How far is the nearest Black Hole?

harry · Post by **harry** » Sat Aug 05, 2006 5:09 am

Hello All

Where is the closest Black hole and how far away is it.

Could it be the Centre of the Milky Way?

Smile and live another day.

harry · Post by **harry** » Sat Aug 05, 2006 7:17 am

Hello All

Star Orbiting a Medium Sized Black Hole

http://www.universetoday.com/am/publish ... khole.html

Our galaxy is filled with millions of stellar-mass black holes, each with the mass of a few suns. These form from the collapse of very massive stars. Most galaxies possess at their core a supermassive black hole, containing the mass of millions to billions of suns confined to a region no larger than our solar system. Scientists do not know how these form, but it likely entails the collapse of enormous quantities of primordial gas.

"In the past decade, several satellites have found evidence of a new class of black holes, which could be between 100 and 10,000 solar masses," said Dr. Jean Swank, Rossi Explorer project scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md. "There has been debate about the masses and how these black holes would form. Rossi has provided major new insight."

These suspected mid-mass black holes are called ultra-luminous X-ray objects because they are bright sources of X-rays. In fact, most of these black hole mass estimates have been based solely on a calculation of how strong a gravitational pull is needed to produce light of a given intensity.

WoW!!!!!!!!!!!
I thought maybe a few hundred or possibly a few thousand black hole. But! milllions of small black holes in our milky way.

Qev · Post by **Qev** » Sat Aug 05, 2006 9:21 pm

About 1600 lightyears away?

http://www.space.com/scienceastronomy/a ... 00114.html

harry · Post by **harry** » Sun Aug 06, 2006 12:47 am

Hello Qev

Darn you got one closer.

iamlucky13 · Post by **iamlucky13** » Mon Aug 07, 2006 7:25 pm

Don't forget that some cosmologists theorize that "micro" black holes could have been formed in the big bang (actually, at the very end of the inflationary period, if I remember right). These could be basically anywhere and not encounter and interact with sufficient matter to be detectable. It is likely that most would Hawking radiate away faster than they acrued matterial.

Of course, this is really just a theoretical allowance of the big bang theory, and it's very much possible that no micro black holes exist.

And if you want really close, although the researchers involved have come up with several alternate explanations, a recent experiment at the Relativistic Heavy Ion Collider produced peculiar emissions that may have been a super-miniature black hole with a mass equivalent to roughly two gold nuclei Hawking radiating into nothingness.

Still, that would've only been the closest black hole for a few femtoseconds.

Qev · Post by **Qev** » Tue Aug 08, 2006 2:20 am

There were some interesting events found by scientists examining archives of seismological events here on Earth. In a couple cases, there were strange 'pairings' of minor earthquakes, separated by a few tens of seconds, on opposite sides of the Earth. One pairing started in Turkey, and ended in Sri Lanka, another in Australia and ended up in Antarctica.

They tentatively theorized that this could be evidence of strangelets passing through the Earth, at over one million kilometers per hour. Though perhaps small black holes would have similar effects.

harry · Post by **harry** » Tue Aug 08, 2006 8:06 am

Hello iamlucky13

Smile,,,,,,,,,,I forgot about the micro Black Holes. You got me there.

As for the Big Bang forming the Black Holes, no way in hell. The so called Big Bang ejected material from a so called singularity that ejected subatomic particals that reformed into athe atoms we know and so on.

As for Black Holes they are part and parcel of the recycling process within the parts of the universe. Some even form during a supernova, or should I say a hypernova, where a super star leaves a compacted core so dense that, not even light is able to escape. These types of Black Holes are numbered in millions within our Milky Way kid.

=================================
Hello Qev

Sorry mate, I do not understand, even if I use my brain.

What are these strangelets?

Qev · Post by **Qev** » Tue Aug 08, 2006 5:36 pm

Oh, strangelets are small collections of stable strange matter (matter containing strange quarks), very tiny and very, very dense. They're purely theoretical at this point (not that strange matter hasn't been created in accelerators), since no-one has been able to show that a stable collection of strange matter is even possible. Well, outside of a quark star.

There was some worry that the LHC (or was it the RHIC?) might accidentally create a stable strangelet, and destroy the Earth, but physicists promptly shot that idea down.

iamlucky13 · Post by **iamlucky13** » Tue Aug 08, 2006 11:53 pm

While I admit I am not an astrophysicist, I maintain based on my reading that black holes formed as an effect of density fluctuations shortly after the big bang are possible. I'm unclear on exactly when, but I would guess before the condensation of individual nuclei. These are referred to as primordial black holes. Stephen Hawking was one of the first physicists to determine that they are a possibility, and others have supported the idea. In fact, according to Wikipedia, NASA's Gamma-ray Large Area Space Telescope (GLAST) will, among other tasks, watch for evidence of primordial black holes. It is also possible that primordial black holes existed, but all were small enough that they would have Hawking radiated away by now. Of course, I'm familiar with the more common and well-supported black hole concepts.

Qev, you may also have heard the speculation that the 1908 explosion near the Tunguska River in Siberia was caused by a small black hole passing through the earth. Of course, this speculation is generally not taken too seriously because there's no direct evidence of it (including no known corresponding exit event).

I thought the proposal of a stable strangelet or micro black hole at LHC destroying the earth was pretty interesting. In response to someone's question about it, I calculated how far a black hole formed from two gold nuclei would fall in the earth's gravity (it's own gravity being negligible) before evaporating (the time being stated in an article about the RHIC). I forget the exact value, but it was on the order of an atomic radius. Realistically, the black hole could not be expected to last long enough to run into another atom, and certainly not multiple atoms.

Qev · Post by **Qev** » Wed Aug 09, 2006 4:41 am

Regarding the Tunguska Event, I've heard all sorts of fun theories, from antimatter to alien spaceships to evaporating black holes. The lack of radioactivity at the site (when researchers finally got there) shot down a lot of these. I think the current explanation is an icy or loosely-bound rocky meteor exploding about five miles above the surface.

I also seem to remember reading that the energy released in the final evaporation of a primordial black hole would be about enough to pulverize Earth's Moon. So maybe we were lucky on that one.

Interestingly, a black hole formed from two gold atoms would have a Schwartzchild radius of much less than the Planck length, so pretty much, they just couldn't exist at all.

harry · Post by **harry** » Wed Aug 09, 2006 10:10 am

Hello All

The way you two are discussing Black Holes, is that they are a singularity.

Not possible.

I will be a happy man if we eventually get one model working, so that we could move on with discussions. I feel sometimes that I'm going around in circles.

Smile, as you know I do not think much about the BBT.

That does not make be right.

Qev · Post by **Qev** » Wed Aug 09, 2006 3:51 pm

Actually, I was discussing them in terms of their Schwartzchild radius, ie. the radius of the event horizon. What goes on beyond that is anybody's guess.

iamlucky13 · Post by **iamlucky13** » Wed Aug 09, 2006 6:34 pm

Oh don't worry Harry, I understand your thoughts on the BBT. Your points are well taken, but like many others, I remain unconvinced that any of the alternative theories are necessarily better, and in light of that it is worthwhile to discuss theories in the context of the BBT.

Qev...interesting note about the radius. Do you know if it has been shown theoretically that a black hole of that size could not exist or merely that things get too funky in GR to describe it? I'd be a little reluctant to believe that the physicists who said it might be a black hole formed at the RHIC were merely blowing hot air.

Among the other interesting tidbits I found on Wikipedia is the claim that a primordial black hole formed with a mass of 10^12 kg (compare to the asteroid Ceres with a mass of 10^21 kg) would be sufficiently large to survive to the present time, and therefore could in theory at least exist within our solar system without being detected gravitationally. Pretty crazy idea, huh?

harry · Post by **harry** » Thu Aug 10, 2006 7:26 am

Hello All

Smile,,,,,,,,,,

read this link
http://metaresearch.org/cosmology/DidTh ... inning.asp

ABSTRACT The big bang theory postulates that the entire universe originated in a cosmic explosion about 15 billion years ago. Such an idea had no serious constituency until Edwin Hubble discovered the redshift of galaxy light in the 1920s, which seemed to imply an expanding universe. However, our ability to test cosmological theories has vastly improved with modern telescopes covering all wavelengths, some of them in orbit. Despite the widespread acceptance of the big bang theory as a working model for interpreting new findings, not a single important prediction of the theory has yet been confirmed, and substantial evidence has accumulated against it. Here, we examine the evidence for the most fundamental postulate of the big bang, the expansion of the universe. We conclude that the evidence does not support the theory; and that it is time to stop patching up the theory to keep it viable, and to consider fundamentally new working models for the origin and nature of the universe in better agreement with the observations.

Test #6: The ages of globular clusters and of superclusters of galaxies
If the universe originated 10-15 billion years ago, then no objects within it can be older than that. Yet the deduced ages of globular clusters of stars in our own galaxy do appear somewhat older than that, perhaps 16-18 billion years old. It is usually assumed that either something is wrong with stellar evolution theory, making the calculations come out too large; or that the universe is actually more like 20 billion years old, as astronomer Sandage has argued. So the age of globular clusters is not presently a strong argument for any model of the universe.

The age problem is a bit more severe in the case of superclusters of galaxies. These huge structures would take perhaps 100 billion years to form, given the typical relative speed of galaxies10. The same problem applies to "great walls" of galaxies, which are even vaster structures. There is no clear way to form structures on such large scales in the time available unless relative velocities were much higher in the past. But higher past velocities would require a dissipation mechanism which would have released tremendous energy. There is no credible evidence at present for the operation of such an enormous energy sink as would be required to resolve this dilemma. Therefore, this test presently favors static universe models, which have essentially unlimited time to form the observed structures through normal processes.

Look the above link is just one of many.

Qev · Post by **Qev** » Thu Aug 10, 2006 9:56 pm

iamlucky13 wrote:Qev...interesting note about the radius. Do you know if it has been shown theoretically that a black hole of that size could not exist or merely that things get too funky in GR to describe it? I'd be a little reluctant to believe that the physicists who said it might be a black hole formed at the RHIC were merely blowing hot air.

Oh, I don't doubt one could create a black hole at that scale, it's just that it couldn't survive as a black hole terribly long. Things get very indistinct at those scales... in fact, as far as we know, things can't even be at those scales. Which, I suppose, is pretty much what they observed. Something that looked very much like a black hole not surviving very long.

Among the other interesting tidbits I found on Wikipedia is the claim that a primordial black hole formed with a mass of 10^12 kg (compare to the asteroid Ceres with a mass of 10^21 kg) would be sufficiently large to survive to the present time, and therefore could in theory at least exist within our solar system without being detected gravitationally. Pretty crazy idea, huh?

Actually, from what I've managed to calculate (thanks to the wonders of Google

), a black hole with that mass would only survive about four hundred million years or so. Of course, that's a non-relativistic calculation, so maybe there's something going on with time dilation that I'm not accounting for.

harry · Post by **harry** » Wed Aug 16, 2006 7:45 am

Hello All

For those who want more info on Black Holes

The Non-Linear Dependence of Flux on Black Hole Mass and Accretion Rate in Core Dominated Jets
http://arxiv.org/abs/astro-ph/0305252
http://arxiv.org/PS_cache/astro-ph/pdf/0305/0305252.pdf

I had a link on sizes of black holes and the distance the event horizon from the black hole.

"I'll be back" as Arnold would say.

Qev · Post by **Qev** » Wed Aug 16, 2006 6:05 pm

harry wrote:I had a link on sizes of black holes and the distance the event horizon from the black hole.

"I'll be back" as Arnold would say.

For non-rotating black holes, it's pretty straightforward:

R(s) = 2GM / c^2

Where G is the gravitational constant, M is the mass of the black hole, and c is the speed of light.

harry · Post by **harry** » Thu Aug 17, 2006 9:22 am

Hello Qev

Smile,,,,,,,,,,straight forward,,,,,,,,,,,,,,,sounds like driving a car.

========================================

In two years time I'll put forward a model that incorporates.

The Big Bang theory
The string
The steady state
The recyclic
The plasma cosmology
The wave
Observations
and so on.

If I knew it was going to be so time consuming I would not have started.
But! now that I have started I cannot stop.
=========================================

DavidLeodis · Post by **DavidLeodis** » Fri Aug 18, 2006 7:38 pm

There may be a Black Hole nearer than we think!

If it works (I hope it does) the link below should bring up an intriguing image that was taken today by a NOAA Arctic webcam. Well the sky has a hole and there is something black in it!

[/url]www.arctic.noaa.gov/latest/noaa3.jpg[url][/url]

Qev · Post by **Qev** » Fri Aug 18, 2006 8:40 pm

Uhoh!

harry · Post by **harry** » Sat Aug 19, 2006 7:38 am

Hello All

Must be my eyes I cannot see the image Davidlees

http://www.arctic.noaa.gov/latest/noaa3.jpg

DavidLeodis · Post by **DavidLeodis** » Sat Aug 19, 2006 1:04 pm

Hi Harry

Unfortunately the link I gave does not bring up the image now. I have tried to paste a copy of the image (which I have saved) but I do not seem able to paste it. If it is possible, could somebody please let me know how to add an image to a 'The Asterisk' post. I am guessing Img may be image, but I get nowhere with that.

Thanks. David.[/img]

harry · Post by **harry** » Sat Aug 19, 2006 1:20 pm

Hello David

Smile,,,,,,,,,,,thanks mate

DavidLeodis · Post by **DavidLeodis** » Sat Aug 19, 2006 2:11 pm

Hi Harry

I have given up trying to work out how to paste the image, so this link should help to see it:-

http://www.arctic.noaa.gov/gallery_np.html

That brings up the NOAA Arctic webcam site. Click on the 'All images from 2006' and then select date range 2006 Aug 18. Click display images and the image I am referring to is noaa3:2006-08-18 15:52:00. It seems to be the only image that day that is not misty or iced up!

I hope you are not disappointed after all this with what the image shows, as I am not seriously suggesting that it shows a black hole!

David.[/url]

BMAONE23 · Post by **BMAONE23** » Sat Aug 19, 2006 4:05 pm

I see what you are talking about.
http://www.arctic.noaa.gov/npole/2006/i ... 8-1552.jpg

It appears to be the sun causing the digital reader to burn out fron the brightness. This can happen when the sun peeks through the clouds and into a digital imager that is has a slightly longer image time set up due to darker overcast conditions.

It is a great shot though