Unexplained Mysteries of 2014 and Into 2015

As we head toward 2015, look back at some of the strangest mysteries of this past year, as well as some of the mysteries that remain as we enter the new year.

Keeping in mind that science is a process of continually refining a body of scientific knowledge -- that what we believe is true today may be changed by some amazing new discovery tomorrow -- here are 10 strange mysteries, both unexplained and recently explained.

For almost a century one of America's strangest mysteries has been found in remote Death Valley, California. It's there -- actually at a specific dry lakebed called Racetrack Playa -- that stones are claimed to mysteriously move on their own, when no one is looking. The phenomenon occurs in a handful of other places as well, though none are as well known as those in Death Valley. They moved very slowly, in some cases only a few inches over months or years, but their trails can clearly be seen in the dried mud behind them.

Over the years many explanations have been offered, ranging from hoaxing to aliens to some sort of localized, unknown magnetic effect.

Others have suggested that the area's strong winds might move the stones, but that doesn't explain why they'd move at different rates and sometimes in different directions. For many years the best scientific explanation was that the rocks moved due to a specific combination of wind, temperature, and water. Racetrack Playa is in a desert, but sometimes collects water from rain and melting snow, providing a slick surface over which the stones might move.

The mystery was finally solved in 2014 when a team of researchers set up cameras over the area and measured the rocks' movement patterns. They concluded that the stones moved under just the right conditions when ice formed under the rocks and moved them, usually only a little bit at a time: "moving sheets of ice tens of meters in extent but only a few millimeters thick are clearly effective at moving rocks in their path." The study, "Sliding Rocks on Racetrack Playa, Death Valley National Park: First Observation of Rocks in Motion" was published on Aug. 27, 2014 in the open-access journal PLoS ONE.

Volcanoes are known around the world, though most of them can be found in the so-called Pacific Ring of Fire. It's where the world's most active volcanoes are located, covering the western edge of the Americas, Hawaii, Japan and into Oceania. The volcanoes there result from the subduction of oceanic tectonic plates moving beneath lighter continental plates.

Most of Australia, however, is spared -- except for an unusual 300-mile stretch in the southeastern part of the country roughly north of Tasmania. It is the continent's only active volcanic region, but for many years no one was quite sure why. Since Australia lies well inside its own tectonic plate (called the Indo-Australian plate), it could not be caused by the same geological processes that spawned others in the nearby Ring of Fire.

A team from the Research School of Earth Sciences finally solved the mystery earlier this year. According to lead researcher Dr. Rhodri Davies, "Volcanoes in this region of Australia are generated by a very different process to most of Earth's volcanoes.... We have determined that the volcanism arises from a unique interaction between local variations in the continent's thickness, which we were able to map for the first time, and its movement...towards New Guinea and Indonesia."

The continent's drift northward creates an isolated region in its southern end which spawned the volcano. But don't stand on Australia's northern shore expecting to reach Indonesia any time soon: the continent is moving northward at about two and three-quarter inches a year. The study was published in the journal "Geology" on Sept. 24.

Water on Mars

The riddle of Mars has captivated people for generations. Dozens of artists, writers, astronomers and dreamers -- from H.G. Wells to Orson Welles, Ray Bradbury to Carl Sagan -- have speculated about what life might be like on the Red Planet.

In 2011, NASA's Curiosity Rover was launched into space, landing on Mars the following year. Mankind's amazing little mechanical scientist trooper has spent the past few years poking, plodding and examining the surface. A lot has been learned about Martian climate and geology, but in 2014 the biggest news was that Curiosity gathered evidence that a peak there, known as Mount Sharp, was created by sediments in a huge surrounding lake bed.

Yes, sediments -- which if you remember high school geology, is particulate matter carried by water or wind (in this case water). And yes, lake bed: There's no water there now, at least not on the surface, but the discovery is very strong evidence that rivers and lakes have existed periodically in Martian history. Having spent a Martian year on the planet, scientists now believe that the environmental conditions on Mars may be favorable for microbial life, and the search continues.

Missing Stars

If you're lucky enough to get away from urban light pollution and into rural areas, it's astonishing how many stars you can see; they seem to litter the sky. And, of course, only a small fraction of the stars are visible to our naked eye. But even still, there should be more of them -- many more.

One of the most enduring astronomical puzzles has been not why there are so many stars, but instead so few. According to computer models there should be an estimated 100 to 300 sextillion stars, or 100,000,000,000,000,000,000,000 to 300,000,000,000,000,000,000,000, give or take a few. It's a number so large that it defies comprehension and raises an interesting question: where are they? Why isn't the night sky positively lit up with stars? Surely the light from a small number of them (say, maybe a few hundred million or so) might be blocked from reaching us by planets or other celestial objects, but that still leaves some ridiculously large number of stars unaccounted for.

Earlier this year astronomer James Geach and his team at the University of Hertsfordshire found that "nuclear bursts of star formation are capable of ejecting large amounts of cold gas from the central regions of galaxies, thereby strongly affecting their evolution by truncating star formation and redistributing matter." In other words, the cold gases used as the raw material for stars -- and driven out during the star formation process itself -- can inhibit the creation of new stars. The article, "Stellar feedback as the origin of an extended molecular outflow in a starburst galaxy," was published in the Dec 4 issue of the journal Nature.

Read more at Discovery News