terrestrial planet


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Related to terrestrial planet: Jovian planet

terrestrial planet,

the earth or a planet that resembles the earth in its physical characteristics. The terrestrial planets in the solar system are the earthearth,
in geology and astronomy, 3rd planet of the solar system and the 5th largest, the only planet definitely known to support life. Gravitational forces have molded the earth, like all celestial bodies, into a spherical shape.
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, MercuryMercury,
in astronomy, nearest planet to the sun, at a mean distance of 36 million mi (58 million km); its period of revolution is 88 days. Mercury passes through phases similar to those of the moon as it completes each revolution about the sun, although the visible disk varies
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, VenusVenus,
in astronomy, 2d planet from the sun; it is often called the evening star or morning star and is brighter than any object in the sky except the sun and the moon. Because its orbit lies between the sun and the orbit of the earth, Venus passes through phases like those of
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, and MarsMars,
in astronomy, 4th planet from the sun, with an orbit next in order beyond that of the earth. Physical Characteristics

Mars has a striking red appearance, and in its most favorable position for viewing, when it is opposite the sun, it is twice as bright as
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. These planets are approximately the same size, with the earth the largest. They are considerably denser than the Jovian planetsJovian planets,
the planets Jupiter, Saturn, Uranus, and Neptune. They are all larger and more massive than the earth. Since they rotate faster, they are more flattened at the poles than are the terrestrial planets. They are all less dense than the earth.
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, ranging from a specific gravity of 4 for Mars to 5.5 for the earth. Because they spin less rapidly than the Jovian planets, the terrestrial planets are less flattened at their poles.

terrestrial planet

[tə′res·trē·əl ′plan·ət]
(astronomy)
One of the four small planets near the sun (Earth, Mercury, Venus, and Mars).
References in periodicals archive ?
Added Siegfried Eggl, associate researcher at JPL: "Perhaps most surprisingly, our findings suggest that, under certain conditions, the presence of a giant planet can actually increase the size of the habitable zone, which is the area where your terrestrial planet receives the right amount of light in order to support liquid water on its surface.
In other words, Vesta may be the preserved remnant of a transitional class of planetary objects--it's no longer a primitive asteroid but it's not quite a classical terrestrial planet either.
"Our understanding is that this kind of meteorite is the starting composition of the terrestrial planets, from Mercury to the Earth."
If water was plentiful in Earth's building blocks, many extrasolar terrestrial planets could also have been born wet.
The discovery of the planet, dubbed COROT-Exo-7b, may ultimately provide groundbreaking information about the composition and structure of terrestrial planets beyond the solar system.
New techniques, however, always are on the horizon, and a pair of upcoming space missions hope to detect a terrestrial planet around another star: the Europeans are launching Corot in 2006 and NASA is unleashing Kepler in 2007.
Measuring the mass and radius of a terrestrial planet reveals a planet's average density, and that in turn may indicate where the body formed.
"It could have been a former ocean world, or even [the core of] a former gas giant that evaporated, or a terrestrial planet that was somehow pushed inward as an outer gas giant migrated inward," comments Brandon Tingley, a member of the CoRoT science team.
That may in turn be a sign of possible terrestrial planet formation, Meyer and his colleagues, including Lynne Hillenbrand and John Carpenter of the California Institute of Technology in Pasadena, argue in the Feb.
In the hopes that a powerful "Terrestrial Planet Finder" telescope will someday be launched, researchers have tested a way to detect the presence of oceans and clouds on Earth-like planets of far stars.
Other sections cover solar telescopes, wavefront sensing and control, mirror technology, NASA's Terrestrial Planet Finder missions, and coronographs.
Papers on theory, attitude dynamics, attitude determination, orbit theory, and orbit and attitude theory describe recent work in areas such as nuclear electric sundiving, attitude estimation with GPS-like measurements, planet detection algorithms for the terrestrial planet finder, and closed-form velocity solutions in lost-in-space attitude and position determination.

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