All Questions
Tagged with dark-energy astronomy
10
questions
0
votes
1
answer
151
views
What if dark matter/energy did not exist?
What if dark matter and dark energy did not exist and were only due to a misinterpretation of the red shift of light or a measurement bias?
What would be the implications/consequences?
3
votes
2
answers
505
views
What is the longest detectable EM wavelength?
What is the longest detectable (by today's technology) EM wavelength? and is there a limit of the energy that those with longer wavelengths that we cannot detect can carry? can there be a galactic or &...
- 553
1
vote
2
answers
95
views
Accelerated expansion of the universe caused by dark energy
Maybe I am misunderstanding this concept but my question is the following: would we state that the universe is accelerating its expansion if we measure the speed of an astrophysical object when it ...
- 2,255
1
vote
1
answer
125
views
Does the Hubble constant measured for huge distances mean it is not the actual Hubble constant but a very old one?
I am citing Wikipedia about Hubble constant....
"Hubble constant is most frequently quoted in (km/s)/Mpc, thus giving the speed in km/s of a galaxy 1 megaparsec (3.09×1019 km) away, and its value ...
- 2,255
0
votes
2
answers
338
views
Relative speed of galaxies in deep space
Let say we observe two galaxies, one little bit closer to us than the other one. If we calculate the speed of the farther one does it mean that according to the Hubble law when the closer one reaches ...
- 2,255
0
votes
0
answers
114
views
What is the co-moving distance to a point, at which the late-time acceleration of the universe began?
First of all sorry for my English - it is not my native language.
According to the following wonderful diagram made by Pulsar,
the late-time acceleration of the universe began at $t_{acc}=$ 7.7 ...
- 85
-1
votes
2
answers
212
views
Is the astronomical magnitude identical to the distance? [closed]
Why do astrophysicists use Magnitude rather than the actual distance to calculate intergalactic parameters? The magnitude is the relative brightness and has no units, the typical distance requires the ...
- 15
0
votes
0
answers
162
views
Matter and dark energy
So dark energy is the biggest thing in the universe, it keeps accelerating the expansion. But it's a constant so at some point there was a matter - dark energy equivalence. My question is how can you ...
- 59
38
votes
1
answer
3k
views
What are the alternative theories of dark energy? ($w \neq -1$)
There has been a lot of related questions about dark energy around here but these are usually 2-4 years old and the closest question to mine hasn't really been answered, so I am going to proceed. ...
- 20.4k
17
votes
3
answers
5k
views
What is Dark Energy, and how was it discovered?
I've heard a lot about Dark Energy, and how it's supposed to be one of the most powerful forces in the universe. What is it, and how was it discovered?
- 3,749