Thermodynamics and Particles in the Early Universe Flashcards
1
Q
What is the comoving distance?
A
The comoving distance accounts for cosmic expansion and is given by:
χ(z)=c∫0,z dz′/H(z′)
2
Q
What is the difference between luminosity distance and angular diameter distance?
A
Luminosity distance (DLDL) relates the apparent brightness of objects:
DL = ( 1 + z )^2 DA
Angular diameter distance (DADA) relates the apparent size of objects.
3
Q
What is the Hubble radius, and how is it different from the particle horizon?
A
The Hubble radius RH = c / H marks where objects recede at the speed of light.
The particle horizon is the maximum comoving distance from which light has traveled to us since the Big Bang.
