All Questions
Tagged with observable-universe galaxy
12
questions
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Universe is a cluster of orbiting Galaxies?
Like planets orbiting stars, solar systems and other celestial objects orbiting a blackhole in the center of a galaxy, are the Galaxies and Galaxy clusters orbiting the centre of a universe (for ...
- 2,640
2
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answers
96
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How many galaxies are predicted in the observable universe? Does it contain dwarfs? Is there any size-ratio diagram?
According to quite recent research the observable universe contains about 2 trillion galaxies ($2 \cdot 10^{12}$). But what is counted there? Does this number also contain dwarf galaxies? According to ...
- 245
7
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2
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493
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Rotation of far away and near by galaxies
Do the far galaxies rotate the same as does the milky way and the near by galaxies?
- 171
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58
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How long does it take for a galaxy (or other object) to disappear behind the cosmic sight horizon?
After looking at this question, I am wondering, how long does it take for a galaxy or other space object, to disappear from our view from the Milky Way due to the expansion of the universe? Assume GN-...
- 6,684
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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
1
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Kardashev scale [closed]
Why is becoming a type 3 from a type 2 civilization the hardest?
I have watched many videos on the topic and still can't figure out why?
Also is there a difference in technology between a type 4 and a ...
- 365
1
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1
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112
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Find a planet with incomplete information of a star chart [closed]
I am wondering why it was so hard to locate Luke in Star Was Episode 7, if you already have the small part of the map.
Suppose we have a sector of our galaxy that roughly equals the one missing in ...
- 121
0
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2
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263
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Are any galaxies partially in the observable universe?
Are there any galaxies that are partially with the visible universe? It seems unlikely as most of the universe is empty space however our circumference makes it seem likely as well. It would be a ...
5
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2
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892
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What fraction of galaxies in the observable universe have we actually observed?
There are a finite number of currently observable galaxies due to the finite age of the universe and the speed of light. What fraction of these galaxies have we actually observed (by eye, telescope, ...
- 3,160
21
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2
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2k
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Are there any galaxies which fell out of sight horizon due to cosmic expansion?
If farthest galaxies run away from us with acceleration making them exceed speed of light, we should expect them to disappear from sky among time with increasing quantity. Did we observe this? Can we ...
24
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8
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14k
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Why can't we see distant galaxies with the naked eye?
If light keeps travelling in a straight line, why can't we see distant galaxies with the naked eye? Surely if you stared long enough, the light from them would eventually hit your eye? I apologize if ...
- 341
12
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Does CIBER Experiment from Caltech suggest that there can be lots of stars which are not in any galaxy?
My question is about the implications of the observations recently made by the Cosmic Infrared Background Experiment, or CIBER, from Caltech. I've read at Caltech web site:
"The total light ...
- 221