Dark matter/Dark Energy

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Message 1744393 - Posted: 23 Nov 2015, 22:37:56 UTC

Study says:

Earth Might Have Hairy Dark Matter

The solar system might be a lot hairier than we thought.

A new study publishing this week in the Astrophysical Journal by Gary Prézeau of NASA's Jet Propulsion Laboratory, Pasadena, California, proposes the existence of long filaments of dark matter, or "hairs."

Dark matter is an invisible, mysterious substance that makes up about 27 percent of all matter and energy in the universe. The regular matter, which makes up everything we can see around us, is only 5 percent of the universe. The rest is dark energy, a strange phenomenon associated with the acceleration of our expanding universe.

http://www.nasa.gov/feature/jpl/earth-might-have-hairy-dark-matter
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Message 1744441 - Posted: 24 Nov 2015, 4:03:07 UTC
Last modified: 24 Nov 2015, 4:04:17 UTC

The XENONIT experiment at Gran Sasso National Laboratory has started. It uses 3500 kg of liquid Xenon ccoled at -95 C temperature to look for dark matter. The experiment is managed by the INFN (Istituto Nazionale di Fisica Nucleare) and has as Director Elena Aprile of Columbia University. Another top woman, like Fabiola Gianotti, Director of CERN from next January.
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Message 1749933 - Posted: 17 Dec 2015, 18:47:16 UTC

A Chinese Long March D2 rocket has launched a research satellite built by Istituto Nazionale di Fisica Nucleare Italy to search for dark matter. It is called DAMPE from DArk Matter Particles Explorer.
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Message 1749934 - Posted: 17 Dec 2015, 19:11:12 UTC - in response to Message 1749933.  

A Chinese Long March D2 rocket has launched a research satellite built by Istituto Nazionale di Fisica Nucleare Italy to search for dark matter. It is called DAMPE from DArk Matter Particles Explorer.
Tullio


Thanks for the update tullio :)
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Message 1750791 - Posted: 21 Dec 2015, 10:27:54 UTC - in response to Message 1749934.  
Last modified: 21 Dec 2015, 10:28:20 UTC

Maybe I was too enthusiastic after reading a news release of the Istituto Nazionale di Fisica Nucleare. Only one of the four detectors aboard DAMPE for various particle kinds was built and tested in Italy. But what is important is the cooperation between Italian and Chinese scientists.
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Message 1752225 - Posted: 29 Dec 2015, 7:45:16 UTC

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Message 1752229 - Posted: 29 Dec 2015, 8:07:11 UTC

Very interesting article. I happen to know prof. Melchiorri, he was one on my authors when I worked at Edizioni Scientifiche Mondadori in Milano. Now he is a professor in Rome.
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Message 1766413 - Posted: 20 Feb 2016, 5:27:12 UTC

The Gran Sasso National Laboratories are starting the XENONIT experiment looking for dark matter particles using a tank containing 3500 kg of liquid Xenon at a depth of 1400 m below the Gran Sasso Mountain. Dark matter particles hitting a Xenon nucleus should emit a flash of light of a particular wavelength and be recorded by detectors.
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Message 1766494 - Posted: 20 Feb 2016, 16:13:41 UTC - in response to Message 1752225.  
Last modified: 20 Feb 2016, 16:15:18 UTC

Is Dark Matter being swallowed up by Dark Energy?


Dark energy is the energy ascribed to the Vacuum that is ostensibly causing the universe to expand.

Dark matter can be ascribed to possibly particles that we have not yet found.

Some suggest neutrinos and so on; but, maybe they are tiny black holes. In any event they are dark because they don't interact with photons. The large black holes that we can infer are there do not account for the apparently missing mass.
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Message 1766644 - Posted: 21 Feb 2016, 7:41:00 UTC

Dark matter is a hypothetical substance that is believed by most astronomers to account for around five-sixths of the matter in the universe. Although it has not been directly observed, its existence and properties are inferred from its various gravitational effects: on the motions of visible matter; via gravitational lensing; its influence on the universe's large-scale structure, and its effects in the cosmic microwave background. Dark matter is transparent to electromagnetic radiation and/or is so dense and small that it fails to absorb or emit enough radiation to be detectable with imaging technology.

The standard model of cosmology indicates that the total mass–energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Thus, dark matter constitutes 84.5% of total mass, while dark energy plus dark matter constitute 95.1% of total mass–energy content.

Pretty accurate forecasts for something nobody can prove exists???

Statistics can be used to prove that Unicorns are busiest at 3am in the morning. That to me is much more likely to be true!
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Message 1766677 - Posted: 21 Feb 2016, 12:25:49 UTC

XENONIT at Gran Sasso is looking for WIMPS (Weakly Interacting Massive Particles). If it does not find them the whole story of Dark Matter must be rewritten. But it took thirty years to detect neutrinos.
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Message 1769010 - Posted: 2 Mar 2016, 16:21:21 UTC - in response to Message 1766677.  

XENONIT at Gran Sasso is looking for WIMPS (Weakly Interacting Massive Particles). If it does not find them the whole story of Dark Matter must be rewritten. But it took thirty years to detect neutrinos.
Tullio


Fingers crossed.
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Message 1769116 - Posted: 3 Mar 2016, 2:11:34 UTC - in response to Message 1766644.  
Last modified: 3 Mar 2016, 2:12:09 UTC

Will dark matter go away if it is assumed that the universe itself is rapidly spinning--if so, then how fast are we spinning?
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Message 1769201 - Posted: 3 Mar 2016, 9:52:40 UTC - in response to Message 1769116.  

Will dark matter go away if it is assumed that the universe itself is rapidly spinning--if so, then how fast are we spinning?


One half the speed of light, is my thought. The LIGO article on the discovery of gravitational waves leaps to mind.

During the final fraction of a second, the two black holes collide into each other at nearly one-half the speed of light and form a single more massive black hole, converting a portion of the combined black holes’ mass to energy, according to Einstein’s formula E=mc2.

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Message 1769426 - Posted: 4 Mar 2016, 6:51:44 UTC - in response to Message 1769201.  

Will dark matter go away if it is assumed that the universe itself is rapidly spinning--if so, then how fast are we spinning?


One half the speed of light, is my thought. The LIGO article on the discovery of gravitational waves leaps to mind.

During the final fraction of a second, the two black holes collide into each other at nearly one-half the speed of light and form a single more massive black hole, converting a portion of the combined black holes’ mass to energy, according to Einstein’s formula E=mc2.


Blogged something I was pondering over last night..

http://juliedetavernier.wix.com/rozz#!What-about-the-Universal-Spin/d0xmh/56d92b040cf20d226f1e3603
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Message 1783284 - Posted: 28 Apr 2016, 18:37:43 UTC - in response to Message 1769426.  

If not dark energy, what's making the universe expand?

"Russian Doll" Galaxy Clusters Reveal Information About Dark Energy

Astronomers have used data from NASA’s Chandra X-ray Observatory, ESA’s Planck and a large list of optical telescopes to develop a powerful new method for investigating dark energy, the mysterious energy that is currently driving the accelerating expansion of the universe.

The technique takes advantage of the observation that the outer reaches of galaxy clusters, the largest structures in the universe held together by gravity, show similarity in their X-ray emission profiles and sizes. More massive clusters are simply scaled up versions of less massive ones.

http://www.nasa.gov/mission_pages/chandra/russian-doll-galaxy-clusters-reveal-information-about-dark-energy.html

Space's Deepest Secrets
Hunt for Dark Energy

EPISODE INFO

Meet the scientists across the world on the hunt for dark energy, an unknown form of energy which is hypothesized to permeate all of space and may be accelerating the expansion of the universe. 61 Min. | PG
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Message 1783329 - Posted: 28 Apr 2016, 22:20:56 UTC - in response to Message 1783284.  

What is making the Universe expand is the Big Bang. What is apparently making the Universe expand faster is also the Big Bang. Let me explain. Suppose you have a balloon with closely spaced dots and you blow it up at a constant rate. As the balloon gets larger and larger the dots will separate from each other at a faster and faster rate even though the input to this process is constant.

Apply this thinking to 3 dimensions and you may have yourself an explanation for "Dark Energy".

You would think that gravity might eventually slow down the rate of acceleration--maybe it will or already has.
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Message 1783347 - Posted: 29 Apr 2016, 0:58:49 UTC - in response to Message 1783329.  

What is making the Universe expand is the Big Bang. What is apparently making the Universe expand faster is also the Big Bang. Let me explain. Suppose you have a balloon with closely spaced dots and you blow it up at a constant rate. As the balloon gets larger and larger the dots will separate from each other at a faster and faster rate even though the input to this process is constant.

Apply this thinking to 3 dimensions and you may have yourself an explanation for "Dark Energy".

You would think that gravity might eventually slow down the rate of acceleration--maybe it will or already has.

Bad analogy William. As the volume of the balloon gets bigger it goes up with the cube of the radius. So to have space expand at a constant rate you need to be pumping gas into the balloon faster and faster.
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Message 1783349 - Posted: 29 Apr 2016, 1:31:55 UTC - in response to Message 1783347.  

I didn't say that space was expanding at a constant rate only that the amount of air entering the balloon was constant--what I said was as the balloon gets larger the dots on the balloon move faster and faster.

The surface area increases as the square of the radius
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Message 1783357 - Posted: 29 Apr 2016, 3:06:00 UTC - in response to Message 1783349.  

I didn't say that space was expanding at a constant rate only that the amount of air entering the balloon was constant--what I said was as the balloon gets larger the dots on the balloon move faster and faster.

The surface area increases as the square of the radius

That doesn't work William.
If a balloon is being inflated with a constant input of air per unit of time
the rate of volumetric change of the balloon will also be constant.
2 points on the balloon diametrically opposite to each other will recede from each other
at twice the rate that the radius changes.
Air input to balloon is constant per unit time.
Volume of balloon will increase at a constant rate per unit time.
As the balloon gets bigger the rate of change of the radius will decrease to accommodate the constant input of air to the balloon.
Thus your balloon analogy, with constant input of air, would have 2 dots on the balloon move more, and more slowly away from each other, not faster.
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Message boards : Science (non-SETI) : Dark matter/Dark Energy


 
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