Robert Pappalardo, Project Scientist, NASA Jet Propulsion Laboratory was the guest speaker at the Gallagher Colloquium Series presented by the University of Calgary this past Tuesday, April 11. As he was introduced we were told that “Rocket scientists are smart guys, this is the guy who tells them what to do. “
Indeed, exploring space is a big science that requires specialty knowledge in a wide range of scientific disciplines combining rocket science, earth science, biology, biochemistry and more. I was fascinated by this lecture because of the beautiful way the scientific argument was woven together to form a coherent and understandable model of how we can know that life exists on another planetary body.
As a long-time Star Trek fan, I know that the captain starts slowing the Enterprise down around Saturn so that the craft comes to a stop by the time it reaches Earth long before his tea, Earl Grey, gets cold. That’s fiction! In reality, a spacecraft launched from Earth during a very narrow launch window of 21 days in 2022 will take 7.5 years to reach Jupiter. The distances are almost inconceivable to the non-specialist.
So what are the assumptions/evidence that are required to encourage us to think life might be possible in one of the ‘oceans beyond earth’?
- First, there must be water, and that has already been verified to exist on a number of the moons of Jupiter and Saturn.
- Second, the critical elements of life must be present: these are generally accepted to be carbon, hydrogen, oxygen, nitrogen and sulfur.
- Third, there must be an opportunity for redox reactions where the gain and loss of electrons produce a way of storing and transferring energy.
- Finally, there must be stability: a long, long period of stable conditions.
At his talk, Robert Pappalardo hinted that today, April 13, there would be a major announcement coming from NASA. That was all he was willing to say about this embargoed information. Today, NASA officially commented on the data collected by the Cassini mission to Saturn which began in 1997, finally arriving at Saturn in 2004. Much has been learned as Cassini travelled through Saturn’s rings and studied the planet. Now in its final stages, the revelations from Cassini are exciting indeed as they have found evidence for redox reactions on Saturn’s moon Enceladus, and thus one more potential for life beyond Earth. When the spacecraft reaches the end of its usefulness in December 2017 it will be destroyed according to NASA protocols designed to ensure no cross-contamination of Saturn or its moons from earth.
Link of interest:
NASA’s Europa Project
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