Can life exist outside Earth? The dwarf planet Ceres, scheduled to be visited by NASA’s Dawn Mission in early 2015, may provide clues to help scientists and astronomers piece together information about this possibility, which looms large in the minds of even casual followers of space exploration.
Ceres, the largest body in the asteroid belt between Mars and Jupiter, was originally named a planet upon its discovery in 1801. Ceres was eventually reclassified as an asteroid for many years, until it was named a “dwarf planet” in 2006, alongside Pluto. Along with its size, other features such as the low density and perfectly spheroid shape of Ceres have provoked excitement in the astronomical community.
The key to researching life on other planetary objects in the Milky Way is water. Whether exploring the possibility that life once existed on a body or the potential for life to exist there in the future, scientists turn to examining the history and context of water on the object.
Ceres has long been thought to harbor a possibly large amount of water in the form of an icy mantle. Spectral analysis of telescope images indicates a lower density than a solid rocky body and “evidence of water-bearing minerals” on its dusty surface. These signs have already led some to suspect Ceres as a potential bearer of life. And as the Dawn mission’s study of Ceres grows closer, scientists are hopeful that the data collected will provide invaluable insight into the nature of water in the solar system, especially in the early part of its history when Ceres was formed.
Britney Schmidt, science team liaison for the Dawn Mission, was quoted in an article on Space.com as calling Ceres a “game changer in the solar system” and a “gatekeeper” of the kind of knowledge they are seeking. Other icy bodies, notably Saturn’s moon Enceladus and Jupiter’s moon Europa, have already been singled out for profitable study in these areas. But Schmidt and planetary scientist from JPL Julie Castillo-Rogez, who spoke with Schmidt in the webinar ‘Destination Ceres: Icy World Revealed?,’ believe that Ceres is just as promising in addition to possibly being easier to study.
Ceres differs from the outer icy moons in several important aspects, not the least of which is its distance from the Sun. Ceres lies a little over 413 million kilometers from the Sun, almost half the distance of Europa and under a third of Enceladus from Sol. In addition to being vastly closer to Earth, this also means that Ceres receives its heat from the Sun, as we do, instead of from the tidal forces of a gas giant. Its surface temperature is also much warmer, raising even the possibility of liquid water.
Castillo-Rogez includes all these factors in her determination of the dwarf planet as a candidate for some sort of life: "The chemistry, thermal activity, the heat source, and the prospect for convection within the ice shell are the key ones that make us think that Ceres could have been habitable at least at some point in its history."
The two scientists also note the viability of Ceres for manned missions, and for a waypoint for embarking on expeditions into the outer solar system.
Will Ceres indeed be a game changer for space exploration? That remains to be seen by the Dawn Mission, but there is little doubt that this unique object will provide new opportunities for astrobiologists and planetary scientists to push their researches to new heights and begin unlocking the mysteries of life in the final frontier.