the furthest planet from the sun is Neptune, no Pluto, no Neptune, no Pluto, no Neptune!

On 23 September 1846, Neptune was discovered, and became the furthest known planet from the sun.

bad luck, Pluto

On 18 February 1930, 87 years ago today, Pluto was discovered, and became the furthest known planet from the sun.

On 7 February 1979, Pluto crossed inside Neptune’s orbit, and Neptune became the furthest known planet from the sun, for the second time.

(Extrasolar planets started being discovered in 1992, but we won’t count them here.)

On 11 February 1999, Pluto crossed back outside Neptune’s orbit, and became the furthest known planet from the sun, for the second time.

third time lucky!

On 24 August 2006, Pluto was downgraded to a “dwarf planet”, and Neptune became the furthest known planet from the sun, for the third time.