Kevin Hand explores the most extreme places on Earth. He is a scientist at NASA, the U.S. space agency. Hand wants to see how life survives in very cold places like Antarctica and Alaska. He also examines life forms living in the deepest oceans. By studying places like these, Hand said, we can understand how life might exist in space.
Moons and planets have extreme environments. They can be very cold or hot or dry. We need to understand in what conditions life can take place, Hand said. Then we can better understand life on distant planets.
However, even a cold day in Antarctica doesn't reach the temperature of Europa, Hand said. Europa is a moon of Jupiter. It sits at -173 degrees Celsius (-280 degrees Fahrenheit). The coldest known temperature on Earth is -89 degrees Celsius (-128 degrees Fahrenheit).
Scientists are hoping to study Europa up close. NASA is currently planning a mission to Europa and three other moons of Jupiter. Hand helps design spacecraft and equipment for the mission. He tests some early versions of these tools by going to Earth's extreme regions.
One of Hand's most fruitful trips was in the middle of the Atlantic Ocean. Hand went in a submarine to explore what's known as "Lost City," a one-of-a-kind underwater location. The "city" is actually a collection of carbonate towers. Carbonate is a type of rock. The towers look like a fancy church, but they are completely natural.
The towers are created by hydrothermal vents. These vents are holes in the ocean floor, often near volcanoes. They spit out hot fluid that carries minerals, especially calcium. When the fluid interacts with seawater, the minerals form white carbonate towers.
Light cannot reach these deep areas, more than a kilometer (about a mile) beneath the ocean surface. Without light, life forms such as bacteria cannot use photosynthesis. This is the process most plants above ground use to turn sunlight into energy. Instead, underwater organisms use a process called chemosynthesis. They use materials found in vent fluid to make energy.
Hand thinks Lost City shows us how life can exist on Europa. This moon is covered in ice. Scientists think there is a liquid ocean beneath its crust. Light and photosynthesis would not be able to make life there. Chemosynthesis could, though.
Places like Lost City also help Hand understand where to look for life on Europa. He thinks there is a good chance hydrothermal vents exist in Europa's oceans.
On Earth, Hand said, wherever there is water there is usually life. The fact that there might be oceans on Europa and Enceladus has excited scientists. They are focusing on these two moons in their search for life in space.
Hand believes Europa holds the best possibility of life. We know the type of land it has. We know why it has an ocean too, he said. He thinks Europa will be easier to study and understand than other worlds. Europa is also smaller than Earth, but it seems to have twice the amount of liquid water, Hand said. There is plenty to explore.
If NASA launches a spacecraft to Europa in 2020, it would take eight years to reach it. Hand is still excited, even if the wait is long. Humans have existed for a long time, he said. When you think about that, the amount of time to wait for the Europa trip is like "the blink of an eye." He said it's "quite exciting" to be alive now and possibly get to answer big questions.