A Brief History of High-Energy Astronomy: 1965 - 1969


In Reverse Chronological Order

20 Jul 1969
16:18 EST
Neil Armstrong reports back to Mission Control Houston "The Eagle has landed" -- the Apollo 11 Lunar Module containing Armstrong and Edwin Aldrin has landed on the Moon. Shortly thereafter Armstrong becomes the first human being to step and walk on the Moon.
3 Jul 1969 First ever detection of a cosmic gamma-ray burst (GRB) with positional information, achieved by the Vela 5A and Vela 5B satellites: see Strong et al. 1974, ApJ, 188, L1 for more details about this discovery.
23 May 1969 Co-launch of the Vela 5A and Vela 5B satellites to monitor compliance with the Limited Test Ban Treaty of 1963. Together with the Vela 6A and 6B satellites, these satellites are often credited with the first discovery of gamma-ray bursts (GRBs) although it was later realized that the Vela 4A and Vela 4B satellites had actually detected at least one GRB in 1967.
Jan 1969 Publication of the first issue of Astronomy and Astrophysics, a European journal which `publishes papers on all aspects of astronomy and astrophysics: theoretical, observational, and instrumental". This journal was the result of the merger of five European astronomical journals of longstanding: Annales d'Astrophysique, Bulletin Astronomique, Bulletin of the Astronomical Institute of the Netherlands, Journal des Observateurs, and Zeitschrift fuer Astrophysik, and is now generally regarded as one of the three premier journals in astronomy.
24 Dec 1968 Crew of Apollo 8 become the first human beings to orbit the Moon.
29 Oct 1968 at 11:32 UT Launch of a rocket from Johnston Atoll that carried two proportional counters sensitive to 1.5 to 25 keV X-rays. This experiment detected several sources, including a spatially extended one towards the Large Magellanic Cloud, the first X-ray detection of another Local Group galaxy: see Mark et al., ApJ, 155, L143, 1969 for more details.
27 Mar 1968 Soviet Cosmonaut Yuri Gagarin is killed in an airplane accident.
1967 - 1968 First Detection of rapidly pulsing radio sources, dubbed pulsars. These strikingly regular pulses, initially suspected to be caused by terrestrial interference, then briefly considered to be possible signals from extraterrestrial life, were within a year agreed to be due to beamed emission from rapidly rotating neutron stars. Two of the then-known handful of pulsars were found to lie in the directions of supernovae remnants (the Crab and Vela Nebulae) in confirmation of Baade and Zwicky's (1934) hypothesis for the origin of supernovae (q.v.).
7 Sep 1967 First reported detection of the Earth's X-ray airglow by two proportional counters flown on a Nike-Tomahawk rocket from Tonopah, Nevada. The team from Lawrence Livermore Lab were conducting a daytime flight to detect X-rays from Sco X-1 and the Crab Nebula when their experiment recorded a high count rate which peaked at an altitude of 130 km. Three weeks later, a flight with similar detectors flown at night detected no such emission. The researchers correctly interpreted this anomalous emission as fluorescent emission from nitrogen and oxygen in the Earth's atmosphere which had been excited by solar X-ray emission: see Grader et al. 1968, JGR, 73, 7149 for more details about this discovery.
2 Jul 1967 First ever detection of a cosmic gamma-ray burst (GRB) (albeit with no positional information), achieved by the Vela 4A and Vela 4B satellites: see Strong et al. 1974, ApJ, 188, L1 for more details about this discovery.
17 May 1967 Launch of an Aerobee rocket equipped with two proportional counters flown by a team from the US Naval Research Laboratory. These instruments detected X-rays from the quasar 3C 273 at a level of about one-thousandth of the brightest known X-ray source (Sco X-1); see Friedman and Byram (1967), Science, 158, 257 for more details.
28 Apr 1967 Co-launch of the Vela 4A and Vela 4B satellites to monitor compliance with the Limited Test Ban Treaty of 1963. Together with the Vela 5A, Vela 5B and the Vela 6A and 6B satellites, the Vela satellites made the first discovery of gamma-ray burst sources.
28 Apr 1967 Launch of the Fourth Octahedral Research Satellite (ORS-4; ERS-18). ORS-4 carried gamma-ray sensors that were the first to detect the diffuse cosmic gamma-ray background above 3.0 MeV (the upper limit of Ranger 3, the only previous gamma-ray detector to observe the gamma-ray background).
27 Jan 1967 A fire in the Apollo 1 capsule during a test on the launch pad kills three American astronauts: Virgil Grissom, Ed White II, and Roger Chaffee.
Aug 1966 The position of the X-ray source Sco X-1 is localized to a few arcminutes (Gursky et al. 1966, ApJ, 146, 310), thereby enabling its optical counterpart, a blue star with an unusual emission-line spectrum, to be identified (Sandage et al. 1966, ApJ, 146, 316).
1 Mar 1966 The Soviet spacecraft Venera 3 ceases to send data just as it arrives at Venus. However, the landing module did descend into the Venusian atmosphere, making this the first impact or landing of a spacecraft on another planet.
14 Jan 1966 Sergei Korolev, father of the Soviet space program, dies during surgery.
6 Dec 1965 In a flight of an X-ray telescope suspended on a balloon, a team from the Goddard Space Flight Center detects an extended X-ray source at the position of the Coma cluster of galaxies, the first X-ray detection of a cluster of galaxies: see Boldt et al. 1966, Phys. Rev. Letters, 17, 447 for more details. In a follow-up paper, Felten et al. (1966, ApJ, 146, 955) argue (correctly, as it later turned out) that the X-ray emission comes from a hot (108 K) intergalactic medium which pervades the entire Coma cluster.
16 Nov 1965 Launch of Venera 3, a Soviet probe sent to the planet Venus.
Apr 1965 Launch of an Aerobee rocket equipped with two Geiger counters flown by a team from the US Naval Research Laboratory. These instruments detected the first discrete X-ray sources identified with extragalactic objects, namely the elliptical galaxy Messier 87 and the `radio' galaxy Cygnus A, and also detected the galactic supernova remnant Cassiopia A. They also found that the previously detected source Cygnus X-1 had varied by a factor of several compared to its strength 9 months earlier, `the first clear example of an X-ray variable'; see Byram et al. (1966), Science, 152, 66 for more details.


Acknowledgements

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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