The Earth's atmosphere is 120 miles thick and is composed mainly of nitrogen, oxygen, carbon dioxide, and a few other trace gases.Ī glow in a planet's ionosphere caused by the interaction between the planet's magnetic field and charged particles from the Sun. The branch of science that explores the chemical interactions between dust and gas interspersed between the stars.Ī unit of measure equal to the average distance between the Earth and the Sun, approximately 93 million miles.Ī layer of gases surrounding a planet, moon, or star.

The orbits of some asteroids take them close to the Sun, which also takes them across the paths of the planets. Most asteroids can be found in a belt between the orbits of Mars and Jupiter. Bright objects have a low apparent magnitude while dim objects will have a higher apparent magnitude.Ī small planetary body in orbit around the Sun, larger than a meteoroid but smaller than a planet. The apparent brightness of an object in the sky as it appears to an observer on Earth. The point in the orbit of the Moon or other satellite where it is farthest from the Earth. The point in the orbit of a planet or other celestial body where it is farthest from the Sun. The size of the opening through which light passes in an optical instrument such as a camera or telescope. The point of greatest separation of two stars, such as in a binary star system. In antimatter, protons have a negative charge while electrons have a positive charge.Ī point that is on the direct opposite side of a planet. Matter consisting of particles with charges opposite that of ordinary matter. The angular distance of an object above the horizon. A perfect mirror would have an albedo of 100% while a black hole would have an albedo of 0%.Ī dark or light marking on the surface of an object that may or may not be a geological or topographical feature. The reflective property of a non-luminous object. As the gas spirals in, it becomes hot and emits light or even X-radiation.Ī stone meteorite that contains no chondrules. The process by where dust and gas accumulated into larger bodies such as stars and planets.Ī disk of gas that accumulates around a center of gravitational attraction, such as a white dwarf, neutron star, or black hole. Absolute zero is reached at 0 degrees Kelvin or -273.16 degrees Celsius.Ī process by where the atmosphere melts away and removes the surface material of an incoming meteorite. The temperature at which the motion of all atoms and molecules stops and no heat is given off. On this scale, the Sun has an absolute magnitude of +4.8 while it has an apparent magnitude of -26.7 because it is so close.

Absolute magnitude measures how bright an object would appear if it were exactly 10 parsecs (about 33 light-years) away from Earth.

A B C D E F G H I J K L M N O P Q R S T U V W X Y ZĪ scale for measuring the actual brightness of a celestial object without accounting for the distance of the object.

Obscure words that begin with n