Science
Pollen grains jitter for no visible reason — it took 80 years to explain why
In 1827, botanist Robert Brown watched pollen grains jitter randomly in water under his microscope and ruled out life as the cause when lifeless dust particles did the same thing. The mystery sat unsolved for nearly 80 years until Einstein's 1905 paper showed the jostling was caused by unseen water molecules colliding with the particles, offering some of the first direct evidence atoms are real.