Chapter 26: Stars and Galaxies

Spectroscope

________: a device that uses a prism or diffraction grating to separate light into its component wavelengths.

Astronomers

________ use constellations to locate and name stars.

Supernova

A(n) ________ is a gigantic explosion in which the temperature in the collapsing core reaches 10 billion K and atomic nuclei are split into neutrons and protons.

Cosmology

________: The study of how the universe began, how it evolves, and what it is made of.

Big Bang Theory

The ________: all matter and energy in the universe was compressed into a single point, which then began expanding outward.

Nuclear Fusion

________ occurs in the Suns core, producing the energy that reaches Earth.

Local Group

________: spread over about a region of about 10 million light- years in diameter and includes about 50 galaxies.

Cloud Fragment

The protostar formed in the center of a(n) ________ continues to collapse until nuclear fusion begins.

White Dwarf

________: The final stage in an average stars evolution.

Energy

________ is emitted as hot gas spirals into the black hole.

Auroras

________ take place when high- energy particles in CMEs and the solar wind are carried past Earths magnetic field.

Nuclear Bulge

The halo is a roughly spherical region that surrounds the ________ and disk and might have a diameter of 200, 000 light- years.

Telescope

Refracting ________: uses a convex lens, which is curved outward like the surface of a ball, to collect light.

Doppler Effect

The ________ occurs for a moving source of sound waves.

solar flares

Gases near a sunspot sometimes brighten suddenly, shoot- ing gas outward at high speed in what are called ________.

Photosphere

The ________ is the layer that emits light into space.

CME

When a(n) ________ is released in the direction of Earth, it appears as a halo around the Sun.

Globular Clusters

The halo is made of ________, which are groups of stars.

Equilibrium

________ is reached when the outward pressure exerted by the emitted radiation balances the inward pull of gravity.

Spiral galaxies

________ are disk- shaped and usually have arms that wind outward from the galaxys center.

Inward Pull of Gravity

When hydrogen in a stars core is used up, the outward radiation pressure becomes less than the ________.

Intense magnetic fields

________ associated with sunspots can cause huge arching columns of gas called prominences to erupt.

Optical telescopes

________ collect much more light from distant objects than can enter the unaided human eye.

Hubble

________ discovered that galaxies tend to be moving away from Earth.

Sun’s Photosphere

The ________ is at the top of the convection zone.

Supernova Explosion

A(n) ________ can emit so much energy that for a short time it can be brighter than an entire galaxy.

Sun’s Outer-Layer

The ________ is the convection zone.

Convection

________ in the convection zone causes magnetized gases to flow upward toward the photosphere.

Largest Object

Although the Sun is an average star, it is by far the ________ in the solar system.

Stars

________ are much closer together in the central region of spiral galaxies than in the disk.

Elements

________ with atomic numbers higher than iron are produced during a supernova explosion.

Spiral Arms

The ________ are regions where the concentration of dust and gas is higher, so that stars are being formed in the ________.

Dark Energy

________: repulsive force causing the expansion to speed up.

Star Formation

________ begins with a large cloud of gas, ice, and dust called a nebula.

Telescope

A refracting ________ uses a convex lens to collect light and form an image at the focal point.

Spiral Galaxies

________ also have a central bulge, or nucleus, where stars are closer together.

Constellations

star patterns

Refracting Telescope

uses a convex lens, which is curved outward like the surface of a ball, to collect light

Reflecting Telescope

uses a mirror to collect light

Radio Telescope

Collects and amplifies radio waves

Spectroscope

a device that uses a prism or diffraction grating to separate light into its component wavelengths

Giant

late stage of a stars life cycle

White Dwarf

The final stage in an average stars evolution

The Sun

A Main Sequence Star

Photosphere

The visible surface of the Sun that you see

Galaxy

a large group of stars, dust, and gas held together by gravity

Local Group

spread over about a region of about 10 million light-years in diameter and includes about 50 galaxies

Cosmology

The study of how the universe began, how it evolves, and what it is made of

The Big Bang Theory

all matter and energy in the universe was compressed into a single point, which then began expanding outward

Dark Matter

matter that cant be detected with telescopes

Dark Energy

repulsive force causing the expansion to speed up

typical neutron star

A(n) ________ is the size of a major city on Earth, but has a mass greater than the Suns.