accretion | Accumulation of dust and gas into larger bodies such as stars, planets and moons. |
adams, john couch 1819-1892 | English astronomer and mathematician who, at the age of 24, was the first person to predict the position of a planetary mass beyond uranus. but, unfortunately, adams did not publish his prediction... |
albedo | The ratio of the amount of light reflected by an object and the amount of incident light; a measure of the reflectivity or intrinsic brightness of an object (a white, perfectly reflecting surface ... альбедо; |
antipodal point | The point that is directly on the opposite side of the planet |
aphelion | The point in its orbit where a planet is farthest from the sun; when refering to objects orbiting the earth the term apogee is used; the term apoapsis is used for orbits around other bodies. (oppo... |
arago, dominique francois jean 1786 - 1853 | French astronomer and physicist and director of the paris observatory, who discovered the phenomenon of the production of magnetism by rotation |
arcuate | Having the form of a bow; curved; arc-shaped |
asteroid | (also "planetoid") a medium-sized rocky object orbiting the sun; smaller than a planet, larger than a meteoroid |
asteroid number | Asteroids are assigned a serial number when they are discovered. it has no particular meaning except that asteroid n+1 was discovered after asteroid n. (see appendix 5) |
atmosphere | = 1.013 bars = 1.03 kg/cm2 = 14.7 pounds per square inch, standard atmospheric pressure at sea level on earth. |
bar | = 0.987 atmosphere = 1.02 kg/cm2 = 100 kilopascal = 14.5 lbs/square inch. |
bolide | A fireball that produces a sonic boom |
bond, william cranch 1789-1859 | One of the earliest american astronomers of note; rose from poverty and overcame a lack of formal education to become the first director of the harvard college observatory where he studied saturn ... |
caldeira | Crater formed by an explosion or collapse of a volcanic vent. |
carbonate | A compound containing carbon and oxygen (i.e. calcium carbonate a.k.a. limestone). |
catena | Chain of craters. |
cavus | Hollow, irregular depression. |
chaos | Distinctive area of broken terrain. |
chasma | Canyon. |
chromosphere | The lower level of the solar atmosphere between the photosphere and the corona |
colles | Small hills or knobs. |
comet | A medium-sized icy object orbiting the sun; smaller than a planet |
congress | The legislative branch of the us government; has proven to be a much more hostile environment for scientific spacecraft than the vastness of space. |
copernicus, nicolaus 1473-1543 | Polish astronomer who advanced the heliocentric theory that the earth and other planets revolve around the sun. this was highly controversial at the time as the ptolemaic view of the universe, whi... |
corona | - Ovoid-shaped feature.
- The uppermost level of the solar atmosphere, characterized by low densities and high temperatures (> 1.0e+06° k).
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coronagraph | A special telescope which blocks light from the disk of the sun in order to study the faint solar atmosphere. |
cosmic ray | An extremely energetic (relativistic) charged particle. |
crater | Bowl-shaped depression formed by the impact of a meteorite; depression around the orifice of a volcano. |
density | Measured in grams per cubic centimeter (or kilograms per liter); the density of water is 1.0; iron is 7.9; lead is 11.3. |
dinosaurs | Large reptiles that lived in the mesozoic era from 230 to 65 million years ago; most probably wiped out by the impact of a large asteroid or comet. |
disaster | Literally "bad stars"; particularly apt in reference to a major asteroid impact. |
disk | The visible surface of the sun (or any heavenly body) projected against the sky. |
doppler effect | The apparent change in wavelength of sound or light caused by the motion of the source, observer or both. (see also) |
dorsum | Ridge. |
effusive eruption | A relative quiet volcanic eruption which puts out basaltic lava that moves at about the speed one walks; the lava is fluid in nature; the eruptions at the kilauea volcano on the island of hawaii a... |
einstein, albert 1879-1955 | German-american physicist; developed the special and general theories of relativity which along with quantum mechanics is the foundation of modern physics. (see fusion, speed of light) (96k gif) |
ellipse | Oval. that the orbits of the planets are ellipses, not circles, was first discovered by johannes kepler based on the careful observations by tycho brahe. |
erg/sec | = 1e-10 kilowatts. |
excentrique | The eccentricity of an ellipse (planetary orbit) is the ratio of the distance between the focii and the major axis. equivalently the eccentricity is (ra-rp)/(ra+rp) where ra is the apoapsis distan... |
explosive eruption | A dramatic volcanic eruption which throws debris high into the air for hundreds of miles; lava is low in silicate; can be very dangerous for people near by; an example is mount st. helens in 1980<... |
exponential notation | "1.23e4" means "1.23 times 10 to the fourth power" or 12,300; "5.67e-8" means "5.67 divided by 10 to the eighth power" or 0.0000000567. |
facula | Bright spot. |
farrum | Pancake-like structure |
filament | A strand of cool gas suspended over the photosphere by magnetic fields, which appears dark as seen against the disk of the sun; a filament on the limb of the sun seen in emission against the dark ... |
fireball | A meteor brighter than magnitude -3 |
flare | A sudden eruption of energy on the solar disk lasting minutes to hours, from which radiation and particles are emitted. |
flexus | Cuspate (pointed) linear feature. |
fluctus | Flow terrain. |
fossa | Long, narrow, shallow depression. |
franklin, benjamin 1706-1790 | American public official, writer, and scientist. played a major part in the american revolution and helped draft the constitution. his numerous scientific and practical innovations include the lig... |
gaia hypothesis | Named for the greek earth goddess gaea, holds that the earth as a whole should be regarded as a living organism and that biological processes stabilize the environment. first advanced by british b... |
gegenschein | A round or elongated spot of light in the sky at a point 180 degrees from the sun. also called counterglow. |
greenhouse effect | Increase in temperature caused when incoming solar radiation is passed but outgoing thermal radiation is blocked by the atmosphere (carbon dioxide is the major factor). very important on venus and... |
hale, george ellery 1868-1938 | American astronomer who founded the yerkes, mt. wilson and palomar observatories. (72k gif) |
hall, asaph 1829-1907 | American astronomer who discovered the two moons of mars, deimos and phobos. |
heliocentric | Sun-centered; see copernicus, kepler, galileo. |
heliopause | The point at which the solar wind meets the interstellar medium or solar wind from other stars. |
heliosphere | The space within the boundary of the heliopause containing the sun and solar system. |
herschel, sir william 1738-1822 | British astronomer who discovered uranus and cataloged more than 800 double stars and 2,500 nebulae. (365k html/gif) |
ice | Used by planetary scientists to refer to water, methane, and ammonia which usually occur as solids in the outer solar system. |
inquisition, the | A renaissance catholic court instituted to seek out and prosecute heretics. |
interplanetary magnetic field (imf) | The magnetic field carried with the solar wind. |
kelvin (k) | 0 kelvin is absolute zero; water melts at 273 k (= 0° c = 32° f); water boils at 373 k (= 100° c = 212° f). (developed by william thomson). |
kilogram (kg) | = 1000 grams = 2.2 pounds, the mass of a liter of water. (see also) |
kilometer (km) | = 1000 meters = 0.62 miles. |
kowal, charles t. 1940- | American astronomer; discovered leda and the comet-like object 2060 chiron (aka 95 p/chiron). |
kuiper, gerard 1905-1973 | Dutch-born american astronomer best known for his study of the surface of the moon; discovered miranda and nereid, found an atmosphere on titan. (dr.kuiper was solidly americanized; his name is pr... |
labes | Landslide. |
labyrinthus | Intersecting valley complex. |
lacus | Lake. |
lagrange, joseph louis 1736-1813 | French (originally italian, giuseppe luigi lagrangia; born in turin, moved to paris and became a french citizen) mathematician and astronomer; made a number of contributions to the study of celest... |
le verrier, urbain jean joseph 1811-1877 | French mathematician whose prediction of the position of an undiscovered planet (neptune) that caused perturbations in the orbit of uranus was the first to be confirmed (by galle) though adams had... |
lidar | An instrument similar to radar that operates at visible wavelengths. |
light-year | = 9.46053e12 km (= 5,880,000,000,000 miles = 63,239 au); the distance traveled by light in a year. |
limb | The outer edge of the apparent disk of a celestial body |
linea | Elongate marking. |
liter | = 1000 cm3 = 1.06 us quarts |