IFLSCIENCE - There may come a point (perhaps for humans, perhaps not) where a civilization may wish to terraform a planet in their Solar System or beyond. Perhaps an environmental disaster was looming on their planet, or they spotted a nearby neighbor planet that looked like – with a few finishing touches – it could make a nice new home.
A new study has looked at what options such a civilization wishing to warm a planet would use, and determined that these methods would likely be detectable from Earth.
The hunt for alien life, at the moment, is fairly elegant in its simplicity. As well as looking out for potential signals deliberately or unintentionally sent out into space by alien civilizations, we scan the stars for tiny dips in light that suggest an exoplanet has blocked our view of its light. Once we have located an exoplanet, we can look at factors such as where the planet is in its solar system to figure out if it is in a habitable zone.
Gases in planets' atmospheres block specific wavelengths of light, meaning that if we measure the spectra, we can get an idea of the chemical composition of the planet. As we've only ever found evidence of life on one planet (you're currently sitting on it) it makes sense to look for planets with a chemical makeup amenable to life on our own planet. But we also look for signs of technological civilizations, including hypothetical megastructures that should emit hefty amounts of infrared radiation.
In the new paper, a team from the University Of California, Riverside suggests another sign we could look for is chemical signatures that suggest a civilization is attempting to warm their planet.