Display the first slide, on the tab labeled "a word." Ask:
Has anyone ever heard of the word "extraterrestrial"?
Some of your students may have heard the word as a synonym for "alien," as in the movie E.T. the Extra-Terrestrial (1982).
Display the second slide on the tab labeled "break it down." Paraphrase:
Let's break down the word into its parts. The prefix "extra" means "out of" or "beyond" while "terr" is for "Terra," another name for our planet Earth.
The electromagnetic waves traveling across the universe are mainly extraterrestrial.
Display the third slide on the tab labeled "the Universe." Ask:
Are there extraterrestrial civilizations out there in the Universe?
Give the students a few minutes complete a KWL chart individually or to turn and talk in a pair-share. Ask students to share their viewpoints with the class. Student interest here is very high, so as they discuss, interject lightly to provide new information or answer questions based on the slides.
For example, you can display the third slide (on the tab labeled "the Universe") and say something along the lines of:
We live in a galaxy, the Milky Way, that is just one among 100–200 billion galaxies in our universe.
Looking through telescopes like the Hubble that captured this image is like a kind of time travel, in that we're looking at light and radio signals from hundreds of thousands of years ago.
If students wonder how many inhabitable planets there are, display the fourth slide (on the tab labeled "the Milky Way"). Paraphrase:
Our own galaxy, the Milky Way, has about 300 billion stars. Each of those stars could have a planet orbiting within a zone that could sustain life.
If students wonder how likely it is that Earth is the only planet with life, display the fifth slide (on the tab labeled "the odds"). Note: this figure is derived from the Drake equation which multiplies seven different factors together to result in this value. Paraphrase:
Through their calculations, scientists figure that the chances of Earthlings being the only beings ever to develop a civilization at about 1 / 1022 — that is, one in 10 billion trillion.
Put another way, scientists believe there's a 99.9999999999999999999% chance there's another civilization out there.
If students wonder whether we have ever heard from another civilization, display the sixth slide (on the tab labeled "Wow! message"). Paraphrase:
The search for extraterrestrial intelligence is called SETI, pronounced "SET-ee" rhyming with Betty.
Have you ever seen a radio with a tuning knob? It makes a lot of noise between the stations. When we listen to the stars we hear the noise cooked up by the cosmos. There's a lot of background radiation criss-crossing the universe.
For 72 seconds in 1977, Ohio State University's Big Ear radio telescope received what SETI researchers considered the most likely possibility of an alien radio transmission ever seen or heard. The data were so impressive, an astronomer monitoring it wrote "Wow!" next to the printout.
Look at all the numbers around it. It really stood out compared to the usual data coming in. The Wow! Message is like a shape or clear sound suddenly emerging from a chaotic background.
But what could "6EQUJ5" mean, if anything?
In 2017, astronomers finally realized the signal was made by a comet, not an extraterrestrial civilization after all.