A brief journey
through the universe

An astronaut (or cosmonaut) is a person who commands, pilots, or serves as a crew member of a spacecraft. There are astronauts from many different countries across the world. The youngest astronaut was 25 years old and the oldest was 77 years old.

The Big Bang theory is the most widely accepted scientific theory of how the universe was formed from its earliest known period. Imagine all the stars and galaxies squished down into one tiny point - even space and time - and then exploding outward! Pretty wild, huh?

A comet is a small icy object that travels through solar systems. As they get closer to stars, a tail can form. Sometimes these tails can be 90 million miles long! Sometimes comets can crash into a star such as our Sun or even planets.

A dwarf planet is an object that is not quite big enough to be a planet but it still has the general shape of a planet. There are currently five recognized dwarf planets, including Pluto, but there are most likely hundreds more!

Earth is the planet we live on. It is the third planet from the Sun. As of today, the Earth is the only planet known to have life on it. The Earth has one natural satellite, the Moon. It takes the Earth 365.25 days (1 year) to travel around the Sun.

Fusion is how stars generate all their energy. The most important fusion process in nature is the one that powers stars. This occurs when hydrogen is fused together to form helium. Fusion allows the Sun to give us energy such as light and heat.

A galaxy is a large group of stars, dust, gas and dark matter that are bound together from gravity. The galaxy that we are in is called the Milky Way. Our galaxy alone has hundreds of billions of stars. There are at least two trillion galaxies in the universe. When you add that all up that’s a lot of stars!