Tom Gehrels (born Feb 21 1925,
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 country in Northwestern Europe, constituting the major portion of the Kingdom of the Netherlands. It is a parliamentary democratic constitutional monarchy. The Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east...
) is 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 pioneered the first photometric system of
asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
s in the 50s, and wavelength dependence of polarization of
starA star is a massive, luminous ball of plasma that is held together by gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun...
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 60s, each resulting in an extended sequence of papers in the
Astronomical JournalThe Astronomical Journal is a monthly scientific journal published by Institute of Physics Publishing on behalf of the American Astronomical Society. It is one of the premier journals for astronomy in the world...
.
He has 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 Mortimer 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
asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
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. They are Earth-crosser asteroids that have orbital semi-major axes greater than that of the Earth and a perihelion distance < 1.017 AU...
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.
Asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
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....
|
| 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 :*...
|
| 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...
|
| 11184 Postma 11184 Postma is a Main-belt Asteroid discovered on April 18, 1998 by Spacewatch at Kitt Peak.- External links :*...
|
Tom Gehrels (born Feb 21 1925,
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 country in Northwestern Europe, constituting the major portion of the Kingdom of the Netherlands. It is a parliamentary democratic constitutional monarchy. The Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east...
) is 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 pioneered the first photometric system of
asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
s in the 50s, and wavelength dependence of polarization of
starA star is a massive, luminous ball of plasma that is held together by gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun...
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 60s, each resulting in an extended sequence of papers in the
Astronomical JournalThe Astronomical Journal is a monthly scientific journal published by Institute of Physics Publishing on behalf of the American Astronomical Society. It is one of the premier journals for astronomy in the world...
.
He has 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 Mortimer 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
asteroidthumb|260px|right|[[253 Mathilde]], a [[C-type asteroid]] measuring about across. Photograph taken in 1997 by the [[NEAR Shoemaker]] probe.Asteroids, sometimes called minor planets or planetoids, are small Solar System bodies in orbit around the Sun, especially in the inner Solar System; they are...
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. They are Earth-crosser asteroids that have orbital semi-major axes greater than that of the Earth and a perihelion distance < 1.017 AU...
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 , at approximately 5,570 ft elevation, is a privately owned observatory located in San Diego County, California, 90 miles southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. 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 in the 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 has discovered a number of
cometA comet is a Small Solar System Body that has coma and is bigger than a meteoroid. When close enough to the Sun, a comet exhibits a visible coma , and sometimes a tail, both because of the effects of solar radiation upon the comet's nucleus...
s.
He was Principal Investigator for the Imaging Photopolarimeter experiment on the
Pioneer 10Pioneer 10 was the first spacecraft to travel through the asteroid belt, which it entered on July 15, 1972, and to make direct observations of Jupiter, which it passed by on December 3, 1973. It was launched from Cape Canaveral Air Force Station's Launch Complex 36A on March 3, 1972 at 01:49:00 UTC...
and
Pioneer 11Pioneer 11 was the second mission of the Pioneer program to investigate Jupiter and the outer solar system and the first to explore Saturn and its main rings. Pioneer 11 used Jupiter's mass in a gravity assist to alter its trajectory toward Saturn...
first flybys of Jupiter and Saturn in the 70s.
CometA comet is a Small Solar System Body that has coma and is bigger than a meteoroid. When close enough to the Sun, a comet exhibits a visible coma , and sometimes a tail, both because of the effects of solar radiation upon the comet's nucleus...
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...
|
| 82P/Gehrels 3 |
| 90P/Gehrels 1 |
* in 1889 bySwiftLewis 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 ScienceSpace science is an all-encompassing term that describes all of the various science fields that are concerned with the study of the Universe, generally also meaning "excluding the Earth" and "outside of the Earth's atmosphere". Originally, all of these fields were considered part of astronomy...
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 teaches an undergraduate course for non-science majors in Tucson in the Fall, and lectures a brief version of that in the Spring at the Physical Research Laboratory in
AhmedabadAhmedabad is a city in India, which is the largest city in the state of Gujarat, with a population of approximately 52 lakhs . Located on the banks of the River Sabarmati, the city is the administrative centre of Ahmedabad district and was the capital of Gujarat from 1960 to 1970; the capital...
, India, where he is a lifetime Fellow. That is in a UN Course for graduate students from countries as Uzbekistan and North Korea, for example.
Presently, his research is on universal evolution, which is 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 military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
Gehrels was, as a teenager, active in the
Dutch ResistanceDutch resistance to the Nazi occupation during World War II developed relatively slowly, but its counterintelligence, domestic sabotage, and communications networks provided key support to Allied forces beginning in 1944 and continuing until the Netherlands was fully liberated.-Prelude:Prior to the...
. 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 and the North Sea to the east, with 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 warfare by means other than direct military engagement...
SOE.
Gehrels was requested by the Journal Nature to write a review on a book regarding
Wernher von BraunWernher Magnus Maximilian Freiherr von Braun was a German American rocket physicist and astronautics engineer, becoming one of the leading figures in the development of rocket technology in Germany and the United States...
, 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 is 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.
Career
- Special airborne services in Europe and Far East, 1944-1948.
- B.S. astronomy and physics, Leiden University 1951.
- Ph.D. astronomy and astrophysics, Univ. of Chicago, 1956.
- Planetary sciences and astronomy, Univ. of Arizona, 1961-present.
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 0-81650-428-8
- Jupiter: Studies of the Interior, Atmosphere, Magnetosphere, and Satellites, edited by Tom Gehrels and Mildred Shapley Matthews (1976), ISBN 0-81650-530-6
- Protostars & Planets: Studies of Star Formation and of the Origin of the Solar System, edited by Tom Gehrels and Mildred Shapley Matthews (1978), ISBN 0-81650-674-4
- Asteroids, edited by Tom Gehrels and Mildred Shapley Matthews (1979), ISBN 0-81650-695-7
- Saturn, edited by Tom Gehrels and Mildred Shapley Matthews (1984), ISBN 0-81650-829-1
- Asteroids II, edited by Richard P. Binzel, Tom Gehrels, and Mildred Shapely Matthews (1989), ISBN 0-81651-123-3
- Hazards Due to Comets and Asteroids, edited by Tom Gehrels, Mildred Shapley Matthews, and A. M. Schumann (1994), ISBN 0-81651-505-0
- 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 1-41967-055-7
External links