# Schwarzschild Radius of the Universe Part 2 [duplicate]

There seems to be some confusion as to what I am asking, so I am editing this for clarity.

I know the universe is not a black hole. But if I could take all of the matter, (seen and unseen including dark matter) and condensed it down until I made a black hole, how big would the Schwarzchild radius be?

I used the online Omni Schwarzschild Radius Calculator and got a Rs of 922,849,991,811,114,802,777,336,648 miles or 156,983,977,244,214.0625 LY which seems WAY too high

I have worked 80+ hours this week so my math may be off but $$10^{55}$$ grams is $$10^{52}$$ kg's, right? So is there a way to calculate the Rs of the observable universe? If for nothing else other than S&G? Would it be a straight forward calculation? or does the mass of the universe cause issues due to the size?

• Something makes me nervous about this question... But then, meeting all friends at once in a single point sounds nice... – Volker Siegel Apr 14 at 7:32
• As explained by the answer to your previous question on this topic, the universe is not a black hole and does not have a Schwarzschild radius. – Ben Crowell Apr 14 at 14:17
• @BenCrowell - Yes I am aware the universe is not a black hole. I am trying to find the Schwarzchild radius if I compressed all of the matter in the universe down and made a black hole out of it. The calculator I used gave me a nonsensical answer of 156B light years. and I am trying to figure out what went wrong. – Rick Apr 14 at 14:23
• Rick, this is tangential to your question, but for this type of the back-of-the envelope calculation always use 900,000,000,000,000,000,000,000,000 instead of 922,849,991,811,114,802,777,336,648. One of my profs used to fail students on tests for this, and rightly so. Probably the most precisely measured physical quantity to date is the electron anomaly ${g_e}-2$, and it is known to "only" 12 significant digits. No number with 28 significant digits can be physical. Since you started with one significant digit in $10^{55}$, so you have no more than one in the result. – kkm Apr 14 at 14:56