More than three decades have passed since the iconic Pale Blue Dot photo was released. Our planet and life have been associated with the presence of the color blue for a long while, which may infer that other habitable worlds should be blue.
However, it is not that simple. While most people tend to think about the actual color, astronomers are interested in the way in which light can be perceived at a specific wavelength. For example, EM radiation is able to traverse space quite easily, and it may appear blue if it reaches wavelengths of 450 nanometers.
More than color
The color of an object can offer interesting details about it. In the case of a star, blue will let astronomers know that the star is hot, while red suggests that it is cooler. Earth features a mix of nuances that reflect the gases found in the atmosphere.
Every gas is associated with a specific wavelength signature generated by their interaction with sunlight. The same rule is available for surfaces, as some surfaces will reflect a specific wavelength and propel it back into space.
New tools will be available in the near future as several space telescopes should become operational in the following year, including the James Webb Space Telescope, LUVOIR, or HabEx. Some researchers have already created guides that could be used to identify exoplanets similar to Earth more easily.
Researchers employed simulations of our planet by using a large number of environments that can be encountered in nature, including sand, snow, clouds, trees, and certain types of rocks. Select planets also featured global surface types, while others had several surface types, as is the case for Earth. The simulated planets were positioned within the habitable zone of a star.
The work has been well-received by the scientific community, and it has been published in scientific journals.