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Fraser
2003-Jul-15, 09:07 AM
SUMMARY: A new image taken by the Chandra X-Ray Observatory shows gas and dust blowing away from a supermassive black hole at the heart of galaxy NGC 1068 at 1.6 million kilometres/hour. The elongated shape of the gas plume is thought to be caused by a donut-shaped ring of cooler dust surrounding the black hole, which acts to focus material pouring away. Instruments on board Chandra have measured the gas plume and found that it's similar in composition to our own Sun and has a temperature of 100,000 degrees Celcius.


Comments or questions about this story? Feel free to share your thoughts.

Charles Bell
2003-Jul-16, 01:54 AM
Black holes are supposed to be sucking all the matter ariund them in, not blowing them out.
This reads like a reversal of physics.
:blink:

Dr. Patrick M. Ogle
2003-Jul-16, 06:03 PM
Dear Mr. Bell,

I am the author of the Chandra study of the active galaxy NGC 1068. I work as
an astronomer in the UC Santa Barbara Physics Department.

Active galaxies such as NGC 1068 and radio galaxies and quasars commonly show
fast winds or even more spectacular jets moving near the speed of light away
from the central black hole. If the black hole is such a strong source of
gravity, then why is the matter blasting away rather than falling in? Good
question.

I do not know a single case where matter has been observed falling directly
into a black hole. It is typically seen moving in circles around the hole in
an accretion disk. The physical reason is conservation of angular momentum
(aka spin). It is the same reason why the planets orbit around the sun instead
of falling in.

Then how does the black hole grow? Astronomers think that magnetic fields which
build up in the plasma in the disk flings a small fraction of matter outward at the same time
the same time pushing matter inward towards the hole. This way total angular
momentum is conserved. The outward flowing matter is additionally accelerated
by the strong radiation field near the black hole, and we observe it as a
wind or jet.

Why don't we see the larger fraction of matter which is moving inward towards
the hole? This is not known for certain. For one, it has to fight against
centrifugal forces which increase as it swirls faster and faster towards the
hole. It may be that we only see the outer skin of the disk which is generally
pushed away from the hole by radiation, while the infalling matter lies unseen
in the dense central plane of the disk.

Black hole accretion disk and wind systems are complicated and fascinating to
study. While we think we understand some basics, we are still a long way from
solving the entire puzzle of how they work. Gravity wins in the end, but
magnetic and radiation forces are important in these very luminous and
energetic objects.

Best wishes,
Patrick Ogle

Keith Nealy
2003-Jul-16, 10:28 PM
Have we ever been able to see an angular size of a black hole or accretion disk? In other words, has one ever been resolved as other than a point source? How close can we come? Can we see any stars other than our sun as disks?

Kevin Milburn
2003-Jul-17, 02:24 AM
Dr. Patrick M. Ogle:

That was an incredible amount of information in such a small amount of words - and the best part is it was in a language I can understand.

I'm a long time Sky & Telescope reader and sometimes the articles in my most favourite astronomy magazine are way over my head. For those of us who are not physics majors we need more people like yourself who can take physics and explain it to us in understandable english.

Thank you for the explanation. It really is fascinating how the universe works.

KEV

Fraser
2003-Jul-17, 02:53 AM
Isn't it great to see the original researcher giving the answer? I love the Internet. :-)

DippyHippy
2003-Jul-17, 03:47 AM
I too would like to thank Dr Ogle for taking the time to explain the subject in terms we can all understand!

Out of curiosity, Fraser, did you invite him to contribute?

Dips

Fraser
2003-Jul-17, 04:15 AM
Yep.

Kevin
2003-Jul-17, 05:43 AM
What would be the opposite of a black hole? A white hole??? Could that have been the origin of the Big Bang?

Matthew3E
2003-Jul-17, 09:46 AM
First, thank you Dr. Ogle for that," Down to Earth", answer. Second I would like to put forth an idea...


Why don't we see the larger fraction of matter which is moving inward towards
the hole? This is not known for certain. For one, it has to fight against
centrifugal forces which increase as it swirls faster and faster towards the
hole. It may be that we only see the outer skin of the disk which is generally
pushed away from the hole by radiation, while the infalling matter lies unseen
in the dense central plane of the disk.


Now, the way I understand Black Holes, the reason they are black is due to the fact that light cannot escape its' gravitational pull. Assuming that this is true (I know little of space or physics), it stands to reason that the very same force which you claim expels matter toward the outer portion of the hole thereby enlarging it, also hides it. Meaning, that at a certain point, matter speeds up past the range of our ability to see it (even with the aid of technology), and is sucked inward.

Perhaps an indication that there is something past the speed of light?

Guest
2003-Jul-17, 10:15 AM
Greetings, Wow what a superb answer that was, Thank you indeed Dr. Ogle!

and to Matthew3E - I was thinking the same as you as I was reading the reply - that the light from the matter being sucked in can't escape from the blackhole to allow us to detect its presence so we don't see matter going in.

And indeed like Matthew I know little of space of physics, but after thinking as Matthew did a little further, I thought that perhaps there are other ways used of detecting the matter going into black holes than simply trying to see the light from them. And if this is the case then are these forces (radiowaves / xrays etc) also affected by the gravitational pull of the black hole?

Light has mass if i understand it - and having this property allows them to be acted upon by outside forces like the extreme gravity in around a black hole- do radio waves or xrays or whatever other technologies are available to us for peering into the sky also get affected by gravity too i wonder?

perhaps trying to "see" the matter giong in won't work but perhaps other ways of detecting it exist already?

just my 2p

peace
mark

SteveT
2003-Jul-17, 08:21 PM
Photons have zero rest mass, though they do have energy of course and as such will be affected by gravity. Since black holes (or rather their accretion disks) are strong sources of all forms of electromagnetic radiation (if I remember correctly it's called synchrotron radiation since it's produced by charged particles in a magnetic field), I would guess that when Dr. Ogle used the word "see," he was referring to x rays and radio as well as visible light.

It has occurred to me that with an accretion disk emitting so much radiation, the particles that it's composed of must be losing energy. When an electron (for instance) in orbit around the black hole emits a photon, it loses energy and moves into a lower orbit, eventually reaching the event horizon. Does anybody know if this is correct?

Kevin Milburn
2003-Jul-17, 08:59 PM
FRASER:

The internet can be a wonderful place to learn...there's a huge dark side to it as well though. But when you can interact with researchers like Dr. Ogle and get information directly from the people who are working on a daily basis with cutting edge technology in areas such a physics it truly is a great place to be...

My own area of expertise in physics is limited to "for every action there is an oposite and equal reaction" so it's delightful to get information that is not only current but direct from a reliable source.

It was a great idea you had to bring these forums to life...

Bye the way I love getting my space related information from Universe Today and I even appreciate the non-intrusive ads, especially the space related stuff...

DR. OGLE:

Do you think that any of Einstein's theories will ever be proven to be wrong?

And since I'm a big Hawking fan I wonder if you think his theories will ever be proven correct someday?

It really does seem to be true that today's researchers do stand on the shoulders of giants that have gone before them, like Einstein/Hawking.

KEV

imported_Mark
2003-Jul-24, 10:03 AM
Originally posted by SteveT@Jul 17 2003, 08:21 PM
Photons have zero rest mass, though they do have energy of course and as such will be affected by gravity. Since black holes (or rather their accretion disks) are strong sources of all forms of electromagnetic radiation (if I remember correctly it's called synchrotron radiation since it's produced by charged particles in a magnetic field), I would guess that when Dr. Ogle used the word "see," he was referring to x rays and radio as well as visible light.

It has occurred to me that with an accretion disk emitting so much radiation, the particles that it's composed of must be losing energy. When an electron (for instance) in orbit around the black hole emits a photon, it loses energy and moves into a lower orbit, eventually reaching the event horizon. Does anybody know if this is correct?
Thanks for clearing up my misguided understandings of all things physics,
thinking a little more i expect you are utterly right that he was refering to all the possible ways of viewing these things, not just 'seeing'

thanks again,
I do like these forums

mark

thomastech
2003-Jul-24, 12:06 PM
Our own sun spews coronal material out along magnetic field lines.

Its not too hard to imagine the same type of material spewing out from a Black Hole along its magnetic field lines?

We only see the Solar Wind at night when it interacts with our atmosphere.

PSmith
2003-Jul-25, 12:45 AM
Thank you, Dr. Ogle, thank you very much indeed. That was one of the deftest pieces of explication of some basic physics that I have ever seen.

John Dedes
2003-Aug-20, 04:52 AM
Dr. Ogle,
I hope to read more of your contributions to discussion forums, I was very impressed with your views and have a few questions in regards to black holes, are they similar {if you just look at the motion} to hurricanes,whirlpools,eddies, tornadoes, that are by-products or a result of a much larger moving "body"? and is it because of the rotation of a much larger body containing matter, i.e a galaxy, probably spiral in its motion, where the onset of black holes are most likely? Does corriolis force have a part in the motion of black holes?

Kumar
2003-Sep-24, 06:27 AM
Originally posted by Dr. Patrick M. Ogle@Jul 16 2003, 06:03 PM
Dear Mr. Bell,

I am the author of the Chandra study of the active galaxy NGC 1068. I work as
an astronomer in the UC Santa Barbara Physics Department.

Best wishes,
Patrick Ogle
I read in some articles on the net that a certain sound is emitting from the black hole, and that it closely resembles the Hindu "Om" sound. Is this true??

damienpaul
2004-Jan-07, 04:10 AM
thank you Dr. Ogle! it all makes a huge amount of sense to me now! thank you fraser for inviting Dr. Ogle (1 more brownie point for you) and i like the analogy that thmoastech makes....

this forum is awesome