Follow the twisted arms of your family tree all the way back to its primitive origins billions of years ago and you will discover that we all came from dust full of organic chemistry.
Just where this organic dust came from has been a topic of debate for over half a century. Now, researchers have discovered the first evidence of organic matter essential for life on Earth on the surface of an S-type asteroid.
An international team of researchers recently conducted an in – depth analysis of one of the grains recovered from the asteroid Itokawa by the Japan Space Agency ‘s original Hayabusa mission (JAXA) back in 2010.
Most of the Earth’s meteorites come from type S asteroids like Itokawa, so it is known that it may have been an essential ingredient for life on our planet is a major step forward in our understanding of how which life-shaping situations may arise. To date, most studies of organic matter have focused on carbon-rich (class-c) asteroids.
Looking into the sample, the team found that organic matter derived from the asteroid itself has evolved over time through adverse conditions – including water and organic matter from other sources.
This is similar to the process that took place on Earth, and helps us to better understand how the earliest forms of terrestrial biochemistry could be just an extension of the chemistry that is takes place inside many asteroids.
“These findings are very interesting because they reveal complex details about the history of an asteroid and how its evolutionary pathway is so similar to the prebiotic world,” said the astronaut. earth science Queenie Chan from London Royal Holloway University.
Microbial models can take some 3.5 billion years back to a time when life was little more than competing layers of nucleic acid.
Take it a step further and we need to consider how elements such as hydrogen, oxygen, nitrogen, and carbon can come together to form incredibly complex molecules that will be able to self-regulate into a material. behaves like RNA, proteins and fatty acids.
In the 1950s, as researchers first considered the busy question of how a simpler ingredient could cook organic soup independently, experiments showed that positioning on the Earth’s surface could be enough work. to do.
Nearly seven decades later, our focus has shifted to the slow and steady chemical processes within the rocks that were entering a world like ours.
Evidence is not difficult to come by. It is now clear that stable water of rock and ice from billions of molecules of cyanide, the sugar ribose, and even amino acids – along with the generous donation of water – could deliver to the Earth ‘s surface.
But the extent to which the chemistry of meteorites has been contaminated with objects on Earth leaves little room for doubt.
Since Hayabusa returned ten years ago, more than 900 grains of asteroid dirt removed from the payload have been segregated and stored in JAXA’s clean room.
Less than 10 were tested for traces of organic chemistry, but it was found that molecules were mostly made up of carbon.
Itokawa is the so-called stony (or siliceous) class of asteroid, or class-s. After early studies of its material, it is also believed to be a conventional chondrite – a type of virtually unchanged space rock that represents a more primitive state of the inner Solar System.
Since these types of asteroids make up a good chunk of the minerals that break into our planet, and are generally not thought to contain much in organic chemistry, the results were early that’s interesting, anyway.
Chan and her colleagues took just one of these grains of dust, a 30 micrometer-wide shape a bit like the South American continent, and did a detailed analysis of its make-up, including a study of the amount of water.
They found a rich combination of carbonaceous compounds, including signs of irregular polyaromatic molecules of clear external origin, and structures of graphite.
“Having been closely studied by an international team of researchers, our analysis of a single grain, nicknamed ‘Amazon’, contains both primary organic matter (unheated). and to maintain processing (heating) within ten microns (one thousandth of a centimeter) of a distance, ”says Chan.
“The heated organic matter shows that the asteroid has been heated to over 600 ° C in the past. The presence of unheated organic material is very close, meaning that growth has reached- organic matter on the surface of Itokawa after the asteroid has cooled down. “
Itokawa has had an interesting history for rock that has nothing better to do than sail cunningly around the Sun for a few billion years, after being replaced by good, dehydrated baking, then re irrigation with a fresh coat of fresh material.
While its story is not as inspiring as the history of our own planet, asteroid activity describes the cooking of organic matter in space as a complex process, and is not limited to carbon-rich asteroids.
Late last year, Hayabusa2 returned with a sample of a c-class, near-Earth asteroid called Ryugu. By comparing the content of its payers with its predecessors, it will no doubt add even more knowledge to how organic chemistry grows in space.
The question of the origin of life and how unique it seems on Earth is one to which we will seek answers for a long time to come. But each new discovery marks a story that stretches far beyond the safe, warm puddings of our newborn planet.
This research was published in Scientific Reports.