TODAY (12 July 2011) the gas-giant planet Neptune celebrates its first birthday.The (now) most distant planet in our solar system was officially discovered by German astronomers Johann Gottfried Galle and Heinrich Louis d’Arrest at the Berlin observatory on the night of 23 September 1846. The pair followed the calculations made by Englishman John Couch Adams and Frenchman Urbain Le Verrier, who had studied the orbit of the then last planet (Uranus) and calculated that another large object nearby was having an effect on the planet’s orbit. Following the Anglo-French calculations, the German pair saw Neptune in almost exactly the right place after only an hour of work. This was the first (and now officially only time) that a planet in our solar system was discovered on purpose.
Now exactly 164.79 Earth years later, one Neptunian year has elapsed. The planet is in the very same place that it was discovered all those years ago.
1846 was the year the Texas state government was installed, the Corn Laws were repealed, the Saxophone and sewing machine were patented, the 49th Parallel boarder between America and Canada was established and Pope Pius IX began the longest papacy in history.
Neptune, named after the Roman God of the sea, is famous for having the fastest recorded wind speeds of any planet in the solar system with speeds of 1,200-mph (1,930-kmph) being clocked on the planet’s surface. The record for fastest wind speed recorded on Earth is a meagre 301ish-mph.
The eighth planet is on average 4.5 billion Km (2.8 billion miles) from the Sun, just over 30-times further away from the Sun than the Earth is. This means surface temperatures are as low as -218˚C (-360˚F, 55K).
With a mean radius of 24,622Km Neptune is around four times larger than Earth and is 17-times more massive (even more massive than Uranus) than Earth, despite not having a solid surface – the atmosphere of Neptune is 80% hydrogen, 19% helium and trace amounts of methane.
There are 13 known moons of Neptune, the most well known of which is Triton. Triton was discovered only 17 days after Neptune and is the only large moon in the solar system to orbit its planet backwards (the opposite direction to which the planet rotates). The theory that I believe is correct for why this is, states that Triton was a Kuiper belt object (like Pluto) that strayed too close to Neptune and was captured by its gravitational pull. It has fascinated astronomers for years because it has frozen nitrogen on its surface and is one of the few moons in the solar system to be geologically active.Unfortunately due to how far away Neptune is from Earth, we have only visited it once. That was back in 1989 when the legendary Voyager 2 spacecraft flew by it and Triton on 25 August 1989, taking the definitive picture of Neptune (above).
So happy first birthday Neptune, and what better way is there to celebrate a planet’s birthday than by playing their piece from Holst’s The Planets?