Blocky, angular, and rough type of lava flow. The growth of planetary bodies from smaller objects by impact, one impact at a time. After formation, bodies are said to have "accreted" from small objects. A class of stony meteorites that crystallized from magmas. The term means without chondrules. Cool, luminous, and pulsating red giant stars. Most stars in the Universe that have left the main sequence will reach their final evolutionary stage as stars on the asymptotic giant branch AGB.
Common particle type in lunar regolith ; agglutinates consist of small rock, mineral, and glass fragments bonded together with glass—a glass that is formed by flash heating when micrometeorite impacts melt the lunar regolith. The heat can also release solar-wind-implanted hydrogen and helium from the lunar regolith, causing vesicles bubbles in the quickly-quenched glass.
Agglutinates are typically tens of micrometers to a few millimeters in size. The brightness of an object or surface; it is the percentage of incoming radiation light that the object or surface reflects. The geologic history of Mars has been divided into three broad time periods, or Epochs. From oldest to youngest, these are Noachian , Hesperian , and Amazonian named after places on Mars.
These Epochs are defined by the number of impact craters on the ground surface; older surfaces have more craters. The Amazonian Epoch extends from about 2. The actual timing of the Epochs is not known because we have different models of the rates of meteorite falls on Mars.
Molecules that are essential components of life as the chemical building units of proteins and enzymes. Amino acids are made of carbon, hydrogen, oxygen, and nitrogen. In the context of planetary science, amino acids are found in carbonaceous chondrite meteorites. There are ongoing research studies of the ramifications of prebiotic chemical reactions in early Solar System environments and delivery of organic material from asteroids and comets to the early Earth.
A gas molecule composed of one part nitrogen and three parts hydrogen; NH3. Lacking long-range crystalline structure; disordered. Dark-colored, fine-grained extrusive igneous rock with about 52 to 63 weight percent silica SiO2. Andesite consists mainly of plagioclase and one or more mafic minerals. The word andesite is derived from the Andes Mountains, located along the western edge of South America, where andesite rock is common.
A type of achondrite meteorite consisting of pyroxene, olivine, and plagioclase. A deviation from the common rule, type, or form; something abnormal or inconsistent. An igneous rock made up almost entirely of plagioclase feldspar. This rock dominates the lunar highlands. The work of the ANSMET teams provides the research community with a steady source of new extraterrestrial materials, including lunar and Martian samples. A conductor by which electromagnetic waves are transmitted or received.
A point on the surface of a sphere that is located diametrically opposite another point. For example, on the Earth the antipode of Hawaii is Botswana. The term is used commonly in lunar geology to describe locations on the Moon in relation to impact basins. Researchers have hypothesized that accumulations of converged ejecta materials, production of impact shock stresses, anomalies in lunar crustal magnetic fields, and geochemical anomalies are associated with antipodes of basins.
Igneous rock texture describing grain sizes too small to see without a microscope, but rock is not glassy. Point in the elliptical orbit of a comet, or asteroid, or planet about the Sun in which it is at its farthest distance from the Sun.
The opposite orbital position is called perihelion. Space Program that included 6 piloted lunar landings between and Apollo astronauts collected and returned kilograms of rock and sediment samples from the Moon. An appearance; in astronomy, the period of observation of a returning periodic comet. A rgument of perihelion: Angle along the orbit of a planet or other Solar System object as measured from the ascending node analogous to right ascension and longitude.
The plane of a planet's orbit or other Solar System object is usually tilted with respect to the plane defined by the Solar System the ecliptic. These 2 great circles intersect at 2 points. As the planet travels around its orbit, at one of the intersection points it will pass from below the ecliptic plane to above it i. This point is called the ascending node.
A small, mostly rocky body orbiting the Sun. Asteroids range in size from kilometers in diameter to tiny objects you could hold in your hand. Most asteroids orbit the Sun between Mars and Jupiter the Asteroid belt , and are the source of most meteorites.
The majority of asteroids fall into three types: C-type carbonaceous , S-type silicate or stony , and M-type metallic, nickel-iron. The region of space between the orbits of Mars and Jupiter, from 2. Group of asteroids with similar orbital elements distance from the Sun, inclination of the orbital plane to the Earth's orbital plane, and eccentricity of the orbit thought to be remnants of one larger asteroid parent.
Study of the origin, distribution, and destiny of life in the universe. These are interdisciplinary studies involving astronomers, astrophysicists, biologists, chemists, geneticists, geologists, paleontologists, planetary scientists, and specialists from other scientific fields. Three broad themes of astrobiology: Is there life elsewhere in the universe?
How did life begin and evolve? What is the future for life on Earth and beyond? Person engaged in or trained for spaceflight. The time when the Sun is degrees below the horizon. When the Sun moves from 19 to 18 degrees below the horizon, astronomers can begin to detect an increase in the brightness of the sky, although to the naked eye the sky still looks dark. Geochemists divide elements into four basic types based on the Goldschmidt classification. Atmophile elements remain largely in the gas phase.
The other types are chalcophile , lithophile , and siderophile elements. Mixture of gases that surround and are gravitationally attached to a planet.
A U Astronomical Unit: The mean Earth-Sun distance, equal to Single-celled microorganisms whose cells lack a nucleus. Bacteria comprise a major domain of life called prokaryotes. In contrast, the cells in eukaryotes have a well-defined nucleus; eukarya include molds, plants, and animals. Another major domain is called archaea, microorganisms with genetic features distinct from prokarya and eukarya.
Most methane-producing bacteria are actually archaea, but for simplicity many biologists informally refer to all non-eukaryotes as "bacteria. Fine-grained, dark-colored extrusive igneous rock with less than about 52 weight percent silica SiO2. Because of its low silica content, basalt has a low viscosity resistance to flow. Basalt is composed primarily of plagioclase feldspar and pyroxene; other minerals such as olivine and ilmenite are usually present.
Basalt is the most common rock on the surfaces of terrestrial planets and differentiated asteroids such as 4 Vesta. Basaltic magmas are made by the partial melting of peridotite.
The part of Earth's crust, water, and atmosphere where living organisms can survive. See also monomict and polymict. Calcium-aluminum-rich inclusions CAIs are found in chondritic meteorites. CAIs are primitive objects that formed in the solar nebula before the planets formed.
CAIs are light-colored objects rich in refractory elements that condense at a high temperature. Besides calcium and aluminum, this includes magnesium, titanium, and rare earth elements. CAIs range in size from about a millimeter to a centimeter. Meteoriticists have identified several distinct varieties of CAIs, but all share a high temperature origin. Some might be condensates from the solar nebula. Other CAIs might be evaporation residues. A large, basin-shaped volcanic depression caused by collapse after withdrawal of magma and eruption of lava.
The generally accepted, or established, procedure or quantity. An element with atomic number 6; symbol: Graphite is a low-pressure form of carbon.
Diamond is a high-pressure form of carbon. Carbon is one of the four elements essential for life. The others are hydrogen, oxygen, and nitrogen. A rare class of red giant stars unusually rich in carbon or carbon compounds. They are chemically primitive meteorites containing water-bearing minerals and carbon compounds including a variety of organic molecules such as amino acids.
Common rock-forming mineral containing the carbonate ion, CO