David James Tholen (born 1955) is an American
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 ...
at the
Institute for Astronomy of the
University of Hawaii
A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...
. He holds a 1984 PhD from the
University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
, and specializes in
planetary and
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 ...
astronomy. He is a
discoverer of minor planets
This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 numb ...
and known for the ''
Tholen spectral classification
An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiated ...
'' scheme used on asteroids.
Professional life
Tholen has discovered a number of
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, including the lost , which may be an
Apohele asteroid
Atira asteroids or Apohele asteroids, also known as interior-Earth objects (IEOs), are asteroids whose orbits are entirely confined within Earth's orbit; that is, their orbit has an aphelion (farthest point from the Sun) smaller than Earth's peri ...
, and , which certainly is; in fact, it had the smallest semimajor axis and aphelion distance among the known asteroids (and still holds both records among numbered asteroids as of March 2010
). He won the
H. C. Urey Prize in 1990.
He co-discovered the asteroid
99942 Apophis
99942 Apophis is a near-Earth asteroid and potentially hazardous asteroid with a diameter of that caused a brief period of concern in December 2004 when initial observations indicated a probability up to 2.7% that it would hit Earth on April&nb ...
(previously known as ). This asteroid will closely approach Earth on April 13, 2029 and very briefly appear as bright as a third
magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
star.
In 1995, Tholen obtained images of the then newly discovered
comet Hale-Bopp
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 are ...
at a time when the comet was moving very slowly with respect to the background stars, thus permitting the red- green- and blue-filtered images to be combined into a color composite without the background stars appearing as separately colored dots. This color composite image was made publicly accessible via the Institute of Astronomy's web site.
Later, then postdoc at University of Hawaii,
Olivier R. Hainaut discovered that a nearly identical image was being discussed by late-night radio host
Art Bell
Arthur William Bell III (June 17, 1945 – April 13, 2018) was an American broadcaster and author. He was the founder and the original host of the paranormal-themed radio program ''Coast to Coast AM'', which is syndicated on hundreds of ...
and one of his guests,
Courtney Brown, who claimed that it proved the existence of an unnatural object following the comet, something supposedly seen by those who had learned how to engage in the technique of "
remote viewing
Remote viewing (RV) is the practice of seeking impressions about a distant or unseen subject, purportedly sensing with the mind. Typically a remote viewer is expected to give information about an object, event, person or location that is hidden ...
". The image provided to Bell by Brown, and eventually made public on Bell's web site, did indeed show an object next to the comet that did not appear in archival images of the sky. In reality, that image had been digitally altered from the original image posted by Tholen, presumably by taking the image of a star near the edge of the frame, adding it next to the comet, and then trimming away the outer edges of the frame.
Tholen and Hainaut exposed the fraud by producing the original image, which showed no such additional object. Nevertheless, some
conspiracy theorists
A conspiracy theory is an explanation for an event or situation that invokes a conspiracy by sinister and powerful groups, often political in motivation, when other explanations are more probable.Additional sources:
*
*
*
* The term has a nega ...
maintained that Brown's version was actually the original image and that Tholen had removed the additional object from the one on the Institute's web site. The
Heaven's Gate cult was so convinced that the additional object was a spaceship coming to take them away from Earth that they committed
mass suicide
Mass suicide is a form of suicide, occurring when a group of people simultaneously kill themselves.
Overview
Mass suicide sometimes occurs in religious settings. In war, defeated groups may resort to mass suicide rather than being captured. Su ...
.
The
Mars-crosser
A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and .
Many databases, for i ...
asteroid
3255 Tholen, discovered by
Edward Bowell
Edward L. G. "Ted" Bowell (born 1943 in London), is an American astronomer. Bowell was educated at Emanuel School London, University College, London, and the University of Paris.
He was principal investigator of the Lowell Observatory Near-Earth ...
in 1980, is named after David Tholen.
Personal interests
David Tholen and
Roy Tucker
Roy A. Tucker (born 1951 in Jackson, Mississippi) is an American astronomer best known for the co-discovery of near-Earth asteroid 99942 Apophis (formerly known as ) along with David J. Tholen and Fabrizio Bernardi of the University of Hawaii. ...
, co-discovers of 99942 Apophis, are both fans of the TV series
Stargate SG-1
''Stargate SG-1'' (often stylized in all caps, or abbreviated ''SG-1'') is a military science fiction Adventure fiction, adventure television series within Metro-Goldwyn-Mayer's Stargate, ''Stargate'' franchise. The show, created by Brad Wrigh ...
, which influenced the naming of the asteroid. The show's most persistent villain is "
Apophis", an alien also named for the Egyptian god. "We considered a number of names, but 'Apophis' kept floating to the top," says Tucker. "Apophis was a very fitting name for not only because of its threatening nature, but also because of its evolution from an Aten asteroid to an Apollo asteroid during the 2029 encounter.".
[
(naming the asteroid Apophis and how Earth's gravity may change its trajectory in 2029)]
Tholen is a fan of the
University of Kansas Jayhawks college basketball team and the
Kansas City Royals
The Kansas City Royals are an American professional baseball team based in Kansas City, Missouri. The Royals compete in Major League Baseball (MLB) as a member club of the American League (AL) Central division. The team was founded as an expans ...
Major League Baseball team.
He also plays clarinet and bass clarinet for the Honolulu Community Concert Band and the Oahu Community Orchestra.
He is also a user of the
OS/2
OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 ...
, Linux, Windows, Solaris, and
Mac OS
Two major famlies of Mac operating systems were developed by Apple Inc.
In 1984, Apple debuted the operating system that is now known as the "Classic" Mac OS with its release of the original Macintosh System Software. The system, rebranded "M ...
operating systems.
Tholen frequently posts to various Usenet groups using the alia
tholen@antispam.ham
List of discovered minor planets
See also
*
Asteroid spectral types
An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiate ...
References
External links
Homepage
{{DEFAULTSORT:Tholen, David J.
1955 births
American astronomers
Discoverers of asteroids
*
Living people
Planetary scientists
University of Arizona alumni
University of Hawaiʻi faculty