3K universal blackbody temperature radiation

[neelakash]

Homework Statement

What does the 3K universal blackbody temperature radiation tell us about the temperature of the outer space?

Homework Equations

The Attempt at a Solution

the 3K universal blackbody radiation is regarded as the remnant of the Big Bang.And this temperature looms all over the space.
I know this much(not sure if correct).

Please check this.

 

[mgb_phys]

It also tells you the lowest possible temperature for empty space.
Heat always flows from hot to cold - if you had any point in space less than 3K and it is surrounded on all sides by a background of 3K what would happen?

 

[neelakash]

so,there cannot be such a place with lower T.That would reduce the Temperature 3K

 

[mgb_phys]

Correct, nothing in space can come to equibrium at a temperature below 3K
Atlthough you can obviously have man(or alien!)-made devices at below 3K but only be using energy.