Just a week after Curiosity celebrated its first Martian year in Gale Crater and we have yet another milestone anniversary in Solar System exploration: as of 10:48 p.m. EDT tonight Cassini will have been in orbit around Saturn for a full decade!
“There are times when human language is inadequate, when emotions choke the mind, when the magnitude of events cannot properly be conveyed by the same syllables we use to navigate everyday life. The evening of June 30, 2004 was such a time.”
– Carolyn Porco, Cassini Imaging Team Leader, CICLOPS “Captain’s Log” on June 30, 2014
That’s ten years and over 2 billion miles of discoveries and explorations of our Solar System’s most majestic planet and its incredibly varied family of moons. Over the course of its primary mission and three extended missions, we have been able to get a close-up look at Saturn and its moons like never before, witnessing first-hand the changes that occur as their seasons change. What’s been discovered by the Cassini mission about Saturn has offered invaluable insight into the evolution of our entire Solar System, as well as planets that could be found elsewhere in our galaxy.
“Having a healthy, long-lived spacecraft at Saturn has afforded us a precious opportunity,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. “By having a decade there with Cassini, we have been privileged to witness never-before-seen events that are changing our understanding of how planetary systems form and what conditions might lead to habitats for life.”
Launched on October 15, 1997, the Cassini-Huygens spacecraft established orbit around Saturn on June 30, 2004 (July 1, UTC).
If you’ve been a faithful reader of Lights in the Dark over the past five years you know that I just love Cassini (and you probably do too!) In orbit around Saturn since 2004, Cassini has taken us on an intimate tour of the Saturnian system for a decade now, revealing the incredible beauty of the ringed planet and its family of moons like no spacecraft ever has before. Thanks to Cassini and the Huygens probe, we have seen the surface of Titan for the first time, witnessed the jets of Enceladus, discovered many previously-unknown moons (and moonlets) and basically learned more about Saturn over the past ten years than since Galileo first pointed his telescope at it.
Although nearing the end of its life span, Cassini still has a few good years left and scientists are taking full advantage of its remaining time around Saturn to learn as much as they can before the spacecraft makes its final dive into the planet’s atmosphere in 2017.* The video above shows what awaits Cassini in the years ahead — some of its best discoveries may be yet to come. Check it out!
*The exact plan for the end of Cassini’s mission has not yet been finalized.
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!
What a year for space exploration! With 2013 coming to a close I thought I would look back on some of the biggest news in space that I’ve featured here on Lights in the Dark. Rather than a “top ten” list, as is common with these year-end reviews, I’m going to do more of a month-by-month (hence the 12) to help recollect some of the amazing stories and sights that 2013 has brought us. And with some of the big headliners we’ve seen this year it’s easy to lose sight of the smaller (but no less fascinating) discoveries — so I’ll be sure to include some of those too. After all, when it comes to learning about the Universe there’s no “little” news!
Ready? Let’s go!
Cassini couldn’t make it to the mall this year to do any Christmas shopping but that’s ok: we all got something better in our stockings than anything store-bought! To celebrate the holidays the Cassini team has shared some truly incredible images of Saturn and some of its many moons for the world to “ooh” and “ahh” over. So relax, sit back and marvel at some sights from a wintry wonderland 900 million miles away…
Earth may display its seas on its surface for all the Universe to see, but further out in the Solar System liquid oceans are kept discreetly under wraps, hidden beneath cratered surfaces of ice and rock. And while Saturn’s moon Enceladus sprays its salty subsurface ocean out into space, other moons are less ostentatious — Europa, Ganymede, Titan… all are thought to have considerable underground oceans of liquid water, based on measurements of their mass, density, and shape.
Now, scientists are suggesting that Saturn’s 700-mile-wide moon Dione may also have a subsurface ocean… and may have even once exhibited icy geysers like its smaller sibling Enceladus.
Thanks to Cassini we’ve known about the jets of icy brine spraying from the south pole of Saturn’s moon Enceladus for about 8 years now, but this week it was revealed at the 44th Lunar and Planetary Science Conference outside Houston, Texas that Enceladus’ jets very likely reach all the way down to the sea — a salty subsurface sea of liquid water that’s thought to lie beneath nearly 10 kilometers of ice.
“To touch the jets of Enceladus is to touch the most accessible salty, organic-rich, extraterrestrial body of water and, hence, habitable zone, in our solar system.”
– Cassini imaging team leader Carolyn Porco