Recent observations from the NASA/ESA Solar and Heliospheric Observatory (SOHO) show that the Earth’s hydrogen envelope reaches up to 391,500 miles (630,000 km) away, or 50 times the diameter of our planet. The extent of Earth’s geocorona. Image credit: ESA. Where our atmosphere merges into outer space, there is a cloud of hydrogen atoms called the geocorona. “The first telescope on the Moon, placed by Apollo 16 astronauts in 1972, captured...
