Questions tagged [universe]

Questions regarding all of time and space and its contents.

10 questions with no upvoted or accepted answers
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As the Universe expands, do things like planets expand also, or just the space in between?

Just what the question says. As the universe expands, and space expands, do objects like planets ever expand? Does the space INSIDE of those objects expand?
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0answers
99 views

Is the acceleration of the expansion of the universe a direct observation or an interpretation?

Is the acceleration of expansion we observe with supernovae direct or is this an interpretation according $\Lambda$CDM model ? I mean what we observe is luminosity distance versus redshift, so to see ...
3
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1answer
145 views

Could the Universe really be 12.5-13 billion years old?

My initial reaction is that "this must be wrong" and apparently that's a lot of people's initial reaction according to the article. https://www.nbcnews.com/mach/science/universe-may-be-billion-years-...
2
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1answer
80 views

The energy density of DM (to be fluid,state parameter=-2)increases with time. Does it violate the concept of accelerating universe?

We know that dark energy with value of state parameter $\omega<-1$ is called phantom dark energy model. In this model if we assume dark energy to be a fluid with value of state parameter $\omega=-2$...
2
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0answers
72 views

How to derive the equation for the age of a flat universe with a positive cosmological term?

Can anyone show the steps involved in deriving this equation from the friedmann equation with the cosmological constant involved
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0answers
40 views

Probability of collision of another bubble universe with our universe

This is rephrased from a previous question and expanding on it. Considering the model of an "inflating" universe which extends infinitely in past (and possibly future) time, constantly creating new ...
1
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1answer
97 views

Energy to expand

I do have a small question, which may seem a bit stupid but we are all here to learn. Anyways my question is: Is the universe expanding using the energy it had from the Big Bang? if so what would ...
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40 views

What is the largest cluster of merging galaxies?

Reading about the Andromeda–Milky Way collision, a galactic collision predicted to occur in about 4.5 billion years between the two galaxies, I went to the galaxy merger page and Wikipedia states that ...
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0answers
47 views

How is “surface brightness dimming” derived from redshift in the NED extragalactic database

I have several questions regarding “Surface Brightness Dimming” in the “Quantities Derived from Redshift” section of the Nasa/ipac Extragalactic Database. As an example, please use quasar IRAS F08279+...
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1answer
77 views

Invisible Mass Affecting the Expansion of the Universe

Are there enough neutrinos & other invisible particles in a cubic light year of space to significantly affect the expansion of the universe,& at a very rough estimate without taking into ...