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seen Sep 21 at 1:45

Sep
20
comment Is redshift a reliable means to know how fast an object is moving away or towards an observer?
But isn't it that these dark matter and dark energy were presumed to exist because we concluded that the universe is expanding because of the redshifts we see?
Sep
19
awarded  Commentator
Sep
19
comment Is redshift a reliable means to know how fast an object is moving away or towards an observer?
I presume when you say "diluted" you mean it increased its wavelength. How could we verify that light doesn't do that when travelling a massive distance?
Sep
19
awarded  Editor
Sep
19
comment Is redshift a reliable means to know how fast an object is moving away or towards an observer?
I'm not really getting what you mean here. I have edited my question by the way.
Sep
19
revised Is redshift a reliable means to know how fast an object is moving away or towards an observer?
deleted 223 characters in body
Jul
18
comment Is redshift a reliable means to know how fast an object is moving away or towards an observer?
Even for great distances like light years?
Jul
18
comment Is redshift a reliable means to know how fast an object is moving away or towards an observer?
How do we know that wavelength doesn't change with distance?
Jul
17
comment Is redshift a reliable means to know how fast an object is moving away or towards an observer?
I'm actually referring to any stuff I'm ignorant about like dark matter or dark energy. Or anything that scientists themselves, I presume, don't have solid understanding.
Jul
17
asked Is redshift a reliable means to know how fast an object is moving away or towards an observer?
Jan
31
awarded  Popular Question
Oct
4
accepted How do astronomers measure the distance of the planets from its star?
Oct
3
awarded  Supporter
Oct
2
comment How do astronomers measure the distance of the planets from its star?
How's the planet's mass has something to do with measuring its distance from its star? Also, how does that stack up against interferometry as described in this link? (en.wikipedia.org/wiki/Astrometry#Applications)
Oct
2
awarded  Student
Oct
2
comment How do astronomers measure the distance of the planets from its star?
Yes, possibly triangulation. But what I actually meant to ask is, do they really have the tools to accurately use triangulation as far as 22 light years? I mean, we can surely measure the distance of something using a ruler but if you're going to use it for long distances, the magnitude of error will surely increase (of course I'm just oversimplifying here but you get the idea). And for a distance of 22 light years I'm skeptical about its accuracy to be any meaningful at all.
Oct
2
asked How do astronomers measure the distance of the planets from its star?
Jul
22
comment Which universe had a beginning? The universe or the observable universe?
Why not? Even Wikipedia makes distinction between the two. It says QUOTE ... the observable universe is a spherical volume centered on the observer, regardless of the shape of the universe as a whole. Every location in the universe has its own observable universe which may or may not overlap with the one centered on the Earth. UNQUOTE en.wikipedia.org/wiki/Observable_universe
Jul
22
comment Which universe had a beginning? The universe or the observable universe?
To my understanding, the observable universe is simply a subset of the entire universe. I'm just confused how sometimes people use those terms interchangeably. And I just wanted to know what universe the theory is trying to refer to when it says the universe had a beginning.
Jul
22
comment Which universe had a beginning? The universe or the observable universe?
So does this also mean that entire universe is not the same as the observable universe? Or does it depend on the theory too?