Scientists examined soil samples from the asteroid Bennu and were perplexed by the shocking truth about life on Earth that this celestial body conceals.

Scientists have analyzed soil from asteroid Bennu, a precious 120 grams of material, and were left utterly bewildered. Yes, the asteroid is brimming with the seeds of life. But this life is not the same type as we have on Earth—it is almost a mirror image. If these seeds were to develop, they would annihilate everything on our planet—quickly, brutally, and without alternatives. Every day, tons of cosmic material fall to Earth. How do we manage to survive at all? And what will happen to us if we suddenly encounter these mirror-image aliens? They could destroy us with just a touch, or rather, with just a glance!

TOUCHING THE ORIGINS

The asteroid Bennu is a remarkable target if we want to understand who we are, what we are, and where we are going (for mission details, see the Reference). It is a "primitive" asteroid, meaning it contains original protoplanetary material as it formed billions of years ago when there were no planets at all. It was believed that Bennu was formed from dust and remained a solid mass (but this turned out to be incorrect—see, by the way).

And we were very eager to see: what are the ingredients of the "soup" from which Earth was "cooked"? On Earth, and even on the Moon, that original material has been significantly altered by geological processes. Meteoroids, while burning in the atmosphere, and afterwards—while lying around, deteriorate. This is part of the reason we cannot understand how life originated. What if the seeds of life were already scattered in the protoplanetary cloud? Then we wouldn’t even need to guess. Comets fall, meteoroids fall, the seeds of life rain down on Earth from the sky, and here we are! This was our belief, and thus the panspermia hypothesis (the "infection" of Earth with life from space) was born.

Indeed, complex organic molecules were found in the soil of Bennu. The very same molecules from which, given the slightest opportunity, nature will begin to create life. But how wrong we were about everything else.

THE LEFT DOES NOT UNDERSTAND THE RIGHT

Earthly life has one characteristic that we do not grasp outright.

The left glove, if you don’t look closely, appears to be a right one. But it won’t fit on your right hand. The building blocks of all living things are long molecules of peculiar shapes. Just like gloves, these molecules can be either right or left, that is, twisted clockwise or counterclockwise. If you twist the molecule differently, it remains the same molecule. It seems straightforward.

However, life on Earth prefers one specific direction. For example, proteins are left-handed, while DNA is right-handed.

Genetic engineering is already capable of constructing a "mirror" organism, with right-handed proteins and left-handed DNA. It seems that someone has already started this, although it will take about a decade for success. Recently, leading global biologists—about 30 names!—issued a warning in the journal Science: don’t even think about it! Mirror life would immediately destroy ours. There’s no protection. There’s no immunity. If you get infected with a right-handed virus, that’s it, you’re gone in an instant, as the hero of a classic film would say.

So, it turned out that the asteroid Bennu has "bricks" for both "left" and "right" life. In equal measure. This raises at least two questions. Why is Earthly life different? What if meteoroids bring us ready-made right-handed viruses instead of amino acids and other necessary but still non-living substances? Would we perish instantly?

EVERYTHING IS EATEN ON EARTH

Thirty-plus biologists and the Science platform is serious, but is it really true that right-handed life will inevitably and irrevocably destroy left-handed life? If you look at how right-wing politicians beat up left-wing ones, and vice versa, it seems to be the case, jokes Doctor of Biological Sciences, Professor of Biological Evolution at Moscow State University Andrei Zhuravlev. But seriously, meteoroids containing both right and left matter fall to Earth every day, and now we have also learned to transport material from asteroids, he reminds us:

- At the material level, meteoroids known as carbonaceous chondrites are constantly arriving on Earth. They contain organic material in a racemic mixture, meaning roughly equal amounts of right and left isomers. And no one has died yet, not even the bacteria that can break down all this organic matter in just a few days if their meteoroid is not "taken away" and placed in an isolated box with inert gases, he says.

Indeed: once a meteoroid lies on the ground (perhaps the infamous 5-second rule applies here), bacteria immediately begin to consume it. Because of this, mistakes have been made before. They found life inside a meteoroid, hurray, wait, that’s just our bacteria that have already gotten in. And they eat it without getting poisoned.

Scientists analyzed soil from asteroid Bennu

Photo: EAST NEWS.

But what if we do encounter right-handed life not in the form of material but as an organism? And that’s not scary either, says Andrei Zhuravlev. Firstly, it’s not a fact that anything can be constructed from right-handed bricks:

- There are far too many biochemical phenomena, including the genetic code, that are specifically tied to our type of symmetry of isomers, he reminds us.

Secondly, even if something were constructed, so what:

- If we don’t know something (and we don’t know a lot), and such a thing is possible, then when "right" and "left" humanoids meet, we definitely wouldn’t be annihilated. Rather, during such contact, events would unfold just like in our own world, where we have yet to learn to come to agreements, emphasizes Andrei Zhuravlev.

Phew, we can breathe easy. As for "negotiating with humanoids," whether they are right or left, it’s rightly noted. How to establish such contact without it backfiring on us is something astronomers have yet to figure out. And they won’t until they try.

IS IT ALL ABOUT THE OCEANS?

Now let’s turn to a less terrifying but even more interesting question: why is life on Earth the way it is? Left-handed? Biologists don’t really know.

- If we believe the "Star Diaries of Ijon Tichy," written by Stanislaw Lem, once upon a time aliens "…stirred the resulting mess with a coal shovel twisted to the left, and with a poker twisted in the same direction, resulting in the proteins of all future earthly beings becoming left-handed…". Thus, we came to be, jokes Andrei Zhuravlev, following the famous science fiction writer.

Back in the distant 1960s, Soviet physicist and Doctor of Sciences Nikolai Zhevandrov had an intriguing hypothesis. Life originated in the ocean, right? Sunlight, passing through ocean water, changes its optical properties. It becomes circularly polarized, meaning the energy beam is twisted. And it twists, you won’t believe it, to the left. What if this is related? The building blocks of life, dissolved in the ocean, absorbed the left-handed light and became left-handed themselves!

Could the findings from Bennu confirm this unfortunately forgotten Soviet hypothesis? In space, where there are no oceans, everything is equal, and the separation occurred only on Earth.

This version is interesting, says Andrei Zhuravlev, but there are nuances:

- The hypothesis is indeed good. It won’t hold if life originated below the photic (illuminated) zone, where sunlight doesn’t reach, or, conversely, in Darwin’s "little warm pond," where such polarization doesn’t matter (the water thickness isn’t enough to twist the light).

Besides light, there are other possibilities:

- If polymer organic molecules naturally assembled on mineral substrates, then chirality (twist) could also have arisen. This was indeed possible both in the depths of the ocean and in small niches filled with water on land. Or perhaps complex Earthly "right" and "left" substances or even organisms went through the crucible of natural selection, says Andrei Zhuravlev.

The last caveat is important. When we say that everything about us is left-handed, it’s not entirely true; there are exceptions:

- For example, in some bacteria, amino acids in the cell wall are predominantly represented by "reverse" is