US gold town now looks for 'dark matter'

2012-05-30 17:39

Lead - Nestled nearly 1 500m beneath the earth in the gold boom town of Lead, South Dakota, is a laboratory that could help scientists answer some pretty heavy questions about life, its origins and the universe.

On Wednesday, when part of the closed Homestake Gold Mine officially becomes an underground campus, Lead's name will be known in scientific circles as the place where the elusive stuff called dark matter might finally be detected.

"This year, 2012, is going to be a very significant year because we get to turn the... detector on and know very soon whether we have actually found dark matter or not," said Rick Gaitskell, a scientist with Brown University who has worked with dozens of scientists over the past few years to move forward with the Large Underground Xenon experiment - or LUX - the world's most sensitive dark-matter detector.

For Gaitskell and scientists like him, dark matter is a mystery of existence.

"It makes up a huge amount of the universe," said Kevin Lesko, of Lawrence Berkley National Lab, who is the principal investigator for the Sanford Underground Research Facility.

They know dark matter is there by its gravitational pull, but unlike regular matter and antimatter, it's so far undetectable. Scientific papers and books have been dedicated to what it could be, but so far, Gaitskell and his colleagues know only that it could explain why the universe isn't made up equally of matter and antimatter.

That, in turn, could explain how the world as we know it came to be.

"It has to be there because of its effects through gravity, but it also has to have properties that make it very unusual - otherwise, we would have detected it already," Lesko said.

Regular matter - people and planets, for example - make up about 4% of the total mass-energy of the universe, he said. Dark matter makes up about 25%.

"So it's five times as much as us, and yet we've never directly observed it."

Scientists hope the new lab will change that.

The Homestead mine opened during a gold rush in 1876 and outlasted many counterparts. In the late 1990s, it still employed about 1 000 people, but as the value of gold dropped, it became clear that the mine's days were numbered. It closed for good in 2003.

The science community seized on the closure. Dark matter is too sensitive to detect in normal laboratories, but one so far underground would help shield it from cosmic radiation. The LUX detector is submerged in water for further insulation.

Experiments are set to begin this year. All told, the site has cost more than $300m a mix of private donations and state and federal funding.

About 70 former mine workers now work for the lab. Greg King is one of them.

"The whole town was built up around the Homestake," King said. "As the property closed and people left, a lot of employees left. Now, there's a lot of excitement in town. People are very thrilled that the Homestake is once again."

  • QuantumDM - 2012-05-30 18:12

    Nice one!

  • Ben - 2012-05-30 19:12

    So if dark-matter constitutes 25% and 'regular'-matter 4%, what makes up the 71%? All anti-matter? Jesus? Missing socks?

      janalbert.vandenberg - 2012-05-30 19:40

      Yep, definitely missing socks. There are so many missing socks, their combined mass will easily bend space-time in on itself. Socks will one day be the cause of the big crunch, when the universe folds in on itself only to bang again later. I tell ya: the socks control *EVERYTHING* :-)

      scott.kirby.752 - 2012-05-30 21:24

      Scientists admit that this is the most embarrassing thing in all of Cosmology that they don't know what 96% of the universe is. Dark energy makes up the rest of the mass of the universe, and scientists are even more confused by that... But these projects will help deepen their understanding and eventually they'll work it out.

      skootzie - 2012-05-30 21:36

      Scientists thrive on the unknown, on the ignorance because it keeps them employed ;-) - imagine there was nothing to discover; imagine if we already knew all the answers - what a boring world that would be.

      don.mcarthur.7 - 2012-05-31 07:06

      Supposedly Dark Energy. Which by a bit of hand waving explains [AFAIK] the acceleration in the expansion of the Universe against its own gravity.

  • gee.raaf - 2012-05-30 19:46

    Why travel 1500 m into the earth? We've got plenty of dark matter in the anc...

  • Mandy Casey - 2012-05-30 20:54

    Yesterday the earth was flat, today round, tomorrow a triangle? Regular matter - people and planets, for example - make up about 4% of the total mass-energy of the universe, he said. Dark matter makes up about 25%. And you are sure of these percentages because you have already explored and measured the whole universe? You are in the dark and it doesn't matter.

      skootzie - 2012-05-30 21:56

      So your argument is based on the premise that because we haven't explored and studied the entire universe then we can't be sure of what the math and science tells us? Fair enough, however; let's put forth a middle ground shall we? Assume that the percentages are based off of the known universe that is available for study. In addition, make allowance for the fact that as we discover and study more of the universe, the percentages (along with our knowledge and research) will be adjusted accordingly. Also take into account the fact that the parts of the universe we do study are both near (local) and far (Andromeda). If the laws of physics apply to our own local system then they must - in all honesty and common sense - apply to the rest of the universe; to think otherwise is to clutch at straws.

  • iwan.v.schalkwyk - 2012-05-31 05:32

    I've heard about matter and anti-matter. What about "anti dark matter"? Would that be regular matter? 0.o ?

  • E=MC2 - 2012-05-31 14:02

    ok, forgive me for possibly sounding dumb here but, and i quote: "It makes up a huge amount of the universe," BUT "and yet we've never directly observed it." So its all over the place, but you've never seen it...? Wow, the brains of the 21st century never cease to amaze me.

      skootzie - 2012-06-01 10:05

      It's possible to observe something directly and indirectly. "They know dark matter is there by its gravitational pull" <- indirect observation. As opposed to direct observation, i.e: viewing a stars effects on the planets around it.

  • Clarissa Vymers - 2013-10-31 08:22

    They know dark matter is there by its gravitational pull on galaxies for instance people came up with dark matter to explain the increase in the orbital velocities of stars that are far remove from the centre of their galaxy. Hence people start looking for it (dark matter) by means of this underground detector.I do not think that dark matter really exist, I think that perhaps we do not really completely understand gravity and that gravity's properties might change under certain conditions.

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