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Questions about the origin, history, evolution and fate of the Universe.

6 votes

If the Universe is infinite, why isn't it of infinite density?

Your assumption is not true. For example: if the probability density function of the atoms decreases quadratic exponentially (i.e. $e^{-r^2}$), then their sum will be finite even in an infinite univer …
peterh's user avatar
  • 3,174
11 votes

Is there anything like a supermassive white hole? How are they formed? And where are they pr...

White holes are a theoretical construction of General Relativity. Despite extensive searches, nothing has been found: not a supermassive white hole, not a stellar-sized white hole, nothing. Thus, the …
peterh's user avatar
  • 3,174
2 votes

Measuring the size and the geometry of Universe

The relative recent WMAP result shows, the Universe seems infinite. However, the "is the Universe infinite" question has a hidden problem: it doesn't matter, how far away can we see, we can't be sure …
peterh's user avatar
  • 3,174
1 vote

Are there other proofs of the expanding universe apart from the redshift?

Yes: Distribution of 1a supernova data WMAP measurements of the CMB Sloan galactic sky survey (catalog of the galaxies) The important thing is that these results not only say the same, but they ar …
peterh's user avatar
  • 3,174
4 votes

I need to study space, planets and black holes, how do I study them on my own

I am sorry to say, but the best resources are still books. If it is really a no-go, read further. It is very likely, that you can find and buy astronomy books on Arabic on the Internet. First start w …
peterh's user avatar
  • 3,174