LMR-073 · Dark Universe
MOND
What if gravity itself is just wrong on huge scales?
§ A first look
§ Depths
Six ways into the same idea — from bedtime story to chalkboard. No order required.
L1 · Crayon
Told like a bedtime story.
For a curious 10-year-old. No jargon. Just a picture in your head.
When we look at how galaxies spin, the outside stars are moving way too fast — gravity from the visible stuff isn't strong enough to hold them in. The popular explanation says there must be lots of extra invisible stuff (dark matter) adding more pull. There's also a different idea: what if there's no extra invisible stuff at all, and instead the rule of gravity itself works a tiny bit differently when the pull is very weak and you're way out in the suburbs of a galaxy? That 'change the rule, no invisible stuff' idea is called MOND. It's the contrarian theory and it has friends.
§ Strange but true
- 01What if dark matter doesn't exist, and gravity itself just works differently at huge distances?
- 02Modified gravity (MOND) explains galaxy rotation curves beautifully — and clusters terribly.
- 03Most physicists don't buy it. But it stubbornly refuses to die.
§ From the field journal
MOND
"What if gravity itself is just wrong on huge scales?"
— observed, sketched, not yet fully understood.
§ Nearby