Ernst Julius Öpik ( – 10 September 1985) was an Estonian
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
and
astrophysicist who spent the second half of his career (1948–1981) at the
Armagh Observatory
Armagh Observatory is an astronomical research institute in Armagh, Northern Ireland. Around 25 astronomers are based at the observatory, studying stellar astrophysics, the Sun, Solar System astronomy and Earth's climate.
In 2018, Armagh Obse ...
in
Northern Ireland
Northern Ireland ( ga, Tuaisceart Éireann ; sco, label= Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. Nort ...
.
Education
Öpik was born in
Kunda,
Lääne-Viru,
Governorate of Estonia
The Governorate of Estonia, also known as the Governorate of Esthonia (Pre-reformed rus, Эстля́ндская губе́рнія, r=Estlyandskaya guberniya); et, Eestimaa kubermang was a governorate in the Baltic region, along with th ...
, then a part of the
Russian Empire
The Russian Empire was an empire and the final period of the Russian monarchy from 1721 to 1917, ruling across large parts of Eurasia. It succeeded the Tsardom of Russia following the Treaty of Nystad, which ended the Great Northern War. ...
. He went to the
University of Moscow
M. V. Lomonosov Moscow State University (MSU; russian: Московский государственный университет имени М. В. Ломоносова) is a public research university in Moscow, Russia and the most prestigious ...
to specialize in the study of minor bodies, such as
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
s,
comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s, and
meteor
A meteoroid () is a small rocky or metallic body in outer space.
Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than this are classified as micr ...
s. He completed his doctorate at the
University of Tartu
The University of Tartu (UT; et, Tartu Ülikool; la, Universitas Tartuensis) is a university in the city of Tartu in Estonia. It is the national university of Estonia. It is the only classical university in the country, and also its biggest ...
.
Astronomical work
In 1916 Öpik published an article in the ''
Astrophysical Journal
''The Astrophysical Journal'', often abbreviated ''ApJ'' (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and Jame ...
'', in which he estimated the densities of visual binary stars. In his sample was
ο2 Eridani B, a
white dwarf
A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...
star. Öpik determined its density as 25,000 times the density of the Sun but concluded that the result is impossible.
In 1922, Ernst Öpik published a paper in which he estimated the distance of the
Andromeda Galaxy
The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala ...
. He determined the distance using a novel astrophysical method based on the observed
rotational velocities of the galaxy, which depends on the total mass around which stars are rotating, and on the assumption that the luminosity per unit mass was the same as that of our galaxy. He concluded that the distance was 450 kpc. His result was in good accordance with other estimates of these days (100 to 1000 kpc) and were closer to recent estimates (778 kpc) than Hubble's result (275 kpc). His method is still widely used.
In 1922 he correctly predicted the frequency of
crater
Crater may refer to:
Landforms
*Impact crater, a depression caused by two celestial bodies impacting each other, such as a meteorite hitting a planet
*Explosion crater, a hole formed in the ground produced by an explosion near or below the surfac ...
s on
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
long before they were detected by
space probe
A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ent ...
s. In 1932 he postulated a theory concerning the origins of comets in the
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
. He believed that they originated in a cloud orbiting far beyond the orbit of
Pluto
Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the S ...
. This cloud is now known as the
Oort cloud
The Oort cloud (), sometimes called the Öpik–Oort cloud, first described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2 ...
or alternatively the Öpik-Oort Cloud in his honour. From October 1931 to the end of July 1933, Öpik,
Harlow Shapley
Harlow Shapley (November 2, 1885 – October 20, 1972) was an American scientist, head of the Harvard College Observatory (1921–1952), and political activist during the latter New Deal and Fair Deal.
Shapley used Cepheid variable stars to estim ...
and Samuel L. Boothroyd headed the Arizona meteor expedition, which detected approximately 22,000 meteors. He also invented a
rocking camera Rocking may refer to:
*Rocking chair
*Uprock, the street dance known as "Rocking"
Music
Albums
*Rockin' (The Guess Who album)
*Rockin' (Frankie Laine album) 1957
Songs
*"Hajej, nynjej" Czech children's carol, recorded as "Rocking" by Julie Andre ...
for the study of meteors. In 1951 he published a paper concerning the
triple-alpha process
The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.
Triple-alpha process in stars
Helium accumulates in the cores of stars as a result of the proton–pro ...
, describing the burning of
helium-4
Helium-4 () is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on Earth. Its nucleus is identical to an alpha particle, and consis ...
into
carbon-12
Carbon-12 (12C) is the most abundant of the two stable isotopes of carbon (carbon-13 being the other), amounting to 98.93% of element carbon on Earth; its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 i ...
in the cores of
red giant
A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...
stars. However, this achievement is often overlooked because
Edwin Salpeter
Edwin Ernest Salpeter (3 December 1924 – 26 November 2008,) was an Austrian–Australian–American astrophysicist.
Life
Born in Vienna to a Jewish family, Salpeter emigrated from Austria to Australia while in his teens to escape the Nazis. He ...
's paper on the same subject had already been published by the time Öpik's paper reached Britain and the United States.
In 1958 he published "Physics of Meteor Flight in the Atmosphere".
In 1972, Öpik published a piece on the
origin of the Moon
The origin of the Moon is usually explained by a Mars-sized body striking the Earth, making a debris ring that eventually collected into a single natural satellite, the Moon, but there are a number of variations on this giant-impact hypothesis, a ...
by capture in the ''
Irish Astronomical Journal'' (vol. 10, pp. 190–238). He included breakup and re-assembly of rings into which the Moon was broken.
Yarkovsky effect connection
The
Yarkovsky effect
The Yarkovsky effect is a force acting on a rotating body in space caused by the anisotropic emission of thermal photons, which carry momentum. It is usually considered in relation to meteoroids or small asteroids (about 10 cm to 10 km i ...
was discovered by the Russian civil engineer
Ivan Osipovich Yarkovsky
Ivan Osipovich Yarkovsky ( pl, Jan Jarkowski) (24 May 1844, Asveya, Vitebsk Governorate – 22 January 1902, Heidelberg) was a Polish Russian civil engineer. Born from a Polish family in Asveya (Russian Empire, now Belarus), he worked for a Russ ...
(1844–1902), who worked on scientific problems in his spare time. Writing in a pamphlet around the year 1900, Yarkovsky noted that the diurnal heating of a rotating object in space would cause it to experience a force that, while tiny, could lead to large long-term effects in the orbits of small bodies, especially meteoroids and small asteroids. Yarkovsky's work might have been forgotten had it not been for Öpik, who read Yarkovsky's pamphlet sometime around 1909. Decades later, Öpik discussed the possible importance of the Yarkovsky effect for moving meteoroids about the solar system.
Exile
Öpik fled his native country in 1944 because the approaching
Red Army
The Workers' and Peasants' Red Army (Russian: Рабо́че-крестья́нская Кра́сная армия),) often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist Republic and, after ...
raised fear among Estonians. Living as a refugee in Germany, he became the Estonian
rector
Rector (Latin for the member of a vessel's crew who steers) may refer to:
Style or title
*Rector (ecclesiastical), a cleric who functions as an administrative leader in some Christian denominations
*Rector (academia), a senior official in an edu ...
of the
Baltic University
The Baltic University in Exile was established in the displaced persons camps in Germany to educate refugees from Estonia, Latvia and Lithuania in the aftermath of the Second World War.
The University was established at Hamburg in the British Z ...
in Exile in the
displaced persons camp
A refugee camp is a temporary Human settlement, settlement built to receive refugees and people in refugee-like situations. Refugee camps usually accommodate displaced people who have fled their home country, but camps are also made for interna ...
s. In 1948 he was offered a post in Armagh and remained there despite offers of lucrative jobs in America. From the early 1960s to the mid-1970s he also held a position at the
University of Maryland
The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public land-grant research university in College Park, Maryland. Founded in 1856, UMD is the flagship institution of the University System of M ...
, which he visited annually, typically for one semester. As air travel became more common, his refusal to fly made travel to the U.S. from Armagh systematically more difficult and he eventually ceased the annual ritual.
Awards
He won the
J. Lawrence Smith Medal
J. Lawrence Smith Medal is awarded every three years by the National Academy of Sciences for investigations of meteoric bodies. The medal is in honor of its namesake, the American chemist and meteoriticist, J. Lawrence Smith.
Recipients
Sour ...
from the
National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
in 1960, the Meteoritical Society Frederick C. Leonard Memorial Medal in 1968, the Kepler Gold Medal from the American Association for the Advancement of Science & Meteoritical Society in 1972, the
Gold Medal of the Royal Astronomical Society
The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...
in 1975 and the
Bruce Medal
The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was firs ...
in 1976.
Legacy
Oort cloud
The Oort cloud (), sometimes called the Öpik–Oort cloud, first described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2 ...
is sometimes called "Öpik-Oort cloud". The
Comet Interceptor's Optical Periscopic Imager for Comets, or OPIC, instrument is named after Ernst Öpik to celebrate the first Estonia's contribution to a science mission of the
European Space Agency
, owners =
, headquarters = Paris, Île-de-France, France
, coordinates =
, spaceport = Guiana Space Centre
, seal = File:ESA emblem seal.png
, seal_size = 130px
, image = Views in the Main Control Room (1205 ...
.
The
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
2099 Öpik is named in his honour. The crater
Öpik on the
Martian
Mars, the fourth planet from the Sun, has appeared as a setting in works of fiction since at least the mid-1600s. It became the most popular celestial object in fiction in the late 1800s as the Moon was evidently lifeless. At the time, the pred ...
moon
Phobos is also named for him.
His grandson,
Lembit Öpik
Lembit Öpik (, ; born 2 March 1965) is a former British politician. A former member of the Liberal Democrats, he served as the Member of Parliament (MP) for the constituency of Montgomeryshire in Wales from 1997 until he lost his seat at the ...
, was the
Liberal Democrat
Several political party, political parties from around the world have been called the Liberal Democratic Party or Liberal Democrats. These parties usually follow a liberal democracy, liberal democratic ideology.
Active parties
Former parties ...
Member of Parliament
A member of parliament (MP) is the representative in parliament of the people who live in their electoral district. In many countries with bicameral parliaments, this term refers only to members of the lower house since upper house members of ...
for
Montgomeryshire
Montgomeryshire, also known as ''Maldwyn'' ( cy, Sir Drefaldwyn meaning "the Shire of Baldwin's town"), is one of thirteen historic counties of Wales, historic counties and a former administrative county of Wales. It is named after its county tow ...
in
Wales
Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
from 1997 to 2010, and has advocated searching for asteroids that may collide with the Earth. Lembit also became Chairman of the Parliament of
Asgardia
Asgardia, also known as the Space Kingdom of Asgardia and Asgardia the Space Nation, is a micronation formed by a group of people who have launched a satellite into Earth orbit. They refer to themselves as "Asgardians" and they have given thei ...
in 2019 and is a member of the Supreme Space Council (SSC).
Protocol №2 Second meeting of the Supreme Space Council of Asgardia
/ref>
References
External links
Optical Periscopic Imager for Comets (OPIC) Tartu Observatory Space Exploration Group
Evening Standard (London); "Lembit and his Very Cheeky Family"
{{DEFAULTSORT:Opik, Ernst
1893 births
1985 deaths
People from Kunda, Estonia
Estonian emigrants to Northern Ireland
20th-century astronomers
Estonian astrophysicists
Estonian astronomers
People from the Governorate of Estonia
Planetary scientists
Recipients of the Gold Medal of the Royal Astronomical Society
Moscow State University alumni
University of Tartu alumni
Members of the Estonian Academy of Sciences
Astronomers from Northern Ireland
Foreign associates of the National Academy of Sciences
Estonian World War II refugees
20th-century Estonian scientists