Beyond the interstellar boundary of our Solar System, there's a universe full of exciting discovery. Journey into deep space to learn more about what we know — and the mysteries that remain! (Image Right: Inside the Coma Cluster of Galaxies, Courtesy of NASA)
Most black holes are the result of a massive star explosion. As the star explodes, its core is crushed by gravity until it disappears from sight. Gravity becomes so extreme that it overwhelms all other forces in the Universe. Not even light can escape.
Asteroids, small solar system bodies composed of rock and metal, are left over from the early days of the Solar System. Most asteroids orbit around the Sun in a belt between Mars and Jupiter and travel in the same direction as the planets.
Learn more on our Galaxies page.
Twinkle, twinkle, little star. How I wonder what you are. Well, wonder no more! Stars are large balls of extremely hot gas or, more accurately, hot gas and a gas-like substance called plasma. They are primarily composed of the two most common elements in the universe: hydrogen and helium.
Gas, dust and debris from star explosions and around star-forming regions are called nebulae (plural of nebula). Nebulae are often very large and span across many light-years. Space holds millions of nebulae that can be observed from Earth.
Learn more on our Nebulae page.
Extrasolar planets, or exoplanets, are planets outside of our Solar System, so they do not orbit our Sun. They orbit other stars and are difficult to detect directly because they are literally lost in the glare of their stars.
Learn more on our Extrasolar Planets page.
