A question about Hubble's Law

[Maartenn100]

 

Hubble's Law = the velocities of recession of galaxies are proportional to their distances from us.

Do we see galaxies following Hubble's law (distant galaxies moving faster and faster away from us) ot do we observe the (light of the) past, where galaxies further away are closer together? (because the further we look, the further we look in the past). 

Are far away galaxies closer together (the further we look in the past, the smaller the expansion of the universe back then) or are far away galaxies been observed further away (following Hubble's law)?

Thank you for answering these questions. 

 

 

Edited May 2, 2018 by Maartenn100

[Mordred]

As you quoted the greater the distance the greater the recessive velocities. So the more distance ftom us the greater the velocity of said object key word "appear to be". Recessive velocity isnt a true velocity but a consequence of seperation distance. It is an apparent velocity.

 The density of galaxes are visually greater in the past so the further you look the greater the density (and temperature increases.

 A little trick here Hubbles constant varies in time, it is only roughly 70 km/Mpc/sec throughout the universe at time now. In the past however this value is greater . However this does not change Hubbles law

[latex]V_{Recessive}=H_O d [/latex] the distance to redshift relations directly associated with Hubbles law is only accurate to the Hubble Horizon. Past Hubbles horizon further redshift corrections must be made.

 

Edited May 2, 2018 by Mordred

[Maartenn100]

Ok thank you.

[Mordred]

Your welcome going to offset some of those neg rep points as you asked some good questions.

[Maartenn100]

I have another question, if I may.

On 2-5-2018 at 5:55 AM, Mordred said:

As you quoted the greater the distance the greater the recessive velocities. So the more distance ftom us the greater the velocity of said object key word "appear to be". Recessive velocity isnt a true velocity but a consequence of seperation distance. It is an apparent velocity.

 

Can the Cosmic Microwave Backgroundradiation also not be interpreted as the dopplershift of the emitted light of the farthest galaxies, doplershifted to the most red part of the electromagnetic spectrum, so we can only observe microwaves and radiowaves on the edge of the observable universe?

 

[Mordred]

No as it also involves percentages of elements such as lithium and hydrogen etc. Then too is the surface of last scattering obscurity and the dark ages which we will not see past using light detection. The CMB conditions depends greatly upon several key thermodynamic processes.

One being symmetry breaking due to inflation with its supercooling then reheating which involves the ideal gas laws and thermal equilibrium dynamics of the SM particles. The other being the subsequent expansion after the inflationary period which also allowed sufficient cooling to allow atoms to form with stability.

 All the above sets the stage for BB nucleosynthesis which is extremely involved with particle physics and thermodynamic laws.

 Discovering the CMB was a major criteria to confirm the BB model as well as confirming expansion itself. 

[Strange]

8 hours ago, Maartenn100 said:

I have another question, if I may.

Can the Cosmic Microwave Backgroundradiation also not be interpreted as the dopplershift of the emitted light of the farthest galaxies, doplershifted to the most red part of the electromagnetic spectrum, so we can only observe microwaves and radiowaves on the edge of the observable universe?

 

The spectrum (levels of different frequencies) does not match the radiation from galaxies (even if red shifted).

It does match the spectrum expected from a uniformly heated plasma - ie. a black body spectrum. Exactly as predicted by the B.B. model. 

[Maartenn100]

ok, thank you!