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# 4 Numerical Fun Facts About the Juno Spacecraft

Did you hear the exciting news that NASA just successfully put the Juno spacecraft into orbit around Jupiter? Want to learn 4 super-cool numerical fun facts about this mission? Then keep on reading!

By
Jason Marshall, PhD
Episode #284

## Fun Fact 3: How Far Away Is Juno (and Jupiter) from Earth?

Exactly how far away from Earth is our giant and super-efficient Jupiter-orbiting spacecraft? Well, instead of talking about distances between planets in units of kilometers or miles, astronomers usually use a more convenient unit called the astronomical unit (shortened to AU), which is defined as the average distance between the Sun and Earth.

As I mentioned before, the distance between Jupiter and the Sun is five times the average distance between the Earth and Sun. So we can say that Jupiter is about five AU from the Sun.

But, if you think about it, you’ll see that Jupiter (and thus Juno) actually isn’t five AU away from Earth. You can think of the planets orbiting the Sun like runners going around a track. The Earth is in an inner lane whipping around the Sun in one year, while Jupiter is in an outer lane (five times farther from the center) and takes nearly 12 Earth years to complete an orbit.

When Earth and Jupiter are both on the same side of the Sun, they can be as close as about four AU apart. When they are on opposite sides of the Sun, they are more than 50% farther away from each other—a bit more than six AU.

Right now, Jupiter—and therefore Juno —is about 5.8 AU away from Earth. That’s, obviously, pretty far away. So far, in fact, that it takes light—and thus any radio communications between Earth and Juno—about 48 minutes to make the one-way trip.

## Fun Fact 4: How Much Did Juno Cost?

Juno is a beautiful spacecraft and a technological marvel, but the real point of the mission is to learn about Jupiter—what it’s made of, how it formed, and what exactly that says about how the rest of the solar system (ourselves included) came to be 4.6 billion years ago. If you want to know more about the science that’s going to be carried out during the mission, check out this week’s Ask Science. And be sure to continue following that show for updates about the mission as it continues.

To wrap things up today, let’s talk about the financial side of a mission like Juno. What’s the total price tag to design, build, launch, and operate a spacecraft like this for the five years it took to get to Jupiter, and the next 20 months of science operations?

A mere \$1.3 billion. I know, that seems like a lot of money, but think about it this way: the spacecraft had to travel 1.8 billion miles to get to Jupiter, which means it only cost around 72 cents per mile. A lot of vehicles on Earth cost around 15 cents per mile to operate (and that's not including the cost to buy and maintain them), so Juno’s price tag isn’t so bad - especially considering it went to Jupiter!

And, as I alluded to before, the scientific insight we will gain about our solar system and our origins is genuinely invaluable. So in my book, it’s an extremely worthwhile investment.

## Wrap Up

Okay, those are all the planetary numerical fun facts we have time for today!

For more fun with numbers and math, please check out my book, The Math Dude’s Quick and Dirty Guide to Algebra. Also, remember to become a fan of The Math Dude on Facebook and to follow me on Twitter.

Until next time, this is Jason Marshall with The Math Dude’s Quick and Dirty Tips to Make Math Easier. Thanks for reading, math fans!

Jupiter images courtesy of Shutterstock.

## Pages

Jason Marshall, PhD

Jason Marshall is the author of The Math Dude's Quick and Dirty Guide to Algebra. He provides clear explanations of math terms and principles, and his simple tricks for solving basic algebra problems will have even the most math-phobic person looking forward to working out whatever math problem comes their way.