Articles from Discover Physics & Math

Here's the Answer That Will Finally Settle the "Is Pluto a Planet?" Debate for Good (Yeah, Right)

I love Pluto. I grew up entranced by this strange little world: What could you be, you rebel that doesn’t seem to follow any of the rules? I even wrote a childhood letter to a local astronomer, offering my homespun hypothesis that Pluto might be a captured fragment of an exploded star. When the New Horizons spacecraft finally revealed the true face of Pluto, I was right there at mission control in Langley, Maryland, to watch the images as they came in.

So I have a lot of sympathy for the

No Eyes? No Problem. Sea Urchins See with Their Feet

Threaten a sea urchin, and you may see it point its spines at you. This defensive response is pretty unremarkable—except for the fact that, if you look closer, you will not see the sea urchin's eyes. It doesn't have any.

Sea urchins are the only animals that have vision despite "conspicuously lacking eyes," write Dan-Eric Nilsson, a biologist at the University of Lund in Sweden who studies animal vision, and his colleagues. In a new study, the researchers gave the spiny sea creatures a ki

665 Days in Space and 47 minutes on TV: A Conversation with NASA Astronaut Peggy Whitson

Life is all about bubbles. Every cell in your body is a bubble, a membrane holding together a miniature world of organelles, ribosomes, and genetic material. Your body itself is another bubble, a skin wrapped around a wet, salty interior that carries a distant memory of the oceans in which our ancestors lived hundreds of millions of years ago. And our entire planet is a bubble, a thin membrane of oxygen-rich air wrapped around a spinning rock warmed by a nearby Sun.

Being able to perceive

Alan Stern on the Pluto Revolution, the Psychology of Persistence, and "Chasing New Horizons"

On July 14, 2015, the New Horizons spacecraft swept past Pluto, returning eye-popping images of the dwarf planet and its huge (relatively speaking) moon, Charon. At the time, the best existing images of Pluto showed nothing more than an enigmatic blur. New Horizons revealed a world of astonishing diversity: organics-coated dark patches, ice mountains, nitrogen glaciers, and methane snows, all in a state of astonishing activity considering the temperatures there are only about 40 degrees abov

From the Overview Effect to "One Strange Rock": A Conversation with Leland Melvin

It’s hard to think of any modern human activity that has had more of a multiplicative impact on the imagination than space exploration. To date, a grand total of 562 humans have left the Earth—a trivial fraction compared to the 7.6 billion people currently staying put. Yet the image of astronauts voyaging away from their home planet has transformed popular culture, education, even business and politics.

Former NASA astronaut Leland Melvin is a lead agent helping to advance that transformation

This may be as close as you can come to going on a spacewalk 240-ish miles above Earth

The vertiginous video also offers an opportunity to consider theories posited by two of the giants of science

While on a spacewalk outside the International Space Station over Mexico, NASA astronaut Randy Bresnik captured this spectacular, vertiginous video with a GoPro camera.

I spotted it in a NASA Tweet yesterday, and when I watched it, I really did have the sensation that this would be as close as I'll ever come to experiencing free-falling around the Eart

NASA's Latest Planet Hunter

It's ready to forge a new path through space.

To Scare Off Predators, Caterpillar Whistles like a Kettle

It's hard to yell "BACK OFF!" when you have no lungs, but this caterpillar has figured out a way. Under attack, the Nessus sphinx moth caterpillar emits a sort of crackling buzz from its mouth. Scientists compare the unusual mechanism to a whistling teakettle. Or a rocket.

Lots of insects make noise, of course, as opening a window on a summer evening will remind you. Conrado Rosi-Denadai, a graduate student at Carleton University, and his coauthors write that sound-making tools in ins

The First Black Hole Close-Up

An Earth-sized telescope will capture the unseeable.

Finding Stephen Hawking's Star—And Finding Your Own

When I look at the night sky, I often view the stars not just in space but also in terms of their places in time. Light moves at a finite speed (299,792 kilometers per second, to be precise), so the journey from star to star is a very long one even for a beam of light. When astronomers talk about light years of distance, they are literally describing the number of years it takes for light to travel from those distant stars to your eyeball.

And so when I heard about the death of Stephen Ha