Gamma ray bursts point to dark matter source?

nickname · 2007-01-10 06:16:01

I just finished watching a program about gamma ray bursts, then immediately the math of them came to mind.

Gamma ray bursts seem to be a large stars collapsing into a black hole in stellar nurseries.

Theses stars can be no smaller than 5 solar masses and on average are 10 solar masses.

If we detect 10 gamma ray bursts a day and only see one in 20,000 of them, that means that 200,000 of them happen a day.

200,000 black holes X 365 days X 15 billion years.

In any account of mass in the universe, the black holes in the universe far outweigh the visible.
Could this be the illusive dark matter, or just a large part of it?

C M Edwards · 2007-01-10 09:03:53

I just finished watching a program about gamma ray bursts, then immediately the math of them came to mind.
Gamma ray bursts seem to be a large stars collapsing into a black hole in stellar nurseries.
Theses stars can be no smaller than 5 solar masses and on average are 10 solar masses.
If we detect 10 gamma ray bursts a day and only see one in 20,000 of them, that means that 200,000 of them happen a day.
200,000 black holes X 365 days X 15 billion years.
In any account of mass in the universe, the black holes in the universe far outweigh the visible.
Could this be the illusive dark matter, or just a large part of it?

Whoa, Nickname.

Where are you getting these figures? Where they mentioned in the program you watched, or are you finding them from another source?

I am particularly suspicious of that 200000 per day figure.

The SWIFT gamma ray observatory is reportedly only detecting about 100 gamma ray bursts per year (one every few days), most of these at intergalactic distances. SWIFT doesn't watch the entire sky, and comparison with other observatories indicates that there is somewhere in the neighborhood of one or more detectable events per day inside SWIFT's detection horizon. 10 events per day seems a reasonable guess. That observable horizon is several billion light years - a big chunk of the volume where those 200000 GRB's per day are supposed to be.

If there really are 200000 per day, SWIFT should be seeing more of them.

This documentary clearly took some liberties with its numbers. I believe you need to adjust your figures downward, and limit your calculations to the sample space we can actually see. 10 GRB's per day inside the sample space (e.g., the volume inside SWIFT's detection horizon), period.

10 black holes x 365 days x 15 billion years = 54.8 trillion black holes

That's a lot, but it's only a fraction of a percent of the number of observable stars in that sample space. Extending that sample to the rest of the universe implies that the number of black holes formed during GRB's is likewise only a fraction of a percent of all stars.

That's not enough to explain the gravitational deviations that Dark Matter was posited to explain.

nickname · 2007-01-10 12:13:45

C M Edwards,

10 gamma ray evens a day was the best guess they had on the show, only about 1/5 or less of the possible events are actually detected.
That was the reason for the 10 a day.

Gamma ray bursts are like nothing else detected, they require gamma rays to be focused from a black hole in two exact very focused opposite directions to traverse the distances to arrive at earth.

If they are not well focused they never traverse the distance. (that is another mass of possible black holes we simple might never know about)

For each one we see at least 1,000, and more like one in 20,000 happen that one of the two focal points simply don't point toward earth.

Like one man standing on the moon with a laser, another man on earth with a laser detector.

The man on the moon randomly starts up the laser in a random direction, the man on earth begins to detect for laser light.
After many thousands of attempts the man on earth detects one laser light.
Probably simple random angles could give a better % here, but i think they are probably close to right about 1 in 20,000.

Even if we are pretty conservative about the math and use the 1/1000 it puts us at
5,400.8 trillion black holes.
Likely as much as 210,600 trillion black holes, not including poorly focused black holes or black holes that have passed the gamma ray production phase or black holes that never produce gamma ray bursts.

Those numbers would surely fill the needed quantity of dark matter.
I couldn't believe none of the scientists put this math together on the show about the inescapable quantity of black holes due to the detection rate.

nickname · 2007-01-10 12:29:15

C M Edwards,

Tough to say what the numbers should be for gamma ray bursts.
If we select a number more closely to the observed and between what they guessed at we might select 2-5 a day.

That is probably a realistic number.
Maybe 3 a day would be easily detected with a full 24/7 search.

We can also be a bit more realistic on the 1/20,000 focus guess.

If we choose the somewhere in the middle point of 1/5,000 it should be closer to the reality.

3 X 5000 X 365 X 15 Billion puts us near the dark matter mass requirements.

The focal point of gamma ray bursts pointing at earth is the real math changer, the 1 or 10 a day gamma burst detected won't make a signifigant change in numbers.

C M Edwards · 2007-01-10 16:50:25

Thanks, Nickname. Upon consideration, 10 events per day and 1/20000 detection probability may be within the realm of the possible, provided their model is correct. I would tend to doubt that, except that none of these has ever repeated to my knowlege (i.e., it's not something rotating) and there have been several cases of associated visible supernovas. So, the model is probably about right, too.

There've probably been about 1 quintillion of these things since the beginning of the universe - each leaving behind around 3 to 10 solar masses.

That's cool. 8)

I still have doubts about the ability of this to explain gravitational deviations on the intergalactic scale, though.

The SWIFT observatory has identified events with redshifts as high as z=3.2. That's near the edge of the visible universe - about 10 billion light years away. At that distance, "brighter" events would be more visible, but that's still one heck of a horizon. There are a lot of stars in that space - probably at least 1000 for every black hole formed in a GRB, and that's a highly conservative estimate (10000 or more would not surprise me - I need a better estimate for the number of stars in a 10 BLY sphere :? ). Most of those won't be solar mass, so the actual mass of black holes will be more favorable. But it's still only a few percent at best - a start, nothing more.

This does not account for the 90% difference in observable mass predicted by "Dark Matter" theories.

Of course, these guesses are quite wild. SWIFT results might only be linear to three billion light years or so. My guesstimate of the stellar density might still be too high, although it's as low as I can take it with a straight face. A combination of either might decrease my calculated stellar mass by as much as a factor of 20, making GRB black holes able to explain as much as - maybe - 50% of the mass in the universe.

Where's the rest?

John Creighton · 2007-01-10 20:58:12

Why do we assume each black hole emits one gamma ray burst per day? Does the frequency or size of a gamma ray burst depend on the size of the black hole?

nickname · 2007-01-11 06:56:03

C M Edwards,

Your welcome.

I had the same thought when the calculation came to me, very cool.
The numbers of black holes are mind boggling.

In pretty short work we can account for maybe 50% of the dark matter, with a little creativity I'm sure most of the rest isn't to hard to find now that we might have the culprit.

Black holes that are undetectable, galactic core black holes that accumulate mass.
Both of them are good candidates for more %.

More remaining unaccounted mass, failed stars to small to shine.
I wonder how many of those are created for every burning star?

Quote "I still have doubts about the ability of this to explain gravitational deviations on the intergalactic scale, though"

This sort of touches on a personal theory of mine so i will take a stab at it and see what you think

If our universe is just one of an infinite number of them (not parallel universes).
Something like bath bubbles that go on forever in every direction.

If our universe is one membrane that nothing can escape, except for gravity being a negative force, wouldn't our universe be pulled from all other surrounding universes in different amounts?

Each universe around ours could be in any state from giant black hole to near fully expanded universe.

When we actually collide with another universe one part of our universe halts its expansion, then our internal gravity is stronger than the external gravity.

That would explain the weird gravitational deviations in our universe, how our universe gets started each time, how it collapses and why it appears that our universe is speeding up it's acceleration.
It could even explain why a universe needs not be a particular size (mass) to repeat itself, it just needs to wait for the inevitable collisions to happen to start the big crunch.

John Creighton,

Good point.
I'm not sure of the data of black holes starting gamma ray bursts then stopping, then starting up again.
I bet that a small % of then do exactly that.

If we looked at size of black hole VS frequency or size of bursts i also bet a correlation exists for that.

Although i bet that all the gamma ray event we see are all very similar.
If they are to big they don't create them, or to small they don't focus them well.
The ones that make it to earth and are detectable are probable very very few of the true number of black hole creation events.

The daily number is just the number detected each day, or best guess of new ones each day.

C M Edwards · 2007-01-11 12:59:44

Why do we assume each black hole emits one gamma ray burst per day? Does the frequency or size of a gamma ray burst depend on the size of the black hole?

As far as I've read, there are no known instances of a GRB source repeating, so they're probably not a constant source that is rotating. One current model suggests that they are supernova-like events, and probably not frequent in any given galaxy.

I believe I've figured out where that 1/20000 figure comes from - it's the ratio of the subtended area of two 1 degree wide jets versus the surface area of a sphere.

Nickname, getting the projected black hole mass up to 50% of the universe takes a lot of fudging. The most likely value with our current assumptions is 0.5% to 5%, with 50% being the crazed outer limit of a wild-ass guess. Realistically, I can only get you to 5%.

nickname · 2007-01-11 13:55:36

C M Edwards,

I wonder how many hidden black holes in each galaxy would account for the signus of any given galaxy?

If we can make a realistic guess of black hole creation with gamma events over 15 billion years per galaxy.
If that guess gets us close to the signus signatures of a galaxy it is probably pointless to look for dark matter.

Dark matter isn't my favorite theory anyway, easier to explain the properties of dark matter with external gravity sources (exterior universes) than it is with impossible to detect matter.

So much possible math is useable for the Gamma bursts Vs black hole creation that it would be very difficult to get any real number.

quantity per day we detect X focal point of earth X quantity per day that make no burst X 365 X 15 billion etc etc.

I wouldn't be shocked at all if we only detected 1 in a million black hole events.
I wouldn't be shocked either if it was 1 in 100.
Lots of room for very variable quantities.

Good point about the 1/20000, i was trying to make sense of why that number was so high.
Seems about right for a max 2 degree focus on an entire black hole sphere.

Wish we had a bit more input here for very educated guesses and could define numbers a bit better.
Even if its just 5% though, it shows that the dark matter idea probably isn't right.

Mars_B4_Moon · 2023-10-07 06:16:12

an old topic worth a maybe

a bizarre explosion the LFBOT a fast blue optical transient an explosion event similar to supernovas and Gamma-ray bursts

Hubble finds bizarre explosion in unexpected place
https://phys.org/news/2023-10-hubble-bi … ected.html

The phenomenon, called a Luminous Fast Blue Optical Transient (LFBOT), flashed onto the scene where it wasn’t expected to be found, far away from any host galaxy.

https://twitter.com/esa/status/1710200006676824209

New Mars Forums

Announcement

#1 2007-01-10 06:16:01

Re: Gamma ray bursts point to dark matter source?

#2 2007-01-10 09:03:53

Re: Gamma ray bursts point to dark matter source?

#3 2007-01-10 12:13:45

Re: Gamma ray bursts point to dark matter source?

#4 2007-01-10 12:29:15

Re: Gamma ray bursts point to dark matter source?

#5 2007-01-10 16:50:25

Re: Gamma ray bursts point to dark matter source?

#6 2007-01-10 20:58:12

Re: Gamma ray bursts point to dark matter source?

#7 2007-01-11 06:56:03

Re: Gamma ray bursts point to dark matter source?

#8 2007-01-11 12:59:44

Re: Gamma ray bursts point to dark matter source?

#9 2007-01-11 13:55:36

Re: Gamma ray bursts point to dark matter source?

#10 2023-10-07 06:16:12

Re: Gamma ray bursts point to dark matter source?

Board footer