Slashdot Mirror
Chandra Provides Support For Dark Energy
starannihilator writes "The Chandra X-Ray Observatory has provided new evidence supporting the existence of dark energy, the force causing the acceleration of universal expansion. The new findings support the theory that the universe will expand forever, provided there is enough dark matter. CNN and Newsday are running the story, originally reported by NASA. Chandra's site has some good images and information on the three galaxies clusters studied (Abell 2029, MS2137.3-2353, and MS1137.5+6625)."
If the universe was expanding at the speed of light. It would look pretty dark out there at night.
Or at the very least it would be awfully hard to see some of those distant galaxies.
Consider for a moment that Einstein might have been wrong? Since we can't actually study anything at the speed of light properly, it's all down to the calculations and even great minds might make errors. So, you never know...
HAH! I just wasted a second of your life making you read this, but I wasted a minute of mine thinking it up. DAMN.
It's not that simple. Cosmology is now in a position pretty much similar to that of a butterfly trying to understand the passing of seasons. Moreover, as the name says, "dark" matter/energy is undetectable directly (at least, so far) - and it's quite challenging to figure out a 'simple' theory for something that not only you can't observe directly, but the indirect observations are difficult and not always very accurate.
Anyway, since it's not very likely that the knowledge of dark matter will have a significant impact on the daily life anytime soon, relax and enjoy the (slow-moving) show.
The headline to this story is an exaggeration. Of course, you can't blame it on the author seeing as the headlines of the major news sources were exaggerations as well.
So what, we have more evidence the universe is expanding at an accelerating rate. WE ALREADY KNEW THAT! This is just another indication that it's happening. This doesn't "prove" the existence of dark energy. It's still entirely possible (and I would suggest probable) that we just don't know the entire story about gravity. Physicists have gotten gravity wrong before after all.
Why can't scientists just make up their minds already?
Because if they did, they'd be theologians, not scientists.
Why are they ignoring the obvious (at least to me) possiblity that the universe oscillates around some optimal size. Imagine the universe as a rubber ball. Squeeze the ball and let it go. Every particle inside will immediately start moving away from the others at an accelerated pace, continuing to accelerate until passing the rest boundary, when it will start slowing down. What's causing the expansion? How about the reduction of space curvature? Imagine space as a tablecloth (ok, so I'm knee deep in analogies :) on a table with a hole in the middle. Place a heavy pitcher in the middle and the tablecloth will be pulled through the hole, pulling its edges closer together. This is what happens around a star according to general relativity theory. Now, the star is constantly radiating energy and losing mass, so the space is constantly uncurving. Because it is uncurving, it is expanding. When all the stars burn out, space will start collapsing again as energy falls into black holes. Then the black holes coalesce and make the big bang singularity, which explodes for some reason and everything starts all over again.
I think it is common for people to make up something that helps fill gaps in science. sometimes it turns out right many times it turns out wrong. many times this happens such as space ether.
When we can't explain something we are sometimes better off makeing something up that fills the gap until we can find the more correct answer. There is no such thing as exact science. Only reproduceable observation which eventually becomes accepted fact. Although there is no reason for it to always stay fact if someone says, "Hey, I tried to do the experiment and used this method to test it and I got a diffrent observation!" Well, now it's time to re think that scientific fact.
What happens typically is that the person is downplayed as doing something wrong, adding some new variable to the mix, or something that would throw off the observation in some way. Politics in science is as complicated and painful as anywhere.
Paying taxes to buy civilization is like paying a hooker to buy love.
It may be possible to have a universe that is expanding and contracting at different times based on variables we have no ability to measure, hence never be able to know which way we are going to go, only where we seem to have gone.
For some great educational sources for the non-astro-physicist, see The Elegant Universe excellent program (my six and ten year olds understood most of it). A few other articales are at Sky and Telescope and Scientific American
InnerWeb
Freud might say that Intelligent Design is religion's ID.
I've always been bothered by the "the universe will expand forever, and it's accelerating" theories.
Not that I have an a fraction the knowledge or mathematical skills of these scientists; but correct me if I'm wrong.
Doesn't gravity effecct objects regardless of the distance between them? Meaning to say, that gravity, however weak, will always have this attractive force.
so, won't this energy causing this accelerating expansion eventually burn up/out?
couldn't the universe be Like the release of a stretched-out, very long rubber band (played back in slow motion). At first release starting from a velocity of 0 and then accelerating. but after expending it's energy, slowing? heck, then even retracting?
in other words, what evidence supports that this thing is going to expand at an accelerating rate forever? seems like gravity is going to get a little upset about that eventually.
Depends on which theory of dark matter you subscribe to. I don't think WIMPs could be considered "normal" matter.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
Heh, and you still wonder why people hate fundamentalist nutters like you. It's weird that fundamentalist muslims and orthodox jews are at each others' throats... You have more in common then you are different
E=mc^2 doesn't mean that mass and energy are the same, it means that's the conversion you use when you convert between them. So if you could turn two 500nm photons into two massive particles (you can't turn a single photon into particles because of conservation of momentum), you could create two 4.4x10^-36 kg particles at rest in the center of mass frame.
:-)
It also means that photons do act as a source of gravity, with a strength equal to something with a mass of E/c^2. But in the current universe, their gravitational effect is tiny compared to the gravity of the mass... as a little exercise, try calculating the equivalent rest mass of the entire luminosity of the Milky Way and compare it to the mass of the moon.
[TMB]