# Universal movement

First of all this is my first post on this forum, or any other forum of this type. I am extremely interested in cosmology, physics etc. on a personal knowledge level. I usually just read stuff on the web, but Im glad to have found a place where people actually actively talk about this.

I wanted to ask a few questions I just recently came up with while reading random posts. How fast are we actually moving? I guess relative to the earth we aren't moving at all, but we are orbiting around the sun. How fast do we move on our orbit? Is our sun orbiting around something larger? if so do we orbit faster in one direction than the other? is that thing(if it exists) orbiting around something larger(is it possible that our entire galaxy is orbiting around something more massive and that thing is orbiting around something more massive etc)? Is there any way to actually stop moving completely? is anything NOT orbiting around something larger? if the entire universe was only composed of 2 atoms at opposite ends of the universe, would their gravitational pull effect eachother? if not replace one atom with a SMBH, then?

I guess i'll see if anyone will answer those before I go on to other stuff.

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SpaceTiger
Staff Emeritus
Gold Member
I wanted to ask a few questions I just recently came up with while reading random posts. How fast are we actually moving? I guess relative to the earth we aren't moving at all, but we are orbiting around the sun. How fast do we move on our orbit? Is our sun orbiting around something larger?
The earth moves around the sun at about 30 kilometers per second and sun around the galaxy at about 220 kilometers per second. Relative to the cosmic microwave background, we move about 600 kilometers per second.

is that thing(if it exists) orbiting around something larger(is it possible that our entire galaxy is orbiting around something more massive and that thing is orbiting around something more massive etc)?
The sun is moving around the center of the galaxy and the galaxy is moving with respect to the center of mass of the local group of galaxies, which is itself moving with respect to the Virgo supercluster of galaxies. The sun's motion could be called an "orbit", since it goes approximately in a circle. The motion of the galaxies isn't really an orbit in the traditional sense, but it is being caused by the gravity of the other galaxies.

Is there any way to actually stop moving completely?
Motion is all relative, so if we stop moving completely from one point of view, we'll still be moving relative to another.

is anything NOT orbiting around something larger?
Everything in the universe that we can see is being effected by gravity (if it weren't, we couldn't see it). The reason is that gravitational effects travel at the speed of light, so anything we can see is, at least, being perturbed by our gravity. There could be things that we can't see, but then we couldn't say anything about them.

if the entire universe was only composed of 2 atoms at opposite ends of the universe, would their gravitational pull effect eachother?
If those atoms were within each other's particle horizon, then yes they would. Same with the SMBH.

Garth
Gold Member
Welcome to these Forums Enkiadu!! Those are good questions, keep thinking about it and keep them coming!

As SpaceTiger has said motion is all relative, however there is one frame of reference that might be seen to be more fundamental than the rest. The Cosmic Microwave Background has come from a time when the entire universe was filled with a hot gas. It was mainly hydrogen that was in the form of a plasma, the electrons were not bound to their protons and the universe was 'foggy'. When the universe cooled to about 3,000oK the electrons combined with these protons to form hydrogen gas and the universe became transparent. That 'surface of last scattering' is spread out all over the entire sky and we receive the radiation from it, the CMB, which is extremely isotropic and now is equivalent to radiation coming from a black body at just less than 3oK. However, we are moving relative to that surface, so it looks hotter in one direction than in the opposite.

In fact we are moving at 370+/-10 kms./sec towards the constellations Leo and Crater. Note that this velocity is 0.1%c and quite large, in fact it is difficult to explain! (Another question for you: "Are we being pulled towards a 'Large Attractor'?")

I hope this helps.

Garth

Last edited:
hellfire