# Homework Help: Very low accelerating objects in the universe

1. Jul 17, 2011

Dear all,

I am searching for some far objects in the universe (anywhere!!!) that have the lowest acceleration from us. Take it for example as an unusual number like 10^-250

Is it too strange?
Do we have such things in the world?

I tried to use Proxima Centauri but it is not as slow as I want.

2. Jul 18, 2011

### cupid.callin

acceleration is a concept of with respect an inertial frame. that small acceleration, maybe not possible to observe, is quite possible according to me.

3. Jul 18, 2011

### cupid.callin

And i just calculated ... an electron and proton separated by 2.53 * 10252m
will exert force such that acceleration is 10-250 ms-2

EDIT: free charges smaller than e are not possible but however the distance will be much smaller for 2 neurons under gravitational force

Last edited: Jul 18, 2011
4. Jul 19, 2011

However, I am looking for something in cosmological scale...
I know there are problems with the inertial frame in cosmology
but lets just talk about the acceleration with which an object is moving apart from us

any idea?

5. Jul 19, 2011

### fluidistic

You forgot to put the units in the original post. Let's say they were m/s². The acceleration you're asking for is so small that I believe no instrument could measure it.

6. Jul 20, 2011

Isn't there even a theory or something that predicts some object would have that little acceleration?

7. Jul 22, 2011

### fluidistic

Also, for how much time do you want the object to accelerate at this rate? Since it's so small and you want a huge precision, I'm sure it's impossible to keep an object with such an acceleration. I'm not even sure the acceleration is a function that can take any real (of real numbers) values.
I'd wait for answers from more qualified people than me.

8. Jul 22, 2011

### DaveC426913

Wouldn't it be sufficient to first identify some - indeed any - distant object(s) whose acceleration or even proper motion wrt to us is zero at least to a small fraction - say, less than a few km/s? Once we identified them, we could start measuring as accurately as possible.

I'll bet the number of distant objects with an apparent proper motion of nearly zero could be counted on one hand.

9. Jul 23, 2011