nicuramar t1_j6807ie wrote
Reply to comment by SailingNaked in If you could instantaneously place a space telescope at any desired distance (LYs), from any planet/galaxy etc., where would it be and what would you be documenting? And for what purpose? by kennyarsen
> At any point in space, the Hubble flow is the same. That is why it’s called a constant. It is the same everywhere.
Yeah, but you said “speed of expansion” in the other comment, which doesn’t exist, since it’s a rate ;). Maybe that’s what they meant.
SailingNaked t1_j680vmz wrote
That is where OP and you are wrong, and that's their point I wanted to clarify. The words are interchangeable. The Hubble flow has a speed and distance component... (km/s)/Mpc... speed over distance. Rate of expansion is just another expression of the speed of expansion that new space is created.
Edit: to try my hardest to clarify and settle this issue...
The expansion is given as (km/s)/Mpc.
That means that there is a rate over a distance.
If you take (10 km/s)/10 km or (20 km/s)/20 km... they are the same.
When the denominator is bigger the numerator will be bigger.
When the distance is greater the speed will be greater.
They are still the same...
(10 km/s)/10 km = (1 km/s)/1 km
(20 km/s)/20 km = (1 km/s)/1 km
The expansion rate/rate of expansion/speed of expansion are all the same everywhere.
nicuramar t1_j68311l wrote
> That is where OP and you are wrong, and that’s their point I wanted to clarify. The words are interchangeable
Well, it’s just arguing semantics. Since I know how it actually works, irrespective of what you or I wish to call it, I am not going to address the rest of the comment.
Anonymous-USA t1_j68rmez wrote
The Hubble flow is indeed constant. Everywhere. We’re all saying the same thing. Cheers to you both, I think we all understand it well from the get go and now surely OP too 🥂
SailingNaked t1_j6a3dyy wrote
You and OP are still wrong, and I am not arguing semantics. There are two things I corrected with my original comment, and they are not interchangeable.
The OP said the speed of expansion is different for something farther away. That is just plain wrong. The speed of expansion does not change just because something is farther away.
The correct thing to say would be the velocity (observation) of a distant object is faster than a closer object. That is what I said to OP in my original comment.
The rate or speed of expansion is the same no matter the distance.
A more distant object's velocity is faster than a closer object.
The velocity of a distant object is not the same thing as rate of expansion.
Velocity increases with distance, but the rate/speed of expansion stays the same.
nicuramar t1_j6abs1h wrote
> You and OP are still wrong,
I’m not OP or defending their views. I am just saying that expansion is stated as a rate, and doesn’t have units of velocity. I know how expansion works, and I wasn’t talking about that. You don’t need to keep explaining it, at least not for my sake :)
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