Uranus

V is for vacuum.

waning crescent moon

X is for X-ray binary stars

Y is for yellow dwarf

Z is for Zenith

A is for asteroid.

B is for Belinda (one of Uranus' moons)

celestial

D is for Delphinus (constellation)

E is for exoplanet.

F is for Fornax (constellation)

G is for gravity.

Hypernova

I is for interstellar.

Jupiter

K is for Kuiper Belt.

L is for Luna

M is for Mercury.

Neptune

O is for orbit.

P is for Pluto

Q is for Quasar.

Radiation

S is for satellite.