How to Measure Distances From Earth to Other Planets

Through understanding orbital planets, scientists predict where a planet will be at any given time.

Since the discovery that the planets revolve around the sun instead of the Earth 500 years ago, astronomers have made various attempts to measure the distances between the planets. Since it is impossible to calculate such extensive lengths simply by sight, astronomers have determined various ingenious methods for determining distances in space. With the help of modern technology, space travel and basic concepts of trigonometry, it is simpler than ever for people to understand the vastness of the solar system.

Things You'll Need

• Pencil
• Paper
• Protractor
• Graphing calculator

Instructions

1. Draw a diagram of the solar system with the sun in the center and each of the planets radiating out on their individual orbits.

2. Using Venus as an example, draw a straight line from the sun to a point in Venus' orbit. With the protractor, calculate a right angle from that line to determine Earth's orbit in relation to Venus.

3. Draw a line from Earth to the sun to create a triangle. Measure the angle at the corner of the triangle where Earth is with the protractor.

4. Using a calculator, determine the cosine of the angle.

5. Multiply the cosine of Earth's angle with the sun's distance from Earth, 150 million kilometers. to get the distance from Earth to Venus.

References

• Cornell University: Curious About Astronomy

Resources

• NASA: How Do Scientists Know the Distances Between Planets+