Sifting Through the Atmospheres of Far-Off Worlds

Gone are the days of being able to count the number of known planets on your fingers. Today, there are more than 800 confirmed exoplanets -- planets that orbit stars beyond our Sun -- and more than 2,700 other candidates. What are these exotic planets made of? Unfortunately, you cannot stack them in a jar like marbles and take a closer look. Instead, researchers are coming up with advanced techniques for probing the planets’ makeup.

One breakthrough to come in recent years is direct imaging of exoplanets. Ground-based telescopes have begun taking infrared pictures of the planets posing near their stars in family portraits. But to astronomers, a picture is worth even more than a thousand words if its light can be broken apart into a rainbow of different wavelengths.