Solar System Quiz


By: Jennifer Post

6 Min Quiz

Image: Adventtr / E+ / Getty Images

About This Quiz

For the longest time, people thought that our solar system comprised the entire universe and that the planets were just randomly floating around Earth. We know now that the earlier thoughts are not true, and through the finding of scientists such as Galileo and Copernicus, we've learned so much about the solar system. Planets other than earth have oceans, volcanoes and mountains. Pluto is no longer a planet, although that depends on who you ask. The moon wasn't always the shape and size that we know today. With the more advances in technology, the more we will learn about this great, vast place.

How much did you pay attention in science class growing up? That information could greatly help you with this quiz. If you've ever watched shows like Planet Earth or Cosmos, you might ace this! There's so much to know about the solar system that the people who study it and explore it for a living don't even know everything. It also turns out, the more you know, the more you don't know. As soon as one question is answered, a hundred more pop up. If you think you know at least some things about the solar system, take this quiz to find out if you're right!

Copernicus correctly observed that the planets revolved around this bright and hot object, after years and years of thinking it was the big rock in the sky instead. What is it?

For the longest time, astronomers thought the planets revolved around the moon, but all it took was one, well, two scientists. Copernicus realized that the planets orbit the sun, but it was Kepler who defined their orbits.


It's getting hot in here! It feels like the surface of which planet, determined to be the hottest?

While people think that Mercury would be the hottest because it's the closest to the sun, Venus actually takes that award. it's because Venus' thick atmosphere prevents heat from escaping back into space.


A topic up for hot debate, how many planets are there currently in the solar system?

Before Pluto was declassified as a planet, there were nine planets in our solar system. That means there are eight planets left, with the inner ones being Mercury, Venus, Earth and Mars.


What's the difference between the inner and outer planets?

The inner planets are know as terrestrial planets, while the outers are known as gas giants. The latter is self explanatory, but the former is derived from the Latin word for Earth. All inner planets, structure-wise, are like Earth.


Earth is known as the blue planet because of all the water, but when it comes to oceans, does Earth have the largest ones?

While Earth's oceans are the ones that give off life and can be surfed in by human beings, Jupiter actually has the biggest ocean in the solar system. It's also not made of water, but rather metallic hydrogen.


Why does Uranus tilt almost completely on its side?

While the most likely explanation is that it has experienced a few titanic collisions, no one knows the exact reason Uranus tilts almost completely on its side. The tilt is at 98 degrees, compared to Earth's 23 degrees.


When you look up at the night sky, it seems like you can see thousands of stars, but how many are there actually in our solar system?

Our solar system has a lone star, the sun. Every planet within the solar system revolves around that sun, and if one got too close, it would burn up into nothing. Hence why gravitational pull is so important.


Which moon is considered the most active in the entire solar system, erupting with hundreds of volcanos ?

Earth's moon is pretty bland compared to the moons of some other planets. But Jupiter's moon really takes the cake. Io is bursting to life with not actual life, but with volcanoes. Hundreds of them, and spacecrafts have even caught them erupting.


Even though Io has hundreds of volcanoes, which planet has the biggest known one?

Named Olympus Mons, the volcano on Mars is three times the size of Mount Everest. The volcano, and all volcanoes on Mars, are able to grow so big beause of the lact of plate tectonics on the planet.


Which planet, or planets, have not been visited by space craft?

There is actually no planet that hasn't been visited by spacecraft of some kind. Exploration has gone of for more than 60 years and has produced close-up pictures of things that we never knew existed.


How long ago was the solar system formed?

Galileo was the first researcher to notice the individual parts of the solar system and details of each physical body. He's the one who discovered the craters no the moon and the sunspots on the sun.


You probably hear the world "galaxy" a lot, but it's just a general term. Which exact galaxy do we exist in?

Out of all the galaxies out there, our solar system exists in the Milky Way. It appears to those on Earth as a band of hazy white light, giving it a milky look, hence the name. There are between 200 and 400 billion stars living within it.


If you thought ours was the only solar system in the Milky Way, you'd be wrong. How many are there?

Before much exploration, it was believed that our solar system made up the entire universe. Within the last about 10 years, over 500 planets orbiting stars have been discovered, signaling the existence of other solar systems. The estimate is now at 100 billion of them!


There are planets known as gas giants, so you know they're big, but there are also small planets in the system. Which is the smallest?

It takes just shy of 90 days for Mercury to orbit the sun. The diameter of Mercury is comparable to that of the United States, but it is getting smaller. Why? Because the hot interior cools and causes the surface to draw together.


You may spin someone right round, but as far as the planets go, do they all spin the same way as one another?

Unlike the other planets that spin in an anti-clockwise pattern, Venus slowly spins in the opposite direction. If you could see the sun from Venus, it would rise in the West and set in the East, but the clouds prevent the sun from being seen.


What else other than the eight planets, the sun and moons, exists in our solar system?

The Kuiper Belt includes dwarf planets like Pluto, which is the largest of the dwarfs. The Oort Cloud surrounds our solar system, but has never observed in a direct manner. It's made up of space debris and chunks of ice.


We know how long ago the solar system was formed, but how exactly was it formed?

The cloud that started it all most likely collapsed due the explosion of a nearby star. A supernova, if you will. The gravitational pull from this collapse pulled matter in and it developed over time into what we now know as the solar system.


How exciting! Which two objects in the solar system could potentially harbor human life?

Europa is Jupiter's moon and Enceladus is Saturn's moon. Buried deep under icy shells are saltwater oceans. This is a good sign, since it's pretty much known that human life formed from the oceans.


Not every planet needs a moon. Which two planets prove that to be true?

There are some tiny asteroids that have moons, but Mercury and Venus do not. It's not 100% known why they don't, but some speculate it's because they're too close to the sun. Any moon close enough to be a moon would be eaten up by the gravitational pull.


Mercury is hot, hot, hot, but is it possible for there to be ice on the planet?

Even though Mercury is the closest planet to the sun, it is not the hottest planet, and can actually sustain ice. The ice is located in a permanently shaded part of the planet that remains cold.


The rings of Saturn are made up of ice, dust and rocks. We know that, but do you know how old they are?

The rings are one of the most interesting and baffling part of Saturn, and yet, no one knows how old they are. Observations of the planet haven't been able to determine 100% what the rings were, and how long they've been there.


You think it gets windy on Earth during a hurricane? That's nothing compared to supersonic winds. What are they?

It's still a mystery as to why Neptune is so windy, but the supersonic winds hit more than 1,100 miles per hour. That's faster than the speed of sound! NASA's Voyager 2 is the first and only spacecraft to capture the winds.


How much of the solar system's mass is taken up by the sun?

Earth makes up the tiniest amount of mass in the solar system with the sun being number one, followed by Jupiter, Saturn, Uranus and Neptune. When the sun formed, it absorbed much of what was there before it.


In the middle of its lifespan, how many years does the sun have left before it goes from hydrogen to helium?

The sun is already 4.5 billion years old, and science says it has about 5 billion years left in its life. At the end of the sun's era, the hydrogen in the sun will turn into helium. This will cause the sun to collapse, just like most other stars.


We can of course feel the heat of the sun on Earth, but how hot is the sun at the surface of it?

The surface of the sun is just shy of 10,000 degrees, but at its core, it's about 27 million degrees. That's quite the difference! It being so hot is the reason we can feel the heat of it all the way on Earth's surface.


There's no denying that the sun in our solar system is a big star, but which star is the biggest?

While UY Scuti doesn't have the same mass as our sun because it isn't as dense, radius-wise it is much bigger. Seventeen hundred times bigger to be exact. The conditions at formation are what determines how big a star will be.


Where did the word "planet" originate from?

"Planetes" is the Greek word that "planet" is based on. It means wanderer and is meant to represent the motion of the planets wandering around, in comparison to the stars, which seemed to stay in one place.


There's a lot of scientific terms that originate in another language. Can you define the term "accretion?"

Accretion is an astrophysics term that refers to matter coming together until there is enough of it to have gravity. This is how the planets were formed. They just kept adding matter until they couldn't anymore.


While the solar system as a whole is 4.5 billion years old, which planet is most likely the oldest?

Studies show that Jupiter began to form less than one million years after the solar system began. It only took two to three million years for it to be fifty times the size of Earth, mass-wise.


Why isn't Pluto a planet anymore?

The three criteria that an object must meet in order to be a planet are that it needs to orbit the sun, be mostly spherical and have cleared the neighborhood of its orbit. While people still consider it a planet, it technically is not.


Even though Pluto was sadly declassified as a planet in 2006, what is it now?

Confusing, we know. While it's not a planet, per se, it does classify as a dwarf planet. This means it meets the first two of the three criteria needed to be a full on planet. Pluto orbits the sun and is mostly spherical.


What was the surface of Earth like before it was known as the blue planet?

When Earth first started forming, there was almost none of what we recognize today. It was constantly being hit by meteorites and asteroids, so the surface was mostly made up of the remnants of that.


How accurate are space movies when it comes to asteroid belts?

Chances are, if you drove through an asteroid belt, you wouldn't see, let along run into, a single asteroid. Yes, there are a lot of them, but the area is so vast that the asteroids are really spread out.


While it looks like stars are basically connected at the hip, on average, how far away are stars in the Milky Way from each other?

Those five lightyears are about 30 trillion miles. To the naked eye, it looks like some stars are right next to each other, but that is not the case at all. If that's average distance between stars, and there's over 100 billion stars in the galaxy, that gives you a good idea of just how big it really is.


The stars are on a path in life just like we are! What is the path the planets take called when orbiting the sun?

The planets orbit the sun in an oval shape called an ellipses. The sun is slightly off center of the path, and is always moving, although that doesn't effect the past of orbit. The path is constantly being monitored to track habits and any changes.


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