@metal-brain saidWhy would you ask a bunch of people on an entertainment site?
How do they measure the distance so they know how far the light traveled to get here accurately? How do they know a galaxy is 30 billion light years away and not 29 billion?
@metal-brain saidI presume there's a standard model they use based on benchmark brightness and probably other factors as well.
How do they measure the distance so they know how far the light traveled to get here accurately? How do they know a galaxy is 30 billion light years away and not 29 billion?
Thing is ,at such enormous distances ,it doesn't really matter.
I'm sure a galaxy is not exactly 30 billion away or any such round number.
Think of the old question given to school children as to why the sun isn't hotter at the top of a mountain because you're nearer to it?
The answer is at a distance of 93 million miles a few thousand feet makes little difference.
@metal-brain saidEver haerd about redshift? (for your convinience: https://en.wikipedia.org/wiki/Redshift you can go to the Astronomical part directly)
How do they measure the distance so they know how far the light traveled to get here accurately? How do they know a galaxy is 30 billion light years away and not 29 billion?
You claim to be one of the top knowledgeable people and fail school physics badly.
If you want to discuss the phneomenon and the applicability please open a thread in "debates".
05 Aug 22
@ponderable saidYes. The JW telescope is measuring the extreme redshift, infrared.
Ever haerd about redshift? (for your convinience: https://en.wikipedia.org/wiki/Redshift you can go to the Astronomical part directly)
You claim to be one of the top knowledgeable people and fail school physics badly.
If you want to discuss the phneomenon and the applicability please open a thread in "debates".
You think you are responding to a child who doesn't know anything about this.
You are clearly projecting your own shortcomings on me.
Good luck with your inferiority complex. Not my problem.
05 Aug 22
@kewpie saidTo demonstrate how little they know about it.
Why would you ask a bunch of people on an entertainment site?
Most people "assume" scientists are calculating these thing accurately and they don't know that at all. The only way to know is to understand "how" scientists are calculating.
@metal-brain saidHow accurate is accurate enough for you? Do we need to know the distance to the Andromeda galaxy to the nearest centimeter?
To demonstrate how little they know about it.
Most people "assume" scientists are calculating these thing accurately and they don't know that at all. The only way to know is to understand "how" scientists are calculating.
It is always possible, of course, that over extremely great distances spacetime plays a trick that astronomers are ignorant of, and galaxies are either much farther or much nearer than currently believed. All we can do is employ our senses and measuring devices to observe, theorize, and experiment. It leaves open a margin of error, and even the prospect of being completely fooled, but you can't live life rejecting every idea because it isn't one hundred percent a sure thing.
Well, maybe you can.
05 Aug 22
@metal-brain saidIn fact you asked about how we measure the distance...so?
Yes. The JW telescope is measuring the extreme redshift, infrared.
You think you are responding to a child who doesn't know anything about this.
You are clearly projecting your own shortcomings on me.
Good luck with your inferiority complex. Not my problem.
@metal-brain saidYou know less than nothing. Those who know nothing know they know nothing. Those who know less than nothing make up all the stuff they think they know to impress people on the internet. You're in that category.
Yes. The JW telescope is measuring the extreme redshift, infrared.
You think you are responding to a child who doesn't know anything about this.
You are clearly projecting your own shortcomings on me.
Good luck with your inferiority complex. Not my problem.
If you know about redshift you wouldn't ask stupid questions like "how do they know how far away stuff is?"
@soothfast saidI expect them to be honest about their accuracy. Is that unreasonable?
How accurate is accurate enough for you? Do we need to know the distance to the Andromeda galaxy to the nearest centimeter?
It is always possible, of course, that over extremely great distances spacetime plays a trick that astronomers are ignorant of, and galaxies are either much farther or much nearer than currently believed. All we can do is employ our senses and mea ...[text shortened]... jecting every idea because it isn't one hundred percent a sure thing.
Well, maybe you can.
All they have to do is say 30 billion light years give or take 1 to 2 billion or something like that.
They are not just measuring distance, they are measuring how many billion years in the past it was. That has enormous implications regarding the expansion of the universe and particularly the rate of expansion.
I simply want to know the margin of error. Is it a secret?
I think you have a lot of nerve trying to trivialize something so obviously important.
Tell astronomers it doesn't matter how much the universe expanded 30 billion light years ago. You know, give or take a couple billion years.
@ponderable saidNo, I asked how they measure the distance accurately.
In fact you asked about how we measure the distance...so?
How do I know it is accurate? How do you?
You could just admit you don't know.
Faith in scientists is not scientific. Scientists are people and people are flawed. They often don't like to admit they are not as certain about things as they lead people to believe. Questioning their method is the first step to get them to admit their margin of error.
@metal-brain saidaccuracy is about 0.4 % which would make the distance 30.00 +- 0.12 billion kilometres...
No, I asked how they measure the distance accurately.
How do I know it is accurate? How do you?
You could just admit you don't know.
Faith in scientists is not scientific. Scientists are people and people are flawed. They often don't like to admit they are not as certain about things as they lead people to believe. Questioning their method is the first step to get them to admit their margin of error.
A short web search did that. (I knew that it was in the lower percentage region a few decades back, when I did my studies. )
I am often impressed with you. On the one hand your science seems to be of the I read a headline ina cheap journal and suddenly you want to discuss accuracy of methods...I was just not sensitive enough to realize you were in earnest mode.
@metal-brain saidWell, even pop-science books on astronomy make it clear that the cosmological constant Λ is still not quite nailed down, and that has implications for distances and just about anything else related to the universe. It's not exactly a secret.
I expect them to be honest about their accuracy. Is that unreasonable?
All they have to do is say 30 billion light years give or take 1 to 2 billion or something like that.
They are not just measuring distance, they are measuring how many billion years in the past it was. That has enormous implications regarding the expansion of the universe and particularly the rate ...[text shortened]... uch the universe expanded 30 billion light years ago. You know, give or take a couple billion years.
06 Aug 22
@ponderable saidWhat is your source of information?
accuracy is about 0.4 % which would make the distance 30.00 +- 0.12 billion kilometres...
A short web search did that. (I knew that it was in the lower percentage region a few decades back, when I did my studies. )
I am often impressed with you. On the one hand your science seems to be of the I read a headline ina cheap journal and suddenly you want to discuss accuracy of methods...I was just not sensitive enough to realize you were in earnest mode.