Timeline for Is our central black hole actually at the CG of the galaxy?
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 19, 2016 at 0:57 | vote | accept | Fattie | ||
| Jun 17, 2016 at 0:20 | comment | added | Jack R. Woods | I guess all I was saying is that just as random interactions during the formation of the solar system has displaced the center of gravity from the center of the sun, the interaction of matter during and since the formation of the milky way has probably displaced the center of the galaxy from the central SMBH. Also, the galaxy is so large compared to the size of the SMBH that the center is probably not inside the black hole. I could be wrong , but this seems logical. | |
| Jun 15, 2016 at 11:53 | comment | added | Peter Erwin | @RobJeffries -- whoops. Yes, of course, you're right; I think I confused myself by thinking of the Earth-Moon barycenter (which is within the Earth). | |
| Jun 14, 2016 at 22:58 | comment | added | ProfRob | @PeterErwin The barycentre of the solar system spends most of its time outside the Sun. | |
| Jun 14, 2016 at 12:53 | comment | added | Fattie | Just to clarify my question for anyone reading, I can see no immediately compelling reason why, particularly, a SBH in a galaxy should be at the middle. For example, say I learned that a SBH forms when (this is just a random-sounding example) "a big star cluster collapses". That could certainly happen anywhere in a galaxy as "big star clusters" are all over; the SBH would then orbit at that radius. I observe that some folks seem to "naturally assume" a SBH would be central: I just don't see that. (By all means someone can tell me different, and why would it be in the middle?) | |
| Jun 14, 2016 at 12:51 | comment | added | Fattie | Hi Jack - hmm, that sort of missed the point: in our solar system,the sun is indeed at the center. (Obviously there is a tiny displacement, due to the other miniscule bodies in the system.) However, alpha centauri is not at the center of it's system, it's a completely different type of system. Our sun is not at the center of the galaxy (kids often assume this is the case); our planet is not at the center of our system (ditto). It would seem completely ordinary to me if I learned that the SBH orbited at (just an example) the bulge radius - or whatever. | |
| Jun 14, 2016 at 10:00 | answer | added | Peter Erwin | timeline score: 5 | |
| Jun 14, 2016 at 9:51 | comment | added | Peter Erwin | @JackR.Woods -- the center of mass of the Solar System is very slightly displaced from the exact center of the Sun in the direction of Jupiter (with a smaller displacement in the direction of Saturn, etc.), though it's still well inside the Sun. If we observed the Sun from a nearby star with an accurate enough telescope + spectrograph, we could measure the Doppler shift from the Sun's wobbling around this center; this is how most of the first few hundred exoplanets were detected (and is still the gold standard for confirming and measuring exoplanets). | |
| Jun 14, 2016 at 0:52 | comment | added | Jack R. Woods | I'd answer the question with a question. Is the "center" of the sun the center of mass in the solar system? I would bet that the CG of the Milky Way is not at the location of the supermassive black hole, but pretty close by galactic standards. Maybe, one day, our instruments will be able to narrow down its location so accurately that we can detect the "wobble" (if we have a few hundred million years to watch). | |
| Jun 13, 2016 at 18:52 | comment | added | Fattie | Dear @PeterErwin - sorry: Center of Gravity. (I guess, that is somewhat common abbreviation in say engineering or video game engineering), cheers.... | |
| Jun 13, 2016 at 18:40 | comment | added | Peter Erwin | What do you mean by "CG"? | |
| Jun 12, 2016 at 12:26 | comment | added | Fattie | You know what, LTK .. that QA does a superb job of (a) explaining the basic newtonian physics of shell orbits (and (b) "what would happen if they flew off.." sort of thing) and (c) that we can "see" these things by looking at the velocities towards/away from us on each side. However! Note in fact RobJeffries final comment: "That's a good question and I do not have the information to hand." indeed, that's just what I want to know here! | |
| Jun 12, 2016 at 9:33 | comment | added | userLTK | Very similar question here: astronomy.stackexchange.com/questions/7861/… | |
| Jun 12, 2016 at 9:28 | history | tweeted | twitter.com/StackAstronomy/status/741925174778400768 | ||
| Jun 11, 2016 at 17:11 | history | asked | Fattie | CC BY-SA 3.0 |