PHYSICS AND ASTROPHYSICS

a physicist

weight

masse

density

the theory of relativity

gravitation

pressure

light

a ray

optics

a lens

infrared rays

acoustics

astronomy

an astronomer

the universe

the Earth

the moon

the Sun

a shooting star

the Pole Star

the Evening Star

the Great Bear

the Milky Way

a light year

a rocket

a space station

an alien

a UFO (Unidentified Flying Object)