Communications of the ACM

porated the now-networked humans into a new node of the swarm.

Once the alien swarm had assimilated them into its hive mind, it quickly assessed and identified the most advanced human technology it could exploit—blockchain. 1 The alien hive quivered with delight at the prospect of adding ironclad reliability to each transaction among network members in its Wi-Fi network by implementing distributed virtual ledgers. With blockchain, radio interference would never corrupt the network’s transactions, ensuring perfect command and control of its members and their collective will. The swarm thus converted all of its transactions to blockchain and sent a radio transmission back to Prox Cen b mission control propagating the blockchain technology to neighboring nodes in the Earthly galactic arm.

Power consumption skyrocketed as the networked humans on Earth and aliens aboard the mother ship burdened each transaction with cryptographic virtual ledger updates. Unsustainable heat built up in the circuits, the mother ship’s processors were overwhelmed and exploded, and the neural connectors to the humans shorted out, leaving only an eerie electric blue glow that briefly filled the Solar System, before winking out.

Shekhov, Caruthers, and the other humans still on the Moon heard panicked messages from the last free humans on Earth via the comsat. They feared for all humankind, but the exponential blockchain wave of networked destruction made short work of the aliens and their threat. The crew of the Hawking’s Nightmare facility then received another message from mission control in Moscow via the comsat: Shut the laser. It had fulfilled its purpose—establishing we are not alone but would probably prefer to be.

Reference

1. Church, Z. Blockchain, explained. MIT Sloan School of Management, May 25, 2017; http://mitsloan.mit.edu/ ideas-made-to-matter/blockchain-explained

David Allen Batchelor ( batchelor@alum.mit.edu) is a scientist and computer engineer for data systems at NASA Goddard Space Flight Center, Greenbelt, MD. His first science fiction novel, The Metalmark Contract, was published in 2011 by Black Rose Writing, Castroville, TX.

swarm in the Earth’s arm of the Milky Way Galaxy, compliant with the hive imperative to exploit Solar System resources.

The mother ship now disgorged several thermonuclear devices, detonating them in low orbits above major cities where the electromagnetic pulses would render human power and computer grids nonfunctional. The descriptions of human culture and technology the swarm received in the laser transmission back on Prox Cen b, and now on their mother ship, made the task straightforward. A few retaliatory ICBMs were launched by Russia, the U.K., and the U.S. but were quickly disabled by the mother ship’s high-energy particle cannons, doing no damage other than alert the Earth’s human population to the aliens’ overwhelming force.

It seemed Hawking would be proved right.

Pods filled with billions of
minidrones entered the atmosphere
and aerobraked until they reached the
troposphere, then dispersed on wings
like a swarm of attacking hornets. They
flew through the night air, identifying
humans and their structures through
their infrared profiles and attached
themselves with neural-connection
electrodes to their brainstems, reduc-
ing them to compliant zombies. An
alien global Wi-Fi network of neural
commands and control quickly incor-
I had to
compete with only a few other can-
didates to get this six-month detail.
Do you think there are beings on Prox
Cen b who can receive the message,
as modulated in the infrared beam,
and actually respond?”
Shekhov grinned, “Now you are test-
ing my faith in the mission and the
skills of its managers in mission con-
trol on Earth. I would not be here long
if I doubted the mission’s scientific
value and ultimate success.”
Caruthers said, “Stephen Hawking,
the English professor, warned that if we
contacted space aliens, we would inevi-
tably risk some kind of attack. We’d be at
such a disadvantage technologically and
intellectually. We’d be overwhelmed in
no time and decimated like the indige-
nous natives of the Americas at the time
of the conquistadors. Our command
of all the resources on our ancient but
familiar Earth and Moon wouldn’t be
enough to protect us.”
“Hawking was projecting his guilt
for the sins of the European empires
in the colonies, along with his own
infirmities and impending mortal-
ity. Just a timid old professor, he was.
I think aliens really might respond to
the message in the laser beam. They
might greet us as fellow intelligent be-
ings in the endless Universe, but there
is no chance they could harm us. For
one thing, they are probably simply too
far away, not only in distance but in the
technological advancement we can ex-
pect from future human generations as
they come and go many times over.”
Caruthers said, “Do you think they
could decode the message in the laser
modulation?”
“It’s complex,” Shekhov admitted.
“If aliens really do exist, we probably
will have to wait for them to decipher
it and compose an intelligent reply we
would be able to interpret.”
. . .

Even as Shekhov gave Caruthers a tour of the habitat, the alien mother ship from the Prox Cen b node used its titanic antimatter engines to decelerate into an orbit 200 km above Earth’s equator and scanned the now-terrified population centers below. The primitives, in their view, were still using vulnerable electromagnetic technology so would be easily subdued into harmless members of the processor