What Use Are 21 Cm Radio Waves to Galactic Astronomers

question 85

Multiple Choice

What use are 21 cm radio waves to galactic astronomers?

• A)They cut through the dusty cocoons to let us watch star birth.
• B)We can reflect them off the core of the Galaxy.
• C)Their Doppler shifts let us map the motions and locations of gas in the spiral arms.
• D)They bounce off stars like our Sun to let us precisely measure their distances.
• E)They pick up the cool, dark matter much better than can optical telescopes.

---

Definitions:

The Military

Refers to the armed forces of a country, responsible for defending it from threats and conducting warfare.

Heterosexism

is an ideological system that denies, denigrates, and stigmatizes any non-heterosexual form of behavior, identity, relationship, or community.

Gay Officers

Refers to law enforcement or military personnel who identify as homosexual, highlighting considerations of sexuality within professional and sometimes discriminatory environments.

Lesbian Officers

Female law enforcement officers who identify as lesbian.