The Hubble Space Telescope released photos of Neptune to celebrate its first 'birthday' since humans confirmed its existence.
So Neptune was discovered last year?
Not quite. Instead, it was discovered in the year of 1846 on earth. Since that year, the earth has rotated around the sun 165 times (i.e. it's been 165 earth years).
However, because Neptune is so far from the sun, it takes 165 earth years for it to rotate around the sun. Since a year is defined as making one rotation around the sun, Neptune has passed one year since mankind first confirmed its existence.
The visual discovery was made by German astronomer Johann Galle on September 23, 1846. Before that, though, astronomers had already predicted the existence of Neptune because of the gravitational pull it exerted on Uranus.
Below are two pictures the Hubble Space Telescope took from June 25 to June 26 to celebrate Neptune's 'birthday.' The two Hubble pictures after that were taken at other times.