Orbit isn't up. It's sideways.
Newton's 1687 thought experiment: fire a cannonball from a mountain, harder and harder. Slow, it falls back. Fast enough, it falls past the curve of the Earth — forever. That's all an orbit is.
Launch speed v
sideways, from 300 km up
0 km/scrash · orbit · escape12 km/s
Try
Newton's own 1687 diagram in the Principia made this exact argument: gravity doesn't stop a fast-enough cannonball, it just bends its straight-line path into a curve that keeps missing the ground. This page uses real two-body orbital mechanics (an ellipse or hyperbola computed from Earth's gravitational parameter GM = 3.986 × 1014 m3/s2), not a scripted animation. The cannon sits at a fixed, imaginary 300 km altitude — like Newton's mountain, but tall enough to clear the atmosphere the equation doesn't model, so a real drag-free trajectory is actually shown. vcirc above is the exact speed needed for a perfect circle at that altitude, close to where the International Space Station actually orbits. Escape velocity from this altitude is vcirc × √2 — the same 41% rule that appears throughout orbital mechanics. Orbital animation speed is not to any real time scale; it exists to show direction of motion, not how fast a real satellite crosses the screen.
Private feedback
Was this clear?
Your response is private and helps improve this page.