Hello again. Last time out, we took a brief look at three of the main hurdles we will need to overcome to cross the gulf of space on our quest to reach Mars. As you saw, it was quite involved.
But there’s a good reason for that.
Mars might be the next main objective, but it’s not the only one. Ongoing missions continue apace as NASA concentrates on broadening our understanding of the origins of life, and where else it might be found.
Does that sound farfetched?
Well, it isn’t. As we’ll go on to see in this brief introduction, it’s not the sky that’s the limit, it’s how far we’re prepared to go. Let me explain, in….
Recently, NASA announced their intention to begin a new phase of exploration concentrating on the search for life beyond Earth. In particular, the emphasis will be on those bodies within our solar system known to harbor oceans and other large bodies of water.
Exciting times, because robotic probes sent into the depths of space over the past twenty years have made one thing perfectly clear: our solar system is a very wet place. Surveys of the giant outer planets Jupiter, Saturn, Uranus and Neptune have exposed the secrets of their enigmatic moons. And some of them, it turns out, are hiding liquid water oceans sealed inside shells of ice.
These ocean worlds are the next frontier in the search for life beyond Earth. And NASA scientists are already developing concepts for return trips by robotic probes bristling with ultra-sensitive instruments. Future missions would be designed to detect any trace of the chemistry, structure or by-products of alien biology.
When you think about it, this is a logical step to take. On Earth – which as we know is an ocean world – liquid water is essential to life. So it begs the question: is it possible that one or more of the dark, alien oceans of the outer solar system might be a suitable habitat for life? If so, how complex might that life be?
****We’re searching for living life. We want to find life and poke and prod at it, and see whether a second origin of life occurred in our solar system, Hand said. Is it easy or hard? Is DNA the only paradigm, the only game in town?
– Kevin Hand, NASA Astrobiologist****
So, over the next decade, NASA is planning to send a spacecraft on repeated flybys of several candidates where oceans are known to exist.
Well, let’s take a brief look at several contenders, and learn why people think they’re the best places in the solar system to start our search for life beyond Earth.
An icy moon of Jupiter, Europa is a solid aspirant, for scientists believe a subsurface, salty ocean very likely lies beneath its icy crust. A tidal tug of war between its parent planet and Jupiter’s other large moons maintains this ocean’s liquid state. It is also possible such interaction creates partially melted pockets, or lakes, throughout the moon’s outer shell.
Titan is also a surefire candidate, as it’s the only other body in the solar system – besides Earth – blessed with surface lakes (Sadly, comprised of methane). According to recent estimates, Titan might also have a subsurface ocean, possibly as salty as the Dead Sea on Earth, beginning about 31 to 62 miles (50 to 100 kilometers) below its icy shell. Meanwhile, on Titan’s surface, “life as we don’t know it” could inhabit lakes and rivers that flow with ethane and methane hydrocarbons instead of water.
Geysers on Saturn’s other dynamic moon, Enceladus, spew the contents of its subsurface ocean far into space. This would be a great place to start, because future mission could, quite simply, scoop up free samples without the hassle of having to land, giving us a head start of what to do next.
But why is Enceladus so accommodating?
Well, a global ocean deep beneath the surface of this Saturn moon feeds jets of material through deep fissures, called “tiger stripes” out into the reaches of space, an event that has been recorded numerous times.
Who can guess what else might be locked away in the stygian depths? Well, we can, actually. And we can say this with a high degree of probability because similar conditions exist right here on Earth.
The Mid-Atlantic Ridge, nearly 7,000 feet (2,100 meters) below the ocean surface, is home to “black smoker” hydrothermal vents, belching plumes of heated water into its frigid surrounds. As we now know, such seemingly hostile conditions create rich ecosystems. Scientists believe similar conditions could exist in the far reaches of our solar system, deep within icy moons orbiting giant Jupiter and Saturn, where nightfeeders might huddle around chimneys of rock, feeding on mineral rich columns of black “smoke” or even on their fellow feeders.
Exciting stuff isn’t it, to realize we live at a unique time in human history – a cosmic crossroads if you like. All the data we’ve collected so far provides tantalizing hints that inhabited worlds may lay within our own solar system. And if they’re here, what lies further out among the stars?
Yes, we stand at the dawn of a new era of powerful technology that might soon answer the ancient question, “Are we alone?”
Wouldn’t YOU love to find out the answer to that question?
I’m sure you would, so, join me next time as we revisit our prime candidates for life and discus each one in more detail and see if we’re really prepared to journey into infinity and beyond…
(Source material – Courtesy of NASA)