Science Flash Cards
Meteorite
a meteor that survives its passage through the earth’s atmosphere such that part of it strikes the ground. More than 90 percent of meteorites are of rock, while the remainder consist wholly or partly of iron and nickel.
Impact crater
a crater on a planet or moon caused by the impact of a meteorite or other object, typically circular with a raised rim.
Universe
all existing matter and space considered as a whole; the cosmos. The universe is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies; it has been expanding since its creation in the Big Bang about 13 billion years ago.
Gravity
the force that attracts a body toward the center of the earth, or toward any other physical body having mass.
Umbra
the fully shaded inner region of a shadow cast by an opaque object, especially the area on the earth or moon experiencing the total phase of an eclipse.
Comet
a celestial object consisting of a nucleus of ice and dust and, when near the sun, a “tail” of gas and dust particles pointing away from the sun.
Tide
the alternate rising and falling of the sea, usually twice in each lunar day at a particular place, due to the attraction of the moon and sun.
Equinox
the time or date (twice each year) at which the sun crosses the celestial equator, when day and night are of equal length (about September 22 and March 20).
Asteroid
a small rocky body orbiting the sun. Large numbers of these, ranging in size from nearly 600 miles (1,000 km) across (Ceres) to dust particles, are found (as the asteroid belt ) especially between the orbits of Mars and Jupiter, though some have more eccentric orbits, and a few pass close to the earth or enter the atmosphere as meteors.
Gibbous moon
The definition of gibbous refers to a moon in between a half-moon but less than a full moon or something that protrudes or creates an obvious bulge. When the moon is more than half full, this is an example of a gibbous moon. When you have a humpback, this is an example of a gibbous back.
Axis of rotation
the straight line through all fixed points of a moon rigid body around which all other points of the body move in circles.
heloencentric
The theory that the earth revolves around the Sun is called the heloencentric theory measures ‘sun’ and centric meaning in the center.’ This theory was developed in parts by different astronomers over many years, namely Aristarchus, Copernicus, Kepler, and Galileo.
Orbit
the curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution.
