What is the hottest and coldest object in the universe?

Answer 1

We have barely managed to explore our own solar system much less the entire universe. Up until recently, the coldest planet in our solar system would have been Pluto with an estimated surface temperature between -235 and -210 degrees Celsius, but Pluto has now been relegated the status of a Dwarf Planet. So now, Neptune would be the coldest planet.

Answer 2

Experimental physics labs cool tiny bits of matter Bose-Einstein condensates) to fractions of a degree above absolute zero (-273 C). Liquid nitrogen widely used in experiments is -196 C.

Vostok station in Antarctica (near the South Pole) is the coldest place on earth (-80 C). And some scientists believe that Dome A might be even colder than Vostok station.

Answer 3

In the laboratory, temperatures of a few nanokelvin have been achieved. It is unlikely that any natural object is that cold, because of the cosmic background radiation, which is equivalent to a temperature of 3 kelvin.

Answer 4

Black holes would be the ultimate blackbody source, radiating no light or heat at all. They tend to be hot, however, because in-falling matter shredded by gravitational tides emits considerable X-ray radiation.

Answer 5

In our solar system Uranus, furthest planet from our sun, is the coldest. There are likely interstellar planets ejected from binary star systems that would be much colder yet--we simply have not found them.

We only know of planets around are star and nearby stars--we don't know of all of them in our galaxy, let alone ANY planets orbiting stars of any of the myriads of galaxies far beyond our own.