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General => The Colosseum => Topic started by: oex on June 21, 2012, 02:09:37 AM

Title: Dark Energy
Post by: oex on June 21, 2012, 02:09:37 AM
Hi Guys,

Yet another crazy question on a topic I know very little about but I was wondering....

I have read about dark energy/matter that it must exist because otherwise gravity doesnt work, the edges of the universe are expanding (aparently because of this misterious dark energy we cant see or prove exists....

All I wondered was could this just be like a lense effect where the curvature of space (because of gravity) made the universe appear to fly apart.... Maybe like a bumpy 3D plane where the real distance is still influenced only by gravity (ie the plane gets deeper troughs) but the distance between points along the plane expands....

I guess this would be a 4th (5th) dimensional effect?

I really dont understand this well but maybe someone will post information that will help me to understand better :biggrin:

http://www.bbc.co.uk/news/science-environment-18503703
Title: Re: Dark Energy
Post by: dedndave on June 21, 2012, 03:24:02 AM
i'm with you, Peter
there might be some un-accounted-for numbers that have been left out of the calculations
something we don't know about or understand
i am more comfortable with things i can hold in my hand - lol
Title: Re: Dark Energy
Post by: FORTRANS on June 21, 2012, 04:55:30 AM
Hi,

   Dark matter is required to explain the anomalous rotation
rates of galaxies, the clustering of galaxies, some hot gas
structures, and some gravitationally bent light.  Without
some sort of matter these do not make sense.  Since we
(they) cannot see the required matter, they call it dark
matter.

   In the late 90's two independent groups of astronomers
found that the universe's expansion rate was growing
rather than slowing.  That led to dark energy.  (Give or
take.)

   Expansion into a negatively curved space would look like
a faster than expected expansion.  (I think it would anyway.)
but they have a bunch of reasons to believe the universe
is uncurved or flat.  Some of this is from analysis of the
cosmic microwave background.  And some of it is from
study of expected products from nucleosynthesis from
the big bang.  And so forth.

   Unfortunately, figuring this out is non-trivial.  Fortunately,
it dosen't have an effect on you or me.  And it's fun stuff.

Cheers,

Steve N.
Title: Re: Dark Energy
Post by: Zen on June 21, 2012, 05:11:00 AM
PETER !!!
I was wondering when you'd show up,...good to see you again,... (baltoro, here...)
Weird,...I was reading a book just recently about the Dark Matter/ Dark Energy "problem"
"The 4 % Universe: Dark Matter, Dark Enery, and the Race to Discover the Rest of Reality", author: Richard Panek, 2011
Here is a review of the book: Exploring the Dark Universe, American Scientist (http://www.americanscientist.org/bookshelf/pub/exploring-the-dark-universe)
However, I would NOT recommend this book. Although it is well-written, and depicts the evolution of the thinking of the astrophysicists and astronomers that have published on the subject in research journals,...it really isn't very skeptical of the science. There is NO rigorous or empirical analysis of the subject. It leaves you even more confused about just what Dark Matter actually is than when you started the book.
FORTRANS...above...describes the situation in condensed form.
Much of the development of the logic is based on the values for Omega, the Density Parameter (http://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe) and Lambda, the Cosmological Constant (http://en.wikipedia.org/wiki/Cosmological_constant).
The Big Bang Theory gave birth to cosmology as a science,...but, it is almost completely hypothetical,...and, the existence of Dark Matter to explain certain observed anomalies is very controversial.
...I get the distinct impression that cosmologists use the term "Dark Matter" to designate that which they do not adequately understand,...
Title: Re: Dark Energy
Post by: dedndave on June 21, 2012, 05:15:28 AM
gosh, let me think....
1) how much mass does a "typical" black hole have
2) how many black holes are out there that we don't know about
3) what is beyond our visible/detectable range with current technology
Title: Re: Dark Energy
Post by: FORTRANS on June 21, 2012, 05:35:38 AM
Hi Dave,

   Stellar mass black holes (BH) are supposed to be 4 - 22
times the mass of the son.  Larger BH go from hundreds to
billions of solar masses.

   Given that there is three times as much dark matter
than regular matter, that would be a troublesome number
of black holes.  You would not be in a safe neighborhood
any more.

   The fact we cannot see it or detect it in other ways means
it is beyond our current technology.  Unless the LHC gets to
find some.  Or one of the other experiments that are trying
to detect dark matter pan out.  No verifiable results so far.
A couple of contested claims have been made though.

Cheers,

Steve
Title: Re: Dark Energy
Post by: Daydreamer on June 21, 2012, 06:03:48 AM
so what comes next?
experts on dark matter/dark energy gets titled Sith? :lol:
Title: Re: Dark Energy
Post by: MichaelW on June 21, 2012, 10:17:53 AM
This dark energy/matter stuff seems to me to be too close to the “black magic” that people used to explain things they didn’t understand in medieval times.
Title: Re: Dark Energy
Post by: hutch-- on June 21, 2012, 01:56:20 PM
There is really a simple explanation for postulating dark matter, not everything in the universe glows in the dark.
Title: Re: Dark Energy
Post by: Daydreamer on June 21, 2012, 02:07:43 PM
This dark energy/matter stuff seems to me to be too close to the “black magic” that people used to explain things they didn’t understand in medieval times.
but that turns out correct that all physic laws etc was invisible energy and gravity,magnetic,radioactivity etc are still is unseen forces for ordinary joe without instruments to reveal for example gammarays, radiotransmitter etc
Title: Re: Dark Energy
Post by: dedndave on June 21, 2012, 02:40:52 PM
that's right - we don't even fully understand the easy stuff yet   :P
Title: Re: Dark Energy
Post by: hutch-- on June 21, 2012, 04:37:30 PM
Actually black holes sound like a ton of fun in open space, if we ever get the technology to travel really long distances, one of the risks is trying to drive through a black hole if you fail to detect it. General drift is you go in and you don't come out. (Splot ! )
Title: Re: Dark Energy
Post by: npnw on June 21, 2012, 06:21:18 PM
Do you go splot???? or do you go to another dimension?  Where the speed of light constant or matter to energy ratio constant is changed?

Are Black Holes uptakes to a faster than light travel? Thus warp drive theory? Heinlein had some interested SciFi ideas on things.

http://en.wikipedia.org/wiki/Quark%E2%80%93gluon_plasma (http://en.wikipedia.org/wiki/Quark%E2%80%93gluon_plasma)

With is type of energy we may be able to develop faster than light travel. Of course that is if we don't develop a black hole first  :t

There is a slight risk.

Also good article http://news.bbc.co.uk/2/hi/science/nature/4462209.stm (http://news.bbc.co.uk/2/hi/science/nature/4462209.stm)

black hole article http://news.bbc.co.uk/2/hi/science/nature/4357613.stm (http://news.bbc.co.uk/2/hi/science/nature/4357613.stm)
Title: Re: Dark Energy
Post by: hutch-- on June 21, 2012, 06:26:22 PM
Einstein frame of reference comes into play here, from an external fixed viewpoint it going SPLOT (albeit silently), if you are on the object going into the hole you may experience time at a different rate to the external fixed point. I seriously doubt you come out the other side into a new dimension unless you are committed to the viewpoint that you end up in heaven.  :biggrin:
Title: Re: Dark Energy
Post by: npnw on June 21, 2012, 06:40:20 PM
http://arxiv.org/pdf/nucl-ex/0410020v1.pdf (http://arxiv.org/pdf/nucl-ex/0410020v1.pdf)

Could be hutch.  They think this is the state of the universe before particles were formed. The first 400,000 years I think? 

If I cross over Hutch and can get back I'll stop bye. Should make the commute time to Australia .... well faster than light :)

Who knows if Heaven isn't another dimension. Would explain the loss of our body here and a new body there. Because of the change from one place to another. Yet maybe the soul or pattern of energy would be transferred to that new body.  Sounds like religion, but may actually be supported in science. 

Remember your article on the bacteria with the electrostatic drive? There is an article about this too... somewhere.
Title: Re: Dark Energy
Post by: npnw on June 21, 2012, 06:49:50 PM
http://en.wikipedia.org/wiki/Faster-than-light (http://en.wikipedia.org/wiki/Faster-than-light)

Dr. Gerald Cleaver, associate professor of physics at Baylor University, and Richard Obousy, a Baylor graduate student, theorize that by manipulating the extra spatial dimensions of string theory around a spaceship with an extremely large amount of energy, it would create a "bubble" that could cause the ship to travel faster than the speed of light. To create this bubble, the physicists believe manipulating the 10th spatial dimension would alter the dark energy in three large spatial dimensions: height, width and length. Cleaver said positive dark energy is currently responsible for speeding up the expansion rate of our universe as time moves on.[51]
Title: Re: Dark Energy
Post by: dedndave on June 22, 2012, 12:20:08 AM
getting in (or out - lol) of a black hole would be the hard part
we will likely never know what's on the other side
we could not survive that kind of gravitational force

ok - now, your thinking like in the movie "Stargate" - where they send in a probe - lol
well - if light can't escape the force, what makes you think the probe's radio signal will

in the movie, i wonder how long it took for the radio signal from the probe to reach them
the planet was supposedly "on the other side of the known universe" - DOH !
Title: Re: Dark Energy
Post by: npnw on June 22, 2012, 05:31:52 AM
Its just fun to read how science is getting close to science fiction.  :t
Title: Re: Dark Energy
Post by: K_F on June 22, 2012, 05:33:52 PM
ok - now, your thinking like in the movie "Stargate" - where they send in a probe - lol
well - if light can't escape the force, what makes you think the probe's radio signal will
:biggrin:
I eventually had to shut-up when watching movies that were 'technically wrong', as the family was screaming at me  :biggrin:

The wiff's all smitten as the main actor is about to kiss his girlfriend and I say - "Look, that wheel's turning the wrong way !!".
a barrage of cushions come flying my way... :greenclp:

I could never understand why, when a person says that nothing is faster than light-speed.. they all believe it.  :icon_rolleyes:
Title: Re: Dark Energy
Post by: dedndave on June 22, 2012, 07:58:00 PM
i enjoy sci-fi movies, too   :P
in order to watch many movies or shows, i have to set what i know aside in order to enjoy it - lol

still, my brain can't help but try to figure out how something might actually be done
Star Trek, Next Generation was an old fave
i was always trying to think up ways to engineer the impossible - lol
Title: Re: Dark Energy
Post by: Zen on June 23, 2012, 07:55:08 AM
...So,...what happened to PETER ???
Title: Re: Dark Energy
Post by: farrier on June 28, 2012, 06:00:29 PM
The second of a 2 part series on NOVA--the best TV show for almost 40 years--aired Wednesday night.  You can watch both at:

http://www.pbs.org/wgbh/nova/

"Hunting the edge of space"

I watched them both, and it's still a mystery!

farrier
Title: Re: Dark Energy
Post by: dedndave on June 28, 2012, 11:08:16 PM
great series - looks like 6 parts, in all   :t
Title: Re: Dark Energy
Post by: npnw on July 03, 2012, 03:21:08 PM
My 3 yr old will have to watch the whole thing!