Prior to the landing of Apollo, the Soviet Union and the United States sent probes to the Moon. During some of the attempts to land some probes crashed while others made a soft landing. Luna 11, a Soviet probe sent back the first close-up pictures of the Moon. The space ship soft landed on the Moon and ejected an instrument capsule. Inside the capsule was a camera and transmitting antennas. Lunar 16, with its long arm a drill attached extracted soil sample that were placed in a container and blasted off back to Earth.
The Soviets used a remote control machine, Lunokhod, to fly over the moon and take pictures to send back to Earth.
Probes are very useful in orbiting or landing on planets and their moons. They have flown to most planets and some are on their way out of the Solar System and into interstellar space. They radio back to Earth informative data and excellent pictures.
In 1989 NASA sent up the Galileo space probe. The purpose of this mission was to orbit and study Jupiter starting in 1995.
The mission of the Viking probes were to study Mars and search for signs of life. In 1976 probes entered the thin Martian atmosphere, soft landed and began to send back photographs and weather information for several years. The soil samples on Mars failed to indicate any signs of life.
The two Voyager space probes launched in 1977 were missioned to study distant planets. The results sent back included great photographs of planets and their moons. The planets visited were Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. The Voyager spacecraft used the gravity of one planet which would fling the spacecraft in the fashion of a slingshot toward another planet.
Aboard the Voyagers were cameras, six computers, fuel tank to feed gas to small jets for stabilization, nuclear generator for the power supply, aerials to pick up natural radio waves from planets, boom carriers which are instruments to measure magnetic fields and large radio antennas to communicate with Earth.
An astronomer is a scientist that studies stellar bodies. Astronomers study the heavenly bodies with huge telescopes housed in domed observatories or on spaceships. At night the dome is opened and the telescope rotates at the same speed as the Earth to make it possible for objects to be photographed over a longer period of time. Most observatories are constructed on mountains where the air is clear.
The reflecting telescope and the refractor telescope are used to observe light rays from stars. The largest telescope in the world are the Keck Twin telescopes in Hawaii.
The Hubble Space Telescope, (HST) is an observatory placed in Earths orbit in 1 990. Churning and blurring in the atmosphere causes distortion in ground based observation. Distant objects appear fuzzy from Earth. The HST, outside the atmosphere sees the object much sharper. The HST can reach seven times farther into space than any ground observatory. It also provides ten times more detail. With the use of the HST, astronomers have made exciting new discoveries.
The infrared telescope is also used by astronomers to pick up infrared radiation given off by stars and planets. Several infrared telescope are perched high on a mountain in Hawaii, and on board satellites.
LIFE CYCLE OF STARS
The life cycle of a star begins as a spinning cloud of gas and dust called a nebula. Gravity then pulls billions of particles to gather into a huge ball. The inward pressure heats up these particles until the central region gets hot enough to start a nuclear reaction that transforms hydrogen into helium and a star is born.
The Harvard classification system divides stars into ten main types, O, B,A, F, G, K, M, R, N, and S. Each type is further divided into subdivisions. O, R, N, and S are considered comparatively rare. Most stars are included in the B to M sequence.
In 1908 E. J. Hertzsprung drew up a diagram where he plotted the luminosity of stars against their spectral types while simultaneously Russell in the United States was conducting similar research. The outcome is both men were credited and the research is known as the Hertzsprung-Russell Diagram or H-R diagrams. On this diagram most stars lie on the Main Sequence. At the left top the very luminous white stars are shown while to the bottom right the feeble red stars are shown.
In the universe the most abundant element is hydrogen, Normal stars contain primarily hydrogen. Inside a star is a tremendous amount of pressure with extremely high temperatures. The hydrogen nuclei combine to form nuclei of helium which yields energy. It is energy that keeps stars radiating.
Modern theory suggests that a star begins inside a nebula and contracts. The star will eventually join the main sequence at a point determined by its initial mass. If a star has a large mass, it joins the stars near the top left on the main sequence. Most of a stars brilliant career remains on the main sequence. When the hydrogen runs out, the core undergoes further contraction while the outside expands. This produces helium and the star becomes a giant. Eventually stars end up as white dwarfs, neutron stars or a black holes. Stars are said to be like people, they are born, they mature, they grow old, and they die.
One day our star will swell into a red giant, swallow up Mercury, and kill all life on Earth. The Sun will eventually shrink into a dim white dwarf about the size of Earth. It will cool down in time, and turn into a dense burned out amber.