jump to other results. 1  1[countable] a particular attitude towards something; a way of thinking about something synonym viewpoint a global perspective Recent events seem less serious when put into an international perspective.
Low earth orbit is only slightly above the Earth, by outer space standards, 124 - 1240 miles (200 - 2000 km) in altitude. Below 124 miles, orbits rapidly degrade, causing surface impact, and above 1,240 miles or even less, the Earth's radiation belts damage electronic equipment, necessitating special shielding. The region from 1,243 miles altitude to geostationary orbit (35,786 kilometers or 22,236 mi) is known as Medium Earth Orbit.
Hence, the number 384,403 km, is an average distance that astronomers call the semi-major axis. At its closest point (known as perigee) the Moon is only 363,104 km (225,622 miles) away. And at its most distant point (called apogee) the Moon gets to a distance of 406,696 km (252,088 miles). This means that distance from the Earth to the Moon can vary by 43,592 km. Thatâs a pretty big difference, and it can make the Moon appear dramatically different in size depending on where it is in its orbit.