Why was M87 targeted for the Event Horizon Telescope instead of Sagittarius A*? The 2019 Stack Overflow Developer Survey Results Are In Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Why couldn't they take pictures of a closer black hole?How is the mass of black hole at the center of our galaxy measured?What happens to the wavelength/frequency of a photon as it passes through an event horizon?Why the center of our galaxy doesn't absorb us?How Can Anything Escape A Supermassive Black Hole?Are black holes in a binary system with white holes, and are they both wormholes?Observer inside event horizon of an extremely large black holeIs it possible the space-time manifold itself could stop at a black hole's event horizon?Picture of Sgr A*First Black Hole Picture TakeawaysWhy couldn't they take pictures of a closer black hole?
How to politely respond to generic emails requesting a PhD/job in my lab? Without wasting too much time
How do I add random spotting to the same face in cycles?
Windows 10: How to Lock (not sleep) laptop on lid close?
Is it ok to offer lower paid work as a trial period before negotiating for a full-time job?
"... to apply for a visa" or "... and applied for a visa"?
Did the new image of black hole confirm the general theory of relativity?
Is it ethical to upload a automatically generated paper to a non peer-reviewed site as part of a larger research?
Relations between two reciprocal partial derivatives?
What was the last x86 CPU that did not have the x87 floating-point unit built in?
What do you call a plan that's an alternative plan in case your initial plan fails?
Can the DM override racial traits?
Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia?
When did F become S in typeography, and why?
Do working physicists consider Newtonian mechanics to be "falsified"?
Who or what is the being for whom Being is a question for Heidegger?
How to copy the contents of all files with a certain name into a new file?
Does Parliament hold absolute power in the UK?
Did God make two great lights or did He make the great light two?
Mortgage adviser recommends a longer term than necessary combined with overpayments
Change bounding box of math glyphs in LuaTeX
I could not break this equation. Please help me
Why can't wing-mounted spoilers be used to steepen approaches?
Netflix Recommendations?
Arduino Pro Micro - switch off LEDs
Why was M87 targeted for the Event Horizon Telescope instead of Sagittarius A*?
The 2019 Stack Overflow Developer Survey Results Are In
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Why couldn't they take pictures of a closer black hole?How is the mass of black hole at the center of our galaxy measured?What happens to the wavelength/frequency of a photon as it passes through an event horizon?Why the center of our galaxy doesn't absorb us?How Can Anything Escape A Supermassive Black Hole?Are black holes in a binary system with white holes, and are they both wormholes?Observer inside event horizon of an extremely large black holeIs it possible the space-time manifold itself could stop at a black hole's event horizon?Picture of Sgr A*First Black Hole Picture TakeawaysWhy couldn't they take pictures of a closer black hole?
$begingroup$
The first image of a black hole has been released today, April 10th, 2019. The team targeted the black hole at the center of the M87 galaxy.
Why didn't the team target Sagittarius A* at the center of our own galaxy? Intuitively, it would seem to be a better target as it is closer to us.
black-holes astronomy event-horizon
edited 2 days ago
Peter Mortensen
1,95511323
asked Apr 10 at 17:24
MaxterMaxter
332210
$endgroup$
add a comment |
$begingroup$
The first image of a black hole has been released today, April 10th, 2019. The team targeted the black hole at the center of the M87 galaxy.
Why didn't the team target Sagittarius A* at the center of our own galaxy? Intuitively, it would seem to be a better target as it is closer to us.
black-holes astronomy event-horizon
edited 2 days ago
Peter Mortensen
1,95511323
asked Apr 10 at 17:24
MaxterMaxter
332210
$endgroup$
9
$begingroup$
Related question on Astronomy Stack Exchange: astronomy.stackexchange.com/q/30313/2153.
$endgroup$
– HDE 226868
Apr 10 at 17:29
1
$begingroup$
Another similar question on Astronomy - Why not take a picture of a closer black hole?
$endgroup$
– BruceWayne
2 days ago
add a comment |
$begingroup$
The first image of a black hole has been released today, April 10th, 2019. The team targeted the black hole at the center of the M87 galaxy.
Why didn't the team target Sagittarius A* at the center of our own galaxy? Intuitively, it would seem to be a better target as it is closer to us.
black-holes astronomy event-horizon
edited 2 days ago
Peter Mortensen
1,95511323
asked Apr 10 at 17:24
MaxterMaxter
332210
$endgroup$
The first image of a black hole has been released today, April 10th, 2019. The team targeted the black hole at the center of the M87 galaxy.
Why didn't the team target Sagittarius A* at the center of our own galaxy? Intuitively, it would seem to be a better target as it is closer to us.
black-holes astronomy event-horizon
black-holes astronomy event-horizon
edited 2 days ago
Peter Mortensen
1,95511323
asked Apr 10 at 17:24
MaxterMaxter
332210
edited 2 days ago
Peter Mortensen
1,95511323
asked Apr 10 at 17:24
MaxterMaxter
332210
edited 2 days ago
Peter Mortensen
1,95511323
edited 2 days ago
Peter Mortensen
1,95511323
edited 2 days ago
Peter Mortensen
1,95511323
1,95511323
asked Apr 10 at 17:24
MaxterMaxter
332210
asked Apr 10 at 17:24
MaxterMaxter
332210
asked Apr 10 at 17:24
MaxterMaxter
332210
332210
9
$begingroup$
Related question on Astronomy Stack Exchange: astronomy.stackexchange.com/q/30313/2153.
$endgroup$
– HDE 226868
Apr 10 at 17:29
1
$begingroup$
Another similar question on Astronomy - Why not take a picture of a closer black hole?
$endgroup$
– BruceWayne
2 days ago
add a comment |
9
$begingroup$
Related question on Astronomy Stack Exchange: astronomy.stackexchange.com/q/30313/2153.
$endgroup$
– HDE 226868
Apr 10 at 17:29
1
$begingroup$
Another similar question on Astronomy - Why not take a picture of a closer black hole?
$endgroup$
– BruceWayne
2 days ago
9
9
$begingroup$
Related question on Astronomy Stack Exchange: astronomy.stackexchange.com/q/30313/2153.
$endgroup$
– HDE 226868
Apr 10 at 17:29
$begingroup$
Related question on Astronomy Stack Exchange: astronomy.stackexchange.com/q/30313/2153.
$endgroup$
– HDE 226868
Apr 10 at 17:29
1
1
$begingroup$
Another similar question on Astronomy - Why not take a picture of a closer black hole?
$endgroup$
– BruceWayne
2 days ago
$begingroup$
Another similar question on Astronomy - Why not take a picture of a closer black hole?
$endgroup$
– BruceWayne
2 days ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Of course they targeted Sgr A* as well.
I think though that this is a more difficult target to get good images of.
The black hole is about 1500 times less massive than in M87, but is about 2000 times closer. So the angular scale of the event horizons should be similar. However Sgr A* is a fairly dormant black hole and may not be illuminated so well, and there is more scattering material between us and it than in M87.
A bigger problem may be variability timescales$^dagger$. The black hole in M87 is light days across, so images can be combined across several days of observing. Sgr A* is light minutes across, so rapid variability could be a problem.
The penultimate paragraph of the initial Event Horizon Telescope paper says:
Another primary EHT source, Sgr A*, has a precisely measured mass three orders of magnitude smaller than that of M87*, with dynamical timescales of minutes instead of days. Observing the shadow of Sgr A* will require accounting for this variability and mitigation of scattering effects caused by the interstellar medium
$dagger$ The accretion flow into a black hole is turbulent and variable. However, the shortest timescale upon which significant changes can take place across the source is the timescale for light (the fastest possible means of communication) to travel across or around it. Because the material close to the black hole is moving relativistically, we do expect things to vary on these kinds of timescales. The photon sphere of a black hole is approximately $6GM/c^2$ across, meaning a shortest timescale of variability is about $6GM/c^3$. In more obvious units:
$$ tau sim 30 left(fracM10^6 M_odotright) rm seconds.$$
i.e. We might expect variability in the image on timescales of 30 seconds multiplied by the black hole mass in units of millions of solar masses. This is 2 minutes for Sgr A* and a much longer 2.25 days for the M87 black hole.
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
$endgroup$
4
$begingroup$
I was going to protest this answer, but now just have a catch to add. In some places (looking at you, Veritasium) a simulated image of SgrA* is easy to mistake as a genuine photo. Now I understand why SgrA* isn't even in the press release. The circulating SgrA* image is just a simulation. See source material and comments section: youtu.be/VnsZj9RvhFU
$endgroup$
– World Outsider
Apr 10 at 23:09
1
$begingroup$
I'd intuitively think that dust in the disk of our galaxy plays a part by obscuring the innermost regions.
$endgroup$
– Allure
Apr 10 at 23:52
4
$begingroup$
@Allure The centre isn't obscured at 1.3mm wavelengths.
$endgroup$
– Rob Jeffries
2 days ago
2
$begingroup$
So why not Andromeda, or any closer galaxy? Size of central black hole? Orientation of galaxy (edge-on, face-on, or in between)?
$endgroup$
– David Conrad
2 days ago
1
$begingroup$
@DavidConrad You will find another question about that somewhere. Yes, the angular size of the Andromeda black hole would be a bit smaller.
$endgroup$
– Rob Jeffries
2 days ago
|
show 3 more comments
Your Answer
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "151"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f471792%2fwhy-was-m87-targeted-for-the-event-horizon-telescope-instead-of-sagittarius-a%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Of course they targeted Sgr A* as well.
I think though that this is a more difficult target to get good images of.
The black hole is about 1500 times less massive than in M87, but is about 2000 times closer. So the angular scale of the event horizons should be similar. However Sgr A* is a fairly dormant black hole and may not be illuminated so well, and there is more scattering material between us and it than in M87.
A bigger problem may be variability timescales$^dagger$. The black hole in M87 is light days across, so images can be combined across several days of observing. Sgr A* is light minutes across, so rapid variability could be a problem.
The penultimate paragraph of the initial Event Horizon Telescope paper says:
Another primary EHT source, Sgr A*, has a precisely measured mass three orders of magnitude smaller than that of M87*, with dynamical timescales of minutes instead of days. Observing the shadow of Sgr A* will require accounting for this variability and mitigation of scattering effects caused by the interstellar medium
$dagger$ The accretion flow into a black hole is turbulent and variable. However, the shortest timescale upon which significant changes can take place across the source is the timescale for light (the fastest possible means of communication) to travel across or around it. Because the material close to the black hole is moving relativistically, we do expect things to vary on these kinds of timescales. The photon sphere of a black hole is approximately $6GM/c^2$ across, meaning a shortest timescale of variability is about $6GM/c^3$. In more obvious units:
$$ tau sim 30 left(fracM10^6 M_odotright) rm seconds.$$
i.e. We might expect variability in the image on timescales of 30 seconds multiplied by the black hole mass in units of millions of solar masses. This is 2 minutes for Sgr A* and a much longer 2.25 days for the M87 black hole.
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
$endgroup$
4
$begingroup$
I was going to protest this answer, but now just have a catch to add. In some places (looking at you, Veritasium) a simulated image of SgrA* is easy to mistake as a genuine photo. Now I understand why SgrA* isn't even in the press release. The circulating SgrA* image is just a simulation. See source material and comments section: youtu.be/VnsZj9RvhFU
$endgroup$
– World Outsider
Apr 10 at 23:09
1
$begingroup$
I'd intuitively think that dust in the disk of our galaxy plays a part by obscuring the innermost regions.
$endgroup$
– Allure
Apr 10 at 23:52
4
$begingroup$
@Allure The centre isn't obscured at 1.3mm wavelengths.
$endgroup$
– Rob Jeffries
2 days ago
2
$begingroup$
So why not Andromeda, or any closer galaxy? Size of central black hole? Orientation of galaxy (edge-on, face-on, or in between)?
$endgroup$
– David Conrad
2 days ago
1
$begingroup$
@DavidConrad You will find another question about that somewhere. Yes, the angular size of the Andromeda black hole would be a bit smaller.
$endgroup$
– Rob Jeffries
2 days ago
|
show 3 more comments
$begingroup$
Of course they targeted Sgr A* as well.
I think though that this is a more difficult target to get good images of.
The black hole is about 1500 times less massive than in M87, but is about 2000 times closer. So the angular scale of the event horizons should be similar. However Sgr A* is a fairly dormant black hole and may not be illuminated so well, and there is more scattering material between us and it than in M87.
A bigger problem may be variability timescales$^dagger$. The black hole in M87 is light days across, so images can be combined across several days of observing. Sgr A* is light minutes across, so rapid variability could be a problem.
The penultimate paragraph of the initial Event Horizon Telescope paper says:
Another primary EHT source, Sgr A*, has a precisely measured mass three orders of magnitude smaller than that of M87*, with dynamical timescales of minutes instead of days. Observing the shadow of Sgr A* will require accounting for this variability and mitigation of scattering effects caused by the interstellar medium
$dagger$ The accretion flow into a black hole is turbulent and variable. However, the shortest timescale upon which significant changes can take place across the source is the timescale for light (the fastest possible means of communication) to travel across or around it. Because the material close to the black hole is moving relativistically, we do expect things to vary on these kinds of timescales. The photon sphere of a black hole is approximately $6GM/c^2$ across, meaning a shortest timescale of variability is about $6GM/c^3$. In more obvious units:
$$ tau sim 30 left(fracM10^6 M_odotright) rm seconds.$$
i.e. We might expect variability in the image on timescales of 30 seconds multiplied by the black hole mass in units of millions of solar masses. This is 2 minutes for Sgr A* and a much longer 2.25 days for the M87 black hole.
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
$endgroup$
4
$begingroup$
I was going to protest this answer, but now just have a catch to add. In some places (looking at you, Veritasium) a simulated image of SgrA* is easy to mistake as a genuine photo. Now I understand why SgrA* isn't even in the press release. The circulating SgrA* image is just a simulation. See source material and comments section: youtu.be/VnsZj9RvhFU
$endgroup$
– World Outsider
Apr 10 at 23:09
1
$begingroup$
I'd intuitively think that dust in the disk of our galaxy plays a part by obscuring the innermost regions.
$endgroup$
– Allure
Apr 10 at 23:52
4
$begingroup$
@Allure The centre isn't obscured at 1.3mm wavelengths.
$endgroup$
– Rob Jeffries
2 days ago
2
$begingroup$
So why not Andromeda, or any closer galaxy? Size of central black hole? Orientation of galaxy (edge-on, face-on, or in between)?
$endgroup$
– David Conrad
2 days ago
1
$begingroup$
@DavidConrad You will find another question about that somewhere. Yes, the angular size of the Andromeda black hole would be a bit smaller.
$endgroup$
– Rob Jeffries
2 days ago
|
show 3 more comments
$begingroup$
Of course they targeted Sgr A* as well.
I think though that this is a more difficult target to get good images of.
The black hole is about 1500 times less massive than in M87, but is about 2000 times closer. So the angular scale of the event horizons should be similar. However Sgr A* is a fairly dormant black hole and may not be illuminated so well, and there is more scattering material between us and it than in M87.
A bigger problem may be variability timescales$^dagger$. The black hole in M87 is light days across, so images can be combined across several days of observing. Sgr A* is light minutes across, so rapid variability could be a problem.
The penultimate paragraph of the initial Event Horizon Telescope paper says:
Another primary EHT source, Sgr A*, has a precisely measured mass three orders of magnitude smaller than that of M87*, with dynamical timescales of minutes instead of days. Observing the shadow of Sgr A* will require accounting for this variability and mitigation of scattering effects caused by the interstellar medium
$dagger$ The accretion flow into a black hole is turbulent and variable. However, the shortest timescale upon which significant changes can take place across the source is the timescale for light (the fastest possible means of communication) to travel across or around it. Because the material close to the black hole is moving relativistically, we do expect things to vary on these kinds of timescales. The photon sphere of a black hole is approximately $6GM/c^2$ across, meaning a shortest timescale of variability is about $6GM/c^3$. In more obvious units:
$$ tau sim 30 left(fracM10^6 M_odotright) rm seconds.$$
i.e. We might expect variability in the image on timescales of 30 seconds multiplied by the black hole mass in units of millions of solar masses. This is 2 minutes for Sgr A* and a much longer 2.25 days for the M87 black hole.
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
$endgroup$
Of course they targeted Sgr A* as well.
I think though that this is a more difficult target to get good images of.
The black hole is about 1500 times less massive than in M87, but is about 2000 times closer. So the angular scale of the event horizons should be similar. However Sgr A* is a fairly dormant black hole and may not be illuminated so well, and there is more scattering material between us and it than in M87.
A bigger problem may be variability timescales$^dagger$. The black hole in M87 is light days across, so images can be combined across several days of observing. Sgr A* is light minutes across, so rapid variability could be a problem.
The penultimate paragraph of the initial Event Horizon Telescope paper says:
Another primary EHT source, Sgr A*, has a precisely measured mass three orders of magnitude smaller than that of M87*, with dynamical timescales of minutes instead of days. Observing the shadow of Sgr A* will require accounting for this variability and mitigation of scattering effects caused by the interstellar medium
$dagger$ The accretion flow into a black hole is turbulent and variable. However, the shortest timescale upon which significant changes can take place across the source is the timescale for light (the fastest possible means of communication) to travel across or around it. Because the material close to the black hole is moving relativistically, we do expect things to vary on these kinds of timescales. The photon sphere of a black hole is approximately $6GM/c^2$ across, meaning a shortest timescale of variability is about $6GM/c^3$. In more obvious units:
$$ tau sim 30 left(fracM10^6 M_odotright) rm seconds.$$
i.e. We might expect variability in the image on timescales of 30 seconds multiplied by the black hole mass in units of millions of solar masses. This is 2 minutes for Sgr A* and a much longer 2.25 days for the M87 black hole.
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
edited 2 days ago
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
answered Apr 10 at 18:12
Rob JeffriesRob Jeffries
71.2k7151248
71.2k7151248
4
$begingroup$
I was going to protest this answer, but now just have a catch to add. In some places (looking at you, Veritasium) a simulated image of SgrA* is easy to mistake as a genuine photo. Now I understand why SgrA* isn't even in the press release. The circulating SgrA* image is just a simulation. See source material and comments section: youtu.be/VnsZj9RvhFU
$endgroup$
– World Outsider
Apr 10 at 23:09
1
$begingroup$
I'd intuitively think that dust in the disk of our galaxy plays a part by obscuring the innermost regions.
$endgroup$
– Allure
Apr 10 at 23:52
4
$begingroup$
@Allure The centre isn't obscured at 1.3mm wavelengths.
$endgroup$
– Rob Jeffries
2 days ago
2
$begingroup$
So why not Andromeda, or any closer galaxy? Size of central black hole? Orientation of galaxy (edge-on, face-on, or in between)?
$endgroup$
– David Conrad
2 days ago
1
$begingroup$
@DavidConrad You will find another question about that somewhere. Yes, the angular size of the Andromeda black hole would be a bit smaller.
$endgroup$
– Rob Jeffries
2 days ago
|
show 3 more comments
4
$begingroup$
I was going to protest this answer, but now just have a catch to add. In some places (looking at you, Veritasium) a simulated image of SgrA* is easy to mistake as a genuine photo. Now I understand why SgrA* isn't even in the press release. The circulating SgrA* image is just a simulation. See source material and comments section: youtu.be/VnsZj9RvhFU
$endgroup$
– World Outsider
Apr 10 at 23:09
1
$begingroup$
I'd intuitively think that dust in the disk of our galaxy plays a part by obscuring the innermost regions.
$endgroup$
– Allure
Apr 10 at 23:52
4
$begingroup$
@Allure The centre isn't obscured at 1.3mm wavelengths.
$endgroup$
– Rob Jeffries
2 days ago
2
$begingroup$
So why not Andromeda, or any closer galaxy? Size of central black hole? Orientation of galaxy (edge-on, face-on, or in between)?
$endgroup$
– David Conrad
2 days ago
1
$begingroup$
@DavidConrad You will find another question about that somewhere. Yes, the angular size of the Andromeda black hole would be a bit smaller.
$endgroup$
– Rob Jeffries
2 days ago
4
4
$begingroup$
I was going to protest this answer, but now just have a catch to add. In some places (looking at you, Veritasium) a simulated image of SgrA* is easy to mistake as a genuine photo. Now I understand why SgrA* isn't even in the press release. The circulating SgrA* image is just a simulation. See source material and comments section: youtu.be/VnsZj9RvhFU
$endgroup$
– World Outsider
Apr 10 at 23:09
$begingroup$
I was going to protest this answer, but now just have a catch to add. In some places (looking at you, Veritasium) a simulated image of SgrA* is easy to mistake as a genuine photo. Now I understand why SgrA* isn't even in the press release. The circulating SgrA* image is just a simulation. See source material and comments section: youtu.be/VnsZj9RvhFU
$endgroup$
– World Outsider
Apr 10 at 23:09
1
1
$begingroup$
I'd intuitively think that dust in the disk of our galaxy plays a part by obscuring the innermost regions.
$endgroup$
– Allure
Apr 10 at 23:52
$begingroup$
I'd intuitively think that dust in the disk of our galaxy plays a part by obscuring the innermost regions.
$endgroup$
– Allure
Apr 10 at 23:52
4
4
$begingroup$
@Allure The centre isn't obscured at 1.3mm wavelengths.
$endgroup$
– Rob Jeffries
2 days ago
$begingroup$
@Allure The centre isn't obscured at 1.3mm wavelengths.
$endgroup$
– Rob Jeffries
2 days ago
2
2
$begingroup$
So why not Andromeda, or any closer galaxy? Size of central black hole? Orientation of galaxy (edge-on, face-on, or in between)?
$endgroup$
– David Conrad
2 days ago
$begingroup$
So why not Andromeda, or any closer galaxy? Size of central black hole? Orientation of galaxy (edge-on, face-on, or in between)?
$endgroup$
– David Conrad
2 days ago
1
1
$begingroup$
@DavidConrad You will find another question about that somewhere. Yes, the angular size of the Andromeda black hole would be a bit smaller.
$endgroup$
– Rob Jeffries
2 days ago
$begingroup$
@DavidConrad You will find another question about that somewhere. Yes, the angular size of the Andromeda black hole would be a bit smaller.
$endgroup$
– Rob Jeffries
2 days ago
|
show 3 more comments
Thanks for contributing an answer to Physics Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f471792%2fwhy-was-m87-targeted-for-the-event-horizon-telescope-instead-of-sagittarius-a%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
9
$begingroup$
Related question on Astronomy Stack Exchange: astronomy.stackexchange.com/q/30313/2153.
$endgroup$
– HDE 226868
Apr 10 at 17:29
1
$begingroup$
Another similar question on Astronomy - Why not take a picture of a closer black hole?
$endgroup$
– BruceWayne
2 days ago