which statement about exoplanets is true

Question

They are discovered when they dim a star they pass by.
They can be detected by ordinary telescopes.
They are objects that are no longer considered planets.
They only appear once before they disappear in space.

Answer 1

The true statement about exoplanets is:

They are discovered when they dim a star they pass by.

This refers to the transit method of detecting exoplanets, where a planet passing in front of a star causes a temporary decrease in the star's brightness.

The other statements are not accurate:

• Exoplanets cannot typically be detected by ordinary telescopes; specialized instruments are often required.
• Exoplanets are still considered planets; the term refers to planets outside our solar system.
• Exoplanets do not only appear once before disappearing; they can be observed multiple times as they orbit their host stars.