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Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region Forumslunatica
(53,410 posts)elias7
(4,001 posts)Response to lunatica (Original post)
MineralMan This message was self-deleted by its author.
lunatica
(53,410 posts)But now I dont see the image in your post.
MineralMan
(146,308 posts)People can open the URL for the image in a new tab, though, and see a much larger image. It's much easier to read.
lunatica
(53,410 posts)I realized the first image I used was illegible so I looked for another one and found the one thats there now.
If you have a better link it would be great if you post it!
MineralMan
(146,308 posts)I just right clicked the image and copied the URL, then opened it in a new tab. The full-size image is about twice as big.
DU shrinks images to fit the display area.
I tried using a text link, but that failed.
I'm not sure why, exactly.
Here's the link in a Tweet:
Link to tweet
lunatica
(53,410 posts)Thanks for the tweet link. It works nicely.
MineralMan
(146,308 posts)Cool image. DU's link system isn't perfect. I'm not sure why it didn't work on this.
byronius
(7,394 posts)PatrickforO
(14,574 posts)Physics isn't my forte, so excuse the ignorance, but I thought black holes were empty spaces, holes.
CloudWatcher
(1,848 posts)They are spheres, they are not really empty "holes" in space. The event horizon is where you no longer get to see what's going on inside. Any light going inside the horizon is bent so strongly that it can't get to us. But the mass of the black hole is still there, not empty or vanished.
The popular press keeps talking about infinite densities at the center of a black hole, and matter spewing into alternate universes. But there is zero evidence of that. All we know for sure is that the math of our current models of the universe are incomplete and fail spectacularly to predict what is going on at the center of one of these things.
Blue_true
(31,261 posts)In one panel it described relativistic jets as particles that are launched from the black hole digesting stars and other matter. In another panel it described the jets as originating from the swirling matter just outside the event horizon. If a black hole has such intense gravity, how can any particle escape to at anytime, unless the particle is of an as of yet unknown type?
There was a second group of astrophysicists that published a paper last summer that had data claiming that Sagittarius A was surrounded by possibly millions of black holes, wouldn't that potentially imply that Sag A is something other than a black hole? The paper from last summer is under peer review if I understood things correctly.
The group that released the image that the graphic diagrams stated that the image was of the center of another galaxy. Would that center have some commonalities with our own Sag A? If so, which group of astrophysicists are wrong, the one that published Hubble data last summer, or the current group that used coordinated earth bound telescopes?
CloudWatcher
(1,848 posts)particle is of an as of yet unknown type?
Yes, confusing! The writers here are using the term "black hole" to describe the entire system ... both inside and outside of the event horizon. The particles in the jets never went inside the event horizon. They started as part of the swirling mass outside the event horizon, were pulled towards the center of the black hole, but missed going in and were whipped around and launched back into space.
The reason the particles are squished into 'jets' (and not just flung out in random directions) is basically due to the rotation of the black hole. Exactly how the jets form and how they work is still a subject of intense research. A couple of cool pages:
Wikipedia: Astrophysical jet
Bad Astronomy: A Distant Black Hole Powers A Colossal Galactic Fountain
On a much (much!) smaller scale, NASA (et al) have used this slingshot (or gravity assist) effect often to save on fuel when sending probes to other planets in our solar system. Check out https://en.wikipedia.org/wiki/Gravity_assist for an impressive list of missions that have swung around various planets to gain (or shed) speed.
I think I found what you were referring to, here's one write-up: The Milky Way Is Hiding Tens Of Thousands Of Black Holes
There is no reason that the "super massive" Sagittarius A couldn't be a black hole surrounded by lots of other more normal sized black holes. Sagittarius A (and the super-massive black holes at the center of most galaxies) are the result of lots of smaller black holes merging. They're estimating now that there are over 10,000 black holes not too far from the center of the Milky Way.
Note the black-hole mergers that LIGO has detected have not involved super-massive black holes (yet). The collisions that they have detected so far range in size from 56 to 80 times the size of our sun. From Phys.org: Scientists detect biggest known black-hole collision
Sag-A is the super-massive black hole at the center of our Milky Way galaxy. The released image was of the super-massive black hole at the center of the "nearby" galaxy M87. The black hole at Sagittarius-A has about four million times the mass of our sun. The black hole at the center of M87 has about 6.5 billion times the mass of our sun. I.e. the M87 black hole is about 1625 times the size of the one at the center of the Milky way. But they are both super-massive black holes at the center of galaxies.
Sorry, I really don't see a conflict. Agree?
Postscript: In theory, mass does slowly escape after falling inside the event horizon. But it's due to Hawking Radiation and has nothing to do with what's producing the observed jets.
Disclaimer: my background is computer science, not physics nor astronomy. Apologies if I've gotten anything wrong.
Blue_true
(31,261 posts)lunatica
(53,410 posts)What they are is matter that is so dense that it has a very strong gravitational pull. So strong that even light cant pull away from it. What we see in space is the light emitted from objects, even if it is reflected light from planets. A black hole doesnt let light travel away from it so we see nothing.
LastLiberal in PalmSprings
(12,586 posts)to attract and consume other celestial matter, and astounded at how little we know about what happens beyond the event horizon. And to think there is a huge one of these suckers smack-dab in the middle of our galaxy!
Here's a TED talk that Dr. Katie Bouman gave about imaging a black hole.
This was given two years ago.
lunatica
(53,410 posts)Thats very interesting though it kind of lost me at the very end.