Observations By Spacecraft
Since the start of the Space Age, a great deal of exploration has been performed by robotic spacecraft missions that have been organized and executed by various space agencies.
All planets in the Solar System have now been visited to varying degrees by spacecraft launched from Earth. Through these unmanned missions, humans have been able to get close-up photographs of all the planets and, in the case of landers, perform tests of the soils and atmospheres of some.
The first artificial object sent into space was the Soviet satellite Sputnik 1, launched in 1957, which successfully orbited the Earth until January 4 the following year. The American probe Explorer 6, launched in 1959, was the first satellite to image the Earth from space.
Read more about this topic: Discovery And Exploration Of The Solar System
Famous quotes containing the word observations:
“The natural historian is not a fisherman who prays for cloudy days and good luck merely; but as fishing has been styled “a contemplative man’s recreation,” introducing him profitably to woods and water, so the fruit of the naturalist’s observations is not in new genera or species, but in new contemplations still, and science is only a more contemplative man’s recreation.”
—Henry David Thoreau (1817–1862)