|Jupiter with the great red spot shot from Voyager 1
On July 9, 1979 the interplanetary spacecraft Voyager 2 passed Jupiter, the largest planet in the Solar System. The space probe had been launched by NASA on August 20, 1977 to study the outer Solar System and eventually to push forward into interstellar space. Until today, operating for more than 30 years the spacecraft still receives routine commands and transmits data back to the Deep Space Network, a world-wide network of large antennas and communication facilities. Besides its passage of the Jovian system including Jupiter’s moons, the primary mission of Voyager 2 ended December 31, 1989 after encountering also the Saturnian system in 1980, the Uranian system in 1986, and the Neptunian system in 1989.
Two weeks after the launch of Vojager 2, the twin Voyager 1 probe was launched on September 5, 1977. However, Voyager 1 would reach both Jupiter and Saturn sooner, as Voyager 2 had been launched into a longer, more circular trajectory through the Solar System.
The closest approach to Jupiter occurred on July 9, 1979. It came within 570,000 km of the planet’s cloud tops and discovered a few rings around Jupiter, as well as volcanic activity on Io, one of the moons. The Great Red Spot, a prominent oval-shaped feature in the southern hemisphere of Jupiter already observed with telescopes in the 17th century, was revealed as a complex storm moving in a counterclockwise direction. Discovery of active volcanism on Io was easily the greatest unexpected discovery at Jupiter. It was the first time active volcanoes had been seen on another body in the Solar System.
|Europa, as seen by the Galileo spacecraft|
The moon Europa displayed a large number of intersecting linear features in the low-resolution photos from Voyager 1. At first, scientists believed the features might be deep cracks, caused by crustal rifting or tectonic processes. The closer high-resolution photos from Voyager 2, however, left scientists puzzled: The features were so lacking in topographic relief that as one scientist described them, they “might have been painted on with a felt marker.” Europa is internally active due to tidal heating at a level about one-tenth that of Io. Two new, small satellites of Jupiter, Adrastea and Metis, also were found orbiting just outside the ring. A third new satellite, Thebe, was discovered between the orbits of Amalthea and Io.
As of February 8, 2012, Voyager 2, traveling at 15.447 km/s relative to the Sun, is about 98.358 astronomical units away from the Earth. It is still transmitting scientific data at about 160 bits per second and will continue transmitting weak radio messages until at least 2025, over 48 years since it was launched.
At yovisto you might learn more about the Voyager space program and the discovery of ouer outer solar system in a NASA special space science presentation on ‘Voyager – Humanity’s Farthest Journey‘
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