Solar System Walk

Visualise the scale of different planet systems by exploring the old crescent and see how different systems are arranged. Along the way, learn about each of the planets in our solar system and discover what we know about the exoplanet system TRAPPIST-1!

Our Solar System

Our solar system is made up of 8 planets, at least 5 dwarf planets, 176 moons, and over 150 million asteroids, all orbiting one sun!

Take a walk around campus to understand the scale of our vast solar system. Check out the map; some planets are farther away than you might expect! Then scroll down for more fun facts about the planets.

Do you have a favorite planet? Take a picture by the sign and share it with us on twitter (@iuastro) #SolarSystemWalk !

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Our Sun

Location on campus: Kirkwood Observatory
The sun is 109 times larger than Earth.
Fun fact: The core of the sun is about 27 million degrees Fahrenheit! Hot Hot Hot!!

Mercury

Location on campus: Kirkwood: Observatory sidewalk
Length of year: 87.97 days
Approximately 2/5 the size of Earth
Fun fact: In 2016, data from MESSENGER revealed that the planet is still contracting!

Venus

Location on campus: Kirkwood Observatory sidewalk
Length of year: 224.70 days
Only slightly smaller than Earth
Fun fact: Venus spins backwards which means the sun rises in the west and one day on Venus is longer than the year!

Earth

Location on campus: Kirkwood Observatory sidewalk
Length of year: 365.26 days
Fun fact: Only known planet in the universe to contain life!

Mars

Location on campus: Corner of Law School near Kirkwood
Length of year: 686.98 days
Approximately half the size of Earth
Fun fact: Mars has both the longest valley and the biggest mountain in the solar system!

Jupiter

Location on campus: Sample Gates
Length of year: 4,300 days
11 times the size of Earth!
Fun fact: The Great Red Spot has been shrinking and becoming more circular; astronomers predict it may disappear within our lifetime!

Saturn

Location on campus: Between Kirkwood and Lindley Hall
Length of year: 11,000 days
Saturn is just over 9 times as large as Earth
Fun fact: This October, astronomers discovered 20 new moons of Saturn, bringing its total up to 82 and beating Jupiter’s record!

Uranus

Location on campus: Between Simon and Myers Hall
Length of year: 31,000 days
Uranus is 4 times as big as Earth
Fun fact: Uranus rotates on its side and astronomers don’t know why!

Neptune

Location on campus: In front of Memorial Hall
Length of year: 60,200 days
Neptune is slightly less than 4 times the size of Earth
Fun fact: Neptune has winds that whip frozen methane across the planet at speeds of more than 1,200mph!

Other Solar Systems: TRAPPIST-1

TRAPPIST-1 Artist's Concept

This artist’s concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets’ diameters, masses and distances from the host star. The system has been revealed through observations from NASA’s Spitzer Space Telescope and the ground-based TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope, as well as other ground-based observatories. The system was named for the TRAPPIST telescope.

The TRAPPIST-1 system was discovered in 2016 with the TRAPPIST telescope in Chile and is one of the best studied exoplanet systems we know about. There are 7 planets all orbiting a red dwarf star as their sun!

The star: TRAPPIST-1

15% mass of our sun and fainter than Pluto
Located in the constellation Aquarius, over 200 trillion miles from Earth

The planets

The TRAPPIST-1 system has 7 Earth-size planets that all orbit incredibly close to their star. In fact, the entire TRAPPIST-1 system could fit inside the orbit of Mercury!

Comparison of TRAPPIST-1 System and Inner Solar System

Fun Facts:

Three of the planets are within the habitable zone, six of them are rocky worlds, and one might be an icy world.
The planets are so close together that if you stood on the surface of one, you could see the nearby planets in the night sky like a moon.
Based on Ultraviolet observations, astronomers predict that the outer planets may have liquid water.
Astronomers are currently studying the atmospheres of these distant worlds, hoping to learn more about what the environment might be like.

* Images by NASA

Department of Astronomy

Solar System Walk