Friday, January 4, 2019

Incoming! A June meteor swarm could be loaded with surprises.

Credit: Washington Post

On June 30, 1908, an object the size of an apartment building came hurtling out of the sky and exploded in the atmosphere above Siberia. The Tunguska event, named for a river, flattened trees for 800 square miles. It occurred in one of the least-populated places in Asia, and no one was killed or injured. But the Tunguska airburst stands as the most powerful impact event in recorded human history, and it remains enigmatic, as scientists don’t know the origin of the object or whether it was an asteroid or a comet.

One hypothesis: It was a Beta Taurid.

The Taurids are meteor showers that occur twice a year, in late June and late October or early November. The June meteors are the Betas. They strike during the day, when sunlight washes out the “shooting stars” that are visible during the nighttime meteor shower later in the year.

A new calculation by Mark Boslough, a physicist at Los Alamos National Laboratory, shows that the tree-fall pattern in Siberia is consistent with an asteroid coming from the same area in the sky as the Taurid meteor swarm. Boslough and physicist Peter Brown of Western University in London, Ontario, gave a presentation at the American Geophysical Union fall meeting in Washington this month in which they called for a special observation campaign this June to search for Tunguska-class or larger objects embedded in the Taurids. (Full story)

Modeling sea ice has impact far beyond the poles

A seal rests on a slab of sea ice while a ship
crew walks in the distance.

The Earth’s polar oceans are cold enough that it’s possible to walk on seawater turned to ice. About nine million square miles of ice rest float on top of the world’s high-altitude seas and oceans. Looking like plates, sheets and mounds of fractured alabaster on a surface of shimmering blue, sea ice is more than a beautiful phenomenon—it influences Earth’s climate, wildlife and the people who must contend with it year-round.

Long ago frequented by just a few rugged groups living in the high north, the polar regions are now home to more people than ever. Their interests range across commercial shipping, mining and energy development; recreational fishing, hunting and tourism; scientific research; and military bases and defense operations.

Sea ice creates challenges for all these activities. It makes navigation hazardous for shipping, for instance, while thick ice complicates the operation and safety of U.S. Navy submarines. On the other hand, disappearing Arctic ice is changing hunting and fishing practices, as well as the ocean’s acoustic properties. (Full story)

Wireless Sensor Network Monitors Earth’s Extremes from Thousands of Miles Away

The Earth is vast, from the poles to the some 25,000 miles of Equator encircling the Earth. Satellites have given humankind new aerial views of almost every nook and cranny of the planet.

But getting “ground-truth” observations for scientists in the desolate miles far from civilization, in the dirt and rock, is a very different thing.

What could be a game changer for monitoring nature from thousands of miles away is now being tested and perfected by Los Alamos National Laboratory: the Long-Range Wireless Sensor Network, or LRWSN. (Full story)