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 the Red Planet: Mars’ Bygone Atmosphere

??????In this latest video update from the Mars Science Laboratory team, Ashwin Vasavada, the mission’s Deputy Project Scientist, discusses the recent findings by the Curiosity Rover. As always, these include ongoing studies of Mars atmosphere, in addition to soil and rock analysis, to determine what the Martian landscape may have looked like millions of years ago.

And in its latest research breakthrough, the rover has determined that Mars doesn’t have the same atmosphere it used to. Relying on its microwave oven-sized Sample Analysis at Mars (SAM) instrument, the rover analyzed a sample of Martian air early in April, and the results that came back provided the most precise measurements ever made of in the Martian atmosphere.

SolarConjunctionWhat it noticed in particular was the isotopes of Argon, a basic element that is present in Earth’s atmosphere, Jupiter’s and even the Sun. In Mars case, the mix of light and heavy Argon – two different isotopes of the element – is heavier than in all the other cases. What this suggests is that the Martian atmosphere has thinned over the course of the past few million years.

This data conclusively confirms another long-held suspicion by scientists, that Mars did indeed have an atmosphere capable of supporting life. Alongside the voluminous evidence obtained by Curiosity for the existence of water, we now know that Mars may have supported life at one time, and that it did not always have the arid, cold climate it now does. More good news for those looking to build a case for settling there one day…

solarConjunction02Check out the video below to hear Ashwin Vasavada speak about these latest findings, including the Solar Conjunction which kept them from communicating with the Rover until today. Now that the conjunction has ended, we can expect plenty more updates and interesting finds from the rover. Who knows? Maybe even some evidence about the existence of a Martian civilization.

Don’t be looking at me like that! It could happen…

Source: universetoday.com