The 19th Century

Urbain Le Verrier used mathematical calculations to predict the existence of Neptune, which was later confirmed by observations made by Johann Gottfried Galle.

The Yerkes Observatory is located in Williams Bay, Wisconsin, and was built in 1897. It has a 40-inch refracting telescope, which is the largest of its kind in the world.

Pierre-Simon Laplace developed the nebular hypothesis in the 18th century, but it was not widely accepted until the 19th century.

Halley's Comet is a periodic comet that orbits the Sun every 76 years. It was first observed in 240 BC and has been seen many times since then.

William Herschel discovered Uranus in 1781 while searching for binary stars.

The Mount Wilson Observatory is located in California and was built in 1908. It has a 100-inch reflecting telescope, which was the largest in the world at the time.

Albert Einstein developed the theory of relativity in the early 20th century.

Neptune was discovered in 1846 by Urbain Le Verrier and Johann Gottfried Galle.

Clyde Tombaugh discovered Pluto in 1930 while working at the Lowell Observatory.

The Lick Observatory is located in California and was built in 1888. It has a 36-inch refracting telescope, which was the largest in the world at the time.

James Clerk Maxwell developed the electromagnetic theory of light in the 19th century.

Mars was discovered in 1801 by Giuseppe Piazzi.

Giuseppe Piazzi discovered Ceres in 1801.

The Palomar Observatory is located in California and was built in 1948. It has a 200-inch reflecting telescope, which was the largest in the world at the time.

Albert Einstein developed the theory of black holes in the early 20th century.