1963: Arecibo Ionospheric Observatory commissioned for service on Nov. 1 for $ 9.7 million.
1965: One of his first accomplishments was to establish the Mercury circulation rate, which turned out to be 59 days instead of the previously estimated 88 days.
1968: Sporadic radio beats from a Crab Nebula supernova remnant led found at Green Bank were shown by Arecibo coming from a 33-ms time pulsar located in the center of the nebula.
1974: New high precision surface reflector installed, planetary radar transmitter installed.
1974: The first pulsar in a binary system was discovered, leading to an important confirmation of Einstein ‘s theory of universal relativity and the 1993 Nobel Prize for astronomers Russell Hulse and Joseph Taylor.
1974: On November 16, the ‘Arecibo message’ was broadcast into space towards the M13 star cluster of 25,000 light – years away.
The main purpose of the message was to demonstrate the capabilities of newly installed equipment in the updated radio telescope and was an attempt to communicate external information.
1979: A major, irregular disturbance of ionospheric travel (i.e., high-altitude airwave) moving southeast to northwest was discovered in the wee hours of the morning – something the researchers had not seen never before. Data helped explain the most likely cause as an air nuclear explosion over the Indian Ocean.
1981: The first radar maps of the geological surface of Venus are produced.
1982: Detect strong megamaser emissions from the hydroxyl (OH) molecules in the galaxy starb Arp 220 (IC 4553).
1982: Find millisecond pulsars, which rotate several hundred seconds. This showed that there were two types of pulsars – the millisecond pulsars and the slower changing pulsars, which rotate about once every second.
1989: The first measurement of hydrogen escape flux from the Earth is displayed, based on distance circulation measurements of hydrogen emissions in the upper atmosphere.
Early 90s: The first planets outside the solar system were discovered around Pulsar B1257 + 12, a rapidly orbiting pulsar with three Earth-like planets in orbit.
1992: In October, ice is found in shady pits at Mercury’s north pole. Later scenes show ice in south pole pits as well.
1996: Coating of helium ions is shown to be a common, but previously unrecognized feature in the ionosphere with a low latitude of nearly 600 km.
1998: The Arecibo Observatory ‘discovered the Solar and Heliospheric Observatory (SOHO) spacecraft on July 28, after losing contact with the European Space Agency and NASA,. by kicking a radar signal off the satellite. The SOHO mission has been restarted and it is releasing data today.
May 2000: Radar Views on Asteroid 216 Kleopatra features a full metal object shaped like a ‘dog bone’.
September 2000: Discovers that 2000 DP107 is the first near – Earth asteroid identified by radar as a binary system. The primary is relatively spherical with a diameter of half a mile and the smaller secondary, which orbits in 1.8 days, is about 1000 feet.
2003: Evidence for hydrocarbon lakes on the Saturn satellite Titan has been established using the Observatory’s planetary radar.
April 2004: Incorporating Arecibo ‘s L – band Feed Array, enabling a wide variety of astronomical studies including the detection of pulsars, mapping the gas in our Galaxy, and the discovery of other galaxies.
2005-2012: Radar images of Mars show near-surface lava flows and geological features not seen in visible images. This offers new perspectives on the surface geology of Mars.
2006: Water ice found in Shackleton Crater’s permanent lunar shade controversial evidence for water ice on the lunar surface.
October 2006: Radar images of the lunar south pole show no evidence for thick ice deposits.
November 2006: Radar images of binary asteroid (66391) 1999 KW4 in May 2001 and again in June 2002 show physical and dynamic features common among binaries near Earth.
March 2007: Radar images of Mercury reveal features that will be further explored by the Messenger spacecraft over the next several years.
2007: The 2005 near-Earth PH5 asteroid was seen to rise in spinning rate, due to non-uniformity and the spread of solar radiation.
2007: Previously undiscovered radio lines of the hydrogen cyanide (HCN) molecule, and the presence of the methanimine (CH2NH) molecule, were recently discovered in the distant starburst galaxy Arp 220.
February 2008: Discover the first triple asteroid system among the asteroids near Earth. The asteroid, 2001 SN263, is about 1.5 miles in diameter, with two moons orbiting.
2008–2012: Comments discover a radio break in the nearby galaxy NGC 660, ten times brighter than a radio supernova.
2011: Watching a brown dwarf find the coldest star to reveal radio broadcasts.
November 2011: Radar image of near – Earth asteroid 2005 YU55, which made very close flight. This dark, spheroidal asteroid was found about 1,148 feet in diameter.
2012: A model of ion-neutral chemistry has been developed to successfully describe thin layers of neutral metal atoms at altitudes above 62 miles.
Further information: National Astronomy Center and Ionosphere