AuroracastUKLearn
Neptune
The last planet, the windiest place in the solar system, and the only one found by mathematics first.
Seeing it from the UK
Not a naked eye object at all, and it never has been. Neptune needs a telescope, and even then it is a very small blue dot rather than anything you would recognise from a photograph. Finding it is genuinely satisfying because it takes a chart and some patience, but nobody stumbles across it. If you have never seen it, that puts you with almost everybody who has ever lived.
Neptune was found with a pencil before anyone saw it. Uranus was not moving quite as it should, so astronomers worked out where an unseen planet would have to be to explain it, pointed a telescope at that spot in 1846, and there it was. Nothing else in the solar system was discovered that way.
It is the windiest place we know of. Winds there reach around 1,200 miles an hour, faster than the speed of sound on Earth, which is remarkable for a world so far from the Sun that it receives about a thousandth of the light we do. Where that energy comes from is still not properly settled.
The dark oval in the picture is a storm, and unlike Jupiter it did not last. When Hubble looked a few years after Voyager 2 flew past, it had gone, and other dark spots have since come and gone elsewhere on the planet.
The numbers
- Distance from the Sun
- About 2.8 billion miles, thirty times further out than us
- A day there
- 16 hours 6 minutes
- A year there
- 165 Earth years, so it has completed one orbit since it was found
- Wind speed
- Around 1,200 miles an hour, the fastest known
- Moons
- 16 known, the largest being Triton, which orbits backwards
- How it was found
- Predicted by mathematics in 1846, then looked for and found
To find out whether it is up tonight, and when it gets properly dark where you are, see Sky Tonight.