Why do scientists believe the universe is still expanding? a
The further away an object is, the higher the temperature and pressure eventually become, causing nuclear fusion
b
Distant objects shift in frequency toward red on the electromagnetic spectrum, which tells us objects are moving away from us
c
Spiral galaxies spin, so they appear to be a rotating disk of stars and dust
d
Distant objects shift in frequency toward blue on the electromagnetic spectrum, which tells us objects are closer to us us