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# A Black Hole's Dinner is fast approaching

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So have you ever wondered how our universe started? Scientists call it the Big Bang which describes the early development of the Universe. According to the Big Bang model, about 13.8 billion years ago the Universe expanded from a single point of extremely dense matter, and it continues to expand today. I still have a hard time understanding how all the billions of gallaxies started from a single point, but the Big Bang is a widely accepted theory. About 1% of the snow that you see on a old analog TV screen is made up of background radiation leftover from the Big Bang, called the Cosmic Microwave Background.

It appears everything in the universe circles some object that has more mass. For example the moon circles the Earth and the Earth circles the sun. Our galaxy (the Milky way) and all other galaxies circle something even more massive, a black hole. The black hole in our Milky way is slowly eating us up. But where does all the matter that a black hole eat up go? So everything circles something, what do black holes circle? Is the black hole the end to a galaxy and the beginning of a new universe? As a black hole eats matter, does it spew it out into a new universe, that single point where our universe began as a big bang (as seen from the other side of the black hole)?

Scientists have been watching a ball of gas travel towards the milky way's black hole, only to be eaten... Interesting

RJ

Well, everything circling everything else if I remember from my Leaving Cert Physics, is a combination of Newtons Universal law of gravitation combined with the equation for conservation of angular momentum, though someone is more than open to point me wrong on that one.

F= GMm/d^2 and F=mv^2/d which combined gives you v^2=GM/d IIRC again, open to correction, that's all 30+ years behind me at this stage.

I'm also lead to believe that a black hole is meerly a very dense object, so dense that it's gravitational effect is large enough to attract the light particles to it, despite their speed. I don't think it leads to another galaxy, but I'm sure lots of research is going into them, I wouldn't consider them mystical or anything like that, or like a tunnel of some sort.

Regards,

Ró.

Black holes circle other black holes, of course.

I suspect that at some point, a black hole will accumulate enough mass that one additional hydrogen atom will trigger a big bang.

Hook

Larry Hookins

Oh! I have slipped the surly bonds of Earth
And danced the skies on laughter-silvered wings;

Well, everything circling everything else if I remember from my Leaving Cert Physics, is a combination of Newtons Universal law of gravitation combined with the equation for conservation of angular momentum, though someone is more than open to point me wrong on that one.

F= GMm/d^2 and F=mv^2/d which combined gives you v^2=GM/d IIRC again, open to correction, that's all 30+ years behind me at this stage.

I'm also lead to believe that a black hole is meerly a very dense object, so dense that it's gravitational effect is large enough to attract the light particles to it, despite their speed. I don't think it leads to another galaxy, but I'm sure lots of research is going into them, I wouldn't consider them mystical or anything like that, or like a tunnel of some sort.

Regards,

Ró.

Well Newton's 'universal' 'law' of gravitation stops being so universal when you're talking about stuff like black holes, or things that go very fast (say 80% of more of the speed of light fast). It's still good for plain old slow moving stuff like satellites though. The equation you've derived looks suspiciously like it tells you the orbital velocity required to maintain an orbit around an object of mass M at distance d, mv^2/d being the centripetal force required to keep going in a circle, but the last time I did orbital mechanics was in the first year of my Bachelor's which is 7ish years ago.

Everything in the universe exerts a gravitational force on everything else. If the conditions are right you will get orbits, especially in for example a solar system, which coalesced from the same cloud of gas, so the conservation of angular momentum will help out. I'm sure there's plenty of other weird and wonderful motions you can get though.

A black hole is indeed a very dense object, dense enough in fact that all it's matter is contained in one infinitesimally small point (the singularity). Any object with mass will attract light. In fact, one of the earliest pieces of evidence in support of Einstein's theory of relativity was the observation during a solar eclipse of how the sun bent the light coming from stars behind it. What makes a black hole black is not that it attracts light, but that it attracts light so strongly that any photons (light particles) that get close to the singularity (enter the Swarzschild radius if you want to be fancy about it) can no longer escape.

On a side-note, a common misconception is that a black hole will suck everything in. However a black hole has a certain mass and will only exert a gravitational force according to that mass. If the sun were replaced by a black hole with the same mass the Earth wouldn't get sucked in, any more than we now get sucked in to the sun, as the gravitational force would still be the same. The thing about normal objects is that they are spread out. If you get close to the surface of the sun, some of it is pulling you sideways, rather than straight 'down' (relative to the sun), because the sun's mass is spread out. In a black hole all the mass in concentrated into one point, so you get a much more 'pure' pulling if you will.

To put it in Newtonian terms (although, as mentioned, Newton breaks down around black holes), the gravitational force is F= GMm/d^2. For normal objects there's a limit to how small you can make d, because normal objects are made up of many particles distributed in space. In a black hole all the mass is in one point, so you can make d as small as you like, and hence F as big as you like, as you get closer and closer to the singularity.

John-Alan Pascoe

It's amusing that the video is talking about this as though it's "happening now," when in fact they are only "seeing it now..."

It happened around 28,000 years ago... :Nerd:

Fr. Bill

AOPA Member: 07141481 AARP Member: 3209010556

Interests: Gauge Programming - 3d Modeling for Milviz

On a side-note, a common misconception is that a black hole will suck everything in.

But it does suck everything in. It's like my MasterCard, it sucks my back account until I'm in a deep hole.

It's amusing that the video is talking about this as though it's "happening now," when in fact they are only "seeing it now..."

It happened around 28,000 years ago... :Nerd:

So true. Every time you look up at the stars, you're looking back in time kinda like my time machine (car). When I look out the front window I see the future, but when I look in the rear view mirror it's the past. :lol:

RJ

Hmmm black hole that might explain why I cant get 60FPS in FSX the 30 I'm missing are getting sucked into a black hole!

David Womacks CFI,CFII,MEI

Copilot: Captain have you ever flown a 777 before?

Captain:Nope,but we got a strong tail wind and the bar in Hong Kong stays open till 5am, so lets kick the tires, light the fires and, get the hell outta here.

Hmmm black hole that might explain why I cant get 60FPS in FSX the 30 I'm missing are getting sucked into a black hole!

:LMAO:

Well, everything circling everything else if I remember from my Leaving Cert Physics, is a combination of Newtons Universal law of gravitation combined with the equation for conservation of angular momentum, though someone is more than open to point me wrong on that one.

While newton got part of the story, the relativity come into play at high speed and huge mass. And finding the origin of the mass that explain gravitation is a risky endeavor these days. There is a large mass missing to allow the galaxy to hold together. This missing mass has been designated as black matter and constitute a large portion of the universe. Its effect are observed but nobody has a certitude about what it is yet. But it account for 25% of the universe mass.

Even more mysterious is the repulsive force that accelerate the dispersion of the galaxies from each other. Again no clues what it is and another funny name was coined with Dark energy to designate this force. When converted to mass (thanks Einstein) it account for 70% of universe mass.

The matter that we see and know are a mere 5% of the universe. And the bunch of it is hydrogen and Helium. There is just a small fraction being heavier elements like carbon and oxygen created from Supernova explosion.

We are constituted from remains of those explosion..... stardust litterally..

But dont see the link with FSX except maybe that our computer are also made of strange quantic stuff.... But thats another discussion...

Pierre

P3D when its freezing in Quebec....well, that's most of the time...
C-GDXL based at CYQB for real flying when its warming up...

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