In an astounding discovery, the robotic probe now on the surface of Comet 67P has found that the cosmic body heading towards the Sun contains organic molecules that are considered as the building blocks of life.
Speaking to Popular Science, Stephan Ulamec, the head of the European Space Agency's Rosetta lander team, revealed that the robotic lander Philae made the tantalizing discovery before its batteries ran out last week.
Ulamec said Philae used some of its last remaining battery power to study the comet and beam the data back to Earth.
Ulamec said Philae appeared to have detected complex molecules but that his team needs more time to study them. "We are currently investigating what kind of species these [molecules] are, and this will be published soon. We want to be sure. But it's definitely several species," he said.
Organic molecules -- which are made primarily of carbon -- form the fats, proteins, sugars, and DNA that make up all living organisms on Earth.
Scientists say a confirmation that Philae found amino acids on the comet would support the theory that the necessary ingredients for life—carbon, hydrogen, phosphorus and nitrogen—were delivered to Earth by comets and asteroids.
"I'm not sure we found amino acids, but that, of course, would be very relevant for life," Ulamec said.
Whatever kinds of molecules were found, Philae's discovery is expected to give scientists a clearer idea of how our solar system was born and how it evolved over time.
"Most probably, this is pristine material," said Ulamec. "This organic stuff we find in the comet was probably readily available from the planetary nebula. It was probably there when our solar system formed."
NASA planetary scientist Mark Sykes also underscored the significance of Philae's findings. Previously scientists were only able to study the molecules in a comet's coma, using them to infer what's happening on the surface.
"When molecules get lifted off the comet's surface into the coma, they get broken down by UV radiation from the sun. And it doesn't take very long to happen," Sykes said.
"Detecting them on the surface of the comet, that tells us what the original molecules are. It'll be very interesting to find out what kind of molecules Philae found," he added.
Philae made the molecular discovery using an instrument that "sniffs" the molecules in the comet and using mass spectrometry to find out what they're made of.
Although the robotic probe managed to drill the surface of the comet, it was not clear whether it was able to put the soil samples into its oven to heat it for analysis.
Philae is now resting in a spot in the comet where it is not getting enough sunlight on its solar panels to recharge its batteries. Scientists are hoping that as the comet travels nearer to the Sun, the lander may receive enough sunlight to recharge its batteries and continue investigating the structure and composition of the comet.
While Philae is in hibernation, the Rosetta orbiter continues to fly around the comet studying its coma.
Life without water?
Meanwhile, a new theory has emerged that alien life could thrive even on planets without water. In a study, astrobiologists Nediljko Budisa and Dirk Schulze-Makuch said supercritical carbon dioxide which abounds in the solar system has been shown to be capable of sustaining life.
Scientists say carbon dioxide becomes supercritical when its temperature exceeds 305 degrees Kelvin (about 89 F) and its pressure goes beyond 72.9 the standard atmosphere (atm) at sea level -- the kind of pressure found about 800 meters beneath the ocean surface.
Scientists say enzymes can actually be more stable in supercritical carbon dioxide than in water. They note that numerous species of bacteria tolerate supercritical carbon dioxide.
Now consider this: The atmospheric pressure of Venus is about 90 times greater than that of the Earth, with an average temperature of 873 F. About 97 percent of Venus' atmosphere is carbon dioxide. Thus, the atmosphere of Venus could consist of supercritical carbon dioxide where organic remnants of life could still be preserved, scientists say.