Sunlight, penetrating a break in the clouds, streamed through the sunroom windows, lighting our faces. It was a life-changing moment. Liz, Milo, and I had just made a promise. The three of us holding hands, our faces lit by the sun, is a picture I’ll never forget.

We were talking about world-famous astrophysicist Stephen Hawking’s dire prediction made in 2017—in 100 years, humans will become extinct on Planet Earth. That’s our lifetime! That’s us! Our amazing civilization has just 95 years left? We can’t let that happen! So we made a promise. Each of us would try to do at least one thing to try to save humanity. We need a better world, more like the one in John Lennon’s song “Imagine,” where humans cooperate instead of fighting. We need to make Earth great again.

I said, “Omigod, wait!”

I ran into Dad’s office, wrote it out on his computer, made it look like an official certificate, and printed it. I grabbed a pen, came back, and handed it to Liz. “Oh, wait! We need to sign it to the Lennon song. It’s like it was written for this!” Milo got it playing on his phone. We all signed the certificate as Lennon sang, “I hope someday you’ll join us, And the world will live as one.”

I left a line at the bottom, so anybody can print it out and sign it too.