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Planet Pinpointer: A 'Pi in the Sky' Math Challenge

Lesson .

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Planet Pinpointer: A 'Pi in the Sky' Math Challenge

Jet Propulsion Laboratory https://www.jpl.nasa.gov/ Last Updated: June 20, 2025
Subject
Math
Grade Levels
10-12
Time Required
Under 30 mins
Standards .
Math Standards (CCSS - Math)
.

Understand radian measure of an angle as the length of the arc on the unit circle subtended by the angle.

Illustration of two planets orbiting the star Beta Pictoris surrounded by a disk of debris. An inset illustration of the Spitzer space telescope shows a triangular beam representing the spacecraft's view of the disk

Overview

The "Pi in the Sky" math challenge gives students a chance to find solutions to real-world problems all while using math and pi just like NASA scientists and engineers. In this problem from the seventh installment of the set, students use the mathematical constant pi to calculate the distance across a disk of debris around the star Beta Pictoris.

Materials

  • Pi in the Sky 7: Planet Pinpointer – Download PDF
  • Pi in the Sky 7: Planet Pinpointer answer key - Download PDF (also available as a text-only doc)

Background

Rays of bright orange and red shoot out diagonally from a blue circle surrounding the star Beta Pictoris
The star Beta Pictoris and its surrounding debris disk are shown in near-infrared light in this composite image. The outer part of the image shows the reflected light on the dust disc. › Full image and caption.
Credit: ESO/A.-M. Lagrange et al.

Our galaxy contains billions of stars, many of which are likely home to exoplanets – planets outside our solar system. So how do scientists decide where to look for these worlds? Using data gathered by NASA's Spitzer Space Telescope, researchers found that they're more likely to find giant exoplanets around young stars surrounded by debris disks, which are made up of material similar to what's found in the asteroid belt and Kuiper Belt in our solar system. Sure enough, after discovering a debris disk around the star Beta Pictoris, researchers later confirmed that it is home to at least two giant exoplanets. Learning more about Beta Pictoris' debris disk could give scientists insight into the formation of these giant worlds. In Planet Pinpointer, put yourself in the role of a NASA scientist to learn more about Beta Pictoris' debris disk, using pi to calculate the distance across it.

Procedures

Planet Pinpointer

Our galaxy contains billions of stars, most of which are likely home to exoplanets – planets outside our solar system. How do scientists decide where to look for these worlds? Researchers looking at data from NASA's Spitzer Space Telescope found that giant exoplanets tend to exist around young stars surrounded by a disk of debris. A prominent debris disk around the star Beta Pictoris, which is 6 x 1014 km away from Earth, led scientists to discover two exoplanets several times bigger than Jupiter orbiting the star! Learning more about the debris disk could give scientists insight into the formation of these giant worlds.

Given the angle of the disk's apparent size is 169 arcseconds, determine the actual distance across it using the formula for small angle approximation, below. (An arcsecond is 1/3,600 of a degree.)

D = dθ D = distance across the debris disk (km) d = distance to Beta Pictoris (km) θ = angle of apparent size (radians)

› Learn more about exoplanets

Illustration of two planets orbiting the star Beta Pictoris surrounded by a disk of debris. An inset illustration of the Spitzer space telescope shows a triangular beam representing the spacecraft's view of the disk

› Download PDF.

Credit: NASA/JPL-Caltech

Assessment

Illustrated answer key for the Planet Pinpointer problem

› Download text-only answer key (doc)

Extensions

Participate

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Pi Day Challenge Lessons

Here's everything you need to bring the NASA Pi Day Challenge into the classroom.

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Slideshow: NASA Pi Day Challenge

The entire NASA Pi Day Challenge collection can be found in one, handy slideshow for students.

Join the conversation and share your Pi Day Challenge answers with @NASAJPL_Edu on social media using the hashtag #NASAPiDayChallenge

Blogs and Features

students.

How Many Decimals of Pi Do We Really Need?

While you may have memorized more than 70,000 digits of pi, world record holders, a JPL engineer explains why you really only need a tiny fraction of that for most calculations.

students.

Slideshow: 18 Ways NASA Uses Pi

Whether it's sending spacecraft to other planets, driving rovers on Mars, finding out what planets are made of or how deep alien oceans are, pi takes us far at NASA. Find out how pi helps us explore space.

Related Lessons for Educators

educators.

Solar Sleuth: A 'Pi in the Sky' Math Challenge

In this illustrated math problem, students use pi and data from the Kepler space telescope to find the size of a planet outside our solar system.

educators.

Exploring Exoplanets with Kepler

Students use math concepts related to transits to discover real-world data about Mercury, Venus and planets outside our solar system.

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Habitable Hunt: A 'Pi in the Sky' Math Challenge

In this illustrated math problem, students use the mathematical constant pi to find the "habitable zone" around a distant star and determine which of its planets are in that zone.

Related Activities for Students

  • Article: Giant Exoplanet Hunters: Look for Debris Disks
  • Video: The Evolution of a Planet-Forming Disk
  • Video: Birth of "Phoenix" Planets?

Multimedia

students.

Infographic: Planet Pi

This poster shows some of the ways NASA scientists and engineers use the mathematical constant pi (3.14) and includes common pi formulas.

Facts and Figures

  • Beta Pictoris b
  • Beta Pictoris c

Missions and Instruments

  • Spitzer

Websites

  • NASA Exoplanets
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