Age-old mystery of Death Valley sailing stones finally solved

There are a few age-old mysteries in this world with theories behind them that don't have sinister undertones. Instead of attributing them to aliens, the paranormal, or time travel, the unsolved mysteries are examined in a more scientific light. Sometimes, mysteries are thought to be explainable by science, but the scientific proof hasn't yet been discovered. Other times, there's an even simpler likely explanation, such as being a hoax. One of these age-old mysteries, the sailing stones of Death Valley, fell into this category -- until now. A team of scientists have solved the mystery, and even caught it on video.

The sailing stones of Death Valley are perhaps the most famous instance of the geological phenomenon where rocks will slide across a landscape, seemingly on their own. They'll leave a trail of their path behind them, as if you dragged something across a smooth plain of sand. The rocks don't necessarily travel in the same direction -- they can start moving in the same direction and at the same speed, but one rock can deviate from the path and go out on its own. The process is incredibly slow, and the tracks will develop over the course of three or four years; sometimes, the stones even flip over.

The famed rocks, which have been studied since the early 1900s, are located in Racetrack Playa, a dry lake within Death Valley. For as long as they have been in the spotlight, a cause for their movement has yet to be confirmed. A popular theory has been that a form of ice shove -- where wind or temperature differences push bits of ice -- is the cause. Normally, ice shove is easily noticeable on a large scale, as it can create ice piles up to 40 feet high, and is accompanied by a sound similar to that of thunder or a train passing by. Considering Racetrack Playa is a dry lake in Death Valley -- which is the hottest, driest area in North America -- it has been difficult to prove that ice shove is responsible for the sailing stones.

Oceanographer Richard Norris of the Scripps Institution of Oceanography and his cousin engineer James Norris of Interwoof in Santa Barbara proved that, in fact, ice shove is what causes the stones to travel. While Death Valley is exceedingly hot in the summer, winter nights can dip below freezing, especially at higher altitudes (Racetrack Playa is at 3,700 feet). You can watch the time-lapse video proof of the ice shove above.

The research team set up time-lapse cameras on Racetrack Playa back in 2011, as well as dropped off stones fitted with GPS devices. In 2013, the team traveled back to the Playa in order to change the GPS devices' batteries and check up on the experiment, and noticed that a frozen lake 2.8 miles in length formed. The team camped at the spot for a few days, and eventually saw the ice crack and flow past the rocks. Soon after, the ice melted and the rocks moved, leaving behind the famous tracks.

The team left room for other causes, but definitely proved that ice shove is at least one reason why the stones sail. For a more in-depth explanation of the sailing stones, explained by Richard Norris himself, check out the video below.