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Astronomer Discovers the Most Distant Stars Ever Observed From Earth
Cryolithic writes to tell us The Vancouver Sun is reporting that a University of B.C. astronomer recently used NASA's Hubble telescope to see a cluster of stars one billion light-years from Earth, the farthest stars ever observed from Earth. From the article: "That's interesting, he explains, because given that light travels at a finite speed -- 300,000 km a second -- the light emitted from the star cluster he and Kalirai saw was emitted one billion years ago. That means the cluster as it appeared to them two months ago was the way it looked one billion years ago. In other words, they were looking one billion years back in time."
Considering this is /., the article quote seems a bit redundant
-Cheers,
The whole notion of factoring time out of spacetime for special treatement is silly. Other than the fact the metric is a bit odd, thinking in terms of a unified spacetime is much easier. The idea of "sometime else" is just as good as "somwhere else" -- it's the whole fact that the English language is stupidly constructed and people say "some other time" that re-inforces the separation. All you really know as an observer is "local and now" -- i.e. your spacetime point. Claiming the images are very old is non-sensical. What reason do we have to assume there is an underlying universal local clock? Other than it seems to work locally we don't really know anything.
(hint - track one starts at the outside edge)
Might want to research some physical cosmology ... the universe has expanded faster than the speed of light.
Cyde Weys Musings - Scrutinizing the inscrutable
...in a vacuum. When not in a vacuum, light can travel at a fraction of the speed of light.
Well no, not exactly. When not in a vacuum it takes rest stops which reduce its average speed, but when not taking rest stops it travels at the designated finite speed; because that's the only speed at which light can travel. There was this Maxwell guy who 'splained it.
You know about the pony express? Well, they had posts along the way to change horses. Let's say, for the sake of simplicity, that these posts were 15 miles apart and that the horses traveled at a finite speed of 15 miles per hour. When the horse is moving it is always going 15 miles per hour, but the average speed of the horses over a full day is 13 miles per hour because of the time it takes for the rider to change them on an hourly basis.
Light is like the Pony Express, only without the horses, which wouldn't be like the Pony Express at all, would it? That would just be some guy taking a walk.
Nevermind.
KFG
Are you sure he isn't just referring to the redshift ? This would have nothing to do with the types of starts observed.
You didn't know that? I don't know in the U.S. but I learned that in 2nd grade in Italy, so I find the above line in the article to be a little too "obvious"
This has nothing to do with inflation. Units for the expansion of the universe are m/(m*s), or just 1/s. Units for the speed of light are m/s. So you can't compare the two. What you can ask is whether there exist two points of the universe that are expanding from each other faster than c, and the answer is probably yes, even today (not just moments after the Big Bang).
No, you are completely missing the concept.
When you see something you are always seeing the past - what that object looked like when the light left it.
Think of it this way... when you see our sun, you are seeing how it looked 8 minutes ago. If the sun blew up right now (ignoring all the other issues associated with the sun exploding), you wouldn't see the explosion for another 8 minutes even though it already happened.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
Occording to relativity, anything travelling at the speed of light doesn't age, which means that the light doesn't age between it leaving its source and reaching you, which means that it is the same light as the past, so you are observing the past - in the present.
To use your china analogy, it's more like, if someone came from china, bringing a photograph they took before leaving, then when they show it to you, the photograph does show what things were like those 12 (or whatever) hours ago. The photograph itself might be in the present, but it's content - what you're looking at - are of the past. This is the same as looking at light from the past; the light may have reached the present, but we're not looking at the light, we're looking at the image carried in the light, which is from the past. Disagree all you want, you'll find you're in the minority opinion.
The revolution will not be televised... but it will have a page on Wikipedia
No, you're just being arsy because you think it sounds clever. It doesn't. Just because some of the light might get absorbed by dust/atmosphere between you and the source, does not mean that what gets through is not from the source. The event that cause the photon to be released happened in the past, and you receiving the photon means you know that the event must have happened. The act of intercepting the photon is known as "looking", therefore receiving photons generated in the past is looking at events that occured in the past, thus, you are looking at something in the past. Of cause things will be different if you go right up to it, because the photon spreads out it you view it from further away, and so the amount of receive will obviously be less. And yes, if it passes close to a planet or something, it can squash the beam, but the information is not lost, and it's still the same light. You can drop words like "philosophical" in all you want, but it's just pseudoscience because you don't understand the reality of it. Don't make the mistake of thinking the universe bends because you lack proper understanding of it or what people are doing.
"Once upon a time, the majority believed the Earth was flat"
This is actually much debated. People used to believe that the earth was center, with the sun/moon going around it, but there's huge evidence showing that the idea of everyone (or even most people) believing the world was round is flawed. Evidence includes discovery of coins with king and globes on them (showing people high up believed it to be round, not just some heretic in some village), people realising that for ships to disapear over the horizon must mean there was a curve (otherwise they would keep getting smaller, not disapear). Right back to Eratosthenes, who devised the system of latitude and longitude, and calculated the circumference of the earth around 220BC with an error of around 15% (measuring difference in angles of shadows cast from the sun in Aswan and Alexandria). Early models of the solar system showing the sun/moon going around the earth clearly shows the earth as a ball (makes sense, to believe the sun goes around something implied the something must be round).
Err, I'm getting carried away, was just a little impressed with what people managed to work out 2000+ years ago, distroyed by rumour created by people trying to show "the light" by showing how barbaric and misinformed people in the past were. If only the earth was at the end of the telescope, maybe we could see what really went on.
The revolution will not be televised... but it will have a page on Wikipedia
Bah! You're both right. Just a difference in semantics.