An American scientist has developed software that experts say could form the basis for developing a system that will allow astronomers to map distant planets. A system that will allow them to determine the proportion of sea and land, as well as analyze the formation and movement of clouds to gain insight into the climate conditions prevailing on a planet.
The reflection
The software was developed by Nicholas Cowan, a planetary scientist at Northwestern University in Illinois. Cowan developed the software based on a technique developed to separate "natural surfaces" (e.g., a forest) from non-natural ones (e.g., military installations) in satellite imagery.
Some of the light that a star "throws" at a planet is reflected, causing its color to change. The hue of the starlight after reflection depends on the characteristics of each planet, in the case of a rocky planet on the proportion of sea and land. The hue is also affected by the presence of clouds.
The new (and next) software
Cowan has already tested the software using Earth as a "target". He used images of our planet taken from Space and more specifically from the EPOXI mission. As he reports, the software was able to confirm the existence of land, oceans and clouds. However, it cannot decipher the water-to-land ratio or the formation and movement of clouds.
The technique is similar to walking into a dark room with a television on but the volume turned down, standing with your back to the television, looking at the reflection of the image on the opposite wall, and trying to figure out what kind of program is being shown. “You’re not seeing the image, you’re seeing the reflection of the image, and you’re trying to figure out what’s in the image,” says Eric Ford, an astronomer at the University of Florida who was not involved in developing the software.
According to experts, this software can be the basis for the development of a system that will be able to calculate the percentage of the contribution of each physical feature (land, sea, clouds) to the hue of reflected starlight. In this way, it is possible to determine what percentage of a planet is covered by land and what by sea, as well as data on its clouds. Such a system will greatly help space exploration until telescopes are built powerful enough to record direct and "clear" images of exoplanets.
