Hey Bill Nye, “How Did You Come Up With the Idea for the LightSail?” | Big Think

Hi Bill. My name is Shia. I am eight years old. My question is how did you come up with the idea for the LightSail?

I love you.

That’s a great question. So it wasn’t really my idea, Shia. People who lived before me, people who were astronomers and physicists, discovered that light, even though it has no mass, has a tiny, tiny bit of momentum. Just while you’re sitting there in a room with the lights on, and when you’re out in the sun, there’s just a tiny, tiny push on you because it’s pure energy.

So when it strikes something, it imparts some energy to it. It gives it a little push. People over just about a century ago realized if you had a spacecraft in space of low enough mass – it wouldn’t weigh very much on Earth – and it was big enough, it would get a push.

And so my old professor, Carl Sagan, was a big advocate of this, making a solar sail, as it’s called, to catch up with Comet Halley, which you may sometimes hear as called Halley’s Comet. And that mission got cancelled. That spaceship got cancelled for other NASA projects.

But now at the Planetary Society, which he started, Carl Sagan started, with the head of the Jet Propulsion Lab, Bruce Murray, and Lou Friedman, who was an engineer at the Jet Propulsion Lab out in California. They worked on that Comet Halley mission, and they held it in their hearts. They wanted this thing to fly.

And now I have become the CEO of the Planetary Society started by those three guys. And now, 39 years after Carl Sagan presented this idea to the world, we are flying a much more modest, nevertheless, when you look at it, it looks very much the same, LightSail spacecraft.

It would have the capability – here’s our patch, our mission patch. It would have the capability to take you to the moon, to Mars, to asteroids at a very low cost, which is a big problem, you know, in anything is how much it costs. That is a great question, Shia.

I hope you follow the mission. We’re in space right now as I talk, and in the next few weeks, after we spread out from other spacecraft, we will deploy our sails, extend our shiny sails, and see if it works.

By the way, if the sails were black, the light would hit it and give it a push. But because they’re shiny, the light hits it and bounces off, and that’s mathematically exactly twice the push.

So Shia, that’s math. And I want you to get good at it. Thanks for the question...