Please remember that neutron stars and black holes are the remnants of massive stars ...

Therefore it is the remaining iron core of the star which collapses in on itself when the remainder of the star blows itself into space as the result of the supernova explosion. One part of the star blows, the other one contracts into itself.

The result of the remaining contraction process leads to either a neutron star or a black hole.

Good brief summary, thanks.

Note that for a neutron star and for any greater collapse, the source elemental composition is likely irrelevant. Whatever different types of atoms you may have started with, are now all subatomically smashed into mainly neutrons ("neutronium") for a neutron star, or whatever subatomic or energy soup forms for further collapse/compression of matter when forming a black hole.


Whatever, all a very heavy weirdness!

Keep searchin',
Martin

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Finally some action in this thread:))

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rOZZ
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I am watching the mentioned YouTube videos right now.

So, by means of defining gravity you are able to describe a four-dimensional space rather than the three-dimensional space which we are able to see and observe.

Isn't gravity indirectly or implicitly defined by means of Einstein's E=mc2 then? Gravity is assumed to be a force on its own, but it is the result of the presence of matter, something which is thought of as being mass and not energy.

Again, the notion of time itself is still not present at all.

... Isn't gravity indirectly or implicitly defined by means of Einstein's E=mc2 then? Gravity is assumed to be a force on its own, but it is the result of the presence of matter, something which is thought of as being mass and not energy.

Again, the notion of time itself is still not present at all.

For all we know, that which we call "time" may be just an "effect" of something else, just as gravity appears to us as an effect of mass-and-or-energy.


Keep searchin',
Martin

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Good point

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rOZZ
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Good point

Hopefully not a singularity!

;-)


Meanwhile, where oh where has our 'expert' gone?

Hope he's not gone the way of Dr Hans Reinhardt in testing out his conjectures...?

:-p


Keep searchin',
Martin

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According to NASA, the discovery of monster black holes were important pieces of a puzzle first unveiled in 1962.


Interesting article.

http://www.hngn.com/articles/12097/20130911/nasa-telescope-captures-10-monster-black-holes.htm

NASA Telescope Captures 10 Monster Black Holes

NASA link: http://www.nasa.gov/mission_pages/nustar/news/nustar20130905.html#.UjFiDX9IHSc


____________________
The universe wastes nothing, it's simply transferred.
Lynn

Rare star probes supermassive black hole

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rOZZ
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Rare star probes supermassive black hole

Thanks for that one, rather interesting and a good interesting addition to the story for the black hole at the centre of our galaxy.

Also, a nicely written accurate article.


Keep searchin',
Martin

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So... To break this down into smaller more tasty chunks ;-)

infinite acceleration frame (infinite gravity). [...fluff points snipped...]

So, for your "infinite gravity" and for your absolutism: With such infinite gravity, could the rest of our universe even exist?

As soon as you are a hair away from the singularity (which has mass) you are no longer experiencing an infinite acceleration frame, "infinite gravity." Now back a bit farther off, to outside the event horizon and it should be obvious a universe can exist.

Mmmmm... I sense a confusion of infinite proportions spanning multiple timeframes...

So that we can agree on what we are talking about...

Are you describing the entire volume of a black hole event horizon a "singularity"?...

Please note that my descriptions are for a discrete and continuously collapsing object that is some smaller volume within an event horizon...

Just the one point from all that:

For there to be "infinite gravity" (due to infinite mass) anywhere in our universe, by the very nature of "infinite", we would all already have instantly succumbed to such an infinite force and already instantly be 'gobbled up' to not exist. Such is the effect of infinite.

Contrary to that, we seem to exist.


Hence, keep all this simple by not suffering any infinities?


Keep searchin',
Martin

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Martin, the question is a tricky one. Things at the event horizon are highly relativistic, whereas our natural intuition is Newtonian because that's the world we live in.

It turns out that one measure of gravity at the EH is indeed infinite, but it also turns out that you can pass through the EH unscathed if the black hole is big enough to limit the tidal forces.

Sadly my background is not broad enough to let me explain clearly what is going on. The way I think of it, and I'm not sure it's 100% right, is that gravity goes to infinity, but time dilation (red shift) goes to zero, so you have an infinity x zero situation. Turns out the limit of that quantity is neither infinity nor zero, but a well defined value in between.

Note I am talking about the proper time, the time experienced by the observer crossing the EH, not a far-away observer. The far-away observer sees the EH crossing traveler slow down more and more, and never actually reach the point of infinite gravity.

One thing I wonder about is the incoming starlight that EH crosser sees. I wonder if it gets highly blue shifted into the gamma spectrum so that the traveler gets zapped to oblivion by it.

I was trying to learn more about space-time diagrams so I could understand what one looks like at the event horizon, and I ran across this:

Penrose diagrams are frequently used to illustrate the space-time environment of black holes. Singularities are denoted by a spacelike boundary, unlike the timelike boundary found on conventional space-time diagrams. This is due to the interchanging of timelike and spacelike coordinates within the horizon of a black hole (since space is uni-directional within the horizon, just as time is uni-directional outside the horizon).

http://en.wikipedia.org/wiki/Penrose_diagram#Black_holes

All to say intuition is the first thing that breaks down in the vicinity of a black hole.

Sadly my background is not broad enough to let me explain clearly what is going on.

+1 Just like that Penrose diagram...

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rOZZ
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Hey now! doing my best ;)

A real actual astrophysicist with a knack for explaining things would be better but I don't have any.

Hey now! doing my best ;)

A real actual astrophysicist with a knack for explaining things would be better but I don't have any.

That makes two of us:)

[edit] or the Drake equation, but that's a little bit more mathematical...

Nothing to do with black holes though

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rOZZ
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The results of the Drake equation always make me say..So where is everybody?

The results of the Drake equation always make me say..So where is everybody?

Lol!!

But that equation gives us some kind of hope and that's what it's all about. Drake is like the founder of what Seti's all about

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rOZZ
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Spacial volume...

Think of trying to find a particular grain of sand in the midst of a fully stacked hay barn....

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

Think of trying to find a particular grain of sand in the midst of a fully stacked hay barn....

I would think they would try to find us or already have. These million-year-old civilizations with who-knows-what technology could have been monitoring Earth for the emergence of technological civilization and already know we're here.

It's not hard to imagine an advanced civilization could have a radio or optical telescope array the size of a solar system. They could read our license plates from light-years away.

Something's just not right. Maybe they're all just mean.

Think of trying to find a particular grain of sand in the midst of a fully stacked hay barn....

I would think they would try to find us or already have. These million-year-old civilizations with who-knows-what technology could have been monitoring Earth for the emergence of technological civilization and already know we're here. ...

You could hope for more than one civilization sending out a probe to hang out at the galactic central black hole...

Your probe could wait it out nearby until the black hole evaporates, meanwhile the rest of the galaxy will have raced ahead in a much faster time frame. Then see if any other probes have come to join the party at the end of the universe...


Only problem with that is... The ride back on Hot Black's ship is a little disconcerting... ;-) (HHGTTG reference... :-) )

Or at least less worse, there is no way to report back to our present time...

Keep searchin',
Martin

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See new freedom: Mageia Linux
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