Happy Opposition Day!

It’s Opposition Day! No, that’s not a political stance but rather a geometric one, relating to the positions of Earth, the Sun, and Mars in the Solar System. Today our neighboring planet Mars will be directly opposite the Sun relative to Earth, which will make it the second-brightest “star” in the night sky after Venus….

ESA Finds Liquid Water on Mars

Water has been found on Mars! (Yes, again.) In what’s turned into the biggest space news of the day, today ESA (and that’s pronounced “eesa”, you don’t need to spell it out) announced that the Italian-run radar experiment aboard its Mars Express orbiter has provided the first good evidence of liquid water present beneath the…

A Twisted Towel of Bright Clouds on Jupiter

This dramatic image, a color-composite I made from raw data captured by NASA’s Juno spacecraft, shows a bright band of high-altitude clouds on Jupiter’s northern hemisphere on July 16, 2018. Because of the abstract nature of Jupiter’s atmosphere in general (and a fun little phenomenon called pareidolia) one could find many different shapes in this…

Ten More Moons For Jupiter!

Jupiter is the reigning heavyweight among the planets in our solar system so it just makes sense that it also possesses the most natural satellites. Over the past year I have been gleefully telling people that Jupiter has 69 moons (usually to a shocked response, occasionally to a giggling one) but now I must admit…

Three Years Ago Today New Horizons Passed Pluto

Holy Hadean history Batman, where does the time go? Today marks the third anniversary of New Horizons‘ flyby of Pluto and Charon, the first, last, and as yet only mission ever to the distant dwarf planet (aka the reigning King of the Kuiper Belt.) All of the close-up detailed images of Pluto and Charon we…

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…

It’s Been 32 Years Since We Last Explored Uranus

Voyager 2 may have been the second of NASA’s famous twin exploration spacecraft but it actually launched first, on August 20, 1977. Eight and a half years later it became the first (and, to date, last) spacecraft to visit Uranus, at 31,500 miles across the third largest planet in the Solar System. Voyager 2 made its closest…

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…

Juno and JEDI Deliver New Discoveries About Jupiter

Saturn has its rings, Mars has its rusty landscape, Earth has its whales, water, and wi-fi…and Jupiter has its Great Red Spot. The giant gas planet’s enormous orange storm—once over twice the diameter of Earth but today “only” about 1.3 times as wide—is one of the most distinctive planetary features in our Solar System. It’s…

We May Have Just Been Visited By An Interstellar Comet

“This object came from outside our solar system.” — Rob Weryk, postdoctoral researcher at University of Hawaii’s Institute for Astronomy On October 14, 2017, what appears to be a comet (er, make that asteroid…read more below) sped past Earth at a distance of about 15 million miles after swinging around the Sun. It had come…