Skywatch

  • July 2, 2009

    Episode 226: Starshades

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    Astronomers are inventing new ways to find planets around other stars. Most of the methods used thus far don't involve actually seeing the planet; its presence is inferred from observations of the parent star. A large, Jupiter sized planet can be detected b y the "wobble" its gravity causes in the parent star's motion. Other planets pass in front of their host stars, making them detectable by the dimming of the stars' light. A new idea is to block out the light from a bright star so that faint planets can be detected. This technique would be used to obtain direct images of the planets that normally cannot be seen right next to the bright star. The device that blocks the starlight is called a starshade and would be placed in orbit far from the main telescope. The starshade is a clever concept, but would be tricky to engineer.