A Brief History of High-Energy Astronomy: 1900 - 1959

In Reverse Chronological Order

13 Oct 1959 Launch of the US Explorer 7 satellite. This satellite operated until Aug 24, 1961, and, like Vanguard 3, carried ion chambers provided by the Naval Research Laboratory that were intended to detect (solar) X-rays (and Lyman-alpha), and thus was arguably the second satellite X-ray observatory. Unfortunately, like Vanguard 3, `the Van Allen Belt radiation swamped the detectors most of the time' and no useful X-ray data were obtained (H. Friedman 1960, AJ, 65, 264).
18 Sep 1959 Launch of the US Vanguard 3 satellite. This satellite transmitted data until Dec 11, 1959; it carried ion chambers provided by the Naval Research Laboratory that were intended to detect (solar) X-rays (and Lyman-alpha), and thus was arguably the first satellite X-ray observatory. Unfortunately `the Van Allen Belt radiation swamped the detectors most of the time' and no useful X-ray data were obtained (H. Friedman 1960, AJ, 65, 264).
13 Sep 1959
22:02 UT
The USSR's Luna 2 spacecraft becomes the first human-made device to reach the Moon. It (intentionally) impacts the surface east of Mare Serenitatis.
1 May 1959 The National Aeronautics and Space Administration (NASA) establishes a new space science laboratory in Greenbelt, Maryland to be called the Goddard Space Flight Center in honor of the American rocket pioneer Dr. Robert H. Goddard.
1 Oct 1958 The National Aeronautics and Space Administration (NASA) is created, absorbing the former National Advisory Committee for Aeronautics (NACA) and some other US government organizations. For information about the subsequent history of NASA, check out the NASA History Office website.
26 Mar 1958 Launch of the American satellite Explorer 3 on a Jupiter-C rocket. Explorer 3's payload consisted of a cosmic ray counter (a Geiger-Mueller tube), and a micrometeorite detector (erotion gauge). Explorer 3 confirmed the existence of the Van Allen Radiation Belts, first discovered by Explorer 1. The discovery of the Van Allen Belts by the Explorer satellites was considered to be one of the outstanding discoveries of the International Geophysical Year (IGY) 1957-1958.
31 Jan 1958 Launch of the first American satellite, Explorer 1 on a Jupiter C launch vehicle. The satellite's total weight was 30.66 pounds, of which 18.35 pounds were instrumentation. Its Instrumentation consisted of a cosmic-ray detection package, a number of temperature sensors, a micrometeorite impact microphone, and a ring of micrometeorite erosion gauges. Once in orbit, the cosmic ray detectors on Explorer 1 indicated a much lower cosmic ray count than had been anticipated. Dr. James Van Allen theorized that the equipment may have been saturated by very strong radiation caused by the existence of a belt of charged particles trapped in space by the earth's magnetic field. The existence of these `Van Allen Belts' was later confirmed by Explorer 3 (launched on 26 March 1958).
4 Jan 1958 Sputnik 1 reenters the Earth's atmosphere. Its batteries had already failed by this date. The much heavier booster which carried it to orbit reentered earlier on 1 Dec 1957.
3 Nov 1957 Successful launch of the first animal in space, the dog Laika on the Soviet Sputnik 2 satellite. At this early stage in the space program, no system for a safe reentry had been developed, so Laika was put to sleep after one week in orbit.
4 Oct 1957 Successful launch of the first human-made satellite, Sputnik 1 by the USSR, marking the beginning of the Space Age.
1957 Publication of the landmark review paper `Synthesis of the Elements in Stars' by Margaret Burbidge, Geoffrey Burbidge, William Fowler, and Fred Hoyle, commonly referred to as B2FH, in Reviews of Modern Physics, 29, 547 (1957). This seminal paper convincingly demonstrated that all elements except for a handful of the lightest ones were (and are still) created by steady and/or explosive nuclear reactions inside stars.
1957 The International Geophysical Year. This was an 18-month (!) international scientific program from July 1, 1957 to December 31, 1958 that fostered the collaboration of 67 countries in a variety of earth and space science activities.
23 Feb 1956 A number of ground-based detectors of cosmic rays registered what was arguably the largest ground level enhancement (GLE) of solar cosmic rays ever recorded in the 75 years that such measurements have been made. The GLE was the result of a giant solar flare that was detected in optical observations of the Sun about 15 minutes earlier: see Rishbeth, Shea & Smart (2009, Advances in Space Research, 44, 1096) for more details.
29 Sep 1949 A Naval Research Laboratory (NRL) photon counter tube, onboard a V2 rocket, which was sensitive only to radiation of wavelengths shorter than 10 Angstroms (i.e., X-rays) detects a clear signal. The rocket developed a slow and steady 12-second roll after the first 60-seconds of its flight, and, once it ascended above 87 km, the X-ray detector showed a sharply modulated response every time the Sun is in its field of view, confirming that the X-rays were from the Sun: see Friedman et al. (1951, Phys. Rev., 83, 1025) for more details of this work.
17 Feb 1949 A Naval Research Laboratory (NRL) experiment, onboard a V2 rocket, which consisted of a thermoluminescent phosphor behind a beryllium filter that allowed only radiation of wavelengths shorter than 8 Angstroms (i.e., X-rays) to pass through registers a clear signal "presumably [X-rays] of solar origin": see Tousey et al., Phys. Rev., 83, 792 (1951) for more details of this work.
5 Aug 1948 A Naval Research Laboratory (NRL) experiment is launched on a V2 rocket. This detector consisted of a photographic plate behind a beryllium filter that allowed only radiation of wavelengths shorter than 4 Angstroms (i.e., X-rays) to pass through. It detected an 'unexpected' intensity level which was interpreted as due to X-rays from the Sun: see Burnight (1949, Phys. Rev., 76, 165) for more details. The Sun and/or solar flares had been suspected as a possible source of X-rays for at least a decade previous to this (by, for example, Hulburt and Vegard in papers published in 1938), and Alfven and Edlen in 1941 had proposed that the solar corona was a 1-million K plasma (which would be hot enough to be a steady emitter of such X-rays).
Apr - Jun 1946 First reported detection of a magnetic field in an extrasolar object, namely the Peculiar A-type (or Ap) star, 78 Virginis, by Horace Babcock, using the 100-inch Telescope at the Mount Wilson Observatory, near Pasadena, California. (Babcock, H.W. 1947, ApJ, 105, 105).
Feb 1942 Discovery of radio emission from the (flaring) Sun by J.S. Hey. This was detected as `interference' by the network of radar installations set up in England during World War II, and was at first thought to be caused by German `jamming'. Due to wartime secrecy regulations, this discovery could not be publically announced until after war's end, by which time Grote Reber (1944, ApJ, 100, 279) had announced that the Sun was a source of `cosmic static' in th radio band.
1 Sep 1939 Publication of the first detailed scientific paper suggesting that the endpoint of massive stars which have exhausted their nuclear sources of energy must be an infinitely collapsed object from which even light could not escape, i.e., what is now called a black hole, by Oppenheimer & Snyder (1939, Phys. Rev., 56, 455). The first convincing (to most scientists) detection of a black hole (the X-ray source Cyg X-1) was reported three decades later, in 1972 (q.v.).
1937 Publication of a paper (1937, ApJ, 86, 217) by Fritz Zwicky in which he reported evidence that the motions of galaxies in large clusters implied, assuming that these were stable structures, that the total masses of the clusters were much greater (by 2 orders of magnitude) than their `visible' masses, the first intimation that most matter in the universe is `dark matter'. The nature of this dark matter (whose existence is now widely accepted) is still not known.
1934 Publication of the first scientific papers suggesting that the enormous energy release observed in supernovae is due to the conversion of gravitational energy caused by the collapse of an "ordinary" (massive) star into a dense neutron star structure, by Walter Baade & Fritz Zwicky: see 1934, PNAS, 20, 259, Phys. Rev, 45, 138, and Phys. Rev., 46, 67. The first unambiguous detections of neutron stars (the rapidly pulsing radio sources dubbed pulsars) were reported three decades later, in 1967 and 1968 (q.v.). The locations of two of these pulsars in the centers of the Crab and Vela Supernova Remnants were triumphant confirmations of Baade & Zwicky's theory for the formation of neutron stars.
5 May 1933 Publication in the New York Times of an article announcing Karl Jansky's discovery of `cosmic' radio emission from the Milky Way (at first he had thought that the emission was from the Sun): this observation is generally considered to mark the birth of the field of radio astronomy.
23 Jan 1930 Discovery of the dwarf planet Pluto by Clyde Tombaugh, in a search which was begun by Percival Lowell. The existence of this object was hypothesized an an explanation for apparent anomalies in the orbits of Neptune and Uranus. Ironically, the mass of Pluto is much too small to have caused these anomalies. For 76 years Pluto was considered to be the 9th planet in the Solar System, until it was demoted to the status of a plutoid, i.e., a trans-Neptunian `dwarf planet", by the IAU in a resolution in 2006 (which was expanded upon in June 2008).
1929 Invention of the Geiger-Mueller radiation detector.
16 Mar 1926 First successful flight of a liquid-propellant rocket, designed & built by Robert Hutchings Goddard.
1925 Wernher von Braun straps six sky rockets to a toy wagon which provide thrust for a five block trip through his home town, terminated when the rockets exploded. Neither the explosion nor the stern lecture from his father which followed reduces his interest in rocketry.
26 Apr 1920 The Shapley-Curtis "Scale of the Universe" debate.
3 Mar 1915 The creation of the US National Advisory Committee for Aeronautics or NACA - the forerunner to NASA - with an annual budget of $5000.
1911 - 1914 Balloon flights by Victor Hess (and Kolhörster) demonstrate the existence of extraterrestrial `radiation', now commonly called cosmic rays: Hess was awarded the 1936 Nobel Prize in Physics for this work. It is now realized that cosmic rays are actually fast-moving energetic particles and not electromagnetic radiation.
30 June 1908 A large explosion occurs in a sparsely populated area near the Stony Tunguska River in Siberia, flattening trees for tens of miles. The Tunguska event is now believed to have been an atmospheric explosion or `air burst' caused by a high-velocity impact of a 60 to 90 meter diameter comet or meteoroid and to have had an energy of at least 10 megatons of TNT, and, if so, this is the largest impact event in recorded history.
June 1908 First reported detection of a magnetic field in any astronomical object , namely a sunspot, using the Zeeman effect, by George E. Hale. Hale used the telescopes at the Mount Wilson Solar Observatory, near Pasadena, California. (Hale, G.E., 1908, ApJ, 18, 315).
17 Dec 1903 The brothers Orville and Wilbur Wright make the first controlled flight of an airplane near Kitty Hawk, North Carolina.
1900 Gamma rays are discovered by Villard and are considered to be a highly energetic form of X-rays.

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We would like to thank the following individuals for their contributions to this page: Jesse S. Allen, and Ian M. George along with JPL's Space Calendar and the Working Group for the History of Astronomy's Astronomiae Historia (History of Astronomy) information pages.

Web page author: Stephen A. Drake (based on an original by Jesse S. Allen)

Web page maintainer: Stephen A. Drake

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