The Building Blocks of Life Aren't Unique to Our Corner of the Galaxy
In a few billion years, will life blossom in the MWC 480?
Concept drawing of a protoplanetary disk. Credit: ESO/L. Calçada
For the first time ever, astronomers have discovered complex organic molecules in an infant solar system, providing yet more proof that the ingredients for life are sprinkled liberally across the universe.
Methyl cyanide (CH3CN), a carbon-rich molecule that helps form amino acids, was detected in the orbital debris surrounding the baby star MWC 480, which is only one million years old (for reference, the Sun is around 4.5 billion years old). The system is still in a very developmental stage, and has only recently condensed from a nebula into a protoplanetary disk of dense gas that will eventually evolve into planets.
"It is the first time we have seen complex organic molecules in a disk," said Karin Öberg, an astronomer with the Harvard-Smithsonian Center for Astrophysics, in an email interview with Motherboard. "We have also not yet detected any complex organics in a mature exo-planetary system."
Öberg is the lead author of a new paper about the discovery, which was published today in Nature. The researchers estimated that there is enough methyl cyanide in the young disk to fill all of Earth's oceans, and that other organic molecules—like hydrogen cyanide—were also present in the disk.
This is significant because it demonstrates that complex carbon bonds, which are the backbone of life as we know it, can survive the hostile, shockwave-heavy environments surrounding young stars. It's clear that such compounds made it through the maelstrom in our own solar system, but the new research indicates that this sequence of events was far from a one-off.
"The implication is that the complex organic chemistry we know was present in the young solar system, based on comet records, is present in other planet-forming disks as well," Öberg told me. "Thus the same chemistry that seeded the nascent Earth from space, is likely present on young rocky planets elsewhere."
"Whether this automatically leads to the origins of life we do not know," she added, "but at least we have removed one more barrier for it."
Öberg and her colleagues used the Atacama Large Millimeter/submillimeter Array (ALMA) facility in Chile to probe MWC 480's energetic disk, which is located about 455 light years away in an active region of starbirth.
In addition to methyl cyanide, ALMA picked up the signatures of less complex organic molecules, like hydrogen cyanide. Naturally, this enticing sneak peek into the molecular composition of a young disk raises the question of what other potentially life-seeding materials may be present in distant alien systems.
"Based on comet abundances of other organics, we have a list of other species we would like to try to detect," Öberg said. "We will therefore propose to do a more systematic survey of complex organics in the coming year to determine whether methyl cyanide is 'special' or whether it is one of many abundant complex organics that are detectable in disks."
"We think that other complex organics must be hiding out in the icy grains, but whether they sublimate off the grains as readily as methyl cyanide and therefore can be observed is another question," she concluded.
Regardless, the study has substantiated the longstanding notion that the building blocks of life are not unique to our own corner of the galaxy.