The Solar System and Beyond

Our solar system is a marvel. It houses millions upon millions of objects and perhaps the greatest marvel of all—life on Earth. With the fast-approaching reality of sending astronauts to Mars, it’s more important than ever to understand our solar system—and what lies beyond it.

The Solar System

Our solar system includes the sun and everything that travels around it. It is about 4.6 billion years old and is an elliptical shape. There are eight known planets in our solar system, along with moons, asteroids, comets, meteors, and dwarf planets.

We have only recently been able to explore the reaches of space beyond Neptune. NASA’s New Horizons flew past Pluto in 2015, as the first spacecraft to explore a region known as the Kuiper Belt. The Kuiper Belt is a region beyond Neptune that has thousands of icy bodies and trillions of comets. Pluto is the best known and one of the larger objects in the Kuiper Belt. Objects in this area are “presumed to be remnants from the formation of the solar system about 4.6 billion years ago,” according to NASA.

Another region sitting at the edge of the solar system is the Oort Cloud, a “thick bubble of icy debris that surrounds our solar system.” This region is so massive that it will take NASA’s Voyager 1 300 years just to reach the Oort Cloud. This region is important to our solar system because it is the area of origin for comets that will eventually orbit the Sun.

Although our solar system is large, complex, and holds many bodies, this solar system is just a small part of the Milky Way galaxy.

Beyond the Solar System

We have been able to observe objects beyond our solar system. Of particular interest are exoplanets, which are planets that lie beyond our solar system. Thanks to NASA’s Kepler telescope, thousands of exoplanets have been discovered in the past 20 years.

These planets are as diverse as the planetary bodies in our own solar system. There have been jagged, rocky planets, gas giants, and icy planets. The search for exoplanets is of particular interest for scientists to find another Earth-like body. Scientists determine whether an exoplanet is conducive to life by calculating if it’s in a habitable zone. The habitable zone is calculated according to an exoplanet’s distance from a star that “allows for liquid water oceans” and a “greenhouse effect of a planet’s atmosphere,” according to These potentially habitable exoplanets will pave the way for future exploration and even colonization.

Beyond our galaxy itself, which holds our solar system and everything beyond it, are other galaxies. The nearest galaxy is Andromeda, which will collide with the Milky Way galaxy in about 4 billion years. The Milky Way is part of the Local Group, which consists of 30 galaxies. While this seems incomprehensively massive, scientists estimate that there may be one hundred billion galaxies in the universe. In the even bigger picture, clusters of galaxies “form a bubbly structure, in which vast sheets and filaments of galaxies surround gargantuan voids,” according to NASA.

Teaching Resources

We’re living in an exciting time for space exploration beyond our solar system. Educators contribute immensely to this effort by developing Earth’s next generation of scientists. Check out these teaching resources to explore the solar system and beyond in your classroom: