What is cosmology? Definition & history

Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. According to NASA, the definition of cosmology is “the scientific study of the large scale properties of the universe as a whole.” Cosmologists puzzle over exotic concepts like string … Read more

Terrestrial Planets: Definition & facts

Terrestrial planets are Earth-like planets made up of rocks or metals with a hard surface. Terrestrial planets also have a molten heavy-metal core, few moons and topological features such as valleys, volcanoes and craters.  In our solar system, there are four terrestrial planets, which also happen to be the four closest to the sun: Mercury, Venus, … Read more

Scientists Say We Should Rethink Moons as Planets… And Reinstate Pluto

The International Astronomical Union (IAU) has a very strict definition of the word “planet”. According to the definition – drafted, tweaked, and agreed upon in August 2006 – an astronomical body is officially a planet if it orbits the Sun, has sufficient mass to be spherical, and has cleared the neighborhood around its orbit.   … Read more