Meet Metis – Jupiter’s Closest, Quickest Moon

Everyone’s heard of Jupiter’s four most famous moons Europa, Io, Callisto, and Ganymede—we’ve known about them for over 400 years, thanks to Galileo—but giant Jupiter has many more moons than that. To date there are thought to be 69 natural satellites orbiting Jupiter. 53 are officially named, while 16 are awaiting further confirmation. So you’d…

Eppur Si Muove: Galileo’s Big Night

On this night in 1610 the Pisan astronomer Galileo Galilei looked up at a bright Jupiter at opposition through his handmade telescope and noted three little “stars” next to it, piquing his natural scientific curiosity. Further observations over the next few nights showed that the planet wasn’t moving relative to the little “stars” as it…

Eppur Si Muove: Galileo’s Big Night, 407 Years Ago Today

407 years ago tonight, on January 7, 1610, the Pisan astronomer Galileo Galilei looked up at a brilliantly-shining Jupiter through his own handmade telescope and saw three bright little “stars” next to it, stirring his natural scientific curiosity. Further observations over the next several nights showed that the planet wasn’t moving relative to the little “stars” as it…

Watch Juno’s Arrival at Majestic Jupiter, Moons and All

We are the stewards of over 400 years of scientific exploration of our Solar System, which it could be said began in earnest when Galileo Galilei first observed the motions of Jupiter’s moons in his homemade telescope in 1610. Over the centuries our knowledge—and our curiosity—about the seemingly endless variety of worlds in the Solar System…

When a Comet Met Ganymede

Captured by NASA’s Galileo spacecraft on April 5, 1997, this image shows Enki Catena, a 161.3-km (100-mile) long crater chain on the surface of Jupiter’s moon Ganymede. Named after the Sumerian god of fresh water, Enki Catena is thought to have been formed when a comet approached too close to Jupiter and was torn into 13 pieces, each impacting Ganymede in…

Eppur Si Muove: Galileo’s Big Night

Note: This is an edited repost of an article from 2014. 405 years ago tonight, January 7, 1610, the Pisan astronomer Galileo Galilei looked up at a bright Jupiter at opposition through his handmade telescope and saw three little “stars” next to it, which piqued his natural scientific curiosity. He soon realized that these little…

Jupiter’s Moons Make Ghostly Auroral “Footprints”

We have all marveled at incredible photos and time-lapse videos of Earth’s auroral displays, captured by talented photographers that have braved the frigid nighttime temperatures of remote high-latitude locations as well as by those privileged few living in orbit aboard the International Space Station. But our planet isn’t the only one with curtains of light crowning its…

An Ocean Beyond Earth: Europa Awaits

It’s no secret that Earth’s ocean is filled with life, much of it still a mystery or totally unknown to science. But what about the ocean on other worlds? I’m not talking about sci-fi planets or suspected alien Earths around other stars, but right here in our own solar system, where an ocean even deeper than ours lies…

Boom! Io Explodes With Volcanic Eruptions Hundreds of Miles High

Three enormous volcanic eruptions on Jupiter’s moon Io were witnessed by scientists last year using the Keck II and Gemini telescopes in Hawaii. The only other confirmed volcanically-active world in the solar system besides Earth, Io is constantly being resurfaced by eruptions and lava flows, due to internal heat and pressures caused by tidal stresses as a…

Europa Is Covered In Bacon. That Is Why We Must Go.

Whether you’re a trend-loving hipster, a breakfast lover, or just fan of meat products in general, you’d have to agree that it does look like a giant piece of bacon* running across the image above. And while the color and shape seems about right, the size and temperature is a bit off — that’d be…