Space & Innovation

Could Dwarf Planet Ceres Support Alien Life?

A NASA probe is about to get the first up-close look at a potentially habitable alien world.

A NASA probe is about to get the first up-close look at a potentially habitable alien world.

In March 2015, NASA's Dawn spacecraft will arrive in orbit around the dwarf planet Ceres, the largest object in the main asteroid belt between Mars and Jupiter. Ceres is a relatively warm and wet body that deserves to be mentioned in the same breath as the Jovian moon Europa and the Saturn satellite Enceladus, both of which may be capable of supporting life as we know it, some researchers say.

"I don't think Ceres is less interesting in terms of astrobiology than other potentially habitable worlds," Jian-Yang Li, of the Planetary Science Institute in Tucson, Arizona, said Thursday (Dec. 18) during a talk here at the annual fall meeting of the American Geophysical Union. [Photos: The Dwarf Planet Ceres]

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Life as we know it requires three main ingredients, Li said: liquid water, an energy source and certain chemical building blocks (namely, carbon, hydrogen, nitrogren, oxygen, phosphorus and sulfur).

The dwarf planet Ceres - which is about 590 miles (950 kilometers) wide - is thought to have a lot of water, based on its low overall density (2.09 grams per cubic centimeter; compared to 5.5 g/cubic cm for Earth). Ceres is likely a differentiated body with a rocky core and a mantle comprised of water ice, researchers say, and water-bearing minerals have been detected on its surface.

Indeed, water appears to make up about 40 percent of Ceres' volume, Li said.

"Ceres is actually the largest water reservoir in the inner solar system other than the Earth," he said. However, it's unclear at the moment how much, if any, of this water is liquid, he added.

ANALYSIS: Vesta is a Baby Planet, Not an Asteroid

As far as energy goes, Ceres has access to a decent amount via solar heating, since the dwarf planet lies just 2.8 astronomical units (AU) from the sun, Li said. (One AU is the distance between Earth and the sun - about 93 million miles, or 150 million km). Europa and Enceladus are much farther away from our star - 5.2 and 9 AU, respectively.

Both Europa and Enceladus possess stores of internal heat, which is generated by tidal forces. This heat keeps the ice-covered moons' subsurface oceans of liquid water from freezing up, and also drives the eruption of water-vapor plumes on Enceladus (and probably Europa as well; researchers announced last year that NASA's Hubble Space Telescope spotted water vapor erupting from the Jupiter moon in December 2012).

Intriguingly, scientists announced the discovery of water-vapor emission from Ceres - which may also possess a subsurface ocean - earlier this year.

Ceres' plumes may or may not be evidence of internal heat, Li said. For example, they may result when water ice near Ceres' surface is heated by sunlight and warms enough to sublimate into space.

"Right now, we just don't know much about the outgassing on Ceres," Li said.

Dawn should help bring Ceres into much clearer focus when it reaches the dwarf planet this spring. The spacecraft, which orbited the huge asteroid Vesta from July 2011 through September 2012, will map Ceres' surface in detail and beam home a great deal of information about the body's geology and thermal conditions before the scheduled end of its prime mission in July 2015.

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Ground-based instruments should also play a role in unveiling Ceres. For example, the Atacama Large Millimeter/submillimeter Array, or ALMA - a huge system of radio dishes in Chile - has the ability to probe deeper than Dawn, going into Ceres' subsurface and shedding more light on the dwarf planet's composition and thermal properties, Li said.

"This is highly complementary to the Dawn mission," he said.

Ceres' relative proximity to Earth also makes it an attractive target for future space missions, Li added.

More from SPACE.com:

Photos: Asteroid Vesta and NASA's Dawn Spacecraft Dwarf Planets of Our Solar System (Infographic)

6 Most Likely Places for Alien Life in the Solar System Originally published on Space.com. Copyright 2014 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

The dwarf planet Ceres, also the largest asteroid in the solar system, is seen here in an amazing view from the Hubble Space Telescope. In March 2015, NASA's Dawn spacecraft is expected to enter orbit around Ceres to study the object like never before.

NASA's Dawn spacecraft orbited the massive asteroid Vesta in 2011 and 2012, giving us an unprecedented look at the protoplanet's landscape, craters and mineral composition. The probe, which is now on its way to dwarf planet Ceres, not only revealed the evolution of Vesta, it also provided vital clues as to the evolution of our solar system. Now,

in new images published by NASA

, an unusually colorful Vesta landscape is on display. Using data from the mission, scientists at Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany have produced a rather psychedelic view of this otherwise bland landscape. Dawn's camera system is equipped with seven filters, each filter sensitive to a specific wavelength of light. Normally, Vesta would look gray to the naked eye, but when analyzing the ratios of light through Vesta's filters, the landscape pops with color. Shown here, the flow of material inside and outside a crater called Aelia is demonstrated. As different minerals reflect and absorb different wavelengths of light, this composite image is alive with color, each shade representing different kinds of minerals littering Vesta's landscape.

This is Antonia, a crater located inside the huge Rheasilvia basin in the southern hemisphere of Vesta. From this image, planetary scientists have been able

to deduce that

"the light blue material is fine-grain material excavated from the lower crust. The southern edge of the crater was buried by coarser material shortly after the crater formed. The dark blue of the southern crater rim is due to shadowing of the blocky material."

The impact crater Sextilia can be seen in the lower right of this image. The mottled dark patches are likely impact ejecta from a massive impact and the redish regions are thought to be rock that melted during the impact. The diversity of the mineralogy is obvious here. "No artist could paint something like that. Only nature can do this," said Martin Hoffman, a member of the framing camera team at Max Planck Institute.

Earlier images of Vesta have shown an unusual "pitted terrain" on the floors of the craters named Marcia (left) and Cornelia (right). Once again, the varied colors demonstrate the different minerals and processes that cover Vesta's surface.

This

"global" model

of Vesta shows the abundance of hydrogen on Vesta's surface. Note that the hydrogen signal is enhanced near the asteroid's equator. The hydrogen is likely from hydroxyl or water bound to minerals in Vesta's surface.

Another, earlier view of Antonia crater, demonstrating the mineral diversity of the region.

This is the distinctive Oppia crater on Vesta, an impact that occurred on a slope. This produced an asymmetric ejecta distribution around the crater -- the red/orange ejecta material is more abundant around the downward slope than around the upward portion.