Solar System Exploration: Solar System 101: Homework Helper

HOMEWORK HELPER

Our Galactic Neighborhood
The words "solar system" refer to the sun and all of the objects that travel around it - planets, natural satellites such as the moon, the asteroid belt, comets and meteoroids. Our solar system is part of a spiral galaxy known as the Milky Way. The sun, the center of our solar system, holds eight planets and countless smaller objects in its orbit.

Extreme Facts

How Big is Our Galaxy? If the solar system, from the sun all the way out to dwarf planet Pluto, were shrunk to the size of a U.S. quarter, the Milky Way would be the size of North America.

Micro Wave The radio signal that a spacecraft uses to contact Earth has no more power than a refrigerator light bulb. And by the time the signal has traveled across space, the signal is only one-billionth of one-billionth of one watt!

Big Ears To detect those tiny signals, the Deep Space Network uses antennas with diameters of up to 70 m (230 feet). That's almost as big as a football field.

Space Travelers The twin Voyager spacecraft have traveled the farthest of any spacecraft -- ever. The Voyagers are currently exploring an uncharted region located far beyond the planets we now know ... a region that forms the outer boundary of the solar bubble. They are on a journey that will ultimately transition into interstellar space.

Got Life Our solar system is the only planetary system known to have life.

Solar System Nicolaus Copernicus' sun-centered (heliocentric) model of the solar system was published in 1543. However, it was not until the 1700s did the idea of a sun-centered system become more widely accepted.

Self-Portrait In 1990, Voyager 1 pointed its cameras back at the sun and took a series of pictures of the planets, making the first ever portrait of our solar system as seen from the outside.

Part of the System There are a lot of space objects in our solar system. Everything that orbits the sun is a part of our solar system. This includes eight planets and their moons, five dwarf planets, their moons, tens of thousands of asteroids, and between hundreds of thousands and about three trillion comets.

How Big is Our Galaxy? If the solar system, from the sun all the way out to dwarf planet Pluto, were shrunk to the size of a U.S. quarter, the Milky Way would be the size of North America.

Micro Wave The radio signal that a spacecraft uses to contact Earth has no more power than a refrigerator light bulb. And by the time the signal has traveled across space, the signal is only one-billionth of one-billionth of one watt!

Big Ears To detect those tiny signals, the Deep Space Network uses antennas with diameters of up to 70 m (230 feet). That's almost as big as a football field.

Space Travelers The twin Voyager spacecraft have traveled the farthest of any spacecraft -- ever. The Voyagers are currently exploring an uncharted region located far beyond the planets we now know ... a region that forms the outer boundary of the solar bubble. They are on a journey that will ultimately transition into interstellar space.

Got Life Our solar system is the only planetary system known to have life.

Solar System Nicolaus Copernicus' sun-centered (heliocentric) model of the solar system was published in 1543. However, it was not until the 1700s did the idea of a sun-centered system become more widely accepted.

Self-Portrait In 1990, Voyager 1 pointed its cameras back at the sun and took a series of pictures of the planets, making the first ever portrait of our solar system as seen from the outside.

Part of the System There are a lot of space objects in our solar system. Everything that orbits the sun is a part of our solar system. This includes eight planets and their moons, five dwarf planets, their moons, tens of thousands of asteroids, and between hundreds of thousands and about three trillion comets.