The names of some man-made satellites are Sputnik 1, Explorer 1, the International Space Station, ORBCOMM FM-107, Gonets-19 and SES-8. In 1957, Russia launched the first man-made satellite called Sputnik 1, and the United States sent Explorer 1 into orbit in 1958. Since that time, over 6,500 satellites have been launched into space by different nations.
As of 2014, there are about 1,000 operational satellites in space, while nearly 2,600 are non-functional and are space debris. There are different types of satellites, such as fixed point, mobile and scientific research satellites. These satellites can orbit at different altitudes. For example, communications satellites, which are fixed point types, orbit Earth at about 22,000 miles.Learn More
A person who studies space is called an astronomer or astrophysicist. These types of scientists are responsible for the discovery of all of the planets, stars, asteroids and other extraterrestrial objects.Full Answer >
A spherical model of the Earth was first suggested by Plato, the Greek philosopher and mathematician. His theory was confirmed by the calculations of Pythagoras, an Ionian Greek mathematician. In 1514, Nicolaus Copernicus proposed that the Earth was a spherical body that revolved around the sun.Full Answer >
Astrolabes work by presenting users with a graphic interface that makes it relatively easy to compute the positions of the sun, the moon and the stars. Astrolabes can be used for navigation as well as predicting the exact times for sunrise and sunset. Turned on its side, an astrolabe can be used as a mechanical calculator akin to a slide rule.Full Answer >
Copernicus discovered that the planets revolved around the sun, rather than around the Earth. Called the heliocentric model of the solar system, the concept was at odds with the conventional wisdom of the time, which held that all heavenly bodies rotated around the Earth.Full Answer >