Color-changing planets could reveal alien life
Scientists think light flickers from exoplanets may show the presence of oceans, continents, and perhaps life.
Mon, May 17, 2010 at 02:36 PM
MEANING OF COLOR: This false color photograph of Neptune was made from Voyager 2 images taken through three filters: blue, green, and a filter that passes light at a wavelength that is absorbed by methane gas. (Photo: NASA)
The Earth may seem just like an orb of gorgeous blues, greens, and brown in outer space. Now scientists think that way color and light flickers off the Earth’s surface could be a model for detecting life on other planets. Space.com reports that researchers have devised a color scheme for how Earth would appear to observers tens of light-years away. Hopes are that scientists will be able to use this model to determine if other planets have Earth-like traits such as oceans, land and more.
Yuka Fujii is a doctoral student at the University of Tokyo and lead author of the study depicting this new model. As he told Space.com, “by comparing the changes in observed hues of an alien planet as it rotates to this distinct Earthly color palette, we can infer the surface composition of the [exo]planet." (An exoplanet is a planet outside our solar system.) Fujii and others say their model will be useful in determining “soil, snow, seas or even plant life” on planets that would be too hard to see directly.
Most exoplanets are simply light sources that are difficult to visualize next to the extreme light of a sun. There simply are not enough light particles that travel across trillions of miles to make it to our telescopes. Spectroscopy can detect different gases on the surface — and now scientists think enough light may be reflected off a planet’s ground to do the same. As Fujii told Space.com, "We cannot directly identify green, blue and red spots on the surface … but we can observe the total color average over the visible surface of the planet and compare it to Earth's known values to take a stab at the world's geology or even biology.”
Oceans, deserts, snow and ice are all reflected as disparate wavelengths, or flickers, in space. Using “Earthshine” as an estimate, scientists can now speculate what other planets may look like. But this new model is not without criticism. Some say it is a work in progress. Scientists point out that the model relies on oversimplifications by not bringing clouds into the equation. It also does not separate the planet’s light from the light of a neighboring star.
However, the scientific community does seem to agree that this new model shows promise. This model may be employed on future terrestrial planet-finding satellites used by both NASA and the European Space Agency.
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