Astronomy Final Study Guide

What is an astronomical unit?

The average distance from earth to the sun

a sphereical object sometimes solid which is usually found orbiting a star

Planet

a ball of very hot plasma undergoing thermonuclear fusion

Star

an “island” or collection of stars sometimes in the shape of a spiral

Galaxy

A cloud of gas and dust where stars sometimes form

Nebula

T/F Galileo invented the telescope

False

What are the primary functions of a telescope?

to improve the details seen in an object

to make otherwise too faint objects visible

what is a light year?

the distance light travels in one year

What is the faintest star mentioned that color was seen with the naked eye?

Fomalhaut

What physical property of a telescope determines its resolution?

the diameter of its primary mirror

Which planet in our solar system is the most similar in size to the Earth?

Venus

The stars as seen from the ground “twinkle” in brightness because of?

turbulence in the earths atmosphere

How does light pollution impact our appearance of the night sky?

it makes it difficult to see the stars with optical telescopes or just our eyes for fun

Between a galaxy, moon, star and astroid which is the largest?

a galaxy

what star is closest to earth?

the sun

What is the light waves in order of increasing energy?

radio waves, microwaves, infrared light, optical light,UV light, X-rays, gamma rays

T/F Radio waves travel at the same speed as a light wave?

True

What property of the blackbody curve tells you the temperature of a star?

the wavelength of the location of the peak of the curve

What does an electron do to produce an absorption line spectrum?

absorb a proton and go from lower energy state to a higher energy state

What happens to the lines in the spectrum of a star that is moving toward us?

the lines shift toward the blue part of the spectrum

What type of spectrum does the moon have?

absorption spectrum

how do astronomers use spectra to determine the composition of a star?

the location of the absorption lines in the spectrum tells us the composition of the star

What is another property of a star which can be used to determine its surface temperature besides its spectrum?

its color

what is the closest star to the earth after the sun?

proxima centauri

What part of the atom is most responsible for the pattern of absorption lines seen in stellar spectra?

the electrons

what type of spectrum do humans produce?

continuous

What causes the stars/sun/planets/moon to rise and set every day?

the rotation of the earth on its axis

If you are standing at the geographical North pole, which answer best describes the motion of the stars on any given night?

all of the stars move parallel to the horizon or circle the north celestial pole

what physical property of a star can you NOT directly measure from its spectrum?

its radius

Which is not a reason to send telescopes into orbit around the earth?

it is cheaper to do so

The change in the position the Sun makes across the sky over the course of a year is caused by…

the earths revolution

Why do we have seasons on Earth?

as the earth goes around the sun, its axis remains pointed toward Polaris and the northern and southern hemispheres alternately receive more and less direct sunlight

what are the two main types of ground-based telescopes?

reflective and refractive

What is the main reason that radio telescopes need to have a larger diameter than optical telescopes?

they need to be larger to achieve a similar spatial resolution to optical telescopes

what is “seeing?”

the blurriness of an object seen in a telescope due to turbulence in the Earth’s atmosphere

T/F The fastest anything can travel in space is the speed of light

True

Why are most ground telescopes on the top of mountains?

to be above the clouds

to get away from light pollution

to get to drier air/ lower humidity

to utilize the stable air often associated with mountain tops

How big is the currently largest, single mirror ground- based telescope?

10 yards

About how much does one teaspoon of a white dwarf weigh?

bus

Which element, when undergoing thermos-nuclear fusion, absorbs energy rather than producing it thus leading in a supernova implosion?

Hydrogen

Iron

Calcium

Mercury

Magnesium

Iron

Which type of star is the smallest in physical size?

Blue Giant

Red Super Giants

White Dwarf

Stars like the Sun

red dwarfs

white dwarf

What “rare” substance was used to cover the mirrors of JWST?

Gold

What is an interferometer?

A collection of multiple telescopes wh

Why do we see lightening ans then hear thunder a bit later

light travels faster than sound

At very early age of the Universe after the Big Bang, it had a temperature of about 3000 K. What color did the video we watched in class say the Universe was at this point?

Orange

The apparent path populated by the Sun, moon and the planets over the year is called the

the ecliptic

If you are in Starkville on March 1st and see the Sun high in the sky at noon, how will the position of the Sun at that time be different a month later?

it will have moved to a higher position in the sky

T/F The precession of the Earth’s orbital axis over ~26000 years will cause its orbital tilt to vary from 0 to 23.5 degrees

false

T/F Most of the stars in any given constellation are at different distances from the Earth

true

What is the circumpolar constellation?

a constellation that always remains above the horizon

What is the name of the constellation to the right?

Ursa Major

Which is one reason winter days are colder than summer days?

the sun is up for less time in the winter

if you are at the South Pole, where is the location of your Zenith?

over your head

You are standing near the north pole. Where is Polaris, the North Star?

directly overhead

How do we most accurately measure the distances to the nearest stars?

Trigonometric Parallax

What type of galaxy is shown to the right?

a barred spiral galaxy

About what day of the year is the winter solstice?

there is not enough information to answer this question

T/F The Sun is further from the Earth during the summer and closer during the winter

there is not enough information to answer this question

In which direction does the Sun set?

west

What is unique about the constellations which compromise the zodiac?

the sun, moon and planets all pass through them

Astronomers wish to study the Sun continuously with the Solar telescope for almost a full six months. Which two places should they build their telescopes?

antartica or the artic

What is a major difference between the characteristics of elliptical versus spiral galaxies?

spiral galaxies contain gas, dust and young stars while elliptical galaxies do not

In what direction does the moon rise?

east

What main property of light mean that the farther away the object observed, the farther back in time we are observing it.

photons travel at the speed of light

Polaris will not always be the North Star. This is due to a phenomenon called

Precession

Which best describes the motion of the stars if you are standing on the equator?

they travel parallel along the horizon

You are standing on the Earth’s equator. Where is the meridian?

it rises from the north, goes directly overhead, and goes down to the south

What is the definition of the celestial equator?

the projection of the earths equator onto the celestial sphere

What is the current best estimate for the age of the Universe?

13.7 billion years

What structure best describes the distribution of galaxies on the largest of spatial scales?

galaxies are distributed evenly across the sky

There are two blue stars, which are the same distance. If they have the same surface temperature but star A is twice as big as star B, which is brighter?

star A

Which is one of the issues with the observed properties of our Universe that inflation helps explain?

that the universe is too flat

The time it takes a Cepheid variable star to get brighter and fainter is directly related to its

luminosity

which nearby galaxy has its spectrum blue-shifted due to its relative velocity to the milky way?

andromeda

when we observe galaxies that appear to be receding or moving away from the milky way, what is the cause of this motion?

the space between the galaxies is expanding

You are lost at sea and it is a clear night, how can you at least determine your latitude?

the angle above the horizon of the north celestial pole

which of the following constellations is circumpolar?

ursa minor

what is the Hubble Law a relationship between?

the distance and recessional velocity of a galaxy

What is the constellation to the right?

orion

What “shape” of the Universe seems to currently match all the observations?

a flat universe

What is some of the evidence that supports the Big Bang Theory?

the detection of the 3K cosmic microwave background radiation

the discovery that most galaxies appear to be moving away from each other

what does the term “inflation” refer to when talking about the early stages of the Universe?

it was a period right after the Big Bang when the Universe expanded at an extremely fast rate compared to now

What is the “cosmic distance ladder?”

the succession of methods by which astronomers determine the distances to celestial objects

Which of the following is the definition of Kepler’s first law of planetary motion?

the orbits of the planets around the sun are ellipses with the sun at one focus

T/F You have the same mass on Earth as you do the moon?

true

T/F astronauts are under the influence of gravity when orbiting the Earth on board the ISS

true

What percent of the Universe is made of matter we can see?

5%

T/F There are enough wondering black holes in the Galaxy that our solar system could one day be swallowed up by a collision with one

False

What are globular clusters?

Spherical clusters of old stars that live in the halo of the Milky Way

What class of black holes resides at the center of our Milky Way galaxy?

A supermassive Blackhole

T/F Orbiting a 10 solar mass black hole is just like orbiting a 10 solar mass star

True

About where does the Sun reside within our Milky Way galaxy?

In the disk of the galaxy about 2/3 of the way out from the galactic center

About how wide is the Milky Way in light years?

100,000 light years across

What type of galaxy is the Milky Way?

A barred spiral galaxy

What object would be closest to representing the overall shape of the Milky Way?

A frisbee

Where are the youngest stars found in the Milky Way?

In the spiral arms of the disk of the galaxy

Toward which constellation is the center of the Milky Way?

Sagittarius

About how big is a neutron star?

The size of a city

Which type of star is the largest in physical size

Red Supergiants

About how many stars do we think compose our Milky Way galaxy?

Over 300 billion