Looking for Dark Matter: The DarkSide-50 Project

darkmatter1If 2013 will go down in history as the year the Higgs Boson was discovered, then 2014 may very well be known as the year dark matter was first detected. Much like the Higgs Boson, our understanding of the universe rests upon the definitive existence of this mysterious entity, which alongside “dark energy” is believed to make up the vast majority of the cosmos.

Before 2014 rolled around, the Large Underground Xenon experiment (LUX) – located near the town of Lead in South Dakota – was seen as the best candidate for finding it. However, since that time, attention has also been directed towards the DarkSide-50 Experiment located deep underground in the Gran Sasso mountain, the highest peak in the Appennines chain in central Italy.

darkside-50This project is an international collaboration between Italian, French, Polish, Ukrainian, Russian, and Chinese institutions, as well as 17 American universities, which aims to pin down dark matter particles. The project team spent last summer assembling their detector, a grocery bag-sized device that contains liquid argon, cooled to a temperature of -186° C (-302.8° F), where it is in a liquid state.

According to the researchers, the active, Teflon-coated part of the detector holds 50 kg (110 lb) of argon, which provides the 50 in the experiment’s name. Rows of photodetectors line the top and bottom of the device, while copper coils collect the stripped electrons to help determine the location of collisions between dark matter and visible matter.

darkside-50-0The research team, as well as many other scientists, believe that a particle known as a WIMP (weakly interacting massive particle) is the prime candidate for dark matter. WIMP particles have little interaction with their surroundings, so the researchers are hoping to catch one of these particles in the act of drifting aloof. They also believe that these particles can be detected when one of them collides with the nucleus of an atom, such as argon.

By cramming the chamber of their detector with argon atoms, the team increases their chance of seeing a collision. The recoil from these collisions can be seen in a short-lived trail of light, which can then be detected using the chamber’s photodetectors. To ensure that background events are not interfering, the facility is located deep underground to minimize background radiation.

darkmatterTo aid in filtering out background events even further, the detector sits within a steel sphere that is suspended on stilts and filled with 26,500 liters (7000 gallons) of a fluid called scintillator. This sphere in turn sits inside a three-story-high cylindrical tank filled with 946,350 liters (250,000) of ultrapure water. These different chambers help the researchers differentiate WIMP particles from neutrons and cosmic-ray muons.

Since autumn of 2013, the DarkSide-50 project has been active and busy collecting data. And it is one of about three dozen detectors in the world that is currently on the hunt for dark matter, which leads many physicists to believe that elusive dark matter particles will be discovered in the next decade. When that happens, scientists will finally be able to account for 31.7% of the universe’s mass, as opposed to the paltry 4.9% that is visible to us now.

planck-attnotated-580x372Now if we could only account for all the “dark energy” out there – which is believed to make up the other 68.3% of the universe’s mass – then we’d really be in business! And while we’re waiting, feel free to check out this documentary video about the DarkSide-50 Experiment and the hunt for dark matter, courtesy of Princeton University:

Sources: gizmag.com, princeton.edu

News From Space: More Happening on Mars!

marsIt seems like weeks since the Red Planet has been featured in the news. But that’s to be expected when the two biggest news makers – the Opportunity and Curiosity rovers – are either performing a long drive or climbing a tall mountain. Not much in the way of updates are expected, unless something goes wrong. Luckily, these rovers always find ways to surprise us.

After over a year on Mars, Curiosity has accomplished a long list of firsts. This latest occurred last week, when NASA announced that Curiosity picked up the pace of its long trek to Mount Sharp by completing its first two-day autonomous drive, in which the rover did one leg of an autonomous drive on Sunday, then completed it on Monday.

mars_scapePreviously, Curiosity’s autonomous drives were only executed after finishing a drive planned by mission control on Earth using images supplied by Curiosity. These images would then be uploaded its on board computer, and the rover would compare them with images taken by its navigation camera to plot a safe path. The drive completed Monday is the first where the rover ended an autonomous drive on one day, then continued it the next day by itself.

This is all thanks to the incorporation of the new autonomous navigation (or autonav) software, which NASA finished incorporating and debuted at the end of August. According to NASA, this new system not only allows the rover to drive itself for longer stretches of time, it also allows mission control to plan activities for several days, which could be implemented on Fridays and before holidays so the rover can continue to work while the staff are away.

curiosity_hirise_tracksAccording to NASA, on Sunday, the new software allowed Curiosity to drive about 55 m (180 ft) along a path planned by mission control, then switched to autonomous mode and traveled another 38m (125 ft) with the rover selecting waypoints and the safest path. It then stored navigation variables in its non-volatile memory, then reloaded them on Monday to drive another 32 m (105 ft).

In all, Curiosity covered about 125 meters (410 ft) in total. This brought it within about 80 m (262 ft) from “Cooperstown,” a rocky outcrop where the rover will be conducting another series of scientific examinations. These will be the first time that Curiosity has had the opportunity to use its arm-mounted instruments since September 22.

mountsharp_galecraterAccording to Kevin Lewis of Princeton University, who spoke about the upcoming studies in “Cooperstown”:

What interests us about this site is an intriguing outcrop of layered material visible in the orbital images. We want to see how the local layered outcrop at Cooperstown may help us relate the geology of Yellowknife Bay [on Mars] to the geology of Mount Sharp.

This stop will be only brief, as the rover team are anxious to get Curiosity back on its way to Mount Sharp. Once there, it will begin digging, drilling and generally seeking out the vast caches of minerals that the mountain is expected to have, ones which could potentially support a habitable environment. Exciting times ahead!

Sources: gizmag.com, jpl.nasa.gov