How do we know that some interstellar matter is dust?
A) We can observe the tiny particles with the Hubble Space Telescope.
B) Dust emits X-rays.
C) Dust obscures and reddens starlight.
D) Interstellar matter is composed only of hydrogen gas.

Question

Quizplus · Accepted Answer

Dust obscures and reddens starlight by scattering and absorbing shorter wavelengths, which is a characteristic effect of dust in space.

How Do We Know That Some Interstellar Matter Is Dust