Since the dawn of the Space Age, close observation by space probes has found that Earth and the other planets share characteristics such as volcanism, hurricanes, tectonics, and even hydrology.
Sejak awal Zaman Angkasa, pengamatan jarak dekat oleh wahana antariksa membuktikan bahwa Bumi dan planet-planet lain memiliki tanda-tanda vulkanisme, badai, tektonik, dan bahkan hidrologi.