The red shift thing?

yep

Ya I gotta read about that

I think it's corraborated in another way

Like the size of the objects has certain things going on

If I cut a circle out of cardboard go@in a field and u don’t know how far away I am I can tell the size of the circle ?

Yes,

U can tell ?

Wanna know how?

I doubt u could

But go ahead

I can tell you

Go tell me

Please

I can stand in one spot and zero out my pointer , targeting the object

Ok

Then walk 45 ft to the right, and read my pointers new angle

Ur pointer ?

Yes a device that tells me the angle I'm pointing

I have a right triangle then

And angle and a side of the triangle, boom I can calc the distance

Then I can measure the angular size of the object

Then calc its actual size

This device

@RogueReflector as I mentioned before, there are two sources of redshift: The most obvious source of redshift is doppler (including time dilation due to special relativity); the less obvious source of redshift is gravitational, which depends on gravitational potential (confirmed through the Harvard Tower Experiment, and similarly repeated experiments).

Is a sextant ?

@jeremy nah a theodolite is better

Hmmm

For the Hubble Law (and the hubble constant) to be valid, gravitational redshift needs to be decoupled from doppler (redshift due to motion)

@SunRazor I see. I don't knowuch about that

Ok

So u got ur sextant or theodolite u do this with the moon and the sun

@jeremy simple geometry

U come up with some valid numbers ?

@jeremy for the sun it doesn't work bc the angles change is too small

If you could quantify how much of the redshift is due to motion (expansion of the universe) and how much redshift is due to a difference in gravitational potential, on one end of a spectrum the galaxies far away could be still and just at a lower gravitational potential than we are today, and on the other end the galaxies are at equal gravitational potential as we are today and are moving away from us. The hubble law assumes that the redshift is due entirely to the doppler effect caused by the expansion of the universe.

For the moon yes it works. We can measure it's parallax from diff places on the earth

Or it could be because we never see the actual sun we see the apparent position of the sun no ?

Dunno what that would do, no matter what we see the apparent position of every object

So ok u got ur pointer u check ur angles to the moon what number u get

That's just a give