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Just Passing By: the Globe of Earth Imaged by OSIRIS-REx

Earth imaged on Sept. 22, 2017 by the MapCam instrument aboard OSIRIS-REx. Credit: NASA/Goddard/University of Arizona

Here’s our beautiful blue marble as seen by NASA’s OSIRIS-REx spacecraft on Sept. 22, 2017 from a distance of 106,000 miles (170,000 km). It had just completed a gravity-assist flyby of Earth—a little 19,000 mph “once around the block” that gave the spacecraft an 8,500-mile-an-hour speed boost necessary to adjust its course toward Bennu, the asteroid target of its mission.

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Ganymede’s Aurorae Hint at an Ocean Ten Times Deeper than Earth’s

Illustration of Ganymede's auroral ovals, the stability of which hint at a global underground ocean. Credit: NASA, ESA, and G. Bacon (STScI).

Illustration of Ganymede’s auroral ovals, the stability of which hint at a global underground ocean. Credit: NASA, ESA, and G. Bacon (STScI).

It’s long been suspected that Jupiter’s giant moon Ganymede may harbor a subsurface ocean of liquid water beneath its icy yet hard-as-rock crust, and now some ingenious observations with the Hubble Space Telescope are making an even more convincing case for it!

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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 hidden beneath a global shell of ice.

Scientists believe there is an ocean hidden beneath the surface of Jupiter’s moon Europa. In the video above, NASA-JPL astrobiologist Kevin Hand explains why scientists are so excited about the potential of this ice-covered world to answer one of humanity’s most profound questions: does life exist beyond Earth?

To learn more about Europa click here, and see the latest enhanced version of a Galileo image of Europa below:

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Cassini Uncovers Even More Evidence for Enceladus’ Hidden Ocean

A concept of the subsurface structure of Saturn's moon Enceladus (NASA/JPL-Caltech)

A concept of the subsurface structure of Saturn’s moon Enceladus (NASA/JPL-Caltech)

It’s been suspected for nearly a decade that Saturn’s 315-mile-wide moon Enceladus harbors a hidden ocean beneath its frozen crust, thanks to observations by the Cassini spacecraft of icy plumes spraying from its southern pole, and now scientists have even more evidence supporting its existence: Doppler measurements of the moon’s gravity taken during Cassini’s flybys show variations indicative of a subsurface southern sea as deep as the Pacific’s Mariana Trench!

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Jupiter’s Moon Europa Has Jets Like Enceladus!

Rendering of Europa's vapor plumes, seen by Hubble UV observations (NASA, ESA, and M. Kornmesser)

Rendering of Europa’s vapor plumes, seen by Hubble UV observations (NASA, ESA, and M. Kornmesser)

“Attempt no landings there?” Ok, FINE. We’ll just fly a spacecraft through Europa’s newly-discovered plumes and get a taste of its underground ocean that way!

Because it has them, and so we could.

This was the big news from NASA, ESA, and Hubble researchers today: Jupiter’s ice-covered moon Europa (yes, the one from 2010) has Enceladus-like plumes of water vapor near its south pole. What’s more, these plumes appear to vary depending on the moon’s distance from Jupiter; the giant planet’s gravity is “squeezing” Europa, causing the plumes to shut off when it’s closer and turn on when farther away. Now I’m no scientist, but I’d call that pretty solid evidence for a subsurface ocean… and darn good reason to scramble some exploration missions out to Europa tout de suite!

Read more in my article on Universe Today here.

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