The Universe and Its Characteristics

The Big Bang Theory is the prevailing cosmological model for the universe from the earliest known periods through its present expansion and cooling.

The estimated age of the universe is approximately 13.8 billion years, based on observations of the cosmic microwave background radiation and other cosmological data.

The shape of the universe is believed to be flat, meaning that parallel lines remain parallel and the angles of a triangle add up to 180 degrees.

The Laniakea Supercluster is the largest known structure in the universe, spanning approximately 520 million light-years in diameter and containing over 100,000 galaxies.

The Andromeda Galaxy, also known as Messier 31, is the closest major galaxy to our Milky Way, located approximately 2.5 million light-years away.

Sagittarius A* is the supermassive black hole at the center of our Milky Way galaxy, with a mass estimated to be between 4.1 and 4.5 million times that of the Sun.

Ton 618 is the largest known black hole in the universe, with a mass estimated to be 66 billion times that of the Sun.

51 Pegasi b was the first exoplanet discovered outside our solar system, announced in 1995. It is a gas giant located approximately 50 light-years away in the constellation Pegasus.

Proxima Centauri b is the closest known exoplanet to Earth that is potentially habitable, located approximately 4.2 light-years away in the constellation Centaurus.

Ganymede is the largest known moon in the solar system, larger than the planet Mercury and slightly larger than the dwarf planet Pluto.

Titan is the only moon in the solar system known to have a substantial atmosphere, composed primarily of nitrogen and methane.

Jupiter is the largest planet in the solar system, with a mass approximately 318 times that of Earth.

Venus is the hottest planet in the solar system, with a surface temperature of approximately 462 degrees Celsius (863 degrees Fahrenheit).

Jupiter has the most moons of any planet in our solar system, with at least 99 known moons.

Pluto was once considered the ninth planet of our solar system, but was reclassified as a dwarf planet in 2006.