1000 Piazzia, discovered in 1923, is a main-belt asteroid

Asteroid belt

The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...

 orbiting the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

. It was the 1000th minor planet

Minor planet

An asteroid group or minor-planet group is a population of minor planets that have a share broadly similar orbits. Members are generally unrelated to each other, unlike in an asteroid family, which often results from the break-up of a single asteroid...

 to be numbered, and was named in honour of Giuseppe Piazzi

Giuseppe Piazzi

Giuseppe Piazzi was an Italian Catholic priest of the Theatine order, mathematician, and astronomer. He was born in Ponte in Valtellina, and died in Naples. He established an observatory at Palermo, now the Osservatorio Astronomico di Palermo – Giuseppe S...

, who discovered the first asteroid

Asteroid

Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

, 1 Ceres.

Its radius is estimated to be 24 km, and measurements of its light curve by Robert D. Stephens in 2001 showed it to be rotating with a period of 9.47 hours.

The planet Piazzia comes closest to is Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. It draws nearer than 1.33 AU eleven times in the 20th and 21st centuries. Rarely, the two are closer than one AU. This last happened in 1638, and won't happen again for another 14,000 years.