Dark science

Here's where you get off topic and off center....Keep it nice, keep it clean, no sniping, no flaming. After that, anything goes.

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Digit
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Post by Digit »

:lol: :lol: If you get any useful tips Min let us know!
Ishtar
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neilmarr
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Post by neilmarr »

***I stopped stamp collecting some years ago!***

Glad you realised that philately will get you nowhere, Digit. Neil
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Digit
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Post by Digit »

Taught me a lot about where various countries are though Neil.
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Post by War Arrow »

I've just done a big poo. It come out me bum. Appropriate links supporting the verification of this statement will be posted shortly and I therefore look forward to a lengthy debate as to whether I merely imagined aforementioned poo and its cited point of exit.
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rich
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Post by rich »

Bah - that's easy - it came from where the sun don't shine - voila - dark matter!!!!!!!!!!!! :D
Last edited by rich on Mon Jun 23, 2008 11:20 pm, edited 1 time in total.
i'm not lookin' for who or what made the earth - just who got me dizzy by makin it spin
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Post by Beagle »

http://www.pbs.org/wgbh/nova/sciencenow/0301/01.html
Watch the program June 25 on PBS, or come back June 26 to watch it online here.
This program can be viewed here this Thursday. :wink:
Ishtar
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Post by Ishtar »

The programme is about a NASA group scientists from the University of Arizona claiming that data from clusters of galaxies colliding long ago provides evidence for dark matter.

This 2006 article from the Washington Post explains the theory, but still leaves doubt:

http://www.washingtonpost.com/wp-dyn/co ... 01139.html

For decades, many scientists have theorized that the universe is made up of nearly undetectable mysterious substances called dark matter and dark energy. But until yesterday there was no proof that the subatomic matter actually exists.

After studying data from a long-ago collision of two giant clusters of galaxies, researchers now say they are certain dark matter does exist and plays a central role in creating and defining gravity throughout the universe....

... Stacy McGaugh, an astrophysicist at the University of Maryland, has been one of the dark-matter skeptics, and he said yesterday that he remained unconvinced.

"I've been aware of this result some time, and I agree that it is interesting and may make more sense in terms of dark matter than alternative gravity," he said. "However, it is premature to say so."

He said that a definitive detection of dark-matter particles would mean "grabbing them in the laboratory, not just inferring that their effects can be the only possible explanation for an observation before the alternatives have actually been checked."

The NASA-affiliated team that announced its findings yesterday said that the next step in trying to understand dark matter (and related dark energy) is, in fact, to identify it in a laboratory. That task has proved difficult so far, they said, because dark matter leaves no detectable traces, except to create a gravitational pull.

"This finding doesn't tell us where dark matter comes from," Carroll said. "It tells us that dark matter exists, but it doesn't say what it is, or why there's so much of it. The real adventure is ahead of us."
rich
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Post by rich »

Hah - "beware the darkside of the force, Luke" :D

i'n't it dark in here!
i'm not lookin' for who or what made the earth - just who got me dizzy by makin it spin
Ishtar
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Post by Ishtar »

I think that the mistake was to call it Space in the first place. To the ancient shaman scientists of the Vedas, there was no such thing as ‘space’. Everything was something. Nothing was nothing. They said it was the gods or spirits that controlled it. That’s why it says in Genesis:

"In the beginning God created the heavens and the earth. And the earth was without form and void, and darkness was upon the face of the deep. And the Spirit of God was moving over the face of the waters."

They Hebrews got it from the Chaldeans and turned the word ‘gods’ or ‘spirits’ into their one God. The Chaldeans got it from the Babylonians, who got it from the Sumerians in 3,000 BC. It’s also in the Egyptian Pyramid Texts.

My bolding

http://en.wikipedia.org/wiki/Dark_matter

Only about 4% of the total energy density in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy, an even stranger component, distributed diffusely in space…… Determining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics. It has been noted that the names "dark matter" and "dark energy" serve mainly as expressions of human ignorance, much as the marking of early maps with "terra incognita."
Or is to serve our fear of just saying ‘we don’t know’?

One reason we cling on to theories that don’t really stack up, imo, is because sometimes they appear to be the lesser of two evils – in this case, the dreaded alternative gravity theory, which would mean moving things around a bit in the holy of holies, Newton’s Law of Gravity.

This is it:

http://en.wikipedia.org/wiki/Dark_matte ... planations

A proposed alternative to physical dark matter particles has been to suppose that the observed inconsistencies are due to an incomplete understanding of gravitation. To explain the observations, the gravitational force has to become stronger than the Newtonian approximation at great distances or in weak fields. One of the proposed models is Modified Newtonian Dynamics (MOND), which adjusts Newton's laws at small acceleration. However, constructing a relativistic MOND theory has been troublesome, and it is not clear how the theory can be reconciled with gravitational lensing measurements of the deflection of light around galaxies. The leading relativistic MOND theory, proposed by Jacob Bekenstein in 2004 is called TeVeS for Tensor-Vector-Scalar and solves many of the problems of earlier attempts. However, a study in August 2006 reported an observation of a pair of colliding galaxy clusters whose behavior, it was claimed, was not compatible with any current modified gravity theories.[21]

In 2007, astronomer John W. Moffatt proposed a theory of modified gravity (MOG) based on the Nonsymmetric Gravitational Theory (NGT) that accounts for the behavior of colliding galaxies.[22]
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Digit
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Post by Digit »

Also of course Ish the idea is pretty old, it used be known as the 'Ether' or 'Aether'.
Ishtar
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Post by Ishtar »

Digit wrote:Also of course Ish the idea is pretty old, it used be known as the 'Ether' or 'Aether'.
Yes - again, that is how material creation is described in the Vedas, made up of: water, fire, air, ether and earth. Notice air and ether are different.
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MichelleH
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Post by MichelleH »

Huge lenses to observe cosmic dark energy

Science and Technology Facilities Council

http://www.alphagalileo.org/index.cfm?f ... z_search=1
UK astronomers, as part of an international team, have reached a milestone in the construction of one of the largest ever cameras to detect the mysterious Dark Energy component of the Universe. The pieces of glass for the five unique lenses of the camera have been shipped from the US to France to be shaped and polished into their final form. The largest of the five lenses is one metre in diameter, making it one of the largest in the world.

Each milestone in the completion of this sophisticated camera brings us closer to detecting the mysterious and invisible matter that cosmologists estimate makes up around three quarters of our Universe and is driving its accelerating expansion. Observations suggest that roughly 4% of the Universe is made up from ordinary matter and 22% from Dark Matter; this leaves 74% unaccounted for - the so-called Dark Energy.
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Ishtar
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Post by Ishtar »

Thanks, Michelle. That's very interesting...although we'll have to wait until 2011 before we get any results.

In the meantime, I have a rookie question for our resident astronomer.

As they say, dark energy makes up 74 per cent of the universe. But we are in the universe, the earth is a planet within this universe. So would not a little of this 74 per cent of dark energy be around us, rather than 'out there' on the edge of space?

I may have misunderstood, but I've always thought if something doesn't reflect light, you can't see it wherever it is - it's not that it's necessarily so far away that you can't see it. It could be right next to you, and you wouldn't see it.

Sorry if this seems a ridiculous question. But up to now, I'd been under the impression that dark energy was as much here as on say a planet on the edge of the universe - after all, it's only on the edge of the universe according to our perspective.

Obviously, if it needs a giant telescope to see it, I must be wrong. But I don't understand why...

Yours confused, :?
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