Health & Science

Seeking clues to a Martian mystery

NASA has launched another spacecraft bound for Mars, this time with the goal of unraveling the mystery behind the planet’s evolution from a warm, wet environment to the cold, dry landscape it is today. The Mars Atmosphere and Volatile Evolution mission, or MAVEN, will arrive at its destination in September 2014 following a journey of more than 440 million miles. Unlike the rovers Curiosity and Opportunity, MAVEN will not explore the Martian surface, but will remain in a lopsided orbit and focus on analyzing the Martian atmosphere. Scientists will use data collected on trace gases from different altitudes to model how the Martian climate changed over billions of years. It’s already known that the atmosphere was once dense enough to support liquid water, as evidenced by geological features such as dried-up riverbeds. Current theory holds that solar wind and cosmic radiation stripped away much of the atmosphere after the planet’s protective magnetic field switched off long ago, but MAVEN will dig deeper to see if that’s true. The biggest unanswered question, NASA science mission director John Grunsfeld tells the Associated Press, is whether Mars ever supported life. “We don’t have that answer yet, and that’s all part of our quest for trying to answer, ‘Are we alone in the universe?’” he said.

An Antarctic volcano

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Seismologists have discovered an active volcano buried more than a half-mile beneath Antarctica, raising the specter that another force besides global warming could one day contribute to the melting of the polar ice sheet. The researchers were studying the structure of the earth’s mantle when they encountered unusual data showing two swarms of low-magnitude earthquakes in a mountainous region of western Antarctica in 2010 and 2011, at a depth of 15 to 25 miles. Seismologists say the vibrations resemble so-called Deep Long-Period earthquakes, which have been recorded in active volcanic regions of Alaska’s Aleutian Islands and the Pacific Northwest. “At some point, it is going to erupt,” Washington University graduate student Amanda Lough tells NBCNews.com. While any eruption is unlikely to break through the half-mile-thick ice above the volcano, magma flow could cause serious ice melting in the western Antarctic and raise sea levels worldwide.

Why women hate ‘sluts’

Women who dress provocatively and are sexually aggressive often face ridicule that some feminists call “slut shaming.” But a new study suggests that it’s women, not men, who do most of the shaming, because of “intrasexual competition.” Canadian researchers placed female students in a room for conversation, then secretly monitored their reactions when an attractive third young woman entered. When dressed in jeans and a T-shirt, the third woman drew little commentary from the students, but when she wore a tight-fitting, low-cut blouse and a short skirt, she elicited very hostile reactions from nearly all the subjects after she left the room—eye-rolling, insults, and shouts of “What the [expletive] is that?” There is an evolutionary rationale for why women want to police female sexuality, University of Ottawa psychologist Tracy Vaillancourt tells The New York Times. “Sex is coveted by men,” she says. “Women who make sex too readily available compromise the power-holding position of the group.” Women are most aggressive toward other women during the years when they’re competing for males; the hostility fades as they get older.

An abundance of asteroids

Asteroids as large as the one that landed near Chelyabinsk, Russia, in February are three to five times more numerous than previously thought, new research suggests, spurring scientists and government officials to consider how to better track and respond to threats from space. NASA has cataloged more than 90 percent of near-Earth objects that are at least 1 kilometer (0.6 miles) wide, but the Chelyabinsk event underlines the risk that much smaller ones pose. A new analysis of data and video on the Chelyabinsk asteroid concludes that it was an estimated 62 feet in diameter when it entered the atmosphere, and released 500 kilotons of energy—over 30 times more than the atom bomb that was dropped on Hiroshima—when it exploded in the atmosphere and injured 1,500 people, mostly by broken and flying glass. “Over a hundred years, we see these large impactors more frequently than we would expect,” University of Western Ontario astronomer Peter Brown tells The Washington Post. A direct hit on a populated area could kill hundreds of people. The U.N. General Assembly is expected to adopt a plan to establish an information-sharing International Asteroid Warning Network. “Here’s the biggest of all natural disasters that we’re talking about,” says NASA astronaut Tom Jones, “and it’s preventable.”