Category Archives: Jupiter

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, either, 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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Dear Jupiter: Use More Sunscreen

Image of Jupiter's Great Red Spot from Voyager 1, 1979 data. Edited by Björn Jónsson.

Image of Jupiter’s Great Red Spot from Voyager 1, 1979 data. Edited by Björn Jónsson.

It’s the signature accessory of the largest planet in our solar system: Jupiter’s Great Red Spot, an enormous anticyclone over twice the width of our entire planet. Visible in even modest backyard telescopes, the GRS has been churning away for at least several hundred years. But, based on recent analysis of data gathered by the Cassini spacecraft during its pass by Jupiter in December 2000, the Great Red Spot’s rusty coloration may actually only be skin-deep – a “sunburn” created by interaction between Jupiter’s upper atmosphere and solar radiation.

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Boom! Io Explodes With Volcanic Eruptions Hundreds of Miles High

A volcanic outburst on Io on Aug. 29, 2013. Credit: Katherine de Kleer/UC Berkeley/Gemini Observatory

Infrared image of a volcanic outburst on Io on Aug. 29, 2013. Credit: Katherine de Kleer/UC Berkeley/Gemini Observatory

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 result of its elliptical orbit around Jupiter. These recent outbursts were exceptionally powerful, sending huge amounts of incredibly hot molten material out into space and likely coating a large area on its surface as well.

“We typically expect one huge outburst every one or two years, and they’re usually not this bright,” said Imke de Pater, professor and chair of astronomy at UC Berkeley and lead author of a paper describing the 2013 eruptions. “Here we had three extremely bright outbursts, which suggest that if we looked more frequently we might see many more of them on Io.”

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

A newly-released image of Europa's surface captured by Galileo (NASA/JPL)

A newly-released image of Europa’s surface captured by Galileo (NASA/JPL)

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 a piece of fried pork 25 miles wide and -300ºF!

All kidding aside, this is actually a newly-released picture of the frozen surface of Jupiter’s moon Europa, made from images acquired by NASA’s Galileo spacecraft in 1997 and 1998. The dark coloration of the river-like bands is thought to be the result of organic compounds staining the water ice that has welled up from the moon’s deep subsurface ocean… all the more reason that yes, we really should attempt a landing there in the very near future!

Read more about this in my article on Universe Today here.

*No pigs were harmed in the production of this image.

Jupiter’s Great Red Spot Isn’t So Great Anymore

A reduction in the width of the GRS observed since 1995 (NASA/ESA/Hubble)

A reduction in the width of the GRS observed since 1995 (NASA/ESA/A. Simon – GSFC)

It used to be said with confidence by even grade-school kids that the largest storm in the Solar System was Jupiter’s Great Red Spot, which has been churning for at least 350 years and could fit three Earths across it. And while it’s true that the GRS is a truly enormous hurricane by Earthly standards, these days it’s not as “great” as it used to be — over the past couple of decades the GRS has shrunk to only about a third of its former size.

“Recent Hubble Space Telescope observations confirm that the Great Red Spot (GRS) is now approximately 10,250 miles across, the smallest diameter we’ve ever measured,” said Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

That equals about 16,500 kilometers, or about one and one-third Earths across. Which is still very big, yes, but nothing compared to what it once was!

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Ganymede Gets a Little Geologic Love

The first geologic map (left) of Jupiter's moon Ganymede

The first geologic map of Jupiter’s moon Ganymede (left) and a composite surface map made from the best Voyager and Galileo images (right)

We don’t get to hear a lot about Ganymede these days, what with everyone paying so much attention to Titan and Enceladus and Europa and several other moons out there. Which is too bad because 1. Ganymede is plenty fascinating in its own right; and 2. it’s the LARGEST MOON IN THE SOLAR SYSTEM (and we shouldn’t forget it!) That’s why I was so happy to see this news come out today: geologists have created the first map of Ganymede that focuses exclusively on its complex geology, as observed close-up by the Voyager and Galileo spacecraft during their respective flybys. The resulting global map — which reminds me of some of the ornate illustrations that Giovanni Schiaparelli made of Mars in the 1880s — is a colorful layout of the many different terrains found across icy Ganymede, providing evidence of its complex history and a guide to future exploration missions.

Read more in my Discovery News article here.

Image credit: USGS Astrogeology Science Ctr/Wheaton/ASU/NASA/JPL-Caltech

E Pur Si Muove: Galileo’s Big Night

Jupiter and the fours "Galilean moons" Europa, Io, Callisto, and Ganymede. (Jan Sandberg/

Jupiter and the fours “Galilean moons” Europa, Io, Callisto, and Ganymede. (Jan Sandberg/

404 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 objects weren’t stars at all but rather moons that orbited the giant planet (and not the Earth). Further observations over the next nights showed that the planet wasn’t moving relative to the little “stars” as it should if they were indeed background stars, and in fact the smaller bodies (of which he soon saw four) were moving along with Jupiter, each in its own little orbit. This revelation helped change our entire view of the solar system, causing no end of trouble for Galileo (as the Church didn’t appreciate a restructuring of their conveniently Earth-centered Universe) but also opening the door for the discovery of many more moons around other planets.

Drawings from Galileo's notebook

Drawings from Galileo’s notebook

Jupiter is now known to have at least 50 moons, with possibly as many as 67.

As a result of his research and publications regarding the (actual) motions of bodies in the solar system, Galileo was eventually sentenced as a heretic by the Inquisition in Rome and spent the last 9 years of his life under house arrest. Still, his legacy of observation and science over dogma and established belief lives on to this day… in fact, if you go outside on a clear night now you can see a brightly shining Jupiter in the eastern sky, just as Galileo did 404 years ago. Take even a small telescope or pair of binoculars and you will easily see its four largest moons as pinpoints of light beside it. Thanks to Galileo and others like him, we now know what those are, and that there are countless other worlds and moons out there like them, just waiting for discovery.

Read more about Galileo here.

*E pur si muove – “and yet it moves” is a quote often attributed to Galileo, in that he muttered it as he “recanted” and accepted his punishment by the Roman court. But it is likely purely apocryphal, as there is no mention of it in records from the time.


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