Oct 312013
ALMA Views the Coldest Place in the Universe: The Boomerang Nebula
This nebula, a mere 5,000 light years away, appears to have a temperature of 1 degree Kelvin. I admit to being confuzzled by this, given that the cosmic background radiation is at 2.8 degrees Kelvin. How can something be colder than that without an active cooling system, with energy being used to run a “heat pump?”