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
|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
|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,
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
Sputnik 2. At this early stage in the space program, no system for a
safe reentry had been developed: Laika was put to sleep after one week in
|4 Oct 1957
||Successful launch of the first human-made satellite,
by the USSR, marking the beginning of the Space Age.
||Publication of the landmark review paper `Synthesis of the Elements
in Stars' by
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.
|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.
|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
|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).
||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'.
|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.).
||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.
||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
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
|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).
||Invention of the Geiger-Mueller detector.
|16 Mar 1926
||First successful flight of a liquid-propellant rocket, designed
& built by Robert Hutchings Goddard.
||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
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.
|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
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.
||First reported detection of a magnetic field in any astronomical object
, namely a sunspot, using the Zeeman effect, by
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.
||Gamma rays are discovered by Villard and are considered to be
a highly energetic form of X-rays.
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of High-Energy Astronomy page
We would like to thank the following individuals for their
contributions to this page:
Jesse S. Allen, and
Ian M. George
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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