What is the correct way of computing their number volume density? ...
- 103
2
votes
2
answers
202
views
How far away are objects whose light will never reach us, because of the expansion of the universe?
I thought I had read this question on Stack Exchange before, but now I cannot find it... In fact, I thought I had posted this question before, somewhere, on Stack Exchange...
I believe the answer ...
- 5,307
0
votes
1
answer
80
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Are the most distant known objects in the universe more than 14 billion light years away? [duplicate]
When I hear about the most distant objects in the universe, such as the recently discovered galaxy GN-z11, their distances are usually stated to be a little under 14 billion light years away....
But, ...
- 5,307
1
vote
2
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214
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How are younger objects outside our observable universe when the older CMB is an observer's temporal "edge"?
We know the observable universe is limited to objects whose light has had time to reach us and that an observer very far away will see a slightly different (assuming cosmological principle) observable ...
- 1,111
4
votes
1
answer
534
views
How did we measure the mass of the universe?
In an wiki article, observable universe, it was mentioned that,
Mass (ordinary matter) 1.5×10^53 kg
I wonder how did we measure the mass of our observable universe?
- 1,007