In the old stories, Medusa was a Gorgon, one of three sisters with wings, terrifying, tusked visages, and serpentine tresses of hair. She was also the only mortal amongst them, which explains quite simply how Perseus was able to cut her head off and flee with it, pursued by her angry sisters. But most tellingly she had the ability to turn people and animals that she looked at to stone, a near-instant petrification that should have kept her safe from would-be assassins and attackers.
In modern stories, told quietly around formica-topped tables in fluorescent-lit canteens by scientists – mostly women now – in white coats, MEDUSA was the name of a tactical weapon that had been devised one hundred and fifty years earlier that achieved the same trick. Point it at a living target and depress the shutter button, and it would petrify the target instantaneously. But, as with all technologies, it outdid its inspiration more by oversight than intent. The range of MEDUSA was orders of magnitude higher than that of Medusa, and it took twenty years of extremely careful research to work out why. The research notes were now kept in a secure room in a bunker below ground that was guarded by three different security forces and had seven heavily fortified doors to pass through to reach it, and the last room before the notes was filled with statues. Only they weren’t statues, of course, they were people who had been turned to stone in the course of the MEDUSA project. Some of them had even been petrified intentionally.
The answer, it turned out, was a guide wave, a specific length of light in the electromagnetic spectrum that was somehow piggybacked on by the petrification ray. In daylight, candlelight, or most equispectral sources of light there was barely enough of that wavelength to support the ray and the limits of human vision were a good indicator of the range. In fact, there were good reasons for believing that the original Medusa would probably have appeared rather short-sighted and certainly couldn’t have stood on a mountain-top and petrified a city below her. But MEDUSA had no such short-comings and a simple laser provided a strongly-focused source of guide-waves and as much range as you could sustain the laser-light for.
By the time that that was understood a period of intense paranoia had already broken out among the four major civilisations and the MEDUSA device had been weaponised and deployed; in some cases it was hand-held guns, in others it was larger, vehicle-mounted weapons. Phalakos, City of the Beautiful, had a wall-mounted weapon that was capable of focusing on a row of men one-hundred across and forty deep. There was much talk, much posturing, and a lot of near-misses before the tension was finally relieved by assassination, corruption and persuasion. The weapons were gathered back in, dismounted from walls and tanks, and dismantled to be stored in boxes on the shelves of military bunkers. “As a deterrant.” “Just in case.” And people returned to their everyday tasks.
What seemingly no-one remembered, or no-one had properly known in the first place, is that Phalakos had had a back-up device in case the wall-mounted one failed. They had converted the telescope in the Crown Observatory to a MEDUSA device, giving themselves the longest-ranged weapon on the planet, though someone unwieldy and slow to manoeuvre. It was rediscovered when it was turned on, and a MEDUSA ray fired from the telescope into the night sky at a planet one hundred light-years distant.
There was nothing the people could do to stop the ray, which was travelling at the speed of light out into the rarefied gases of space. Calculations were done and redone, and the diffusion and spread of the beam were checked and re-checked. All the results came out the same. When the beam struck the planet it would still be energetic enough to petrify the entire face of it.
Phalakos executed everyone they could find with any association to the MEDUSA project. Their streets ran red with blood and the corpses were piled up waist high in the morgues for two weeks before they could all be processed. They issued a very public apology and pictures of what they’d done, which was immediately viewed as an atrocity by the other civilisations. War broke out within a few days and MEDUSA weapons re-enabled and redeployed. Millions died.
When the dust settled the survivors came out and looked at the dead; most of it turned to stone and cluttering the place up and agreed to unilaterally disarm the MEDUSA weapons. They wondered briefly if there was anyway to save the unnamed, unknown planet one hundred light years distant, but the lives lost in the war included most of their scientists and the population losses had set them back nearly one hundred and fifty years in terms of technology and manufacturing capability. They had little choice but to accept that the planet would probably die.
The MEDUSA ray was calculated to strike four weeks ago. All that’s left to do is wait for light from the event to reach Phalakos, and the people will understand what they have wrought in a way they’ve not had the opportunity for before.