Unit 1: Place and Space and Big Bang Theory (copy)

CER, Place and Space and Big Bang Theory

Andromeda Galaxy

Our closest neighboring spiral galaxy, about 2.4 million light years away

Astronomical Unit

The average distance between Earth and the sun, about 150 million kilometers

Big Bang Theory

Theory of creation of Universe by expansion of an extremely small single mass of extremely high density and temperature

Cecilia Payne-Gaposchkin

Discovered the hydrogen (H) and helium (He) rich composition of matter in space which is evidence for the Big Bang Theory

Comet

a mass of rock, ice, dust, and gas traveling around the sun usually in a highly eccentric orbit. most originate from region beyond Neptune

Cosmic Background Radiation

Discovered by Penzias & Wilson in 1964. Radiation left over from the early development of the universe, predicted by supporters of Big Bang over steady state model.

Dependent Variable

The experimental factor that is being measured; the variable that may change in response to changes of the independent variable

Doppler effect

The apparent change in wavelength of radiation caused by the relative motions of the source and the observer

Dwarf Planet

A spheroid celestial body revolving around the sun, similar to a planet, but not large enough to have gravitationally cleared its orbit. Category Pluto belongs in.

Edwin Hubble

An astronomer who discovered in 1929 that galaxies are receding from us at a speed proportional to their distance (Hubble's Law) which lead to the conclusion that our universe was expanding

Elliptical galaxy

A galaxy that has a round or elliptical outline. It contains little gas and dust, no disk or arms, and few hot, bright stars

exoplanet

A planet outside of our Solar System.

Fermi Paradox

There is a high probability that life exists elsewhere in the universe, but there is also a lack of evidence; where is everybody?

Galaxy

a group of millions, even billions, of stars held together by gravity

Galaxy Cluster

groupings of galaxies that are gravitationally bound and travel through space together, our is Virgo Cluster 2000 galaxies

Hypothesis

a model/explanation based on observed facts but not yet tested

Independent Variable

The variable in an experiment that is manipulated by the experimenter; the variable being tested to see if it causes the expected result.

Irregular galaxy

A galaxy that has an undefined shape; irregular galaxies have large numbers of young stars and greats amounts of gas and dust are usually found near larger galaxies.

Jovian Planet

Jupiter-like planets Jupiter, Saturn, Uranus and Neptune

Kuiper Belt

A region outside the orbit of Neptune where most short-period comets are thought to originate

Light Year

The distance that light travels in a year, about 9.5 trillion kilometers

Local Group

group of 80 nearby galaxies that the milky way belongs to

Milky Way Galaxy

the galaxy that contains our solar system. Spiral shaped with at least 3 arms, billions of stars in a disk 100,000 ly across and 10,000 ly thick at the galactic bulge center

Penzias and Wilson

Scientists who discovered cosmic background radiation in 1964. One of the 3 main lines of evidence that support the Big Bang theory

Planet

A celestial object that revolves around the sun, is a spheroid, and has cleared most of its orbit of large debris

Proxima Centauri

the next closest star to Earth (other than Sun), 4.3 light years away

redshift

shift of light to a longer (redder) wavelength as it moves away; indicates that universe is expanding

Singularity

An infinitely small point which contained all the of the Universe at the beginning of time. Also refers to the single point of intense gravity left behind after a very massive star dies.

Solar System

The sun and its family of orbiting planets, moons, asteroids, dwarf planets, and other debris left over from the disk

Spiral galaxy

A galaxy with a bulge in the center and very distinctive spiral arms. Our Milky Way is a spiral galaxy.

Star

A mass of incandescent gas, where a balance exists between the nuclear reactions pushing outward from the interior and the gravitational forces pushing inward.

Terrestrial Planet

Earth-like planets: Mercury, Venus, Earth, Mars

The Drake Equation

Calculates the probability used to estimate the number of extra-terrestrial civilizations in the solar system

Universe

Everything. All existing matter, space, time, and energy

Virgo Supercluster

The super cluster of galaxies of which our local group is a member. Contains roughly 2000 galaxies