1、We have very strong evidence that a vast sub-surface ocean exists on Jupiters moon Europa. Its an incredibly compelling place to explore in our search for life beyond Earth.”The best chance of discovering life beyond Earth may not be where youd expect. Todays weather forecast for Europa, Jupiters fo
2、urth largest moon, is 280 degrees below Fahrenheit. A layer of ice several miles thick coats its fractured surface, with 1,000-foot ice cliffs piercing a pitch-black sky. Its devoid of atmosphere, bombarded by fierce radiation, about 485 million miles from the sun, at times nearly 600 million miles
3、from Earthand Kevin Hand can hardly wait to get there.Hand works at the Jet Propulsion Laboratory (JPL), which is under contract with NASA, researching Europa and preparing to send an orbiting probe there. “When it comes to the search for life beyond Earth, NASAs mantra has long been follow the wate
4、r. Well, the water is on Europa.” Planetary scientists believe a global ocean of liquid water swirls beneath the icy surface. “Europa is about the size of our own moon,” Hand explains. “Its vast ocean is likely more than 60 miles deep (Earths ocean depths reach only about seven miles). That means Eu
5、ropa may harbor two to three times the volume of all liquid water on Earth.”How do we know the ocean exists? When the Galileo spacecraft explored Jupiters neighborhood, it detected an induced magnetic field between the planet and Europa. Hand notes that “ice isnt conductive enough to create such a f
6、ield, so the best explanation is a region of salty, liquid water below the frozen surface, which supplies a conductive layer. When you go through a metal detector at the airport with a conductor such as keys in your pocket, the alarm goes off. Likewise, when Galileo flew by, Europa set off the alarm
7、.”Today Hand helps plan a NASA mission to Europa to give Earthlings a closer look. The precise timetable is uncertain, but an orbiting probe is projected to launch sometime around 2020, make its six-year journey to Jupiter, then spend two years touring the planets four largest moons before spiraling
8、 down into orbit around Europa. “By the time we get there,” Hand observes, “Ill be a much older man. This business is not for the faint of heart.” A large antenna and several cameras will transmit pictures and data. The probes ice-penetrating radar will gather clues about the frozen shells interior
9、structure, possibly identifying where ice and ocean meet. Other instruments will analyze surface chemistry, examine the magnetic field, and investigate radiation environments.To create instruments that will travel hundreds of millions of miles through space, Hand voyages to the most forbidding envir
10、onments on Earth. “Im trying to understand extremes of life here, so we can better assess and investigate habitable environments on alien worlds like Europa.” He has explored the north slope of Alaska, the glaciers of Mount Kilimanjaro, the valleys of Antarctica, and the depths of our oceans to see
11、how microbes eek out a living in our worlds harshest climes. “One of my key challenges is figuring out how best to detect, characterize, and map complex organic chemistry out there in the solar system to see if Europas ice-covered ocean is, in fact, inhabited. The new tools were developing at JPL wi
12、ll evolve and hopefully someday wind up bolted to the side of a spacecraft or strapped to the end of a robotic arm.”Of course, no place on Earth can match Europas true conditions. “Thats why my colleague Robert Carlson and I have built what we call Europa-in-a-can, here in our lab,” Hand explains. “
13、It replicates low-temperature, low-pressure, high-radiation environments, so we can study the chemical processes and dynamics that may drive what well see on distant worlds.” Their experiments also help interpret data gained from the Galileo mission, and inform the design of future missions and inst
14、ruments.“The fundamental questions were trying to answer are questions humanity has asked ever since we first gazed into the night sky: What is life and could it exist out there beyond Earth? I want to know if DNA is the only game in town. Are there different biochemical pathways that could lead to
15、other kinds of life? Thats at the heart of why I want to go to Europato find something living in that ocean we can poke at and use to understand and define life in a much more comprehensive way.”For someone focused on a world millions of miles away, Hand is remarkably engaged in his own planets prob
16、lems. “When I think about the desire to connect with life elsewhere in the universe, it gives me an incredible sense of the fragility of life here on Earth and how crucial it is to protect our collective home.” This led him to found Cosmos Education, a nonprofit working to advance critical thinking
17、skills and empower some of Africas poorest children through science, health, and environmental education. “You can do all kinds of fun experiments with everyday items; you dont need elaborate resources. The activities we bring into schools can be easily reproduced with materials found right in their
18、 villages. We also do a lot of mentoring and career counseling. Our local teams are made up of African engineers, teachers, scientists, health activists, and development leaders who are amazing role models. We want to inspire the next generation of great teachers, doctors, lawyers, and politicians.”
19、Hand speaks from experience. His own inspiration to study planetary science came in part from an engaging elementary school science teacher and growing up under clear night skies in Vermont. “Our complex industrial, technological society has really disconnected us from the stars above. We need to remember to stop, look up, and let the wonder take over.”Share
