Are we alone in the universe? Top NASA scientists say the answer is almost
certainly “no.”
"I believe we are going to have strong
indications of life beyond Earth in the next decade and definitive
evidence in the next 10 to 20 years,"
Ellen Stofan, chief scientist for NASA, said at a public panel
Tuesday in Washington.
"We know where to look, we know how to
look, and in most cases we have the technology," she said.
Jeffery Newmark, interim director of
heliophysics at the agency put it this way: "It's definitely not an if,
it's a when."
However, if visions of alien invasions are
dancing in your head, you can let those go.
"We are not talking about little green
men," Stofan said. "We are talking about little microbes."
Over the course of an hourlong presentation,
NASA leaders described a flurry of recent discoveries that suggest we are
closer than ever to figuring out where we might find life in the solar system
and beyond.
For example, Jim Green, director of planetary
science at NASA, cited a study that analyzed the atmosphere above Mars' polar
ice caps and suggests that 50% of the planet's northern hemisphere once had
oceans up to a mile deep, and that it had that water for a long period of time
-- up to 1.2 billion years.
"We think that long period of time is
necessary for life to get more complex," Stofan said.
She added that getting human field geologists
and astrobiologists on Mars would greatly improve the chances of finding
fossils of past life on our nearest planetary neighbor.
Green also described another recent study that used measurements of aurora on Jupiter's moon
Ganymede to prove it has a large liquid ocean beneath its icy crust.
The findings suggest that previous ideas about
where to find "habitable zones" may have been too limited. (A body
considered to in a habitable zone is not too hot or too cold for liquid water
to exist on its surface.)
"We now recognize that habitable zones
are not just around stars, they can be around giant planets too," Green
said. "We are finding out the solar system is really a soggy place."
He also talked NASA's plans for a mission to
Europa, another moon of Jupiter with an icy ocean.
"I don’t know what we are going to find
there," he said.
Newmark described how NASA is learning more
about the role of Earth's magnetic field in protecting our
planet's water and atmosphere from being blown away by the solar wind, thereby
playing a role in the ability for life to develop.
"Mars does not have a significant
magnetic field, so it lets the wind strip away the water and atmosphere,"
he said.
Paul Hertz, director of astrophysics at NASA,
talked about how future telescopes already in the works will help
scientists scan the atmospheres of large rocky planets around distant stars for
chemical markers of life.
"We are not just studying water and
habitability in our solar system, but also looking for it in planets around
other stars," he said.
NASA associate administrator John Grunsfeld,
said part of what excites him most about the search for life beyond our planet
is to see what that life looks like.
"Once we get beyond Mars, which formed
from the same stuff as Earth, the likelihood that life is similar to what
we find on this planet is very low," he said.
Grunsfeld said he believes that life beyond
Earth will be found by the next generation of scientists and space explorers,
but Green said he hopes it is sooner than that.
"The science community is making enormous
progress," he said. "And I've told my team I'm planning to be the
director of planetary science when we discover life in the solar system."
