Question

Exoplanets are usually very hard to see directly because:

(a) They emit mainly at ultraviolet wavelengths.
(b) They do not reflect the light from their parent stars.
(c) They are circling their parent stars with very long orbital periods.
(d) They are much fainter than their parent stars.
(e) They are located inside the frost line.

Answer 1

Exoplanets are hard to detect directly because they are much fainter than their parent stars and are overshadowed by the stars' brilliant glare.

Step-by-step explanation:

Exoplanets are usually very hard to see directly because they are much fainter than their parent stars. Furthermore, they also tend to be lost in the brilliant glare of these stars. When we explain the detection of exoplanets, we often refer to the indirect methods used, such as observing the gravitational pull on the star or the transit method where the planet blocks some of the star's light as it passes in front of it. The challenge of detecting reflected light from exoplanets is compounded by the fact that a planet like the Earth reflects less than one billionth of its parent star's light, making its brightness in visible light extremely weak compared to the luminosity of the star.