1Two things to know first
The Sun tugs everything — and the tug fades with distance
You need two small ideas. Watch each one happen:
The Sun is always pulling
Gravity is a tug. The Sun pulls on every planet, comet, and speck of dust — reaching out across empty space.
Farther = weaker
Move something twice as far and the tug drops to a quarter. The closer arrow is strong; the far one is faint.
2So which way does it work?
Two ways the tug could end
A wall at the edge? 🧱
Maybe gravity reaches out a long way, then hits a fence — past that line, nothing. Pull = zero.
A fade that never ends? 🌌
Or maybe it just keeps shrinking — smaller, smaller, smaller — but always a little bit there. Keep this in mind…
3Drive it yourself
Slide the probe out and watch the pull change
Here's the Sun and a little space probe. Drag it farther out and watch the coral pull-arrow — and the meter — shrink. At 2× the distance the pull is ¼; at 3× it's 1/9.
Double the distance, quarter the pull. The arrow never quite vanishes — but does it ever hit exactly zero?
4Now go WAY out and predict
Keep flying outward — past Neptune, and farther still 🚀
You saw the pull shrink fast. Now imagine pushing the probe out and out, way past every planet. Make your call first, then watch it happen.
Guess before you launch
Keep moving the probe farther and farther. Does the Sun's pull suddenly STOP at some faraway edge — or keep shrinking but never quite hit zero?