The icy moons in space, which were once potential sites for life, might not be able to host living beings like on Earth, a recent study by NASA suggests.
Titan, the largest moon of Saturn, is frequently considered a potential contender for hosting life. This celestial body stands out as the sole location in the Solar System, besides Earth, where surface liquids are confirmed to exist, comprising rivers, lakes, and seas.
The rivers, lakes, and seas on Titan are filled with liquid hydrocarbons, mostly methane. Scientists were particularly interested in a huge ocean hidden beneath Titan’s icy surface. This ocean is believed to be over 12 times bigger than Earth’s oceans and lies about 55 to 80 kilometres (35 to 50 miles) beneath the ground.
Why Titan could not be the next Earth?
“Titan’s rivers, lakes and seas of liquid methane and ethane might serve as a habitable environment on the moon’s surface, though any life there would likely be very different from Earth’s life,” NASA explains.
Having liquid water below the surface is good for life, but you also need organics. Scientists earlier believed that these essential ingredients could be brought to the ocean beneath Titan’s surface. There, they could mix together, get heated up, and possibly start life when space objects hit the surface.
The theory was that the surface, which is full of organics, would mix with the ocean underneath when objects hit it and melt patches of ice. As it’s heavier than the ice around it, this mixture would sink down into the ocean below.
However, a study by the University of Western Ontario tried to figure out how many comets hit Titan each year and how much organics they brought to the ocean below. Sadly, the team discovered that only about 7,500 kilograms (16,500 pounds) of glycine, the simplest amino acid, would be delivered to the ocean. That’s about the weight of an adult elephant.
“One elephant per year of glycine into an ocean 12 times the volume of Earth’s oceans is not sufficient to sustain life,” astrobiologist Catherine Neish said in a press release.
“In the past, people often assumed that water equals life, but they neglected the fact that life needs other elements, in particular carbon.”
“This work shows that it is very hard to transfer the carbon on Titan’s surface to its subsurface ocean –basically, it’s hard to have both the water and carbon needed for life in the same place,” Neish added.
However, there’s still a possibility of life if there are more organics on the surface than we thought. And if organics could come from the core, or other processes could bring organics from the surface to the ocean below.
(With inputs from agencies)