We are helping a pair of high school students with a spinoff of our PHL projects about exoplanets light curves. The students are constructing sphere models (out of ping-pong balls) of various Earth-like planets and measuring the light reflected from the spheres as a function of the planet rotation (figure 1). This is analogous to what astronomers plan to do in the next decades to determine the presence of ocean and land areas in Earth-like planets. As far as we know, this is the first time anybody tries to study the light curves from Earth-like exoplanets using scale models. Previous efforts included the use of computer simulations and directly observing Earth from its moonshine or from space missions (i.e. NASA Epoxi Mission).
The scale models has the combined advantage in that they test true physical optics including CCD camera effects plus are easily customizable for different conditions. The students are painting the spheres trying to match the colors and reflective properties of land and oceans. They later add a removable white paint to simulate various cloud and ice covers. Living in a tropical area, it was their idea to check how the light curve of an exoplanet will be affected with large localized cloud covers, as those produced by cyclones (i.e.hurricanes). The title of their project "Exoplanets on Sight" was also their idea, certainly a great name. They will try first to emulate the terrestrial visible light curve and later move forward to different Earth-like planets (figure 2). Their science project will be presented as part of the Google Global Science Fair 2011.
This is nice project for students where they learn about astronomy, exoplanets, and astrobiology, and probably contribute to scientific knowledge. We will post more information about the students and their project results on April.
Figure 1. This image is not a low resolution photo of Earth, an Earth-like exoplanet, or computer graphics (CGI). This is a scale model of Earth constructed from a ping-pong ball and painted with the colors and reflectivity of Earth as part of a high school project to study exoplanets. See the animation here for two full rotations.
Figure 2. Light curves for two full rotations produced by PHL software based on the images created of the first scale model of Earth created by high school students project "Exoplanets on Sight." Although the reproduction of the color of the oceans, including the glint (a bit saturated), was quite right, the continents were too dark, thus giving a different light curve than current Earth. The students are creating a corrected version and this is now a model for a Dark-Earth exoplanet.