Colors of distant exoplanets: blue doesn’t always mean life


Our Earth is also known as the blue ball. It was named by the famous astronomer Carl Sagan, in honor of the publication of the photograph of the same name, which was captured in 1990 by Voyager 1. This photograph captures the Earth from afar 6 billion km, writes the Universe Today portal.

Pale blue point – Earth from a distance of 6 million km. Source: NASA / JPL – Caltech

Our planet is already inextricably linked to the color blue. At the same time, the Earth is the only planet we know of capable of supporting life. It is therefore quite logical to think so habitable planets, like ours, may also be blue.

But it has a problem. Color is defined by astronomers as the intensity of light at a certain wavelength. The length of the wavelength that transmits the light determines its color. For example, if we had electromagnetic radiation with a wavelength of 450 nanometers, it would appear blue to our eyes. But what the human eye considers color is only a small part all wavelengths of the electromagnetic spectrum.

Different parts of the spectrum

Telescopes can perceive different parts of the spectrum that our eyes cannot perceive, such as the ultraviolet or infrared spectrum. These parts could also be used considered a certain color. If people were able to perceive the full range of the electromagnetic spectrum, the night sky would be much brighter for us.

Electromagnetic spectrum
Zdroj: Imagine the Universe from NASA

But how would we perceive distant exoplanets? Currently scientists they do not have telescopes powerful enough to distinguish the light of the planet, similar in size to the Earth and its stars. These two different light sources blend together. Scientists know there are exoplanets out there. They can even determine their size and whether they have a solid surface, but they don’t know any more. Even with the advent of more powerful telescopes, scientists wouldn’t be able to determine what they’re looking at. They would have no point of reference for comparison.

Astronomers admit that they have no idea what our Earth would look like if we looked at it from hundreds of light years away and it would orbit another star. Our planet would be similar completely differentif the light of a red or blue star falls on it.

You might be interested

Source link