Space Is Not Completely Empty
Even deep space contains particles, radiation, magnetic fields, and traces of matter spread across enormous distances.
Knowledge Base
Science
Space, nature, time, and discoveries that help explain how the world works.
One Species, Many Foods
Cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy cabbage, kohlrabi, and gai lan are all cultivars of the same plant species, Brassica oleracea. Over time, they were bred to emphasize different parts of the plant, such as leaves, stems, flower buds, or sprouts.
Seeing Into the Past
There is no single universal “now.” Because light takes time to travel, everything you see is actually a glimpse into the past. Even the person sitting across from you is seen as they were a tiny fraction of a second ago, while looking at the Sun means seeing it as it was about eight minutes earlier.