Hello, SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asking the reason alien civilizations might be rare is because most aliens are huge.

To hear it and every episode early and add free, plus hours of bonus content, check out

go.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

Gravity is a fascinating force. It's what holds everything on our planet together, and it might one day help us travel to other planets.

Gravity is a strange thing. On the one hand, it's the oldest and best known of the fundamental

forces, on the other it's the weakest and least understood. Within that uncertainty

may lie the key as to escaping this world and traveling to countless others, or building

structures of incomprehensible scope and amazing purpose.

While we'll cover gravitic technologies beside Propulsion in February, today we'll focus

solely on moving spaceships.

We'll explore everything from mundane uses of gravity for proportion, like slingshining

around planets and the Earth effect, to more hypothetical varieties, such

as spacetime warping, gravitational wave proportion, anti-gravity, dark energy, negative

matter, frame-dragging, the diametric, differential, pitch, and bias drives, and more.

That's a lot to cover, so grab a drink and a snack, hit those like and subscribe buttons,

and let's dive into the topic.

We might as well begin with the best known use of gravity for moving spaceships, preventing

them from moving by giving them a massive gravity well to drag themselves out of, while also

making them drag through a thick atmosphere.

This is where something like anti-gravity could change the game.

If you could simply ignore gravity or activate something that counters it, it would be revolutionary.

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