Celestial Bodies
This star sits at the center of our solar system and makes up about 99% of its total mass.
The Sun
To be classified as a planet by NASA, an object must be round, orbit the Sun, and clear this area around its orbit.
Its neighborhood
This unit of measurement represents the rough distance from the Earth to the Sun, equaling 150,000,000 kilometers.
Astronomic Unit
This early model assumed that Earth was the center of the solar system and everything revolved around it.
Geocentric Model
This interactive 3D website lets users look around the solar system and press an "animate" button to watch things move.
The Sky Live
This type of celestial object is defined as a body that orbits around a planet.
Moon / Natural satellite
This type of celestial body orbits the Sun and is nearly round, but has NOT cleared the neighborhood around its orbit.
Dwarf planet
This is the exact distance in Astronomical Units from the Sun to the Earth.
1 AU (150 000 000)
Developed by Copernicus in the 1500s, this model placed the Sun at the center of our solar system.
Heliocentric Model
Students can use this online star map tool to toggle a constellation button and find patterns in the night sky.
Stellarium
These small, rocky objects orbit the Sun and can range in size from a pebble to 1,000 kilometers across.
asteroids
Measuring 11 times the size of Earth, this is the most massive planet in our solar system.
Jupiter
Orbiting at 1.5 AU, this planet sits directly outside of Earth's orbit.
Mars
This 1609 model calculated that planets do not orbit the Sun in perfect circles, but rather off to one side.
Keplerian Model
This web model emphasizes the massive scale of empty space by shrinking Earth's companion down to a single display dot.
"If The Moon Was Only 1 Pixel"
These huge chunks of ice and dust expel gas and form a visible tail when they get close to the Sun.
Comets
This planet is the smallest of the true planets, measuring only about one-third the size of Earth.
Mercury
This ringed planet sits nearly ten times further from the Sun than Earth, at a distance of 9.6 AU.
Saturn
Johannes Kepler was able to calculate his model of the universe using precise data collected by this teacher.
Tycho Brahe
This space agency's website features a digital simulation titled "Our Solar System" to help students explore space.
This is the specific name for a small chunk that has broken off from an asteroid.
Meteoroid
These two outer gas giants are identical in scale, both measuring roughly 4 times the size of Earth.
Uranus and Neptune
This is the distance in Astronomical Units to Neptune, the furthest planet listed in the unit chart.
30 AU
This is the actual geometric shape of planetary orbits around the Sun, as proven by Kepler.
an ellipse (or elliptical path)
Standard textbook or slide drawings are usually inaccurate because matching real size and distance ratios requires drawing planets as these impossibly small objects.
dots