Dark matter/Dark Energy

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Profile Julie
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Message 1514371 - Posted: 10 May 2014, 13:30:00 UTC
Last modified: 10 May 2014, 13:30:16 UTC

The LHC and Super LHC may find answers, we don't yet know.


If anyone ever finds an answer to it, it will surely be with the help of those two.
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Message 1514427 - Posted: 10 May 2014, 17:03:15 UTC - in response to Message 1514371.  

The LHC and Super LHC may find answers, we don't yet know.


If anyone ever finds an answer to it, it will surely be with the help of those two.

yes, and also with mine, since I am running LHC@home 1 and LHC@Home 2.
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Message 1514640 - Posted: 11 May 2014, 4:25:00 UTC - in response to Message 1514435.  

Thanks Tullio, I'll have a look at those. I did look at it once but they had problems with it at the time.

Test4Theory@home is running fine on both 6.10.58 client and 7.2.41 or 7.2.42. Of course you need to install Virtual Box. LHC@home is having some problems with Windows XP but runs fine on my Linux box.
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Message 1514682 - Posted: 11 May 2014, 8:12:35 UTC
Last modified: 11 May 2014, 8:43:53 UTC

One very interesting theory I have read about and heard about (from M-theory) is the possibility that there is gravitational leakage from one or more other universes that exist in separate branes from ours. The only particles that can pass from one brane to another are gravitons (since they are closed strings, while open strings such as photons and fermions are bound to their respective branes). If the search for WIMPs ultimately fails, this may be a good possibility.

It would also explain why the gravitational force is comparatively weak.
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Message 1515715 - Posted: 13 May 2014, 23:01:02 UTC - in response to Message 1515390.  

Can super-fast stars unveil dark matter's secrets?


Zoom! A star was recently spotted speeding at 1.4 million miles an hour (2.2 million km/hr), which happened to be the closest and second-brightest of the so-called "hypervelocity" stars found so far.

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Message 1515719 - Posted: 13 May 2014, 23:10:02 UTC - in response to Message 1515715.  

Can super-fast stars unveil dark matter's secrets?


Zoom! A star was recently spotted speeding at 1.4 million miles an hour (2.2 million km/hr), which happened to be the closest and second-brightest of the so-called "hypervelocity" stars found so far.

More


Wow... I learn something new every day! :) Thanks Lynn - very interesting post! They seem to think the black hole at the centre of the milky way has something to do with it, and as the star is much further away from it than we are, it must have been speeding away for some time... I wonder if I should try to do the maths on that now... or leave it till the morning when I'm less likely to go cross-eyed :)
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Message 1517798 - Posted: 18 May 2014, 8:07:26 UTC - in response to Message 1517362.  

I think it useful to define "space". What we call space, outer space, interstellar space, cosmos etc, is that which is outside the Earths atmosphere. Space officially begins at an altitude of 100Km above sea level (Kármán line) but anything less than 160Km will experience rapid orbit decay. The ISS at 425 Km decays at 2 Km/month, Hubble is at 570 Km.

Outer space is between the planets, and interstellar space is between the star systems in a galaxy. It is believed that Voyager One has now left the solar system and entered into interstellar space. Russia and the Eastern Bloc call space travellers Cosmonauts from the Greek words kosmos meaning "universe", and nautes meaning "sailor". The USA and others call them Astronauts from Greek words ástron meaning "star", and nautes meaning "sailor".

Some background and info on dark matter and energy here outer space


You know the old saying what goes up doesn't always come down? looks like that's not totally true.
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Message 1517803 - Posted: 18 May 2014, 9:26:50 UTC - in response to Message 1517801.  

NASA will test a kind of flying saucer destined to land on Mars. It will be tested in high atmosphere with density similar to Mars atmosphere after being carried there by a balloon.
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Message 1517804 - Posted: 18 May 2014, 9:27:11 UTC - in response to Message 1517801.  
Last modified: 18 May 2014, 9:30:42 UTC

You know the old saying what goes up doesn't always come down? looks like that's not totally true.

There was an urban myth once many years ago of someone who invented a model flying saucer. It was about 2 feet diameter, and fitted with 1/2 a dozen powerful contra rotating gyroscopes. Apparently when all powered up, it took off vertically at a high speed never to be seen again.


One guy in the state of Washington had made wire frame and applied 10,000 volts to it. It floated, ended up as an Ion flow pushing it up.
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Message 1518006 - Posted: 19 May 2014, 3:33:14 UTC - in response to Message 1517804.  

You know the old saying what goes up doesn't always come down? looks like that's not totally true.

There was an urban myth once many years ago of someone who invented a model flying saucer. It was about 2 feet diameter, and fitted with 1/2 a dozen powerful contra rotating gyroscopes. Apparently when all powered up, it took off vertically at a high speed never to be seen again.


One guy in the state of Washington had made wire frame and applied 10,000 volts to it. It floated, ended up as an Ion flow pushing it up.


Huh... :) thanks Grant! Very interesting :)

Are there any theories out there as to what it would be like, or even if it would be possible to fly/move through dark matter?

I could look it up tomorrow I suppose... bit late now... should have been in bed AGES ago...
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Message 1518825 - Posted: 20 May 2014, 22:05:26 UTC - in response to Message 1518006.  

Could an Australian gold mine help unlock the secrets of the universe? Scientists to build underground laboratory in Victorian mine shaft to search for dark matter

The Stawell Gold Mine in Victoria is undergoing tests to determine if it would be suitable for an underground laboratory.
If approved, the scientists would use the lab to search for dark matter at the bottom of the 1,500m-deep mine
Laboratory would be the first of its kind in the southern hemisphere
Unused mine shaft presents perfect conditions for finding dark matter

http://www.dailymail.co.uk/news/article-2633715/Could-Australian-gold-help-unlock-secrets-universe-Scientists-set-build-underground-laboratory-search-dark-matter.html

I hope it gets approved.
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Message 1519073 - Posted: 21 May 2014, 7:10:56 UTC - in response to Message 1518825.  
Last modified: 21 May 2014, 7:15:52 UTC

The Homestake gold mine in South Dakota, which hosted Raymond Davis and his apparatus for detecting solar neutrinos, has hosted the LUX experiment. LUX stands for Large Underground Xenon, and found no trace of dark matter, The Gran Sasso National Laboratory in Italy has hosted the DAMA/LIBRA experiments, whose experimental apparatus gave a wrong indication of the speed of neutrinos coming from CERN due to a faulty cable and they are still red faced. The CoGeNT experiment is running in Soudan, Minnesota. I gather all this information from a "Nature" article of March 6, 2014, "Broaden the search for dark matter".
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Message 1519108 - Posted: 21 May 2014, 10:08:37 UTC - in response to Message 1519073.  

As to Dark matter:

How do we know that the Universe is expanding at an increasing rate. The further out that we look, the more we are seeing what happened in the long ago past. Aren't we seeing the universe nearer in time to the Big Bang when gravity did not have time enough to start slowing down the expansion.
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Message 1519112 - Posted: 21 May 2014, 10:36:26 UTC - in response to Message 1519108.  

This is based on supernova observations Supernovae are used as "standard candles". By measuring their luminosity you can infer their distance. By measuring their red shift you can infer their velocity.According to Hubble's law (it really should be Hubble-Lemaitre) their velocity is proportional to distance.But how do you get an acceleration parameter? This I don't know.
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Message 1519113 - Posted: 21 May 2014, 10:36:31 UTC
Last modified: 21 May 2014, 10:44:19 UTC

How do we know that the Universe is expanding at an increasing rate.


Edwin Hubble proved the expansion of the Universe:

http://www.pbs.org/wgbh/aso/databank/entries/dp29hu.html

In fact, Hubble found, space has been expanding since it began with the Big Bang 13.7 billion years ago. Then, in the 1990s, astronomers shocked the world again with the revelation that this expansion is speeding up (this discovery won its finders the 2011 Nobel Prize in Fyzix).
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Message 1519122 - Posted: 21 May 2014, 11:45:46 UTC - in response to Message 1519113.  

Abbe' Georges Lemaitre, a Belgian, had proposed an expansion of the universe in 1927. But he wrote it in French,and when his paper was translated in English it was too late.
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Message 1519167 - Posted: 21 May 2014, 14:08:24 UTC - in response to Message 1519113.  

Edwin Hubble proved the expansion of the Universe:


Yes of course. The Universe has been expanding from the moment of the Big Bang. What I was questioning is how and why we think that the expansion rate is accelerating. Spots on a balloon move away from each other, Spots that are farther away from each other move away faster yet the balloon is being blown up at a constant rate. So if we look further out and compare the movement to that further in (close to us) do we erroneously conclude that the acceleration (i.e. the rate of expansion) is increasing.

It seems to me that we might observe this phenomenon simply from the big bang and not some unseen force or "negative gravity".
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Message 1519310 - Posted: 21 May 2014, 18:41:16 UTC - in response to Message 1519167.  

Hubble's law says that velocity is distance times Hubble's constant. So, if you plot velocity vs distance, you should get a straight line. What was found in 1998 is that Hubble's constant isn't actually constant but increases with time--that is, it's higher for nearer objects.
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Message 1519354 - Posted: 21 May 2014, 19:25:33 UTC - in response to Message 1519310.  

Hubble's law says that velocity is distance times Hubble's constant. So, if you plot velocity vs distance, you should get a straight line. What was found in 1998 is that Hubble's constant isn't actually constant but increases with time--that is, it's higher for nearer objects.

Nearer?
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Message 1520229 - Posted: 23 May 2014, 11:59:57 UTC - in response to Message 1519354.  

Nearer to Earth (and thus more recent).
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