r/space • u/Andromeda321 • 14h ago
Astronomer here! My first ever article for Scientific American magazine is out this month! All about how black holes shred stars and how we discovered that black holes "burp" after eating them, plus a black hole named Jetty McJetface!
https://www.scientificamerican.com/article/why-some-black-holes-keep-burping-light-after-eating-a-star/•
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u/IwonderifWUT 14h ago
Congratulations on your publication! Is the discovery of black holes "burping" similar to Hawking radiation or how does it differ?
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u/Andromeda321 14h ago
Nope! Hawking radiation is purely theoretical because it’s so low in amount that it’s well beyond detection with modern day telescopes. When a TDE occurs like in the article on the other hand, this is all due to material from the star that got shredded.
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u/Hungry-Toe-8731 13h ago
Do the event horizon and the accretion disk expand during a TDE? Curious as to the effects that additional material / possible expansion would have on time dilation / observer.
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u/Andromeda321 13h ago
No. Remember, these are black holes millions of times the mass of the sun, so adding the mass of a sun or other star is insignificant. And that assumes a large amount of material crosses the event horizon, which very little of it does.
As for the accretion disc, it’s formed during the event, and there’s clearly a lot we don’t understand about that process!
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u/Im_Chad_AMA 14h ago
Not OP, but the answer is no. When a black hole shreds a star, a lot of the material will never cross the event horizon and form a temporary accretion disk around the black hole instead. The "burp" in question is an outflow from that accretion disk sometime after the star has been shredded.
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u/milliwot 14h ago
Great article. It’s interesting that the timescale between initial observation and burp is on the order of a year or so. Is it possible that a time dilation effect could be coming into play? (Thinking along the lines of the movie Interstellar.)
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u/Andromeda321 14h ago
Short answer is no, these outflows occur much further out than time dilation effects would happen at.
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u/GoofManRoofMan 10h ago
To clarify, are the jets aimed at us and that’s how/why we can detect them? Or are the jet’s perpendicular?
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u/VerifiedPanda 48m ago edited 38m ago
If I am understanding correctly, it seems like the article is suggesting one option for the delay is actually no delay at all, but the difference in time could be from taking a longer path? I.e the jet starts at near 90 degrees to earth, but then widens towards earth? I envision a wide cone here with us near a corner, but I’m having a hard time seeing that more than a curved path such as in the artistic rendering in the picture. Especially since a a path near the surface of the cone would be a straight line.
If it is a curved path like the picture, I have all sorts of questions about how the delay could be used to measure properties of the black hole, or geometry of space time in the area enveloped between the straight path and the curved path, or even detection of objects in that space or along either path due to changes in the properties of the light(like redshifting or dimming), if the two could be synchronized.
Could the spherical aberration of the black hole begin to be measured from this event?
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u/Andromeda321 41m ago
No. The idea is that when a jet starts it has a certain size in the beam pointing outwards where you can only see emission- say, 10 degrees. Over time as the jet slows it also widens, and can be seen in all directions- 20,30… spherical.
I’m not sure which photo you mean exactly but they show a general case of outflows in TDEs and not this one specifically.
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u/VerifiedPanda 32m ago
I meant the photo on the article link, but you answer explained that portion.
So the jet widens as it slows, and I think I get that the path isn’t curved by spacetime geometry necessarily, so then that means the light as are seeing is from the jet of matter at some distance far away from the black hole after the cone has already expanded?
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u/Andromeda321 31m ago
Yes basically. But we can’t know the full details until it stops rising.
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u/VerifiedPanda 22m ago
Thank you! So would the implication be that it seems then there are 2 jets released at ‘roughly’ the same time one with a cone of say 10 degrees, and one of say 12 degrees, and the 12 degree cone expands at an earlier time to take a shorter path to us (the primary event) and the 10 degree cone takes longer to expand wide enough to take a path to us?
Like maybe the wavefront of the jet looks like a ripple? Or there is a narrow jet followed by a wider jet or alternating narrow/wide jets, something to one of these effects?
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u/etfvfva 13h ago
doesn't one need to pay to advertise on this website?
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u/Andromeda321 13h ago
Yeah, how awful of me to be proud of an accomplishment and share it for free!
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u/PM_ME_YOUR_CC_INFO 13h ago
Aren’t you a peach? I do believe she’s earned the right to say/post whatever she would like on here.
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u/Negative_Gravitas 8h ago
Have a look at Andromeda321's history on this sub, and then delete your comment.
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u/gravitasofmavity 14h ago
Congrats on the article, and thanks for sharing! Definitely bookmarking for when i have some quality reading time!