<p>This is ruled out because that's not what we see when we look back in the past. </p>

<p>If this was the case at the beginning, we would see these huge stars, with probably different characteristics from the ones formed only recently. But we don't see anything like that. </p>

<p>From what we see when we look very far away - that's few hundreds of millions of years after the beginning - we see signatures of first generation stars forming, very big stars indeed, but nothing close to what you're talking about. </p>

CC BY-SA 3.0
2017-06-30T14:50:42.393Z
+1 (beat me) You might add how SMB holes did form and grow, and how big Pop III stars could really be.
James K
CC BY-SA 3.0
2017-06-30T15:19:29.177Z
You could also add that although supernovae can create a black hole, not every black hole must be the result of a supernova. (A -> B does not imply B -> A, which seems to be the implicit assumption behind the question.)
Alex
CC BY-SA 3.0
2017-06-30T15:59:16.463Z
How is not every black hole a result of a star explosion? How can they appear otherwise?
Antons Voitov
CC BY-SA 3.0
2017-06-30T16:06:47.570Z
The search is on for primordial black holes (meaning they'd have been there since the big bang), a little while ago LIGO saw a merger of two black holes into a larger one (so "big black hole" doesn't mean "big supernova"), neutron star mergers could create a black hole (not sure if observed yet), and, given the right conditions, a gas cloud might collapse directly into a black hole without a star igniting beforehand (which is one hypothesis for the SMBH in galaxy centres). Also, black holes accrete matter, so their current size is not an indicator of their size at their formation.
Alex
CC BY-SA 3.0
2017-06-30T14:45:09.440Z
2017-06-30T14:45:09.440Z
J. Chomel
<p>Is it possible that most galaxies (and our galaxy) were formed from leftovers of supernova explosions?</p>

<p>In order to have a black hole 4,000,000 x solar mass the initial mass of the star should have been even greater. </p>

<p>So I was thinking, is it possible that <strong>after the big bang, gas formed much bigger stars 1,000,000,000,000,000,000,000x bigger than the sun</strong>, which later exploded forming: </p>

<ol>
<li>black holes in the middle of future galaxies</li>
<li>Gas, which later created smaller stars, planets, etc.</li>
</ol>

<p>Am I trying to reinvent a bicycle here? </p>

<black-hole><galaxy><big-bang-theory>
Was Milky Way formed after Sagittarius A Explosion?
Antons Voitov
# Was Milky Way formed after Sagittarius A Explosion?

(Asked by: username_0 on 2017-06-30)

Is it possible that most galaxies (and our galaxy) were formed from leftovers of supernova explosions?

In order to have a black hole 4,000,000 x solar mass the initial mass of the star should have been even greater.

So I was thinking, is it possible that **after the big bang, gas formed much bigger stars 1,000,000,000,000,000,000,000x bigger than the sun**, which later exploded forming:

1. black holes in the middle of future galaxies
2. Gas, which later created smaller stars, planets, etc.

Am I trying to reinvent a bicycle here?

**Tags:** black-hole, galaxy, big-bang-theory

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## 1 answers

### Answer by username_1 on 2017-06-30. Score: 3

This is ruled out because that's not what we see when we look back in the past.

If this was the case at the beginning, we would see these huge stars, with probably different characteristics from the ones formed only recently. But we don't see anything like that.

From what we see when we look very far away - that's few hundreds of millions of years after the beginning - we see signatures of first generation stars forming, very big stars indeed, but nothing close to what you're talking about.

> **Comments:**
> **username_2**: +1 (beat me) You might add how SMB holes did form and grow, and how big Pop III stars could really be.  
> **username_3**: You could also add that although supernovae can create a black hole, not every black hole must be the result of a supernova. (A -> B does not imply B -> A, which seems to be the implicit assumption behind the question.)  
> **username_0**: How is not every black hole a result of a star explosion? How can they appear otherwise?  
> **username_3**: The search is on for primordial black holes (meaning they'd have been there since the big bang), a little while ago LIGO saw a merger of two black holes into a larger one (so "big black hole" doesn't mean "big supernova"), neutron star mergers could create a black hole (not sure if observed yet), and, given the right conditions, a gas cloud might collapse directly into a black hole without a star igniting beforehand (which is one hypothesis for the SMBH in galaxy centres). Also, black holes accrete matter, so their current size is not an indicator of their size at their formation.  

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