How do we expect that the first Earth-sized extrasolar planets will be discovered (if they exist)?
A)by the transit technique from an observatory in space
B)with photographs from a new generation of large,ground-based observatories
C)by NASA's Terrestrial Planet Finder mission
D)by the Doppler technique

Question

Quizplus · Accepted Answer

The transit technique involves observing a planet as it passes in front of its host star, causing a small decrease in the star's brightness. This method is sensitive to the planet's size and can detect planets as small as Earth. The use of an observatory in space, such as NASA's Kepler mission, allows for a long-term and uninterrupted observation of a specific region of the sky, increasing the chances of detecting an Earth-sized planet. Other methods, such as the Doppler technique, are better suited to detecting larger planets. Ground-based observatories may also face limitations, such as atmospheric distortion and limited visibility. NASA's Terrestrial Planet Finder mission was planned to use a combination of techniques, including the transit and direct imaging methods, to detect Earth-sized planets, but it was cancelled in 2011.

How Do We Expect That the First Earth-Sized Extrasolar Planets