Superman may have been able to see through walls with his X-ray vision, but European scientists have developed an even more remarkable ability. With the MARSIS radar sounder on ESA’s Mars Express orbiter, they can look through several kilometres of solid ice or rock.
Until recently, it was only possible to explore a planet’s surface. The only way to obtain information about conditions underground was to land on the surface and start digging or drilling. But such methods could only probe to a depth of perhaps half a metre and were only good for a single site on an entire planet.
MARSIS, the first radar sounder to orbit another world, has shown that it is possible to look beneath the surface of an entire planet from orbit. Now, armed with a better understanding of what a radar sounder can achieve, the MARSIS team is beginning to think about exploring other objects in the Solar System.
Jupiter’s moon, Europa, is one place where a MARSIS-type experiment could make exciting discoveries. Europa is thought to have an ocean (with life?) beneath its thick, icy crust. Radar could also measure the depths of the hydrocarbon lakes on Saturn’s moon, Titan. It could also study the powerful geysers that blast into space from Enceladus, another moon of Saturn.
The interiors of asteroids and comets could be thoroughly scanned by a radar sounder. Here on Earth, the MARSIS technique could be invaluable for studying Antarctic ice sheets. For the first time, there is the potential for three-dimensional studies of planets and moons – thanks to radar’s see-through vision.
