Everyone knows that Earth is a “water-world,” with oceans covering 71% of its surface and at least as much contained within our planet’s mantle deep below its crust. But there’s also liquid water to be found elsewhere in the Solar System: on Mars, on the dwarf planets Ceres and Pluto, and also on the icy moons of Jupiter, Saturn, and Neptune.
NASA is on the hunt for this water, for the main reason that it’s the key ingredient for the evolution of Earth-type life. Where liquid water exists, if there are organic molecules and energy sources as well then the stage is set for life having evolved independently of Earth. And if we can find that that’s the case somewhere, anywhere else in the Solar System, then that would be a huge – no, make that giant – step toward answering the Big Question: are we alone in the Universe?
Today NASA scientists held a conference about the search for oceans beyond Earth, and how we are currently and plan to find out where and how much is (or even was) out there. An infographic accompanied the press materials released.
“What we’re finding out is that the Solar System really is a soggy place.”
– Dr. Jim Green, NASA’s Planetary Science Director
Check out the full infographic below, along with a video of the conference.
This July the New Horizons spacecraft will perform its long-awaited flyby through the Pluto system, capturing unprecedented data and images of the distant icy planet and its companion satellites Charon, Nix, Hydra, Kerberos, and Styx. The first two worlds, in particular, will have their surfaces seen in high-resolution, allowing scientists to observe and map their features for the very first time. But as landforms come into view – craters, mountains, scarps, plains, and who knows what else – what will they be named?
This is where YOU come in.
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 objects weren’t stars at all but rather moons orbiting the giant planet (and, most importantly, not Earth). Further observations over the next few 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 data contradicting their conveniently Earth-centered Universe) but also opening the door for the discovery of many more moons around other planets.
Today Jupiter is now known to have at least 50 moons, with possibly as many as 67!
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 poles – aurorae have been observed on Jupiter, Saturn, Uranus, and Neptune as well (and Venus may even have them too.) While we know that these light shows are caused by interactions between atoms in planets’ upper atmospheres and charged particles from the Sun that get caught up in magnetic fields focusing out from around the poles, Jupiter in particular is known to have a peculiar additional type of auroral feature, created by the moons that orbit it.
The image above, captured by the Hubble Space Telescope Imaging Spectrograph (STIS) on November 26, 1998, shows Jupiter’s north polar region in ultraviolet light. The planet’s energetic aurorae can be seen wrapping around its pole in wavy circular arcs, just like Earth’s does. But there are also several bright spots that aren’t due to solar activity but are instead the “footprints” of three of its largest moons: Ganymede, Europa, and Io.
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.
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.
*Eppur 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.
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…