In space, the temperature is around -270 degrees Celsius – just about three
degrees above absolute zero. But as you reach the tops of Jupiter’s atmosphere,
things start to heat up.
Don’t take off your coat just yet, though – it’s still -130
degrees Celsius (-200 F). The wisps of clouds around you produce a pressure of
only about a fifth of one bar (the pressure at Earth’s sea level).
The clouds consist of ammonia and ammonium hydrosulfide, and
are very bright. Jupiter reflects more than half the sunlight that hits it,
making it the solar system’s second most reflective planet after Venus.
As you continue to plummet, the clouds thicken and warm up.
After 30 kilometers, the pressure around you is about one bar and the
temperature is now a balmy -100 degrees Celsius (-150 F). After another 40