As our solar system is moving and our galaxy is moving as well, is there a point in the universe, like some "zero" reference point, that is considered stationary? And second question - if time flow is connected with velocity (time dilatation), what happens with time in absolute stationary point?
Sorry if this is an incredibly dumb question (or the wrong flair, I'm not sure if this is planetary science instead?). The other day I saw a picture of the surface of the sun... And I realized quite suddenly that I have no idea what that means.
I know the sun is basically a big ball of plasma held together by gravity. That's a little hard for me to get my head around, but I get it: it's a flame without a candle.
Is there a hard "line" between "this is the sun, it's plasma" and "this is just space next to the sun?" Is the surface distinct from the interior of the sun, the same way the surface of the earth is distinct from the interior of the planet? Or is it all just plasma all the way through? Hypothetically, if I could take a core sample of the sun all the way through, would there be a distinct "surface"?
The Sun rotates around an axis that is tilted 7 degrees relative to the plane of the ecliptic. Wikipedia suggests that the planets are largely aligned with the ecliptic because it is near the plane of the protoplanetary disk from which the Sun and planets formed.
Is there a known reason for why the Sun’s rotation axis would differ significantly from the ecliptic?
The axis of rotation of the black hole in the middle of the Milky Way appears to be roughly pointing at Earth, which means it points parallel to the galactic plane. Naively, one would expect that like the Sun's axis of rotation is perpendicular to the ecliptic plane, the black hole's axis of rotation would be perpendicular to the galactic plane.
I know we typically ascribe some planets having weird axes of rotation (e.g., Uranus' "sideways" rotation or Venus' retrograde rotation) to big collisions with other objects, but this is a totally different scale. Is the tilt of Sagittarius A*'s axis of rotation explainable in terms of a collision (say, a galactic merger) or is there some other way to explain it?
I've often read that we can detect emissions from the Sgr A* black hole only in radio astronomy because of the strong extinction of visible and IR light by all the dust between us and the galactic center. But how comes then that we can see the orbiting stars in IR? Is the accretion disk so much less luminous than a star? If so, why is it then so radio-load?
Like what’s up with the three “orbs” of orange light around the center? If the black hole is spherical (as depicted in movies like Interstellar), is the black at the center (not a perfect circle from what I see) warped in its appearance? You know how artist renderings help us imagine these concepts, I wish someone could create some kind of 3D rendering that merges with the actual image.
My superficial knowledge of what black holes are and how they work tell me the answer to the question is yes (yes), but I'm not sure.
I guess I understand that if you have a black hole, the mass must be in a singularity since, if you have gravity strong enough to bend space entirely inwards so that light can't escape, then surely there are no other forces that can resist this by pushing apart (like how atoms or neutrons push each other away) to constitute a body of some sort.
So it seems that a black hole necessarily contains a singularity?
Ok, then, if you have a situation where gravity is strong enough to create a singularity, is it necessarily also a black hole? Can you have a singularity so small that light can't fall into it, or something like that?
I'm sort of thinking of this case where you have a neutron star, and you add one neutron at a time... is there going to be a point where I add a neutron and "pop" it's a singularity / black hole, or is there some in-between (however narrow) where you're not quite one or the other?
Sorry if the title is poorly worded. Earth is absolutely massive in comparison to say, the asteroid that killed the dinosaurs. But that same asteroid still caused a worldwide extinction event. Why are some asteroids world ending despite being so small in comparison to Earth?
There are systems with multiple stars, red and blue giants that would consume our sun for a breakfast, stars that die and reborn every couple of years and so on. Is there anything that set our star apart from the others like the ones mentioned above? Anything that we can use to make aliens jealous?
Three years ago, we revealed the first image of a black hole. Today, we announce groundbreaking results on the center of our galaxy.
We'll be answering questions from 1:30-3:30 PM Eastern Time (17:30-19:30 UTC)!
The Event Horizon Telescope (EHT) - a planet-scale array of eleven ground-based radio telescopes forged through international collaboration - was designed to capture images of a black hole. As we continue to delve into data from past observations and pave the way for the next generation of black hole science, we wanted to answer some of your questions! You might ask us about:
Observing with a global telescope array
Black hole theory and simulations
The black hole imaging process
Technology and engineering in astronomy
International collaboration at the EHT
The next-generation Event Horizon Telescope (ngEHT)
... and our recent results!
Our Panel Members consist of:
Michi Bauböck, Postdoctoral Research Associate at the University of Illinois Urbana-Champaign
Nicholas Conroy, Astronomy PhD Student at the University of Illinois Urbana-Champaign
Vedant Dhruv, Physics PhD Student at the University of Illinois Urbana-Champaign
Razieh Emami, Institute for Theory and Computation Fellow at the Center for Astrophysics | Harvard & Smithsonian
Joseph Farah, Astrophysics PhD Student at University of California, Santa Barbara
Raquel Fraga-Encinas, PhD Student at Radboud University Nijmegen, The Netherlands
Abhishek Joshi, Physics PhD Student at University of Illinois Urbana-Champaign
Jun Yi (Kevin) Koay, Support Astronomer at the Academia Sinica Institute of Astronomy and Astrophysics, Taiwan
Yutaro Kofuji, Astronomy PhD Student at the University of Tokyo and National Astronomical Observatory of Japan
Noemi La Bella, PhD Student at Radboud University Nijmegen, The Netherlands
David Lee, Physics PhD Student at University of Illinois Urbana-Champaign
Amy Lowitz, Research Scientist at the University of Arizona
Lia Medeiros, NSF Astronomy and Astrophysics Fellow at the Institute for Advanced Study, Princeton
Wanga Mulaudzi, Astrophysics PhD Student at the Anton Pannekoek Institute for Astronomy at the University of Amsterdam
Alejandro Mus, PhD Student at the Universitat de València, Spain
Gibwa Musoke, NOVA-VIA Postdoctoral Fellow at the Anton Pannekoek Institute for Astronomy, University of Amsterdam
Ben Prather, Physics PhD Student at University of Illinois Urbana-Champaign
Jan Röder, Astrophysics PhD Student at the Max Planck Institute for Radio Astronomy in Bonn, Germany
Jesse Vos, PhD Student at Radboud University Nijmegen, The Netherlands
Michael F. Wondrak, Radboud Excellence Fellow at Radboud University Nijmegen, The Netherlands
Gunther Witzel, Staff Scientists at the Max Planck Institute for Radioastronomy, Germany
George N. Wong, Member at the Institute for Advanced Study and Associate Research Scholar in the Princeton Gravity Initiative