AsteroidAsteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s discovered, for example:
1979 Sakharov 1979 Sakharov is a main-belt asteroid discovered on September 24, 1960 by Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld and Tom Gehrels at Palomar Observatory.It is named in honour of a distinguished Russian physicist Andrei Sakharov....
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| 2247 Hiroshima 2247 Hiroshima is a main-belt asteroid discovered on September 24, 1960 by Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld and Tom Gehrels at Palomar Observatory.- External links :*...
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| 4065 Meinel Meinel is an S-type asteroid of the Flora family native to the Main Belt. It was discovered on September 24, 1960 at Palomar Observatory by Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld and Tom Gehrels...
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| 11184 Postma 11184 Postma is a main-belt asteroid discovered on April 18, 1998 by Spacewatch at Kitt Peak.- External links :*...
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Tom Gehrels (February 21, 1925 – July 11, 2011), was an American
astronomerAn astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
, Professor Planetary Sciences, and Astronomer at the
University of ArizonaThe University of Arizona is a land-grant and space-grant public institution of higher education and research located in Tucson, Arizona, United States. The University of Arizona was the first university in the state of Arizona, founded in 1885...
, Tucson.
Gehrels, who was born at
HaarlemmermeerHaarlemmermeer is a municipality in the Netherlands, in the province of North Holland. It is a polder, consisting of land reclaimed from water, and the name Haarlemmermeer means Haarlem's Lake, still referring to the body of water from which the region was reclaimed in the 19th century.Its main...
,
the NetherlandsThe Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, pioneered the first photometric system of
asteroidAsteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s in the 1950s, and wavelength dependence of
polarizationPolarization is a property of certain types of waves that describes the orientation of their oscillations. Electromagnetic waves, such as light, and gravitational waves exhibit polarization; acoustic waves in a gas or liquid do not have polarization because the direction of vibration and...
of
starA star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s and
planetA planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s in the 1960s, each resulting in an extended sequence of papers in the
Astronomical JournalThe Astronomical Journal is a peer-reviewed monthly scientific journal owned by the American Astronomical Society and currently published by Institute of Physics Publishing. It is one of the premier journals for astronomy in the world...
.
He discovered, jointly with the husband and wife team of
Cornelis Johannes van HoutenCornelis Johannes van Houten was a Dutch astronomer, sometimes referred to as Kees van Houten.Born in The Hague, he spent his entire career at Leiden University except for a brief period as research assistant at Yerkes Observatory...
and
Ingrid van Houten-GroeneveldIngrid van Houten-Groeneveld is a Dutch astronomer.In a jointly-credited trio with Tom Gehrels and her husband Cornelis Johannes van Houten, she was an extremely prolific discoverer of many thousands of asteroids...
, over 4000
asteroidAsteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s, including
Apollo asteroidThe Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, the first asteroid of this group to be discovered by Karl Wilhelm Reinmuth...
s,
Amor asteroidThe Amor asteroids are a group of near-Earth asteroids named after the asteroid 1221 Amor. They approach the orbit of the Earth from beyond, but do not cross it. Most Amors do cross the orbit of Mars...
s, as well as dozens of
Trojan asteroidThe Jupiter Trojans, commonly called Trojans or Trojan asteroids, are a large group of objects that share the orbit of the planet Jupiter around the Sun. Relative to Jupiter, each Trojan librates around one of the planet's two Lagrangian points of stability, and , that respectively lie 60° ahead...
s. That was done in a sky survey using the 48-inch Schmidt telescope at
Palomar ObservatoryPalomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology...
and shipping the plates to the two Dutch astronomers at
Leiden ObservatoryLeiden Observatory is an astronomical observatory in the city of Leiden, Netherlands. It was established by Leiden University in 1633, to house the quadrant of Snellius, and is the oldest operating University observatory in the world Leiden Observatory (Sterrewacht Leiden in Dutch) is an...
, who analyzed them for new asteroids. The trio are jointly credited with several thousand discoveries. Gehrels also discovered a number of
cometA comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s.
He was Principal Investigator for the Imaging Photopolarimeter experiment on the
Pioneer 10Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...
and
Pioneer 11Pioneer 11 is a 259-kilogram robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind, cosmic rays, and eventually the far reaches of the solar system and heliosphere...
first flybys of Jupiter and Saturn in the 1970s.
CometA comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s discovered, for example:
64P/Swift-Gehrels* |
78P/Gehrels 278P/Gehrels, also known as Gehrels 2, is a periodic comet in the Solar System.- Outward migration :Comet 78P/Gehrels' aphelion of 5.4AU is in the zone of control of the giant planet Jupiter and the orbit of the comet is frequently perturbed by Jupiter...
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| 82P/Gehrels 3 82P/Gehrels is a comet that was discovered on October 27, 1975 by Tom Gehrels at the Palomar Mountain Observatory in California. It has an estimated diameter of 1.46 km. This object has been identified as a quasi-Hilda comet, which means it is in a 3:2 mean-motion resonance with the planet Jupiter....
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| 90P/Gehrels 1 |
* in 1889 by SwiftLewis A. Swift was an American astronomer.-Discoveries:He discovered or co-discovered a number of comets, including periodic comets 11P/Tempel-Swift-LINEAR, 64P/Swift-Gehrels, and 109P/Swift-Tuttle...
, rediscovered |
Gehrels initiated the
Space ScienceThe term space science may mean:* The study of issues specifically related to space travel and space exploration, including space medicine.* Science performed in outer space ....
Series of textbooks, which are at the most advanced level, was General Editor for the first 30 volumes of the University of Arizona Press, and set the style by participating in the editing of six of them. He also initiated the Spacewatch program and was its Principal Investigator (PI) for electronic surveying to obtain statistics of asteroids and comets, including near-Earth asteroids. Bob McMillan was co-investigator and manager, and became the PI in 1997.
Gehrels taught an undergraduate course for non-science majors in Tucson in the Fall, and lectured a brief version of that in the Spring at the Physical Research Laboratory in
AhmedabadAhmedabad also known as Karnavati is the largest city in Gujarat, India. It is the former capital of Gujarat and is also the judicial capital of Gujarat as the Gujarat High Court has its seat in Ahmedabad...
, India, where he was a lifetime Fellow. That is in a UN Course for graduate students from countries as
UzbekistanUzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....
and
North KoreaThe Democratic People’s Republic of Korea , , is a country in East Asia, occupying the northern half of the Korean Peninsula. Its capital and largest city is Pyongyang. The Korean Demilitarized Zone serves as the buffer zone between North Korea and South Korea...
, for example.
His recent research was on universal evolution, which was woven in as the guiding thread through these courses. He was the named winner of the 2007
Harold Masursky AwardThe Harold Masursky Award for Meritorious Service to Planetary Science, usually called the Masursky Award, is awarded annually by the Division for Planetary Sciences of the American Astronomical Society...
for his outstanding service to planetary science.
During
World War IIWorld War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
Gehrels was, as a teenager, active in the
Dutch ResistanceDutch resistance to the Nazi occupation of the Netherlands during World War II can be mainly characterized by its prominent non-violence, summitting in over 300,000 people in hiding in the autumn of 1944, tended to by some 60,000 to 200,000 illegal landlords and caretakers and tolerated knowingly...
. After he escaped to
EnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, he was sent back by parachute as an organizer for
Special Operations ExecutiveThe Special Operations Executive was a World War II organisation of the United Kingdom. It was officially formed by Prime Minister Winston Churchill and Minister of Economic Warfare Hugh Dalton on 22 July 1940, to conduct guerrilla warfare against the Axis powers and to instruct and aid local...
SOE.
Gehrels was requested by the Journal
NatureNature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
to write a review on a book regarding
Wernher von BraunWernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...
, in which he quotes inmates of concentration camp
DoraMittelbau-Dora was a Nazi Germany labour camp that provided workers for the Mittelwerk V-2 rocket factory in the Kohnstein, situated near Nordhausen, Germany....
. He has therefore charged that von Braun was there regularly and much in charge, and that von Braun bears greater responsibility and guilt than his official biography would imply. Towards the end of the book review it reads:
Von Braun needs no phony defense, for he was a great man in his own scientific specialization... What is needed is a more sophisticated historical perspective....
Tom Gehrels was the father of
Neil GehrelsNeil Gehrels is an astrophysicist specializing in the field of Gamma-ray astronomy. He graduated in 1976 with Bachelor's degrees in music and physics from the University of Arizona. He received his Ph.D. in physics in 1982 from the California Institute of Technology. He is married to Ellen...
, George Gehrels and Jo-Ann Gehrels. He died in Tucson, Arizona.
Career
- Special airborne services in Europe and Far East, 1944-1948.
- B.Sc. astronomy and physics, Leiden University 1951.
- Ph.D. astronomy and astrophysics, Univ. of Chicago, 1956.
- Professor of Planetary Sciences and Astronomy, Univ. of Arizona, 1961–2011.
Books
- Physical Studies of Minor Planets, edited by Tom Gehrels (1971), NASA SP-267
- Planets Stars and Nebulae Studied With Photopolarimetry, edited by Tom Gehrels (1974), ISBN 0-8165-0428-8
- Jupiter: Studies of the Interior, Atmosphere, Magnetosphere, and Satellites, edited by Tom Gehrels and Mildred Shapley Matthews (1976), ISBN 0-8165-0530-6
- Protostars & Planets: Studies of Star Formation and of the Origin of the Solar System, edited by Tom Gehrels and Mildred Shapley Matthews (1978), ISBN 0-8165-0674-4
- Asteroids, edited by Tom Gehrels and Mildred Shapley Matthews (1979), ISBN 0-8165-0695-7
- Saturn, edited by Tom Gehrels and Mildred Shapley Matthews (1984), ISBN 0-8165-0829-1
- Asteroids II, edited by Richard P. Binzel, Tom Gehrels, and Mildred Shapely Matthews (1989), ISBN 0-8165-1123-3
- Hazards Due to Comets and Asteroids, edited by Tom Gehrels, Mildred Shapley Matthews, and A. M. Schumann (1994), ISBN 0-8165-1505-0
- On the Glassy Sea, in Search of a Worldview, Tom Gehrels (2007, originally published in 1988), ISBN 1-4196-8247-4
- Survival Through Evolution: From Multiverse to Modern Society, Tom Gehrels (2007), ISBN 1-4196-7055-7
External links