Nola Taylor Tillman

Reference Cosmology by definition is the branch of astronomy involving the origin and evolution of the universe, from the Big Bang to the future of the cosmos.

Reference This list of famous astronomers includes great scientists in history who mastered many fields and modern astronomers who helped popularize astronomy.

Jupiter is composed of gases — hydrogen and helium, mostly.

REFERENCE Kalpana Chawla's story has inspired millions to pursue careers in space.

Reference The temperature of Uranus averages minus 320 degrees Fahrenheit. Uranus holds the record for the coldest temperature ever measured in the solar system.

Nibiru has been linked to NASA, and is also sometimes referred to or confused with Planet X, another supposed world for which there is no evidence.

Reference How big is the moon? Our moon is the fifth largest moon in the solar system, with a radius of 1,079.6 miles (1,737.5 kilometers).

Everything you wanted to know about the basics of galaxies.

Since its 1990 launch, the Hubble Space Telescope has provided countless amazing images and contributed to many big discoveries. Learn more here.

Reference Based on what we can observe, the universe appears to be almost 28 billion light-years in diameter. However, it is far larger than that.

Material from the solar system's creation clumped together to form our closest star.

Reference There are three theories as to how Earth's satellite could have been created.

Nicolaus Copernicus proposed his theory that the planets revolved around the sun in the 1500s, when most people believed that Earth was the center of the universe.

Referene Italian astronomer Galileo Galilei made a number of inventions and discoveries that remain important to astronomy and science in general today.

Like all of the planets, Jupiter was formed out of the solar nebula.

Reference Carl Sagan was a scientist and educator best known for his TV series Cosmos, the Pale Blue Dot image of Earth and quotes about life and Earth.

Scientists have calculated that Earth is 4.54 billion years old, with an error range of 50 million years.

Yes, the moon rotates on its axis. The moon's rate of rotation nearly matches its orbital period, which keep the same side facing Earth.

The moon's surface tells the story of the solar system's beginnings.

Astronaut Michael Collins felt "absolutely isolated" in orbit while his Apollo 11 crewmates walked on the moon.