Primordial black holes = dark matter ?

[Drone]

Well done, Qubit *goes to read*

It's fascinating how gravity - the weakest force of nature can be so powerful.

Cheers!

[3870x2]

I have never understood this about Quasars (and other materials of the like)

If nothing can escape the gravitational field of a black hole, how do these? (they shoot out both ends of a black hole, most predominantly at the center of galaxies.)

[qubit]

They take shortcuts with the wording - indeed nothing can come out from the event horizon. Ever.

Somehow, an infalling accretion disc can generate right angled jets of matter close to the event horizon. It doesn't make sense to me how this can happen though, because the matter has to physically change direction, which takes "work" and I've never seen it adequately explained.

[3870x2]

Care to expound upon this Drone?

[Drone]

Originally Posted by qubit

It doesn't make sense to me how this can happen though, because the matter has to physically change direction, which takes "work" and I've never seen it adequately explained.

Originally Posted by 3870x2

Care to expound upon this Drone?

There's a "good" explanation for that process. By good I mean how scientists understand that lol.

In a nutshell: The spin of the black hole powers the jets via magnetic fields in the accretion disk.

You can see these links:

http://phys.org/news/2012-01-black-hole-jets.html
http://www.wired.com/wiredscience/20...-jets-exposed/

[3870x2]

Originally Posted by Drone

There's a "good" explanation for that process. By good I mean how scientists understand that lol.

In a nutshell: The spin of the black hole powers the jets via magnetic fields in the accretion disk.

Black holes have enormous gravitational field and not only this, they also have very strong magnetic fields.

You can see these links:

http://phys.org/news/2012-01-black-hole-jets.html
http://www.wired.com/wiredscience/20...-jets-exposed/

The Quasars are actually produced beyond the event horizon maybe...

[Drone]

Most likely. Nothing seems to escape the event horizon except for Hawking Radiation (which was never detected). All this process is a big mystery that's for sure. Nobody knows all the processes that can happen there, maybe there can be some other forces that mess with matter. And I'm not even talking about the black hole interior. What happens inside can never be described by physics. All our (I mean entire humankind) knowledge seems so limited and incomplete lol,


EDIT:

I've found another very interesting snippets:

<The magnetic coupling process can transfer energy and angular momentum from a rotating black hole to its surrounding disk>.

<Magnetic fields in the vicinity of an accreting, rotating black hole could become twisted, enabling them to carry away energy as an electromagnetic jet>

[Drone]

Maybe Dark Matter exists ...

http://phys.org/news/2012-09-mystery...eciphered.html

The Planck satellite, which was launched in 2009, has extremely sensitive instruments that can map microwave radiation in the entire sky with great precision. The latest data from the Planck mission reveals unusual radiation from our own galaxy, which open a new direction in understanding the most fundamental properties of the space, time and matter in the Universe.

So we have it

The image shows emission from the centre of the Milky Way, detected by PLANCK satellite. The black zone mask is emission from the galactic disk, the blue-red-white zone in the centre of the map is the new abnormal radiation.

What could it be?

Dark matter may consist of very heavy particles that are around 10 times as heavy as the Higgs particle, that is to say, 1,000 times heavier than a proton. But they have very unique properties and do not interact with 'normal' matter particles. Dark matter particles are also usually very scattered and do not interact with each other.

So they say:

But we know from theoretical predictions that the concentration of dark matter particles around the centre of galaxies is very high and we have a strong argument they can collide there and in the collision electrons and positrons are formed. These electrons and positrons start to rotate around the magnetic field at the centre of the galaxy and in doing so produce this very unusual synchrotron radiation.

So if their theory works then it's indeed mysterious Dark Matter

"The radiation cannot be explained by the structural mechanisms in the galaxy and it cannot be radiation from supernova explosions. We believe that this could be proof of dark matter. Otherwise, we have discovered absolutely new (and unknown for physics) mechanism of acceleration of particles in the Galactic centre".

[Inceptor]

Originally Posted by 3870x2

The Quasars are actually produced beyond the event horizon maybe...

A quasar is either the jet of a supermassive black hole, in an active galactic nucleus, pointed towards us, or just a massive starbirth and stardeath event in and around an active galactic nucleus, due to the massive amounts of gas swirling in those regions. Or both those things.

[Drone]

Haven't posted in a while but this stuff is postworthy:

Researchers from Cardiff University have discovered a new property of black holes: their dying tones could reveal the cosmic crash that produced them.

That's interesting, I haven't heard about that before.

Two black holes orbiting around each other emit gravitational waves and lose energy; eventually they come together and collide to produce a black hole that is initially highly deformed. Gravitational waves from a deformed black hole come out not in one tone but in a mixture of a number of different tones, very much like the dying tones of a ringing bell. The frequency of each tone and rate at which the tones decay depend only on the two parameters that characterize a black hole: its mass and how rapidly it spins. By comparing the strengths of the different tones, it is possible not only to learn about the final black hole, but also the properties of the original two black holes that took part in the collision.

So basically they say that it would be possible to weigh two black holes after they've collided and merged. I hope that advanced gravitational wave detectors will be built in the future. I can't even imagine how sensitive they must be.

http://phys.org/news/2012-09-spaceti...ack-holes.html

[Drone]

More interesting news:

Two stars S0-102 and S0-2 orbit our galaxy's supermassive black hole in much less than a human lifetime. S0-102 orbits our Galaxy's supermassive black hole with a period of just 11.5 years. And S0-2, which is 15 times brighter than S0-102, will go through its closest approach to the black hole in 2018. You say who cares and why is this important? Here's why:

The exciting thing about seeing stars go through their complete orbit is not only that you can prove that a black hole exists but you have the first opportunity to test fundamental physics using the motions of these stars. Showing that it goes around in an ellipse provides the mass of the supermassive black hole, but if we can improve the precision of the measurements, we can see deviations from a perfect ellipse - which is the signature of general relativity.

As the stars come to their closest approach, their motion will be affected by the curvature of spacetime, and the light traveling from the stars to us will be distorted.

They have a chance to see whether Einstein's theory of general relativity is valid near a black hole, where this theory has never been tested before. The deviation from a perfect ellipse is very small and requires extremely precise measurements. I hope they can do it.

I found that article in Science Magazine.

[3870x2]

A bit off topic, but here is a good question:

If we can take high resolution photos of things 13.2 billion LY away, how is it so difficult for us to get a good image of pluto?

My educated guess: There is a gap in what distance instruments can measure, and pluto is in that gap.

[patrico]

Originally Posted by 3870x2

A bit off topic, but here is a good question:

If we can take high resolution photos of things 13.2 billion LY away, how is it so difficult for us to get a good image of pluto?

My educated guess: There is a gap in what distance instruments can measure, and pluto is in that gap.

i think its because pluto is so tiny and when we look back we are looking to things that are many light years across, that my interpretation of why not, but hey i may not be totally correct


And hey,
has anyone watched a set of films (theres two of them) by scientists called "THE BIG BANG IS WRONG"? its very good and has some good arguements against the big bang theory, after all is just a theory.

[Inceptor]

Originally Posted by patrico

i think its because pluto is so tiny and when we look back we are looking to things that are many light years across, that my interpretation of why not, but hey i may not be totally correct


And hey,
has anyone watched a set of films (theres two of them) by scientists called "THE BIG BANG IS WRONG"? its very good and has some good arguements against the big bang theory, after all is just a theory.

So, because that video says that a Quasar looks like it is somehow connected to a much closer galaxy, the verifiable and reliable redshift measurement is somehow wrong? That's pathetic reasoning, no, that's not even reasoning, it's just foolish thinking.

[Drone]

Astronomers discover a new black hole in our galaxy

Yay! There's another one, far away from us, close to the center of the Milky Way. X-ray outbursts revealed its location.

On Sept. 16, NASA's Swift satellite detected a rising tide of high-energy X-rays from a source toward the center of our Milky Way galaxy. The outburst, produced by a rare X-ray nova, announced the presence of a previously unknown stellar-mass black hole.
An X-ray nova is a short-lived X-ray source that appears suddenly, reaches its emission peak in a few days and then fades out over a period of months. The outburst arises when a torrent of stored gas suddenly rushes toward one of the most compact objects known, either a neutron star or a black hole.

Named Swift J1745-26 after the coordinates of its sky position, the nova is located a few degrees from the center of our galaxy toward the constellation Sagittarius. While astronomers do not know its precise distance, they think the object resides about 20,000 to 30,000 light-years away in the galaxy's inner region. The pattern of X-rays from the nova signals that the central object is a black hole.

The black hole must be a member of a low-mass X-ray binary (LMXB) system, which includes a normal, sun-like star. A stream of gas flows from the normal star and enters into a storage disk around the black hole. In most LMXBs, the gas in the disk spirals inward, heats up as it heads toward the black hole, and produces a steady stream of X-rays.

http://svs.gsfc.nasa.gov/vis/a010000/a011100/a011108/

[eidairaman1]

Originally Posted by Drone

Astronomers discover a new black hole in our galaxy

Yay! There's another one, far away from us, close to the center of the Milky Way. X-ray outbursts revealed its location.



http://svs.gsfc.nasa.gov/vis/a010000/a011100/a011108/

this is cool so the visible center of our galaxy is near view my astrological constellation sign of Saggitarius.

[patrico]

Originally Posted by Inceptor

So, because that video says that a Quasar looks like it is somehow connected to a much closer galaxy, the verifiable and reliable redshift measurement is somehow wrong? That's pathetic reasoning, no, that's not even reasoning, it's just foolish thinking.

if you had watched both of the vids its not just the Quasar issue,
but im not saying that its true,
but that there are many differing theory's about how the universe works,
and when observations dont match the big bang theory they just make some thing to fit what they think is going on,
like dark enery and dark matter thats just scientist way of saying they dont know whats going on,
i dont think we should be so set in our views, as always as new tech opens up new corridors of research and old theorys change as our understanding of the universe deepens

[Drone]

Suppermassive black hole (called ULASJ1234+0907) has been found:

In the new study, the team from Cambridge used infrared surveys being carried out on the UK Infrared Telescope (UKIRT) to peer through the dust and locate the giant black hole.

It's amazing what infrared can do, it simply peers through the dust so we're able to "see" what's been unseen.

ULASJ1234+0907, located in the direction of the constellation of Virgo, is so far away that the light from it has taken 11 billion years to reach us, so we see it as it appeared in the early universe. The monster black hole has > 10 billion times the mass of the Sun and 10,000 times the mass of the supermassive black hole in our own Milky Way, making it one of the most massive black holes ever seen.

That thing is really massive and so far away! Yet they were able to detect it.

http://phys.org/news/2012-10-giant-b...ng-survey.html

[douglatins]

I frigging love black holes

[qubit]

Black hole simulation laser closer to testing. Simulates a white hole inside a black hole!

In a laboratory in Scotland, a revolutionary kind of laser is taking shape – the first one to be made out of an artificial black hole.

Once complete, the device could help confirm mounting evidence that real black holes, despite their name, emit light. A black-hole laser could also find practical uses in devices that probe a material's properties without damaging it.

At the heart of such a laser is a phenomenon that Stephen Hawking predicted in the 1970s, and that physicists have been hunting ever since. Although not even light can escape their gravity, Hawking calculated that black holes should nonetheless emit a faint glow, now called Hawking radiation.

This is a consequence of quantum theory, which says that a vacuum is not truly empty, but fizzes with fleeting pairs of particles and their antimatter counterparts. Normally, these pairs rapidly annihilate and disappear again, but if a pair of photons pops out too close to a black hole, one falls in – and the other escapes.

New Scientist

So, imagine if a black hole and a white hole of equal mass were to meet. Their gravities would be equal and opposite so they'd pass right through each other as if they had no gravity, wouldn't they? Regardless, the physics would be extremely weird and just as fascinating.

[Drone]

Originally Posted by qubit

This is a consequence of quantum theory, which says that a vacuum is not truly empty, but fizzes with fleeting pairs of particles and their antimatter counterparts. Normally, these pairs rapidly annihilate and disappear again, but if a pair of photons pops out too close to a black hole, one falls in – and the other escapes.

Not a pair of photons but a pair of virtual particles. (because photon is an antiparticle of itself). Or did they mean something else?

[qubit]

Originally Posted by Drone

Not a pair of photons but a pair of virtual particles. (because photon is an antiparticle of itself). Or did they mean something else?

I'd never heard of photons being referred to as antiparticles before. You could be right about the virtual particles though. However, if they're virtual, then how could you ever see the black hole glow?

For what it's worth, I can't see the singularity being a point of infinite density. I reckon it only looks that way with general relativity because the theory is incomplete in such an extreme environment. I'll bet it fizzes madly with enornous energy dictated by quantum mechanics and is of a definite size. How this thing would look or behave, of course, I have no idea. I'll bet time is bent totally out of shape there too and would be unrecognizable. That's my 2 cents worth, anyway.

[Drone]

Originally Posted by qubit

I'd never heard of photons being referred to as antiparticles before. You could be right about the virtual particles though. However, if they're virtual, then how could you ever see the black hole glow?

You can see this post. Hawking radiation deals with a pair of electron and positron. They don't actually glow but they emit waves.

And photon is not the only particle which is own antiparticle. For example neutral pion is its own antiparticle. Here you can read about it, it's from a book Richard Feynman wrote:

Photons look exactly the same in all respects when they travel backwards in time...so they are their own anti-particles.

Gravitons, and some WIMPs are believed to have this property too.

For what it's worth, I can't see the singularity being a point of infinite density. I reckon it only looks that way with general relativity because the theory is incomplete in such an extreme environment. I'll bet it fizzes madly with enormous energy dictated by quantum mechanics and is of a definite size. How this thing would look or behave, of course, I have no idea.

Some scientists believe that true singularity doesn't exist at all. They say when neutrinos get packed too close they turn to super-fluid substance which won't let further collapse happen, and hence they prevent the singularity.

[Drone]

I'm not even sure how many times I re-watched this video

[qubit]

Originally Posted by Drone

I'm not even sure how many times I re-watched this video

Hehe, the narrator sounds like the G-man out of Half-life!