Have you ever wondered that when astronomers from Earth train their telescopes on exoskeletons beyond our solar system, how do they decide whether the speck of discernible light that they can see harbours life or not?
Now, according to a study, soon to be published in The Astrophysical Journal Letters, a team of scientists have turned the problem around to find out what might the Earth look like if someone from another galaxy viewed it. They took images of Earth — a habitable planet — and transformed it into something alien astronomers might see from light years away.
Accordingly, a story published in Science details that the team started with about 10,000 images of Earth taken by NASA's Deep Space Climate Observatory (DSCOVR) satellite at 10 specific wavelengths every 1 to 2 hours during 2016 and 2017. Notably, the DSCOVT sits at a gravitational balance point between Earth and the sun, allowing it to only see the daytime side of Earth.
Furthermore, in an attempt towards stimulating an alien point of view, the researchers reduced the images into a single brightness reading for each wavelength. These included 10 dots, that when plotted over time, created 10 light curves that represent what a distant observer might see if they steadily watched Earth for 2 years.
On analysis, the researchers figured out which parameters of the curves corresponded to land and cloud covers in the images. Once they were aware of the relationships, they picked out the parameter resembling closest to land area and created a contour map.
Notably, in the map, the black lines marked the median values of land parameter — or approximate coastlines — and rough outlines of Africa, Asia and the Americas were also visible.
While it is not an actual representation of how aliens may view the planet, it may allow future astronomers in figuring out whether an exoplanet has characteristics required to make it habitable, including oceans, clouds and icecaps.