Science Vocab Astronomy

Cosmos/Cosmosphere

another name for the Universe. Using the word cosmos implies viewing the universe as a complex and orderly system or entity

**Spectral lines/Emission spectra**

image of individual lines against a dark background. Frequency of light that makes the lines is determined by specific elements-can help to identify what objects in space are made of

Doppler Effect

the change in frequency of a wave in relation to an observer who is moving relative to the wave source

Redshift

displacement of the spectrum of an astronomical object toward longer (red) wavelengths

Big Bang Theory

the rapid expansion of matter from a state of extremely high density and temperature that according to current theories marked the origin of the universe.

Electromagnetic Spectrum

the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies

Cosmic microwave background radiation

microwave radiation that fills all space-leftover from the earliest stage of the universe. It is the oldest identified electromagnetic radiation.

Gravitation

universal force of attraction acting between all matter (gravity, gravitational fields)-pulls objects towards or inward

Angular momentum

measure of an object’s tendency to continue to spin

Stellar nebula

“star nursery” cloud of dust, gases where new stars are forming 

Protostar

very young star that is still gathering mass

Meteoroid

small rocky or metallic body in outer space.

**Meteor**

streak of light seen as a meteoroid passes through the atmosphere

Meteorite

a meteor that survives its passage through the earth's atmosphere and hits the ground. More than 90 percent of meteorites are of rock, the remainder are iron and nickel

Condensation

order in which chemical compounds transition from gas to solid phase in solar nebula

Accretion

 in planet formation, small clumps of matter that stick together and accumulate causing the planet to increase in size

Planetesimals

(preplanets)-solid objects thought to exist in early solar nebula

Proto-planets

early beginnings of a planet that has undergone melting to produce a differentiated interior (more dense elements and materials moved inward, less dense toward the surface)

Fusion

joining together of atomic nuclei