LONDON: Nasa is all set to launch one of its most ambitious projects — to find whether Jupiter's icy moon Europa is habitable.
The world's leading space exploration agency is certain that Europa may be able to support life.Nasa has commissioned a team of experts to consider the goals for a landed spacecraft mission to the surface of Europa and to investigate the composition and geology of its icy shell and the potential for life within its interior ocean.
The Nasa-appointed Science Definition Team on Thursday presented the three main objectives of a future mission designed to land a robotic spacecraft on the surface of Europa and to investigate its potential to support life. It will investigate the composition and chemistry of Europa's ocean, characterize the thickness, uniformity , and dynamics of its icy shell and study the moon's human-scale surface geology.
"Landing on Europa and touching its surface is a visionary goal of planetary science. Europa is the most likely place in our solar system beyond Earth to have life today , and a landed mission would be the best way to search for signs of life," says Robert Pappalardo from Nasa's Jet Propulsion Laboratory. Europa is slightly smaller than the Earth's Moon. Like the Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Scientists know there may be enough oxygen in the waters of Europa to support millions of tons worth of fish.
The finding suggests the satellite could be capable of supporting the kinds of life familiar to us here on Earth, if only in microbial form. Europa is enveloped by a global ocean 160 km deep, with an icy crust that may be only a few miles thick.
The ice on the surface is made from hydrogen and oxygen, and the constant stream of radiation pouring in from Jupiter reacts with this ice to form free oxygen and other oxidants such as hydrogen peroxide. The reactivity of oxygen is key to generating the energy that helped multi-cellular life flourish on our planet.
Europa orbits Jupiter every 3.5 days and is phase locked -- just like Earth's Moon -- so that the same side of Europa faces Jupiter at all times. However, because Europa's orbit is eccentric (an oval or ellipse not a circle) when it is close to Jupiter the tide is much higher than when it is far from Jupiter.
Thus tidal forces raise and lower the sea beneath the ice, causing constant motion and likely causing the cracks we see in images of Europa's surface from visiting robotic probes.
This tidal heating causes Europa to be warmer than it would otherwise be at its average distance of about 780,000,000 km (485,000,000 miles) from the sun, more than five times as far as the distance from the Earth to the sun.
The warmth of Europa's liquid ocean could prove critical to the survival of simple organisms within the ocean, if they exist.
Europa was discovered on 8 January 1610 by Galileo Galilei. The discovery, along with three other Jovian moons, was the first time a moon was discovered orbiting a planet other than Earth. The discovery of the four Galilean satellites eventually led to the understanding that planets in our solar system orbit the sun, instead of our solar system revolving around Earth. Galileo apparently had observed Europa on 7 January 1610, but had been unable to differentiate it from Io until the next night.
Europa was originally designated Jupiter II by Galileo because it was the second satellite of Jupiter . Europa is named for the daughter of Agenor.
No comments:
Post a Comment