Nicolaus Copernicus is one of the most known figures in the discoveries related to astronomy. He was the first to come up with a heliocentric model of the solar system, during Renaissance. His findings were later corrected and continued by Galileo Galilei and Johannes Kepler.
Kepler described correctly the motions of the planets and their position related to the Sun, but he was unable to formulate a theory. Newton was the one that gave a theoretical explanation with his gravity and celestial dynamics laws. He also invented the reflecting telescope.
John Flamsteed, an astronomer of English origin, further developed the quality and size of the telescope and made a stars catalog with 3,000 entries. William Herschel specialised in nebulosity and clusters, and eventually discovered the planet Uranus, the first planet discovered. Laplace and Lagrange invented a method to estimate the masses of planets and moons from their perturbations.
The new inventions if the photography and spectroscope allowed Fraunhofer and Kirchhoff to describe different attributes of the planets, such as temperature, mass or size.
Milky Way, the galaxy the Earth is in, together with other galaxies, was part of the discoveries made in the 20th century. The models of the Big Bang and the expansion of the universe were made by physical cosmologists. The Big Bang model states that the universe expanded from an abundance of density and temperature, approximately 13,8 billion of years ago, form a moment of singularity.
The particles cooled into atoms, that later laid the foundation of stars and galaxies under the law of gravity. The discovery of different space objects such as quasars, pulsars, blazars, radio galaxies, neutron stars and black holes are also products of the modern astronomy. The space telescope allowed scientists to measure other kind of data, such as the electromagnetic waves, that are normally blurred by the atmosphere around our planet.