Test Review: Astronomy (Night Sky, Universe, Galaxies, and Stars)

Name: ______Date: ______Period: ______Test Review: Astronomy (Night Sky, Universe, Galaxies, and Stars)

Night Sky

A __asterism__ is a group of stars within a constellation that forms a recognizable figure used to find and identify the constellation.

True or False: The Big Dipper is a constellation.

The __celestial sphere_ is the dome of stars that lies overhead.

Ursa major is known as the big __bear_____, and Ursa minor is known as the __little___ bear.

Horoscopes are supposed predictions of future events and stem from the study of _astrology__.

The system used to catalogued celestial (space) objects was developed by Charles __Messier___.

Why do constellations change from season to season?

_Our perspective of the universe changes as we travel our path around the sun.______

The five constellations that seem to rotate around Polaris and never set in the northern sky are called the ______circumpolar______constellations.

A __star______map___ shows some of the constellations during each season and can be used to observe constellations in the night sky.

The ___ecliptic______is the apparent path that the sun takes across the celestial sphere.

The angular distance (like latitude) north or south of the celestial equator is called __declination____.

The angular distance (like longitude)measured eastward from the position of the vernal equinox is called _____right ascension____.

The boundary between Earth and sky is called the ____horizon______.

The point directly overhead in your local sky is called your ______zenith______.

When measuring angular distance with an outstretched arm, your ___finger__ is 1 degree, your __fist/hand__ is 10 degrees and __spread width pinky to thumb___ is 20 degrees.

The North Star is known as ____Polaris____.

Polaris is at an altitude of ___30______degrees in Georgetown. Universe

The electromagnetic spectrum includes radio waves, ___microwaves___, __infrared rays__, visible light, ____ultraviolet rays____, _____X-rays____, and __gamma rays__.

Any change in wavelength due to motion is called the ____doppler___ effect.

Electromagnetic waves do not require a _____medium______to move through space.

The shortest wavelengths in the visible light spectrum belong to the color, __violet/purple_ while the longest belong to ____red_____.

The Big Bang theory states __12 to 15 billion years ago the universe exploded from an infinitesimally small point of infinite density and continues to expand and lose energy today __.

The three pieces of evidence that support the Big Bang theory are:

 _red shift in the light from galaxies at the farthest reaches of the universe______

 _composition of all stars showing mostly hydrogen (75%) and basically the rest as helium (25%)

 __cosmic background radiation suggesting leftover energy from a massive explosion____

The universe is about ____12-15 billion_____ years old.

The Steady State theory states __the universe exists in a constant state of density with new matter appearing as the edges of the universe expand___.

The Oscillating Universe theory states __as the universe continues to expand, it will lose energy and gravity will pull everything back to the center, reversing time, in a sort of “big crunch”__.

The Oscillating Universe is a variation of the ___Big Bang__ theory.

The most distant objects in the universe that give off radio waves and x-rays are called __quasars__.

A light year is ____the distance light travels in a year (at 300,000 km/s) or about 6 trillion miles______.

When an object is moving towards the earth, it appears to have a __blue__ shift on a spectroscope, but a ___red___ shift if it’s moving away.

Galaxies

We live in the ____Milky Way_____ galaxy which is a ____spiral______galaxy.

The three types of galaxies are ___spiral_____, ____elliptical____, and ____irregular___.

The oldest galaxies are ____elliptical___ galaxies.

The youngest galaxies are ____irregular____ galaxies. Giant clouds of dust and gas within galaxies are called ____nebulae___.

An _____open cluster____ is a group of hundreds of stars that appear to be loosely grouped together inside a galaxy.

A ___globular cluster__ is a group of 100-1000 stars that appear as a ball of stars inside a galaxy.

The center of a black hole is called a ____singularity___.

The hottest stars have a ___blue-white___ color while the coolest stars have a __red____ color.

If two stars are different colors, we can infer that they have different _____temperatures___.

_Stellar Parallax___ occurs when stars near Earth appear to move relative to more distant stars as Earth revolves around the sun. This movement and mathematical calculations help us find the distance of the star from Earth.

The brightness of a star as it appears from Earth is called ____apparent magnitude______.

The actual brightness of a star is called _____absolute magnitude______.

If Star A has an absolute magnitude of 0, Star B has an absolute magnitude of +3, and Star C has an absolute magnitude of -5, which is brightest? ___Star C____ Dimmest? _____Star B__

Stars are most likely born in a ______nebula______.

The majority of the stars in our galaxy are ______main sequence_____ stars. (think H-R diagram).

Explain the death of a dwarf star. as the star uses up its fuel, it will expand and gases will begin to spread out. After these gases puff off a dim hot white dwarf will be left from the heavier metals at the center._

Explain the death of a massive or super-massive star. ___on a shorter timeline, the fuel of this hot burning star will be used up. The result of the this fuel outage will be a great explosion called a supernova. After this event the leftover heavy metals will be left behind in a super dense core known as a neutron star. In the case of the most massive stars, the mass will be too great and it will shrink into the fabric of space and time forming a black hole.___

A supernova is ____the explosion of a massive or super-massive star______.

The oldest stars are __red__ in color.

What will happen to our sun when it dies? it will expand into a red giant and become a white dwarf.

Stars burn because of nuclear ___fusion___.

A ___black hole______forms when the leftovers of a supernova are so massive that they collapse to form a dense object whose gravity is so strong that light cannot escape.