Asteroid Ryugu Is Packed With Life-Building Molecules, Latest Tests Reveal : ScienceAlert

Ongoing efforts to deconstruct the chemistry of the most pristine asteroid sample to ever grace a laboratory have now uncovered a treasure trove of organic molecules that provide evidence for theories that suggest biology ultimately has its roots in space.

It has been more than two years since material from the surface of asteroid Ryugu was transported to Earth in an airtight capsule. Since then, researchers from around the world have collaborated to study its composition to better understand how it fits into the evolution of our solar system.

These latest results confirm links between the carbon-based compounds found on stony ‘chondrite’ meteorites that have fallen to Earth’s surface and the chemistry of the asteroids from which they originate.

By considering the similarities and differences between the Ryugu samples and carbonaceous chondrite meteorites on Earth, scientists can take a fresh look at the meteorites in our collections. In other words, real asteroid samples are useful for confirming hypotheses stemming from their parts arriving on our planet’s surface after a brief bake through the atmosphere.

“Previous analyzes have revealed organic molecules in carbonaceous chondrites, but until now we have not been able to see if these primitive projectiles differ from what has been found on asteroids,” says cosmochemist Larry Nittler, formerly of the Carnegie Institution of Washington and now with Arizona State University.

“Our work on the Ryugu samples provides the first direct link between the organic material found in chondrites and that of asteroids.”

The newly identified molecules, often referred to as the building blocks of life because they play a role in the origin of life, include several types of amino acids that together make up the proteins that organisms rely on to build to exist.

In all, around 20,000 organic molecules were identified in just 5 grams (0.18 ounces) of material. These include organic compounds such as carboxylic acids, amines and aromatic hydrocarbons; Compounds that are closely related to a variety of molecules that are vital throughout the living world.

The results support the assumption that the ingredients necessary for the emergence of life reached our planet in an already complex form through collisions with asteroids. How this organic dust might have combined into some sort of replicating chemistry remains a matter of debate, but knowing that space offers the right conditions for the formation of so many relevant compounds gives scientists a good start for experiments.

Since these asteroids are essentially the leftovers from when the solar system formed some 4.5 billion years ago, they can also teach us much about the earliest moments of our planet’s formation.

By using certain chemical markers—including the amount of water present—scientists can attempt to determine when and where Ryugu formed, giving us a snapshot of conditions at a particular point in the solar system’s evolution.

“At least some of the organic matter in Ryugu samples predates the Sun and was formed under extremely cold conditions,” says geochemist George Cody of the Carnegie Institution for Science in Washington, DC.

These new studies show the utility of probes collecting material from asteroids, like the Hayabusa2 spacecraft, that mined the rocks of Ryugu. Unlike meteorite samples, this dust and rock has not been affected by weathering as it is exposed to soil, water and air.

Additionally, trying to analyze an asteroid in space is also difficult — not least because they’re moving so fast and reflect little light, which limits the readings instruments can get. In the laboratory, much more time and attention can be devoted to extracting data from these materials.

“In the past, our research was limited to examining space rocks that came down to us from a crash on Earth,” says Cody.

“With Hayabusa2, we were finally able to go to a carbon-rich asteroid and see how it compares to the meteorites that reach Earth.”

Both works were published in Science. You can find them here and here.