Exoplanet Hunting? In History Class? Interpreting Transit Graphs

David Burzillo, BHP Teacher
Massachusetts, USA


Kepler-186f was the first rocky planet to be found within the habitable zone. Credit: NASA Ames/SETI Institute/JPL-Caltech. Public Domain .

When I started teaching many years ago, the only known planets in the Universe were considered to be in our Solar System. In the last 20 years, more than 3,200 exoplanets have been confirmed, another 2,400 are being vetted, and over 2,400 solar systems have been discovered. Amazing! Even more fascinating than this proliferation of planets are the techniques that astronomers are using to detect exoplanets and determine their characteristics. Like so many of the great discoveries described in the Big History Project course, the ingenious methods astronomers are using to study exoplanets are a great testament to the creativity and ingenuity of humans in their quest to understand the world—and Universe—around them.


Light curve of a planet transiting its star. Credit: NASA Ames. Public Domain.

Interpreting planet transit data is one example of this ingenuity, and Interpreting Transit Graphs, an activity in Lesson 4.5, is a great way to take students’ understanding of transit from conceptual to concrete. By completing the activity worksheets on transiting exoplanets, students come to understand how astronomers “see” distant planets. A very distant star is incredibly small when observed by an Earth-based telescope, and, as you can imagine, any planet orbiting such a star would be miniscule in comparison. But astronomers have developed a method for noting the presence of these miniscule planets. By measuring the light reaching the Earth from a star and noting the periodic fluctuations in the amount of light, astronomers are able to “see” a planet passing in front of the star. By measuring these periodic fluctuations, astronomers can determine if, in fact, more than one planet is causing the changes. They can also determine the diameter of the planet and they can determine how far the planet is from the star. Knowing how big the planet is and how far it is from its star is critical for understanding if life on it is possible. With this knowledge, astronomers who are searching for evidence of life in other parts of the Universe are able to focus on those planets in a particular star’s “Goldilocks zone.”

Interpreting Transit Graphs is a number-heavy activity that will require the close attention of you and your students. But there’s a great payoff: a deeper understanding of the creativity of astronomers and the exciting work they are pursuing to discover the possibility of life in other worlds.

About the author: Dave has taught for over 30 years, more than 25 of them at his current school, a private high school in Weston, MA. For the last 7 years, he has taught BHP to ninth-, eleventh-, and twelfth-graders. His school runs on a trimester system, which gives him about 90 days to cover 13.8 billion years of history. Recently, Dave began offering an online Big History Project course in the summer.

BHP + Newsela = Love

Chris Scaturo, Big History Teacher
New Jersey, USA

“Hey, Mr. Scaturo, can I take some more quizzes?” I swear on my union-mandated, 28-minute, uninterrupted lunch break a student said that to me this morning. He wants to take more quizzes. He wants to read more articles. He likes using Newsela.

One of the beautiful things about the Big History Project is that the curriculum is only limited by your students’ imaginations as well as your own. Newsela allows your students’ worlds to be enriched and expanded. Together, the possibilities are endless.

What Is Newsela?

Newsela.com is a website that posts current newspaper articles in multiple reading levels. The articles cover a wide variety of topics (a typical day’s worth might cover the US presidential debate, coral reefs in Hawaii, hurricane Matthew, and elephants) from respected sources (Washington Post, The Guardian, and the Associated Press, to name a few).

Each article is available in four Lexile levels (much like the readings in Big History) that usually range in difficulty from third- to twelfth-grade reading levels. Each article also contains a quiz that (gasp!) my students enjoy taking. Seriously. There are other great features, including an option that allows students to annotate the article while they’re reading; articles in Spanish; a linking system with Google Classroom; and a wide variety of text sets for each unit of BHP.

The incredible resource, available to all, looks like this:


Why It’s Great!
I don’t know much about teaching (just ask the people I eat lunch with every day, they’ll tell you) but I do know if you give students options, let them choose a topic they care about, make the work challenging, meaningful, and set it at an appropriate level, they tend to be more engaged. I also know that designing 150-or-so lessons that does all that is hard. And, I know that Newsela does that stuff for me. They’re kind enough to:

…provide thousands of options:
Newsela adds at least three articles EVERY day to their library. The articles are organized by subtopic (science, law, money, sports, for example) and are easily searchable. A quick search for “turtles” produced this:


…make the quizzes useful:
We aren’t talking about the typical end-of-chapter textbook questions, here. These quizzes are thought-provoking and cover a wide range of Common Core State Standards for grades 3–12. My students enjoy the challenge of them. They’re hard, but they’re short and instantly scored.

…level the readings:
There is nothing worse than wanting to learn about something and not being able to understand it. Newsela takes reading material and moves it down the Lexile scale so that more readers can understand the information. Basically, the lower the Lexile number, the easier it is to read. Guess what—y students know that as well, and they use it!

…make it free:
Now, there is a pay-to-play version that adds additional assessment tools, but the basic (free) version provides a vast library of resources. It’s awesome. I promise.

Newsela + Big History = Love
This site is a perfect complement to BHP. Periodically, I ask students to find an article on Newsela somehow connected to the unit we’re currently studying. I suggest they read the article at least twice—once at a level where they feel comfortable and then again at a level higher or lower. I then ask them to claim-test it.


One of my students who reads a few notches below grade level just completed an assignment on Proxima B, adapted from Scientific American. Another student who reads at a college freshman’s level read about the formation of Jupiter. They were then able—without help from me—to have a conversation about what planets would require to support life as we know it. Thanks, Newsela!

About the author: Chris has been teaching for 15 years; this is his fourth teaching Big History. He teaches the course as a semester-long elective to middle-schoolers in Allentown, New Jersey. Chris loves that Big History inspires his students to ask questions on a regular basis.

Communing with Other Worlds: Is Proxima Centauri B Ready for a Text Message?

Lucy Bennison Laffitte, MEd, PhD
Executive Committee, International Big History Association
North Carolina, USA

People have been pondering other worlds since we first crawled down from the trees onto the grasslands and looked up at the night sky. Watching the nightly rising and setting of stars, monthly changes of the moon, periodic meteor showers, yearly shifts in the constellations, and the curiously wandering stars, it’s easy to imagine that even the most ancient of people yearned for communion with other celestial life. It’s a uniquely human urge.


We have been reaching out for a long time. This golden record, carried by the 29-year-old Voyager Probe, contains pictures and sounds of Earth along with symbolic directions on the cover for playing the record and data detailing the location of our planet. It is the first human-made object to leave the Solar System. Public Domain.

A quick jump through the last 5,000 years of astronomy’s history demonstrates how the instruments and insights of the discipline have evolved as technology has developed and collective learning increased.

  • In ancient Babylonia, astronomers recorded the rise and set of the planets and unusual events like Haley’s comet on cuneiform tablets. They also divided the firmament into 360 degrees for tracking planets in space.
  • In ancient Greece, astronomers named the constellations, and marked the ecliptic with the zodiac. They also measured and mapped the location of stars using sextants and parallax (BHP students can learn to measure distances using parallax in Lesson 1.4).
  • In Enlightenment Europe, astronomers used optical telescopes to find moons around planets to bolster the idea that the Earth revolved around the Sun.
  • During the Industrial Revolution, astronomers used spectroscopes to analyze the spectrum of light from distant objects. The spectral absorption and emission lines provided the evidence to determine which elements other planets and stars were made of.
  • In the Information Age, we are building telescopes of all sizes to capture the data from all wavelengths of the electromagnetic spectrum. Infrared telescopes, when put into orbit above the Earth’s atmosphere, are able to measure the transit and radial velocity of tiny planets as they pass through the habitable zones around the suns of other solar systems.

The discovery of Proxima Centauri B this summer has energized those thinking about finding extraterrestrial life. The planet orbits Proxima Centauri, the closest star to our Sun, which is only 4.2 light years from Earth. It has a temperature range that would make liquid water possible. But the likelihood of finding life there diminishes when you consider the other details of this planet.


Artist’s conception of Proxima Centauri B. ESO/M. Kornmesser. CC BY 4.0.

Proxima Centauri is a small red dwarf star only one-eighth the size of our Sun. The planet Proxima B is similar to Earth in size, but has a drastically short year—11 days long. And it orbits very close to its sun. The Earth is 20 times farther from our Sun as Proxima B is from Centauri. The solar wind coming off Centauri is predicted to be 2,000 times stronger than what Earth experiences, and we have a magnetic shield.

The exoplanet community is not deterred by this, however. They hope to send robots to the surface, anticipating the thrill of understanding another planet outside of our Solar System. Proxima Centauri B may not be a world ready to receive text messages and emoticons, but a visit there will no doubt aid us in our quest to find a planet that is.

About the author: Lucy Bennison Laffitte, MEd, PhD, has been teaching science in-context for over 30 years. She currently teaches Big History through the Honors College at North Carolina State University and in the Summer Accelerator Program for the North Carolina School of Science and Math. Lucy has published in print, on air, and on the web—authoring a newspaper column, founding an award-winning environmental radio program, creating certificate programs, and developing digital learning objects for public television.