Stars and Galazies

What is a galaxy?

A galaxy is a large group of stars, gas, and dust held together by gravity.

What is the difference between absolute and apparent magnitude?

Absolute Magnitude-a measure of light given off by a star. Apparent Magnitude-a measure of the amount of light received from a star., as seen from Earth.

After a supernova, what type of object forms if the remaining dense core collapses?

Black Hole

What are groups of galaxies called?

Clusters

What are the different layers that make up the Sun?

Core, radiation zone, convection zone, photosphere, chromosphere, corona

Which galaxies are sometimes shaped like footballs?

Elliptical

How do stars produce energy?

Fusion

Why are giants not in the main sequence on the H-R Diagram?

Giants are large, relatively cool stars. Their temperatures compare with small main sequence stars, but their absolute magnitudes compare with the larger, more massive main sequence stars.

Describe how stars are classified.

Hertzberg-Russell Diagram is a graph that placed temperatures across the bottom and absolute magnitudes up one side to show the relationship of a star's temperature to its absolute magnitude.

Sun

It is the source of most energy on Earth.

What is the name of the galaxy that you live in?

Milky Way Galaxy

How do the three types of galaxies differ?

Shape

What is the Doppler shift?

Shift in wavelength caused by movement.

What are the three main types of galaxies?

Spiral, Elliptical, and Irregular Galaxies.

What motion do the Milky Way's stars exhibit?

Stars orbit its nucleus.

How are stars born?

Temperatures in nebula increase, fusion begins, energy radiates.

What is the most accepted theory about the origin of the universe?

The Big Bang Theory - universe began with a huge explosion and continues to expand from the size of a pinhead to 2,000 times the size of the Sun.

What group of galaxies is the Milky Way a part of?

The Local Group. It is a spiral galaxy that contains about 200 billion stars.

What characteristics does the Sun have in common with other stars and what makes it different?

The Sun's size, temperature and absolute magnitude are similar to yellow stars on the main sequence. The Sun is not part of the binary system.

What is a sunspot cycle?

The regular pattern of increasing and decreasing sunspot activity on the Sun.

What is a black hole?

The remaining dense core from a very massive super nova, collasped down into a point, where gravity is so strong nothing can escape, not even light.

What are the characteristics of sunspots?

They are darker and cooler than surrounding areas of the Sun.

How far away are the most distant galaxies?

They are more than 10 billion light years away.

What kinds of stars are on the main sequence?

They are small, red stars. Not, blue, bright stars and medium-temperature yellow stars are also on the main sequence.

What happens to stars that are the size of the Sun?

They will become giants, white dwarfs, and finally black cinders.

If no light is given off, how are black holes located?

X-rays are emitted by matter as it is pulled into the black hole.

Sequence the following in order of most evolved to least evolved.

neutron star, supergiant, main sequence star, nebula

Constellations

patterns of stars in the night sky, a group of stars that forms a shape or pattern

What do scientists study to determine shifts in wavelengths of light?

spectrum