The travelers look out onto the
shore of a strange and hostile world. They don’t leave the spacecraft; a probe shows
that the atmosphere is mostly nitrogen, with smaller but lethal amounts of sulfur
dioxide and methane, and a hint of ammonia. Volcanoes belch gases into the sky and
the spacecraft trembles every few minutes from seismic activity. A young star perches
on the horizon, orange and bloated.
It’s a young planet. The newly-minted
crust is still warm and plastic. Oceans have recently condensed from steam and are
still kept warm and turgid by geothermal energy. Samples drilled from the crust
show an age of 200 million years—only 2% of cosmic time and the same fraction of
the time the star will provide warmth to this planet.
Working swiftly, the visitors wrap
up their experiments. It’s not safe here. This soon after its formation, the planetary
system is still strewn with debris. Every hour or so, the spacecraft shudders as
a meteor slams into the ground nearby. There’s a continuous light show overhead
as smaller fragments burn up in the atmosphere. The large moon looming in the sky,
which was splashed off in an earlier impact, is a reminder of the potential for
Finally, results start coming in
from a remote fleet of probes sent out a day earlier. Equipped with biosensors,
they have fanned out across the landscape and the seascape. They found nothing larger
than a sand grain, but the results are all consistent. There are microbes everywhere:
at the edge of volcanic craters, near deep sea fumaroles, floating on lapping lakes,
buried in solid rock, even borne on currents of air. Life grips this young planet
like a fever.