Dark Matter and Dark Energy

[phee]

I love the subjects...

What are your thoughts about it? Theories? implications? etc...

Discuss

[Simon Bar Sinister]

I'm all for dark energy tearing apart all the matter in the universe in the long run if it means antigravity in the short run. :D

[Darkmatter]

The most widely accepted theory is that Dark matter accounts for about 80% of the matter in the universe, or about 25% of the mass-energy density.

It's like many things in the model of life. Invisible , unknown , and accounting for 80% of all known things. Like our brain. If we could better understand time's relationship with space we might know more. However our brains are most likely not able to yet.

[phee]

The last figure I heard was dark matter was only 22% and dark energy was more...

[Darkmatter]

22% of mass-energy density yes. But 80% of the actual matter in the observable universe. (All theory of course)

Edited August 8, 2010 by Darkmatter

[Troy Spiral (13)]

Love the science stuff. Wish I had more (read: anyone) in my personal life that i talked to on a regular basis that had similar interest. I'm kind of on an intellectual island.

Having read about such things for a long time its interesting. (I read Discover & Scientific American pretty much religiously and most of the books i read are nonfiction, either history or science of some sort.)

The idea being "ok we have done the grand calculation, and matter/energy (and more recently a huge extra-universal gravitation known as "dark flow") is unaccounted for. So I've always thought...

Well, ok. Part of the fun/interesting/mystery of things is that there are so many unknowns. In the back of my mind i've just assumed that the universe is so vast that we have no hope of knowing where everything is anytime soon (if ever) so the idea that there is "unknown quantities" (in vast numbers) out there just seems to me to be a big "duh". Why we need a sub category called something other than "unknown matter" for instance, seems a bit odd to me for some reason.

Of course there are things we are unaware of as yet what confuses me a bit is why there is mystery in this mystery. We just don't have enough tech and enough knowledgeable to know where everything is, did someone say we should?

Now if you drill down a bit more and say "ok in the solar system we can see pretty well, there are a lot of things that should be here to account for the gravity we experience, but we aren't sure what is causing it... lets look around some more." Ok cool thats interesting. But if we are talking about the universe as a whole, well hell yeah we don't know what/where everything is, I'd just take that as a gimi.

I'm thinking part of it is just the fact that this "unknown" was given cool names like Dark Matter that its taken on some specific meaning.

Now having said all that, I read every article on the subject that comes across me (and I've watched many, many documentaries on the subject(s)) I still watch them and think "DUH we don't know where all the matter/energy is." But i still listen to all the talk about MACHOS and WIMPS and such. (Last months Discover had an interesting article.)

Also since we still don't have a complete physics "theory of everything" the whole calculation could be flawed. Not that I want to diminish any enthusiasm about the universe, I just always looked at the terms "dark XYZ" with a bit of a cocked eye.

Random aside: Currently reading (almost done) Micho Kaku's Visions: How Science Will Revolutionize the 21st Century. Great book, highly recommended.

[Simon Bar Sinister]

Troy, do you ever go over to www.edge.org? it's a wide open discussion site that draws many of the world's best scientists in various disciplines to...well, have a verbal steel-cage death match at times. Discussions are usually polite, but they've been known to get heated on occasion.

There's a book of some of the more provocative contributions from edge.org called Science At The Edge that you may be able to find at your local library. It's a very good intro to the edge.org world. I highly recommend it.

[Troy Spiral (13)]

Oh and as for the dark matter/energy breakdown, its interesting but it just depends on what level of "microscope" you look at it with. Matter/Energy that we think we are looking at is just the tip of the iceberg of these actual objects, we cant see the whole. That is, "stuff" (matter/energy and the associated spacetime) we see are the tip of the ice that peeks out into our 3-4 observable parts (dimensions) of the larger multidimensional iceberg of which we can only see the tip. What the stuff really is in its "essence" or its totality in all the dimensions? Strings? Membranes of space-time? Flaps of other universes slapping up against ours? /boggle /boggle /doubleboggle.

Until we get that Theory Of Everything, we could be missing out on 80% of all that is or 99.99999999999999999999999(approach infinity with these 9s)for all we can really be sure of.

[torn asunder]

there's actually another theory that doesn't include dark matter at all.

By suggesting that mass, time, and length can be converted into one another as the universe evolves, Wun-Yi Shu has proposed a new class of cosmological models that may fit observations of the universe better than the current big bang model. What this means specifically is that the new models might explain the increasing acceleration of the universe without relying on a cosmological constant such as dark energy, as well as solve or eliminate other cosmological dilemmas such as the flatness problem and the horizon problem.

(whole article at link above...)

[synthier]

Also since we still don't have a complete physics "theory of everything" the whole calculation could be flawed. Not that I want to diminish any enthusiasm about the universe, I just always looked at the terms "dark XYZ" with a bit of a cocked eye.

I think I read all of these terms and theories with a skeptical eye, given the unknowns - which is part of the fun. At this point, any theory that begins to explain more - particularly in a kind of novel way - intrigues me. Just as an example, I came across this last week: http://www.physorg.com/news199591806.html ...a model which describes a universe with no beginning and no end, and happens to fit the redshift data better than the big bang theory. And look, no need for the dark matter/dark energy explanation...

Since humans are so limited, like Troy said, I would guess that a working, genuine "theory of everything" that gets at what is out there would likely seem very strange and non-sensical to our daily experiences. Bring it!

[synthier]

there's actually another theory that doesn't include dark matter at all.

Look at you, stealing my link-thunder. I'll deal with you later.

[torn asunder]

Look at you, stealing my link-thunder. I'll deal with you later.

look at you, not fully reading the thread before posting!

[synthier]

look at you, not fully reading the thread before posting!

Right, cuz I tend to not be thorough.

Phone call came in between typing post and posting post.

[Simon Bar Sinister]

Shu's theory is already taking a beating for, among other things, failing to account for the cosmic background radiation - that 3 degrees K microwave noise that's regarded as one of the chief pieces of evidence for the Big Bang. From what I've gathered ( just heard about his idea a couple of days ago myself), if he's right, then it shouldn't be there - but it is.

Doesn't mean he's completely wrong...but he gots lots of 'splanin' to do.

personal fave theory at the moment: M-brane.

[synthier]

Shu's theory is already taking a beating for, among other things, failing to account for the cosmic background radiation - that 3 degrees K microwave noise that's regarded as one of the chief pieces of evidence for the Big Bang. From what I've gathered ( just heard about his idea a couple of days ago myself), if he's right, then it shouldn't be there - but it is.

Doesn't mean he's completely wrong...but he gots lots of 'splanin' to do.

Don't they all, though?

Do you have a link to anything online relating to said beatings? I haven't been able to get much out of the peeps I know that should know about this - it's just been grumbled "hm, interesting," which isn't very helpful.

personal fave theory at the moment: M-brane.

Go on... why?

[Simon Bar Sinister]

i didn't forget about you - i just have to figure how to word it in such a way that a) I hit most of the general points, and b) I don't make myself sound like I've eaten 2 handfuls of 'shrooms.

[synthier]

i didn't forget about you - i just have to figure how to word it in such a way that a) I hit most of the general points, and b) I don't make myself sound like I've eaten 2 handfuls of 'shrooms.

Ha! Well, best of luck, I think the subject matter & a "why" question lend themselves to that...

[Simon Bar Sinister]

here's some dark reading:

http://io9.com/5607692/are-physicists-just-making-up-dark-energy