Hubble

[TheMercenary]

Hubble Pictures Too Crisp, Challenging Theories of Time and Space

http://www.space.com/scienceastronom...ts_030402.html

[Elspode]

There are pretty good arguments for doing science with unmanned probes, not the least of which being bang for the buck. However, *nothing* can capture the public imagination, elevate the morale and interest of the public in science, like manned spaceflight and real live humans doing on the spot science. There is a need for both, and both should be done.

[Elspode]

Originally Posted by TheMercenary

Hubble Pictures Too Crisp, Challenging Theories of Time and Space

http://www.space.com/scienceastronom...ts_030402.html

God is screwing with us, in much the same way that He put dinosaur fossils in the ground to test our faith. He does shit like this all the time. I mean, haven't you ever tied a balloon to your dog's tail, or put tape on your cat's feet to freak them out? It's pretty much the same kind of thing.

[TheMercenary]

[Beestie]

Originally Posted by TheMercenary

Hubble Pictures Too Crisp, Challenging Theories of Time and Space

Something is obviously missing. Galaxies dispersing at increasing rates of speed, way more gravity than visible mass accounts for, huge regions of void where there ought to be millions of galaxies, objects farther apart than they would be if they traveled at light speed... Inflationary theory would seem to indicate that space expanded at what amounts to faster than light speed, then slowed down and now its speeding up again. I think I like Bruce's explanation better.

Even if the big bang theory is accurate, it still doesn't explain where all this stuff came from or why it acts the way it does.

Sometimes I think we are missing a force that exists out there somewhere only a derivative of which is expressed in dimensions we are able to observe. Sort of like the vibration caused by thunder caused by lightning that may or may not ever touch the ground.

There's something else out there. Either right in front of us, or just beyond the edge of the universe. And the way things seem to work, forces exert until their energy supply gets used up. So where is the energy coming from and what happens when it expires? Dark matter? Dark energy? I doubt it - too convenient an explanation that exactly explains that which is otherwise unexplainable - a mere placeholder for what's really going on.

[ZenGum]

I agree with your views on dark matter and dark energy as they are currently defined, as mere placeholders for "whatever-the-hell-it-is-that-is-causing-this-messy-result". Dark energy sounds better. But these probes are investigating and we might get a bit clearer about what DM and DE are.

But, your thoughts about us missing something important is exactly what motivated the Whitecoats to come up with the idea of Dark Matter/Energy. There is indeed at least one big gap still in our understanding of the world, and a nobel prize awaits the clever bunny who figures it out.

[Beestie]

I do wonder about one thing.

What if what we think is happening is not what's really happening? What if the universe isn't accelerating outward? If our observations are wrong about that then there is no need to create 'dark energy' to come up with the missing force to explain the observed acceleration.

Light can play games as it traverses over vast distances. And isn't red shift the only real 'evidence' of the increasing acceleration? And unless we are exactly in the center of the universe, wouldn't celestial objects at similar distances in opposite directions display differing degrees of red shift or, if they are moving with a lateral component, substantially less red shift?

I checked out a book to read the other day - I actually requested it be delivered to my branch: Warped Passages by Lisa Randall. Problem is, its 512 pages of thick, dense material and I just can't manage a book that big right now so I grudgingly returned it and its been nagging at me ever since.

I bet there's some good information in there. She's leaning towards the multi-dimensional model which ties in with string theory and all that. I've read some good articles about that but have to confess that I don't think I really get it.

[ZenGum]

First, let me say, i think I am getting out of my depth here. I studied philosophical metaphysics, I teach critical thinking. Astrophysics and cosmology are just hobbies. But .... here goes:

Originally Posted by Beestie

I do wonder about one thing.

What if what we think is happening is not what's really happening? What if the universe isn't accelerating outward? If our observations are wrong about that then there is no need to create 'dark energy' to come up with the missing force to explain the observed acceleration.

That would be called "being wrong". Learned that in Philosophy of Science.

Light can play games as it traverses over vast distances. And isn't red shift the only real 'evidence' of the increasing acceleration? And unless we are exactly in the center of the universe, wouldn't celestial objects at similar distances in opposite directions display differing degrees of red shift or, if they are moving with a lateral component, substantially less red shift?

The red shift is mostly uniform in all directions, increasing with apparent distance. It is primarily NOT due to galaxies rushing apart through space, but due to space itself stretching. Remember the balloon inflating.
If you want you can draw a smiley face on a ballon and watch how it stretches uniformly as the balloon inflates. We are at any randomly chosen point on that image. All points are moving away from us, in proportion to the distance they already are from us.

I checked out a book to read the other day - I actually requested it be delivered to my branch: Warped Passages by Lisa Randall. Problem is, its 512 pages of thick, dense material and I just can't manage a book that big right now so I grudgingly returned it and its been nagging at me ever since.

I bet there's some good information in there. She's leaning towards the multi-dimensional model which ties in with string theory and all that. I've read some good articles about that but have to confess that I don't think I really get it.

That does sound a bit weighty. Try that New Scientist article, and browse through the links of related articles. There are always plenty and most are digestible, bite-size and fairly accessible. I think they have a cosmology page to organise all of them. You won't get all the discussion all at once, but that is probably a good thing.

[TheMercenary]

Originally Posted by ZenGum

I agree with your views on dark matter and dark energy as they are currently defined, as mere placeholders for "whatever-the-hell-it-is-that-is-causing-this-messy-result". Dark energy sounds better. But these probes are investigating and we might get a bit clearer about what DM and DE are.

But, your thoughts about us missing something important is exactly what motivated the Whitecoats to come up with the idea of Dark Matter/Energy. There is indeed at least one big gap still in our understanding of the world, and a nobel prize awaits the clever bunny who figures it out.

That and maybe this idea of a God.

[glatt]

Originally Posted by ZenGum

Remember the balloon inflating.
If you want you can draw a smiley face on a balloon and watch how it stretches uniformly as the balloon inflates. We are at any randomly chosen point on that image. All points are moving away from us, in proportion to the distance they already are from us.

When I took astronomy in college, this concept really blew me away. It's so counter-intuitive when you are thinking about it, but if you grab an actual balloon and do it, you can see it happening clearly.

[Clodfobble]

Since the surface of a balloon is two-dimensional... does that mean our universe is on the three-dimensional surface of a four-dimensional balloon?

[SteveDallas]

Or the 3-dimensional surface of a 10-dimensional string. Whatever.

[xoxoxoBruce]

Ten Things You Don’t Know About Hubble, by Phil Plait, one of the guys who actually used it for years. You have to click through the ten but it's worth it.

[TheMercenary]

Originally Posted by Clodfobble

Since the surface of a balloon is two-dimensional... does that mean our universe is on the three-dimensional surface of a four-dimensional balloon?

On a treadmill?

[glatt]

Originally Posted by xoxoxoBruce

Ten Things You Don’t Know About Hubble, by Phil Plait, one of the guys who actually used it for years. You have to click through the ten but it's worth it.

Excellent link