Can We Deflect Asteroids?

Will an asteroid hurtling through space some day crash into Earth and cause massive damage? The odds are small, but they’re real. Deflecting an incoming asteroid might seem like the stuff of science fiction, but scientists say it can bedone—if the asteroid is detected in time. Given enough prior knowledge, former U.S. astronaut Ed Lu says, governments could launch one or more spacecraft into the threatening asteroid and change its path enough so that it would miss Earth. These “kinetic impactors,” Lu says, could even divert an asteroid the size of the one that brought down the dinosaurs. Lu is one of the co-founders of the B612 Foundation, a non-profit organization that monitors asteroids and other Near Earth Objects (NEO) and studies how to protect Earth from them. Its goal is to fund the building and launch of a space telescope named Sentinel. The telescope, scheduled for launch in 2018, will map all the asteroids around Earth. Realizing the threat of an asteroid collision is real, in 2013 the United Nations called for the creation of the International Asteroid Warning Network. The goal is to bring together scientific organizations and nations with active space programs so they can share knowledge about the asteroid threat.

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What Causes Volcanic Lightning?

On March 10, 2010, Eyjafjallajökull volcano, a caldera in Iceland covered by an ice cap, erupted. It sent plumes of clouds across most of Europe and the Atlantic Ocean. Photos of the eruption show lightning originating and ending in the cloud of ash that hovered over the volcanic opening. The largest volcanic storms are similar to supercell thunderstorms that spread across the American Midwest. But while those thunderstorms are fairly well understood, volcanic lightning still remains mysterious. The remote location of volcanoes and infrequent eruptions make volcanic lightning difficult to study. In general, lightning occurs through the separation of positively and negatively charged particles. Differences in the aerodynamics of the particles separate the positive and negative. When the difference in charge is great, electrons flow between the positive and negative regions. A lightning bolt is a natural way of correcting the charge distributi...

Is the Y Chromosome Doomed?

Humans store their genes in 23 pairs of chromosomes, 22 of which are identically matched. The 23rd is a two-sided biological coin—twin Xs mean you’re female; an X and a Y, male. Chromosome pairs often trade bits of DNA in a process called recombination, the purpose of which is to keep genes functioning properly. Talk of men’s path toward extinction began in the late 1990s, when it was discovered that the human Y chromosome, which is stumpy compared with the X, does not share enough genetic material with the X to practice recombination. Left without a way to renew damaged genes, the Y would continue to degrade and would eventually disappear, geneticists announced. They slapped an expiration date on the male half of the species of sometime in the next 5 to 10 million years. To get a perspective on this prediction, scientists looked to our closest genetic relatives—the chimps. Because humans and chimpanzees shared a common ancestor 6 million years ago, genet...

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