Life on other planets might be possible without water
What's the story
A new study by scientists at the Massachusetts Institute of Technology (MIT) has challenged the long-held belief that water is essential for life on other planets. The research, published in the Proceedings of the National Academy of Sciences, suggests that a different type of liquid, ionic liquids, could support life on rocky planets and moons where water is scarce. Ionic liquids are salts that remain in liquid form at temperatures below 100 degree Celsius.
Unique properties
Sulfuric acid, nitrogen compounds can produce ionic liquids
Ionic liquids have a very low vapor pressure and don't evaporate easily, making them stable at higher temperatures and lower pressures than liquid water. The researchers found that a mixture of sulfuric acid and certain nitrogen-containing organic compounds can produce these ionic liquids. Sulfuric acid could be produced by volcanic activity on rocky planets, while nitrogen-containing compounds have been found on asteroids and planets in our solar system, indicating their possible presence in other planetary systems.
Expanded definition
Pockets of ionic liquid could exist on rocky planets
The researchers, led by Rachana Agrawal, have proposed that even in extreme conditions where liquid water can't exist, pockets of ionic liquid could be present. "We consider water to be required for life because that is what's needed for Earth life," Agrawal said. "But if we look at a more general definition, we see that what we need is a liquid in which metabolism for life can take place."
Finding
How did the research start?
The team's work with ionic liquid began while preparing for a mission to search for signs of life on Venus. They saw that sulfuric acid was chemically reacting with glycine, an organic compound, resulting in a fluid mixture of salts or ions, an ionic liquid. This accidental discovery led them to wonder if these liquids could form and exist naturally on exoplanets under the right conditions.
Future research
New area of research in astrobiology
The study opens up a new area of research in astrobiology, with the potential for ionic-liquid-based life on planets without water. The team plans to investigate further what biomolecules and ingredients for life might survive and thrive in ionic liquid.