(left to right): JPL CALTECH/NASA; FRANS LANTING/NATIONAL GEOGRAPHIC IMAGE COLLECTION; YVA MOMATIUK AND JOHN EASTCOTT/MINDEN PICTURES

Top stories: Voyager 1 probes dark matter, life’s explosive origin, and monogamy’s genetic basis

Aging Voyager 1 spacecraft undermines idea that dark matter is tiny black holes

Humanity’s most far-flung spacecraft, NASA’s 41-year-old Voyager 1, has poked a hole in a long-shot theory of dark matter. Some theorists have argued the mysterious, unseen stuff, which makes up 85% of the universe’s matter, could consist of countless black holes lingering from the big bang. But Voyager 1, which launched in 1977 and slipped out of the solar system 6 years ago, sees no signs of such hordes, a pair of theoretical physicists reports.

How an ancient cataclysm may have jump-started life on Earth

An ancient cataclysm may have jump-started life on Earth, according to new evidence. Some 4.47 billion years ago—a mere 60 million years after Earth took shape and 40 million years after the moon formed—a moon-size object sideswiped Earth and exploded into an orbiting cloud of molten iron and other debris. Some scientists are now proposing that after things cooled down, simple organic molecules eventually linked up to form RNA, a molecular player long credited with sparking life.

Monogamy may have a telltale signature of gene activity

In the animal world, monogamy has some clear perks. Living in pairs can give animals some stability and certainty in the constant struggle to reproduce and protect their young—which may be why it has evolved independently in various species. Now, an analysis of gene activity within the brains of frogs, rodents, fish, and birds suggests there may be a pattern common to monogamous creatures. Despite very different brain structures and evolutionary histories, these animals all seem to have developed monogamy by turning on and off some of the same sets of genes.

Dog breeds really do have distinct personalities—and they’re rooted in DNA

American Kennel Club descriptions of dog breeds can read like online dating profiles: The border collie is a workaholic; the German shepherd will put its life on the line for loved ones. Now, in the most comprehensive study of its kind to date, scientists have shown that such distinct breed traits are rooted in a dog’s genes. The findings may shed light on human behaviors as well.

U.S. government shutdown starts to take a bite out of science

The partial shutdown of the U.S. government, in its third week, halted the work of tens of thousands of scientists. Many have been furloughed without pay, barred from working at home, and prohibited from checking their government email. The shutdown is also creating chaos for university researchers, private contractors, and others who collaborate with idled federal scientists, or depend on affected agencies for funding, facilities, and data.