‘Yes.’

Elena joined in. She leaned against the wall, arms crossed.

‘Even though we’d never go back. We’d never see Earth again.’

‘Yes.’

She looked at me hard. ‘We might live longer than our time on those worlds would allow for.’

‘I know.’

‘And if we did simply live out our lives, we’d do it in the Merian, off-planet.’

‘I know.’

‘Life support wasn’t intended to last through a second mission. We could die before our work there is done.’

I returned the look. ‘So, you’re saying we’ll either die old and housebound, or relatively young, in some kind of accident or disaster.’ I let that sit. ‘Those are the same options we’d get on Earth.’

She gave the smallest of smirks.

Jack paced more ardently. ‘Okay, but we didn’t make the decision to come out here. Thousands of people all over the world made that call. Do we have the . . . the . . . fuck, I don’t know – the right to decide this?’

‘Those thousands of people wanted this work done,’ Elena said. ‘Yeah, but those thousands of people are mostly dead,’ Jack replied. ‘We can’t say we’re doing this work for Earth if the Earth that’s out there now didn’t give us their thumbs up. We’d be doing it for ourselves.’

‘Would we be doing this for ourselves?’ Elena asked. ‘I’m fine dying out here, in concept, but I am looking forward to going back. I didn’t sign up for a one-way trip. None of us did. I’m not saying yes to this at all, I’m exploring the—’

‘Yes!’ cried Chikondi. ‘Oh, my – oh, my God. Oh, my God.’ He gestured frantically at his tablet, his body about to explode. ‘Everybody, please, come look, come look.’

‘What is it?’ I said, as we drifted over.

Chikondi held his screen up to us, his test results complete. ‘Look, look, look,’ he said.

My eyes scanned over the dense table of numbers and letters. I didn’t see it at first.

Elena saw it. She covered her mouth with her hand in surprise, but her smile was so big it inched out past her fingers.

Jack saw it. ‘Holy shit,’ he said.

The connection clicked. I saw it, too. ‘Oh,’ I gasped. ‘Oh, they’re—’

Chikondi beamed at us, his face reverent. ‘Look what we found.’

For a brief time in my life, I was ambidextrous. I remember a craft project in preschool where we were tasked with cutting shapes out of thick, coloured paper. My right hand quickly tired, my fingers cramped and weary within the confines of the handle (I imagine, in hindsight, that I’d been at it for all of five minutes). But this was no problem. I merely swapped the scissors into my left hand, and continued along. I wish I could still perform this trick, but alas, a teacher made me pick a side when we began to learn to write the alphabet. I chose right, because most kids used their right, and this seemed the least bother. The left has never served me well again. I don’t blame it for holding a grudge.

Molecules have a ‘handedness’ as well. This is called chirality, and if you’ve never encountered this concept before, it’s one of those that can make you sit back and stare into the distance for a while. I’ll walk you through it as simply as I can.

Take a moment to look at your hands (assuming that you have two; if you do not, borrow someone else’s, for science). Stretch them out and splay your fingers. Both hands, naturally, are made up of the same parts: wrist, palm, fingers, knuckles, nails. Matching ingredient lists. The exact same equipment.

If I were to give you a right-handed glove, you would not be able to wear it on your left hand. It wouldn’t matter how you flipped or twisted your appendage around. You might be able to cram your fingers in there, but the fit would be terrible, and you wouldn’t be able to use the glove properly. Even though your left hand has the same physical parts as your right, it will never, ever be the same shape.

The same is true for molecules. If you take two identical mixes of atoms and arrange them so that they are mirror-image configurations of each other, the molecules you’ve created are no longer the same thing, and the differences in how they interact with the world can be as different as night and day. To use the most famous (and disastrous) example of this, consider thalidomide, a compound that was widely prescribed to treat morning sickness in the 1950s. While right-handed thalidomide does indeed ease those symptoms, its left-handed twin causes severe birth defects. Chirality is a detail not to be ignored.

As a rule, life on Earth uses left-handed amino acids and right-handed sugars. This is an age-old puzzle of biochemistry, one that bleeds out into many adjacent fields. One can safely assume that when life began, it utilised whatever organic compounds were directly in front of it. Now, right-handed amino acids and left-handed sugars can easily be created in a lab. Anytime you whip up a batch of these things, you can expect an even spread of handedness. So, why, then, does life on Earth have a bias? Why would it feed on one and not the other, if both should have been naturally available? Why would there be only left-handed amino acids and right-handed sugars in the spot where our single-celled ancestors woke up?

The most likely answer is meteorites. We know that space rocks carry organic compounds aplenty, and if one of these smacks into a planet, it serves as something akin to a seed bomb lobbed into a vacant lot. If such a rock landed on Earth, and if, by either chance or the intricacies of chemistry, it carried mostly left-handed amino acids, you can see how life that developed in that delivery site might get accustomed to such homogeneity and pass that template on to its offspring.

But what if, instead, a handed preference is merely an intrinsic quality of life? What if life just works that way, for reasons we’ve yet to untangle? For a long time, we had only a single test subject to work with – the Earth – and any scientist will tell you it’s impossible to determine anything from a sample size of one.

As we branched out to other worlds, the species we found also exhibited rigid preferences one way or the other. Life on Aecor is Earth’s opposite: right-handed amino acids and left-handed sugars are the norm there. Life on Mirabilis prefers everything left-handed. The findings from Lawki 5 are in concert with this; everything they found leaned one way or the other. This confirmed the suspicion that life does not have to arise under the exact same conditions as life on Earth, but it doesn’t answer the underlying question: are meteorites responsible for chiral preferences in life, or is a chiral preference a requirement of life?

In the pool in the cave carved by Lei’s River, Chikondi sampled one hundred species of single-celled organisms. None of them possess a chiral preference. They freely use amino acids and sugars of both types. They are, in effect, ambidextrous. And when Elena tested the water and Jack tested the rock, their findings confirmed what Chikondi’s indicated: the chirality of amino acids on Votum exists in a balanced ratio.

This means that chiral preference is not a requirement of life.

This means that emergent life forms do use whatever is on hand.

This strongly suggests that life on Earth only arose thanks to ingredients that originated off-planet.

This further suggests that life in the galaxy typically does rely on concentrated deliveries of organic molecules via meteorite in order to get started, but this is not the only way it can happen.