orbits

[Xyphos]

everything is orbiting something, the moon orbits the earth, earth orbits the sun, the sun orbits a black hole, but what does the black hole orbit? and what does that object orbit? and so on, and so fourth....

[Tourist]

a giant space turtle I believe. 

Either that or it's just elephants all the way down. 

[Ksp Slingshooter]

Moon orbits earth, earth orbits the sun, the sun orbits milky way's black hole, this black hole orbits andromeda's black hole, these orbit within our universe, our universe could be orbiting other universes within our dimension and our dimension could be orbiting other dimensions (my mind blew away ).

[cubinator]

Earth orbits the sun, the sun orbits the galactic center. The galactic center doesn't orbit anything in particular in the universe, it's just kind of there. It does move and interact with nearby galaxies though, such as Andromeda which we will collide with in a mere four billion years, and several satellite galaxies such as the Magellanic Clouds. The gravitational pull between galactic superclusters form colossal web patterns eerily similar to the shapes of neurons in the brain. The galaxies themselves, however, don't really orbit anything that we know of. The universe itself may be influenced by the presence of other universes nearby too, but we really don't know.

[Aloriel]

I am not sure about the Andromeda orbit that Slingshooter proposes.

As I understand it, all of Laniakea (our super cluster) is heading for "The Great Attractor", which is a vaguely understood region that is pulling many nearby superclusters to it.

This video should help explain it: Video concerning Laniakea

[Frybert]

Since this is about real world rather than Kerbal, moved into science and spaceflight.

[FancyMouse]

I wouldn't quite believe sun orbits a black hole (note I do believe that black hole exists) until we figure out what's the deal with dark matter...

[Aloriel]

FancyMouse also has a point. While we sort of technically orbit the galactic center, there is a problem with standard orbital calculations in regards to that. First of all, why the spiral arms? These appear to be a sort of density wave issue, and thus not a true orbit. Also, the impulse of the orbit does not conform with the standard math for calculating orbits.

For instance, outer objects appear to be orbiting faster than inner ones, and this is the opposite of standard orbital mechanics.

Edited March 24, 2016 by Aloriel

[cubinator]

7 minutes ago, Aloriel said:

For instance, outer objects appear to be orbiting faster than inner ones, and this is the opposite of standard orbital mechanics.

My view on that is the outer objects get pulled along faster by the mass of the stars near them, so the whole galaxy is kind of rigid as opposed to fluid like conventional orbital mechanics might predict it to be...somehow. Of course, we don't know exactly what's happening.

Edited March 24, 2016 by cubinator

[Xyphos]

5 minutes ago, Aloriel said:

For instance, outer objects appear to be orbiting faster than inner ones, and this is the opposite of standard orbital mechanics.

oh yeah, I heard about this, something about objects moving faster than they're supposed to (or at least appear to) - I suspect time-dialation because recently we've been able to prove such a thing exists when two black holes merged.

[Aloriel]

Just now, cubinator said:

My view on that is the outer objects get pulled along faster by the mass of the stars near them, so the whole galaxy is kind of rigid as opposed to fluid like conventional orbital mechanics might predict it to be...somehow.

That explanation is reasonable as well. It's one of those things we don't quite have the math for yet. Especially with the lack of understanding of dark matter.

[Laie]

1 hour ago, Xyphos said:

everything is orbiting something, the moon orbits the earth, earth orbits the sun, the sun orbits a black hole,

everything is orbiting around each other

There. Fixed that for you.

Orbiter/orbitee is not a parent/child relationship, even though in many cases it seems that way. The black hole orbits around all the other stars in it's galaxy, as well as around neighbouring galaxies... though I'm not sure if you still call it orbit if it's in no way circular or even hyperbolic.

[cubinator]

1 minute ago, Xyphos said:

oh yeah, I heard about this, something about objects moving faster than they're supposed to (or at least appear to) - I suspect time-dialation because recently we've been able to prove such a thing exists when two black holes merged.

Actually, we had the ability to measure time dilation long before that, when we flew two synchronised atomic clocks around the world in opposite directions and they came back showing different times as predicted by relativity. I think you're referring to the gravitational waves measured recently for the first time?

[GoSlash27]

It breaks down at the Earth orbiting the sun. Beyond that, the solar system is traveling around the supermassive black hole at the center of the galaxy, but it's not "orbiting", at least not due to gravity. Everything in the galaxy revolves about the center at the same angular rate, like a phonograph record (or a CD for you young'uns), They think this is due to the halo of dark matter that surrounds our galaxy.

The galaxy doesn't seem to be orbiting anything at all as far as they can tell.

Best,
-Slashy

Edited March 24, 2016 by GoSlash27

[cubinator]

2 minutes ago, Laie said:

I'm not sure if you still call it orbit if it's in no way circular or even hyperbolic.

Well, Mercury's orbit precesses and is not elliptical, for example, and it's pretty clear that it orbits the sun. I would define an orbit as 'going around something else' and leave it at that. Whether the orbit's barycenter is outside the surface (binary) or whether it's stable is a different story. The black hole Sagittarius A* seems to be what holds the galaxy together, so we say the stars orbit it. Of course the stars exert a force on it too, but that force is fairly negligible, unless you are planning to put a station in orbit a picometer* above the horizon, but then you probably have other problems to worry about.

*total guess

[RocketBlam]

5 hours ago, Tourist said:

a giant space turtle I believe. 

Either that or it's just elephants all the way down. 

I believe they're working on a mission to establish the sex of the turtle.

[kerbiloid]

As a result - any orbit is a quasi-ellipse.

Once you escape from the Earth, you just go ellipse around the Sun.
Once you escape from the Sun, you just go ellipse around the galaxy center.
Once you escape from the galaxy center, you are on a hyperbola..  yeah, right.. You are just ellipsing around some another thing.
So, there is no hyperbola in the Universe - only ellipse.
Except photons, of course... not of course: a straight line is just a singular case of ellipse.

And as probably all massive objects in this hierarchy are black holes, any flight far from the Earth is just an  elliptic slalom around black holes.

[Darnok]

5 hours ago, cubinator said:

Earth orbits the sun, the sun orbits the galactic center. The galactic center doesn't orbit anything in particular in the universe, it's just kind of there. It does move and interact with nearby galaxies though, such as Andromeda which we will collide with in a mere four billion years, and several satellite galaxies such as the Magellanic Clouds. The gravitational pull between galactic superclusters form colossal web patterns eerily similar to the shapes of neurons in the brain. The galaxies themselves, however, don't really orbit anything that we know of. The universe itself may be influenced by the presence of other universes nearby too, but we really don't know.

And you know this because you discovered entire universe?

I thought we know how Andromeda was travelling millions of years ago, but we have no idea what is it course today.

[YNM]

There're no orbits, there's only trajectory. Trajectories can be said as orbits only when they comes back to nearly the same place, so hyperbolic and parabolic trajectory shouldn't be called orbit at all.

For your question... Hmm, hyperbolic trajectory to Andromeda's SMBH ?

Edited March 24, 2016 by YNM

[GeneralVeers]

7 hours ago, Xyphos said:

everything is orbiting something, the moon orbits the earth, earth orbits the sun, the sun orbits a black hole, but what does the black hole orbit? and what does that object orbit? and so on, and so fourth....

Well, in the strict sense, the Moon and Earth orbit each other, each orbiting the system's summed-up center of gravity. The Sun and Earth orbit each other, the Earth and the center of the galaxy orbit each other, the center of our galaxy and the centers of the other galaxies all orbit each other. Everything either orbits everything else.....or is on a collision course with something.....

Depending on your reference frame, it simply looks like one thing is orbiting the other. A few hundred years ago, for example, most people thought the Sun orbited the Earth because our reference frame was Earth.

[kerbiloid]

40 minutes ago, YNM said:

There're no orbits, there's only trajectory. Trajectories can be said as orbits only when they comes back to nearly the same place

The Sun revolves around the galaxy center with 200 mln period.
Its (and the Solar System's) appearance took about 50-100 mln years.
Does it mean that the first 100 mln years of its existence (i.e. until the first orbit turn) it had no orbit?

Earth does spiral around the Sun, while the Sun does spiral around the Sag A*, while Sag A* flies its own way.
No same place can be here at all. In any moment of time all this pieces are far away from the point of the Universe where they had been a turn ago.

So, any tracjectory is just a superposition of orbits.

 

[Lukaszenko]

As others have mentioned, don't forget that the sun also orbits the earth. Once you understand that, the rest of your question is also answered.

[cubinator]

5 hours ago, Darnok said:

And you know this because you discovered entire universe?

I thought we know how Andromeda was travelling millions of years ago, but we have no idea what is it course today.

Well, according to the laws of gravity (which have proven themselves to be pretty consistent with what we see in the universe) it shouldn't really change direction. There are plenty of simulations that suggest it will merge with us in a few billion years. If your Duna rocket is on an interplanetary collision trajectory, it's rather unlikely for that to change if you don't do a correction burn, even if you leave it to the last minute, giving it plenty of time to decide to go somewhere else. The same principle applies to your Andromeda argument. Sure, we can't observe where it is today, but we can predict it's motion because we know where it was in the past. 

[kerbiloid]

19 minutes ago, Lukaszenko said:

As others have mentioned, don't forget that the sun also orbits the earth. Once you understand that, the rest of your question is also answered.

Sun orbits not only (around) the Earth, but (around) every particle of the Universe, as any of them has some mass.

Edited March 24, 2016 by kerbiloid

[p1t1o]

9 minutes ago, kerbiloid said:

Sun orbits not only (around) the Earth, but (around) every particle of the Universe, as any of them has some mass.

Its helpful to remember the basic premise behind the operation of the Total Perspective Vortex^TM, which contains at its heart, a small piece of fairy-cake. As every object in the universe influences, and is influenced by, every other object, a complete picture of the universe can hypothetically be derived from any piece of matter - in this case, some cake.