Category Archives: Astronomy

Could asteroids have supplied enough water to fill Earth’s oceans?

Physics Today reports: Three-quarters of the asteroids orbiting the Sun are of the carbon-rich C-type, whose significant freight of hydrated minerals has a similar ratio of deuterium to hydrogen as the water in Earth’s oceans. Asteroids of all types were far more abundant when Earth’s oceans formed around 4.6 billion years ago. Unsurprisingly, asteroids are… Read More »

Is the universe open-ended?

Caleb Scharf writes: One of my favorite albeit heavily paraphrased quotes from Albert Einstein is his assertion that the most incomprehensible thing about the universe is that it is comprehensible. (What he actually said, in his 1936 work “Physics and Reality,” is more longwinded, and includes a digression into Immanuel Kant and the meaning of… Read More »

The day the dinosaurs died

Douglas Preston writes: If, on a certain evening about sixty-­six million years ago, you had stood somewhere in North America and looked up at the sky, you would have soon made out what appeared to be a star. If you watched for an hour or two, the star would have seemed to grow in brightness,… Read More »

Aliens, science, and speculation in the wake of ʻOumuamua

Matthew Bothwell writes: There’s an iconic moment, filmed in the shadow of the Very Large Array in New Mexico, that many people who visit this giant telescope try to duplicate. A young astronomer sits cross-legged on the bonnet of her car, the towering line of radio dishes vanishing into the distance behind her. With her… Read More »

The most detailed 3D map of the Universe ever made

Nature reports: A survey of the southern sky has reconstructed how mass is spread across space and time, in the biggest study of its kind. The data provide striking evidence that dark energy, the force that appears to be pushing the Universe to accelerate its expansion, has been constant throughout cosmic history. The Dark Energy… Read More »

Life deep underground and inside other worlds

Jordana Cepelewicz writes: Scientists poke and prod at the fringes of habitability in pursuit of life’s limits. To that end, they have tunneled kilometers below Earth’s surface, drilling outward from the bottoms of mine shafts and sinking boreholes deep into ocean sediments. To their surprise, “life was everywhere that we looked,” said Tori Hoehler, a… Read More »

Solar storms are back, threatening chaos around the world

The Associated Press reports: A few days ago, millions of tons of super-heated gas shot off from the surface of the sun and hurtled 90 million miles toward Earth. The eruption, called a coronal mass ejection, wasn’t particularly powerful on the space-weather scale, but when it hit the Earth’s magnetic field it triggered the strongest… Read More »

How the Pentagon started taking UFO’s seriously

Gideon Lewis-Kraus writes: Leslie Kean is a self-possessed woman with a sensible demeanor and a nimbus of curly graying hair. She lives alone in a light-filled corner apartment near the northern extreme of Manhattan, where, on the wall behind her desk, there is a framed black-and-white image that looks like a sonogram of a Frisbee.… Read More »

How radio astronomy reveals the universe

Emily Levesque writes: If you ask an astronomer to choose the single most exciting picture in all of astronomy, many of us will point to a familiar orange ring. At a glance it may not look like much — a fuzzy glowing doughnut, bulging slightly at the bottom and, as of last month, streaked with… Read More »

What makes Elon Musk and Carl Sagan worlds apart

Shannon Stirone writes: There’s no place like home—unless you’re Elon Musk. A prototype of SpaceX’s Starship, which may someday send humans to Mars, is, according to Musk, likely to launch soon, possibly within the coming days. But what motivates Musk? Why bother with Mars? A video clip from an interview Musk gave in 2019 seems… Read More »

Have we already been visited by aliens?

Elizabeth Kolbert writes: On October 19, 2017, a Canadian astronomer named Robert Weryk was reviewing images captured by a telescope known as Pan-STARRS1 when he noticed something strange. The telescope is situated atop Haleakalā, a ten-thousand-foot volcanic peak on the island of Maui, and it scans the sky each night, recording the results with the… Read More »

Astronomers get their wish, and a cosmic mystery deepens

Natalie Wolchover writes: On December 3, humanity suddenly had information at its fingertips that people have wanted for, well, forever: the precise distances to the stars. “You type in the name of a star or its position, and in less than a second you will have the answer,” Barry Madore, a cosmologist at the University… Read More »

The surface of the moon is a galactic time capsule

Paul Sutter writes: You wouldn’t know it by looking at it, but the moon is a time capsule. Its surface has been completely exposed to vacuum for almost 4.5 billion years; meanwhile, it has been soaked by particles from the sun and beyond the solar system. Those particles remain, buried under the lunar surface, providing… Read More »