Uranus is the seventh farthest planet from the Sun the Solar system refers to the planets-giants. Was discovered March 13, 1781 English astronomer William Herschel (William Herschel), when compiling them with a full systematic review of the starry sky. Herschel had originally decided that he had discovered a new comet, but the comet hypothesis had to be abandoned soon.
Astronomer proposed to call the planet “Georgieva star” (in honor of the British king George III), however, in order not to break traditional ties with mythology, adopted the name Uranus after the Greek God of the sky.
The planet is at a distance 19,18 astronomical units (2871 million km) from the Sun and makes a complete revolution around the earth for 84 years.
Among the classical planets Uranus is unique in that the plane of its equator is inclined to the orbital plane at an angle of 98°. Thus, the planet rotates around the axis as lying on your side. As a result, Uranus is facing the Sun alternately the North pole, the South, the equator, the middle latitudes and the duration of the day and night on it considerably exceeds the axial rotational period of the planet. At latitude 30° day and night for last 14 years, at the latitude of 60° for 28 years, and at the poles for 42 years.
The direction of rotation is opposite to the direction of the planet rotation around the Sun, or the negative.
A theoretical model for the structure of Uranium is as follows: its surface layer is getitnow shell, under which there is ice (a mixture of ammonia and water ice) mantle and even deeper core of solid rock. Like other planets-giants, the atmosphere of Uranus consists mostly of hydrogen, helium and methane.
The planet has a poorly articulated system of rings, consisting of particles with a diameter from a few millimeters to 10 meters.
The uranium is surrounded by a system of satellites, the orbits of most of which almost coincide with the plane of the equator of the planet. The satellites of Uranus do not move in the plane of its orbit (as is the case with the satellites of all other planets) and almost perpendicular to it. Until 1986 it was known only about five moons.
The study of Uranium is difficult because of its remoteness. New data about the planet and its satellites allowed us to obtain a relatively close span of the American space probe of “Voyager-2”, made on 24 January 1986.
“Voyager-2” (Voyager-2) became the first and so far only spacecraft, which is managed as close to the Uranium.
Space probe developed at the jet propulsion Laboratory (JPL) for NASA. In the scope of his scientific instruments included two television cameras, magnetometers, spectrometers, ultraviolet and infrared ranges, photopolarimeter, detectors of cosmic radiation, charged particles, and more. Most devices found on a special rod, some of them on the rotating platform mounted on the end of this post.
“Voyager-2” was launched from Baikonur Space center. Kennedy on 20 August 1977 rocket “Titan 3E-Centauri”. Initially the spacecraft was launched to Jupiter and Saturn, but later its mission was extended.
At the turn of the 1970s and 1980s, all the giant planets (Jupiter, Saturn, Uranus and Neptune), which is located in a relatively narrow sector of the Solar system (“parade of planets”, which occurs about once every 175 years), which made possible a further flight to Uranus and Neptune.
During the flight of “Voyager-2” has been applied gravitational maneuvers used to change the trajectory of the gravitational field of planets, which reached the spacecraft. The necessary energy is taken from the planet and, according to the law of conservation, was added to the kinetic energy of the system. Changing the direction of flight of the probe was achieved with virtually no fuel costs.
With the help of two planets — Jupiter and Saturn (each of them with its powerful gravitational field has a strong influence on the probe), “Voyager-2” made two steep left turn, before he went out to the estimated point of meeting with Uranus on 24 January 1986. Due to such gravitational maneuvers the spacecraft reached Uranus is much faster than if he travelled all the way only on the strength of the momentum they received at the start with 3емли — it would take about 30 years.
During their journey of “Voyager-2” to the Uranium scientists and engineers had to solve a number of problems associated with the operation of the equipment on Board the space station remote from the command post on a distance twice more than projected. Onboard computers have been completely reprogrammed; one of them was set to compress video signals to reduce the transmission time to the Ground. To receive extremely weak radio signal “Voyager-2” multiple antenna network tracking stations in deep space have been electronically merged into the so-called lattice to strengthen their reception capacity.
Spacecraft by passage of the trajectory crossed the orbit of Uranus. Most information about the planet were obtained for several hours until “Voyager-2” was nearby, flying at a distance of 81.5 thousand kilometers from the surface of the clouds. The camera, mounted on a rotating platform, constantly rushed the planets and satellites, turning on automatically to a preset program. Due to the large distance from the Sun, Uranus receives very little sunlight, so the filming was done with very long exposures to record the image of the planet and its satellites. For this shooting the station to turn together with the camera with the shutter open after the planet, like the cameraman, the leading pan for a fast moving object.
During the flight of “Voyager-2” to the axis of rotation of Uranus, which lies almost in the plane of its orbit, was sent toward the Sun, so the resulting photographs depicted only the southern lit at that time the hemisphere of the planet. The pictures were found 10 previously unknown small satellites of the planet. From the spacecraft were received detailed photos of the five previously known satellites, and images of narrow rings of Uranus.
Discovered two new faint rings.
Like other giant planets, in the atmosphere of Uranus were discovered vortices, jet streams, spots (but much less), and in the depth of its registered methane clouds. Helium was three times less than previously estimated-just 15%. The circulation of the atmosphere occurs at high latitudes with greater speed than at the equator.
Probe “Voyager-2” has been performed measuring the temperature of the upper atmosphere of Uranus at a time when winter and summer at the poles reached its highest development. It turned out that, despite the extremely uneven distribution of solar heat on the planet, and temperature values at both poles and at the equator are almost identical. This suggests the existence of some mechanism of heat transfer in the atmosphere of Uranus from more heated areas to less heated, and Vice versa.
Spacecraft specified size of Uranus — the planet’s diameter (the cloud layer) was found to be 51.2 per thousand kilometers, which is about four times more than 3емли. The upper limit of the atmosphere, the capacity of which reaches about 7000-8000 miles that make up clouds.
The probe was detected and magnetic field of Uranus as well as to study the structure of its magnetosphere. It was found that the magnetic loop of this planet created perfectly unique magnetic lines of force is not stretched in a straight line, as in other planets, and twisted into a double helix.
Received by the spacecraft data showed that the period of rotation of Uranus around its axis is 17 hours and 14 minutes.
After Uranium, “Voyager-2” was displayed on the flight path to the planet Neptune, which approached 25 August 1989.
After the flyby of Neptune the spacecraft was sent to the outer boundary of the Solar system, continuing to transmit to Earth scientific information. It is expected that “Voyager-2” will be able to collect scientific data until about 2025.
The study of Uranium continues from ground-based and space telescopes. Since 1997, observations from Earth were discovered several distant moons of Uranus. Currently in its system open 27 natural satellites. The names selected for them by names of characters in the works of William Shakespeare and Alexander Pope.
The material is based on information RIA Novosti and open sourceRelated posts: