The Universe Is Teeming With Complex Organic Molecules

Asteroids are not as pristine as comets and are often subject to the effects of heating and liquid water. But these effects can create dramatic new organic complexities. Scientists have known for decades that chondrites derived from asteroids contain an extremely diverse range of organic molecules. The Murchison meteorite, which fell in Australia in 1969, contains more than 96 different amino acids. Only use about 20 in a lifetime. Osiris-Rex and Hayabusa2 have demonstrated that the asteroids Bennu and Ryugu are as complex as those meteorites. At least some of this complexity appears to have arisen before the asteroids themselves: preliminary analysis Studies of Bennu samples have shown that it retains organic material from the protoplanetary disk, including polycyclic aromatic hydrocarbons.

The chemistry of life?

Organic molecules on the early Earth took a new, dramatic step in complexity. them organized in some way Become a living thing. Some hypotheses about the origin of life on Earth involve a starter kit of organic materials from space. For example, the “PAH world” hypothesis posits a primordial soup phase dominated by PAHs. From this slurry emerged the first genetic molecules.

Overall, understanding how complex organisms form in space and end up on planets may give us a better understanding of whether life has emerged on other planets. If the raw materials for life on Earth were formed in the interstellar medium, then the materials for life should be ubiquitous in the universe.

For now, these ideas remain largely untestable. But because life itself represents a new level of organic complexity, astrobiologists are looking for complex organics as possible biosignatures, or signs of life, on other worlds in the solar system.

The European Space Agency’s Juice mission has begun studying Jupiter and its three icy moons, while NASA’s Europa Clipper mission launched to one of its moons, Europa, in October. Both will use onboard instruments to search for organic molecules in the atmosphere, as will a future Dragonfly mission to Saturn’s moon Titan.

However, determining whether a given organic molecule Is it biometric?. If scientists could find a complex enough combination of organic molecules, it would be enough to convince at least some researchers that we’ve discovered life on another world. But as comets and asteroids reveal, the nonliving world is inherently complex. Compounds thought to be biosignatures are found on inanimate rocks, such as dimethyl sulfide, which Hänni’s team recently discovered on 67P.