Space questions, answered

How cold is space?

Empty space far from any star sits at about 2.7 kelvin — roughly −270°C (−455°F), just a few degrees above absolute zero.

That 2.7 K figure is the temperature of the cosmic microwave background, the faint afterglow of the Big Bang that fills all of space. It's the coldest the empty universe gets on its own.

Near a star it's a different story: an object in direct sunlight can heat up enormously while its shaded side stays frigid, which is why spacecraft and spacesuits work so hard to manage both extremes at once.

Sources: NASA — the cosmic microwave background