When the sun reaches close to the centre of the Milky Way galaxy while revolving around it (like the earth closes down on the sun while revolving around it, perihelion), will the gravitational effect of the relatively nearby stars and that of the black hole itself be affecting the planets of the solar system?
$\begingroup$
$\endgroup$
2
-
6$\begingroup$ The Sun won't reach the centre of the Galaxy in the forseeable future. It is on a roughly circular orbit. Perhaps your question should be addressed to hypothetical planets around a star near the galactic centre? $\endgroup$– ProfRobCommented Apr 3, 2017 at 7:07
-
$\begingroup$ The Sun's orbit around the centre of the galaxy is almost perfectly circular, the distance from the Sun to the centre does not change significantly. $\endgroup$– PM 2RingCommented Aug 12, 2019 at 5:05
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
2
You might want to consult this Wikipedia page on the formation and future of our solar system and galaxy.
Two events to note :
In about 4 billion years our galaxy and the Andromeda galaxy will collide (although not with a bang and they'll basically merge).
Sometime around 5-7 billion years from now the Sun will become a red giant.
No mention of us heading into the center of the galaxy.
It's estimated we "orbit" the galaxy about once every 240 million years note that even if we were falling in it would take an minimum of that kind of time scale to reach the center of the galaxy, something I've heard no evidence for. It's only 16 galactic orbits until the Milky Way - Andromeda merger is under way, and that's probably not enough for the solar system to "fall" into our galaxy's center even if we thought it might.
So most likely scenario is that we end up in the merged galaxy long before we end up reaching our solar system.
the gravitational effect of the relatively nearby stars and that of the black hole itself will be affecting the planets of the solar system?
On this point note that the black hole and the rest of the galaxy already effect us gravitationally, and have done for about 20 galactic orbits already with no obvious effect.
The black hole at the galaxy's center is large, but actually not very much of a problem - it's gravitational influence is pretty relaxed until you're very, very, very close to it - think light year. This is not an issue we're going to have.
Gravitational forces between individual stars are pretty small on average, and we'd expect no major effect from those unless we had a relatively close approach. The most "worrying" of these is the one coming in about 1.3 million years with Gliese 710. I personally expect to be dead by then, but good luck to the rest of you.
There is another possible close approach by a star in about 250,000 years, but that's not as widely accepted an estimate. Again, I'll be dead by then anyway, but there's plenty of time to build a shelter in the basement if ya want to.
answered Apr 3, 2017 at 23:14
-
$\begingroup$ Thee free fall time and the circular velocity are both given by dynamic timescales and hence of the same order. $\endgroup$– pelaCommented Apr 4, 2017 at 4:43
-
3$\begingroup$ Also, note that the gravitational attraction from the black hole in the center of the Milky Way is of the same order as that of a small tomato at the distance of 1 km. $\endgroup$– pelaCommented Apr 4, 2017 at 4:47