The Solar System is the gravitationally bound planetary system of the Sun and the objects that orbit it, either directly or indirectly of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects

Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry in an effort to explain the origin of those objects and phenomena and their evolution

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter.The word galaxy is derived from the Greek galaxias literally “milky”, a reference to the Milky Way.

The Universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. While the spatial size of the entire Universe is unknown, it is possible to measure the size of the observable universe, which is currently estimated to be 93 billion light years in diameter.

Spaceflight is ballistic flight into or through outer space. Spaceflight can occur with spacecraft with or without humans on board. Yuri Gagarin of the Soviet Union was the first human to conduct a spaceflight