ES U1 Vocabulary

Absolute magnitude

the intrinsic brightness of an object.

Apparent magnitude

is a measure of the brightness of an object as seen by a particular observer

Astronomical Units

a unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of the sun.

Big Bang Theory

the idea that the universe began as just a single point, then expanded and stretched to grow as large as it is right now

Black Hole

a region of space having a gravitational field so intense that no matter or radiation can escape.

Blue Shift

the displacement of the spectrum of an approaching celestial body toward shorter wavelengths.

Constellation

a group of stars that appears to form a pattern or picture

Doppler Effect

an increase (or decrease) in the frequency of sound, light, or other waves as the source and observer move toward (or away from) each other

Elliptical/Eccentricity

The eccentricity of an ellipse refers to how flat or round the shape of the ellipse is. The more flattened the ellipse is, the greater the value of its eccentricity. The more circular, the smaller the value or closer to zero is the eccentricity.

Fusion

the process that powers the sun and the stars

Galaxy

a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity

Gravity

the force by which a planet or other body draws objects toward its center.

Light Years

a unit of astronomical distance equivalent to the distance that light travels in one year, which is 9.4607 × 1012 km (nearly 6 trillion miles).

Magnitude

the great size or extent of something.

Milky Way

a broad luminous irregular band of light that stretches completely around the celestial sphere and is caused by the light of myriads of faint stars.

Nebula

enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars.

Neutron star

any of a class of extremely dense, compact stars thought to be composed primarily of neutrons

Nova

any of a class of exploding stars whose luminosity temporarily increases from several thousand to as much as 100,000 times its normal level.

Red giant

a star that has low surface temperature and a diameter that is large relative to the sun.

Red Shift

the wavelength of the light is stretched, so the light is seen as 'shifted' towards the red part of the spectrum.

Spectroscope

an instrument for forming and examining spectra, especially in the visible region of the electromagnetic spectrum.

Supergiant

any star of very great intrinsic luminosity and relatively enormous size,

Supernova

the colossal explosion of a star.

Universe

The universe is everything. It includes all of space, and all the matter and energy that space contains

White dwarf

stars that have burned up all of the hydrogen they once used as nuclear fuel.