The Astronomical Society of the red Sea of Arabia, ASRA is pleased to publish, for the first time, some parts from an article written in the respectful Astronomy Magazine, the world's best seller astronomy magazine.
The title of the article is : 100 years of astronomical discoveries.
The complete article was published in the September 2016 issue of the magazine.
CONTINUATION OF THE ARTICLE.
THE FIFTH DECADE THE 1940s.
1940
On March 15, a plane flying at 20,000 feet above Antarctica measures cosmic rays, trying to learn more about these elusive and mysterious signals.
(Grote Reber Publishes "Cosmic Static")
Fascinated by the work of the American physicist and radio engineer Karl Jansky, an American amateur astronomer named Grote Reber wants to investigate the Milky Way Galaxy at meter wavelengths. He is more or less alone in his interest. Reber spent half his yearly salary into building a 30 foot (9 meter) dish in his backyard and observing at different wavelengths until he begins to see results. Between 1940 and 1944, he publishes a series of papers on "cosmic static" in various journals, essentially founding the field of radio astronomy. Over the next decade, radio operator mostly involved with the war effort begin to notice various astrophysical signals. By the end of the war, Reber's lonely field becomes a veritable crowd.
1941
(The Discovery Of Type l and Type ll Supernovae)
After searching the sky with his observing partner German astronomer Walter Baade, American - German astronomer Rudolph Minkowski concludes, from a list of 14 supernovae, that two families exist : type l supernovae with no evidence of hydrogen in their chemical signatures, and type ll supernovae which do contain hydrogen. This distinction isn't perfect. In fact, astronomers later learnt hat some species of type l supernovae share a common progenitor with type ll supernovae - they come from the death throes of massive stars. It is only the subset of explosions known as type la supernovae that are truly unique. But Baade and Minkowski's discovery is the first attempt to classify different kinds of supernovae events, and it starts astronomers down the path to understanding these cosmic explosions.
1942
Famous English physicist Stephen Hawking is born.
In April, the Dutch astronomer Jan Oort and the American astronomer Nicolas Mayall conclusively identify the Crab Nebula (M1) as the remnant of the supernova of 1054 seen by the Chinese, Japanese, and Arab astronomers.
German astronomer Walter Baade and American - German astronomer Rudolph Minkowski, in two independent papers in the September issue of The Astrophysical Journal, tentatively identify the central star of the Crab Nebula.
On October 3, Swedish electrical engineer and plasma physicist Hannes Alfvén describes a particular kind of plasma wave, later called Alfvén waves, which help astronomers understand processes occurring in objects such as the sun's corona and the interstellar medium. This work earns him the Noble Prize in physics in 1970.
The Italian physicist Enrico Fermi and his team working in the Manhattan Project - (the nickname of the the project of building the first atomic bomb) - achieve the first self sustaining nuclear reaction at the University of Chicago on December 2.
(Radio Emission From The Sun)
Working with the British Army, English physicist and radio astronomer James Stanley Hey is trying to track German ships in The English Channel. As a member of the army Operational Research Group, he is also keen to understand the various radar jamming techniques the German have been employing against the Allied Forces. On February 27, he notices a source of radio noise that tracks with the Sun. After contacting the Royal Observatory in Greenwich, he discovers that a particular large sunspot group is active. He writes a report about his findings, correctly connecting the two phenomena. Later in the same year, American radio engineer George Clark Southworth from Bell Laboratory, also studying radio interference, likewise observe radio emission from the Sun. Both reports remain classified until the end of the war, although rumors somehow make their way into the fledgling radio astronomy community.
(First Successful V-2 Rocket Launch)
World War ll casts its shadow into all corners, and the first modern rockets carry not satellites to space, but bombs into Western Europe. What American rocketeer Robert Goddard could not achieve in peacetime, the Nazis German accomplish with military efficiency in war time. Nonetheless, the German V-2 rocket that inflects so much damage across Europe becomes, on October 3, the first man-made object launched to space (assuming the military's definition of space starting at an altitude of 80 kilometers). Later, it becomes the basis for America's rocket program. The V-2 is the brainchild of Wernher von Broun, though he admits after the war that Goddard's work was crucial to his success. After the war, von Broun and most of his engineering team move to the United States, where he continues his work.
1943
American astronomer Carl Keenan Seyfert identifies a new type of active galaxy that later would bear his name. They have bright centers, like quasars, but have lower energies and their surrounding galaxies are visible.
1944
In November, Dutch–American astronomer and planetary scientist Gerard Kuiper observe methane absorption lines while conducting spectroscopy of Saturn's largest moon Titan, indicating that it has extensive atmosphere.
American amateur astronomer Grote Reber, unbound by war time secrecy, publishes the first detections of radio signals from the Sun in November.
(Tow Populations Of Stars)
With the threat of World War ll pressing down, the city of Los Angeles goes dark to avoid detection from possible enemy bombers. The bright side of the dark is felt at Mount Wilson Observatory, where German astronomer Walter Baade takes full advantage and pushes the 100 inch (2.5 meter) Hooker Telescope to its limits. He had the equipment mostly to himself, as his German citizenship bars him from participating in the war effort like most of his fellow astronomers. He resolves distinct stellar populations in the nearby Andromeda Galaxy (M31). The blue and red stars are segregated in the galaxy's disk and bulge, respectively. The full impact of his discovery - that the bulge's red stars are an older population than the blue conglomerations in the disk - takes a few more years to resolve, but this findings are immediately invaluable.
1946
The U.S. Army Corps bounces radio signals off of the Moon on January 10, the first example of radio astronomy.
American astronomer Horace Babcock discovers a magnetic field around the star 78 Virginis, the first stellar magnetic field ever observed.
The U.S. Army announces the world's first fully electronic computer - the Electronic Numerical Integrator And Computer, also known as ENIAC - to the public February 15, ushering in a new era of scientific computing.
English astronomer Fred Hoyle conceives the idea of stellar nucleosynthesis, that stars can creat elements in their hot and dense interiors.
American theoretical physicist and astronomer Lyman Spitzer writes an article titled "Astronomical Advantages of an Extraterrestrial Observatory", discussing the need for and challenges of a telescope that would orbit outside earth's atmosphere. Spitzer is widely credited with seeding the idea of a space telescope.
(Radio Interferometry)
English radio astronomer Martin Ryle, with a team of Australian radio astronomers, builds the first radio interferometer. Interferometry is the process of combining multiple wave signals to learn more than a single signal can reveal. Ryle goes a step further and figures out how to network multiple telescopes to work together as one large telescope. This "synthetic aperture" technique allows a collection of small dishes or antennas to function like one dish as big as the separation between the individual pieces. Ryle's team makes the first observations with his new array in 1946. This work earns him the Noble Prize in physics in 1974, the first ever Nobel prize in history awarded in recognition of astronomical research.
1947
In March, Dutch - American astronomer Bart Bok publishes a paper about "Bok globules", a small dark nebulae he theorizes are cocoons for star formation.
United States Air Force test pilot Chuck Yeager breaks the sound barrier October 14 in the Bell X-1 plane, the first in a long line of advanced experimental aircrafts.
Physicists at Bell Laboratory invent the transistor, which replaces vacuum tubes and becomes the basis for virtually all electronic equipment moving forward, allowing calculators and cell phones to fit in one's hand, and computers to cram into the limited area of a space satellite.
1948
American cosmologist Ralph Alpher and American scientist collaborator Robert Herman predict that a microwave background glow from the Big Bang should exist, and advocate a search. An unconvinced astrophysics community ignores their efforts, and their work is mostly forgotten until American astronomers Arno Penzias and Robert Wilson stumble onto the predicted microwave signal by chance in 1964. Penzias and Wilson received the 1978 Nobel Prize in physics for their discovery.
On February 16, Dutch–American astronomer and planetary scientist Gerard Kuiper discovers Miranda, the smallest of Uranus round moons and the last to be discovered before the 1986 Voyager 2 flyby.
(The Steady State Universe Theory)
English astronomer Fred Hoyle, American astrophysicist Thomas Gold, and Austrian mathematician and cosmologist Hermann Bondi develop a "steady state universe" theory, which emerges as the primary competition to the "Big Bang" theory - a term Hoyle coins in a 1949 radio interview to emphasize the difference between the two theories. By 1948, the universe is known to be expanding, but steady state theory claims that matter is created continuously, so that the universe's density remains constant.
(Big Bang Nucleosynthesis)
American cosmologist Ralph Alpher, with his adviser the Soviet - American theoretical physicist and cosmologist George Gamow, and Gamow's friend German - American nuclear physicist Hans Bethe, publishes a paper titled "On the Origin of Chemical Elements". Within its pages, he posits that the hot swirl of material following the Big Bang is responsible for creating the elements of the universe in the proper observed abundances. While it mistakenly assumes this process works for all elements, it is a crucial first step in what comes to be called Big Bang nucleosynthesis, and is fundamental to understanding how the universe's lighter elements - hydrogen and helium, which make up most of the cosmos - came into being.
1949
On May 1, Dutch–American astronomer and planetary scientist Gerard Kuiper discovers Nereid, a moon of Neptune, and the last to be discovered before the 1989 Voyager 2 flyby.
In September, American scientist Herbert Friedman uses Geiger counters aboard a launched V-2 rocket to observe X-rays from the Sun's hot outer layer, the corona.
American president Truman establishes rocket testing ground at Cape Canaveral, Florida, on May 11, setting the scene for decades of future space flights.
Italian physicist Enrico Fermi suggests that cosmic rays achieve their incredible energies when they are accelerated by magnetic fields in interstellar clouds.
(The Palomar Sky Survey)
Using the brand new 48 inch (122 centimeter) Schmidt telescope at Mount Palomar Observatory, the National Geographic Society fund an all sky survey of the northern hemisphere. It isn't completed until 1958, and the final data encompass 936 photographic plate pairs - one sensitive to red light and the other sensitive to blue - to map more than there quarter of the sky. Astronomers studying the survey data discover and catalog thousands of previously unseen celestial objects, and refer back to the survey's images and data for decades. As the century progresses, such immense sky surveys will become more and more common, as teams of astronomers use large instruments to carry out extensive mapping. The Palomar sky survey is the beginning of a new era in astronomy.
(The Glass Giant Of Palomar)
The 200 inch (5 meter) Hale Telescope is an engineering feat, doubling the size of the world largest telescope. It maintains its title well into the later half of the century. More than 11 years pass from the time the glass is melted for the primary mirror in 1934 until it is ready to be installed on Palomar Mountain. The behemoth weights 14.5 tons. Dedicated June 3, 1948, American astronomer Edwin Hubble takes the first image January 26, 1949, and research begins in earnest by the end of the year. The telescope is the workhorse of the 20th century, and astronomers use it to determine the size of the universe, study stellar populations in near by galaxies, and discover bright active galaxies at the far reaches of the cosmos.
To be continued in part 4
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