How do I convert miles to astronomical units?

You’re part of a team at Space Z managing a rocket that will travel to Jupiter and need to calculate its landing. You're given the rocket's current distance from the Sun: 483,000,000 miles.

That's a huge number to work with! Thankfully, you know that you can use astronomical units (au) to make your calculations. Let's review what astronomical units are and how to convert miles into au!

An astronomical unit (au) is the distance between the Earth and the Sun.

1 astronomical unit (au) = 92,955,807 miles. When converting between the two units, astronomers round the ratio to 1 au = 93,000,000 miles.

Scientists and astronomers use au because the distance between objects in space is huge, and it may be inconvenient to use large numbers. Using au makes it much easier to compare distances, especially because it is a universal unit. This prevents confusion between different units like miles and kilometers.

Let's say you need to convert 465,000,000 miles to astronomical units.

Step 1

Set up your conversion ratio on the left side (1 au/93,000,000 miles). Write another ratio on the right side and fill in the information that you know. Write "x" for the part that you're figuring out.

Place an equal sign between them.

Step 2

Cross-multiply. Multiply following the arrows' directions, and write down the new equation.

Step 3

Solve for the variable. Divide by the variable ("isolate the variable") on both sides.

Convert 10,000,000 miles to au. What is the answer?

A. 11 au

B. 0.11 au

C. 1.1 au

D. 0.011 au

Planet Zee is 750 million miles from the Sun. Convert to au:

A. 8.1 au

B. 0.12 au

C. 4.5 au

D. 1.2 au

Two planets are 310 million miles apart. What is the distance in au?

A. 0.3 au

B. 3.0 au

C. 3.33 au

D. 33.3 au

Let's go back to your space mission from the beginning. Convert 483,000,000 miles to astronomical units, and you have 5.2 au. That number is much easier to deal with!

Now you can confidently convert and calculate the landing of the rocket and so much more!

Convert miles into astronomical units using these tips: