Super-Kamiokande Neutrino Detector in Japan

Neutrinos are some of the most abundant yet mysterious particles in our universe. Every second 65 billion neutrinos pass through every square centimeter of our body and the Earth. Neutrinos do not carry electric charge, which means that they are not affected by the electromagnetic forces that act on charged particles such as electrons and protons. They are also extremely tiny because of which they travel mostly undisturbed through matter. This makes neutrinos extremely hard to detect, and the harder a particle is to detect, the more massive and sophisticated the detectors have to be. The Super Kamiokande in Japan is one such neutrino observatory.

The Super Kamiokande or Super-K for short is located 1,000 meters underground in the Mozumi Mine in Hida's Kamioka area. The observatory was designed to search for proton decay, study solar and atmospheric neutrinos, and keep watch for supernovae in the Milky Way Galaxy. The observatory was built underground in order to isolate the detector from cosmic rays and other background radiation.

The observatory consists of 50,000 tons of pure water in cylindrical stainless steel tank that is 41.4 meters tall and 39.3 meters in diameter. This is surrounded by 11,146 photomultiplier tubes (PMT). When a neutrino interacts with the electrons or nuclei of water, it produces a charged particle that moves faster than the speed of light in water (not to be confused with exceeding the speed of light in a vacuum, which is physically impossible). This creates a cone of light known as Cherenkov radiation, which is the optical equivalent to a sonic boom. The Cherenkov light is projected as a ring on the wall of the detector and recorded by the PMTs. The distinct pattern of this flash provides information on the direction and flavor of the incoming neutrino.

The Mysterious Sailing Stones of Racetrack Playa

The Racetrack Playa is an exceptionally flat and dry lakebed located above the northwestern side of Death Valley, in Death Valley National Park, California. The playa is best known for one of the most strangest mysteries of the planet – the sliding rocks. These rocks can be found on the floor of the playa with long trails behind them. Although no one has actually seen the rocks move, the long meandering tracks left behind in the mud surface of the playa attest to their activity. Some of these rocks weigh several hundred pounds and have traveled as far as 1,500 feet, which leaves us with the question: "How do they move?"

The stones move only every two or three years and most tracks develop over three or four years. Stones with rough bottoms leave straight striated tracks while those with smooth bottoms wander. Stones sometimes turn over, exposing another edge to the ground and leaving a different track in the stone's wake.

Trails differ in both direction and length. Rocks that start next to each other may travel parallel for a time, before one abruptly changes direction to the left, right, or even back the direction it came from. Trail length also varies – two similarly sized and shaped rocks may travel uniformly, then one could move ahead or stop in its track.

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