Astronomy

Halley's Comet was given that name because Edmond Halley was

the scientist who predicted that the comet would return every 76 years

aperture

the size of the opening of an optical instrument, for your eyeball about 15mm

Which of the following is not a type of electromagnetic wave with lower energy than visible light waves?

the sound waves coming from your transistor radio

The strip of the sky through which the Sun, the Moon, and the bright planets appear to move in the course of a year is called:

the zodiac

Edwin Hubble developed a classification scheme for galaxies that looked like a tuning fork. By what characteristic did he classify galaxies?

their shape, elliptical or spiral

Why do satellites launched into low-Earth orbits not remain there indefinitely

they lose speed due to friction with the upper layers of the Earth's atmosphere

Your sweetheart gives you a piece of gold jewelry as a present to celebrate your passing your astronomy class. Where did the gold atoms in that gift originally come from (where were they most likely made)?

they were built up from smaller nuclei during a supernova explosion

interstellar dust

tiny particles that float between the stars and make up a large portion of the mass of the galaxies

when one astronomical object moves in front of another

transit

a supernova formed when a white dwarf exceeds 1.4 solar masses and has causes standard sized explosion. This is useful as a standard candle to determine distance.

type Ia (one-Aye) supernova

a binary star that can be seen in a telescope

visual binary

Astronomers identify the "birth" of a real star (as opposed to the activities of a protostar) with what activity in the star?

when nuclear fusion reactions begin inside its core

From a scientific perspective, which of the following statements about life elsewhere in the universe is best supported by current evidence?

while we have evidence of the building blocks of life elsewhere in the universe, we have no definite evidence about life around other stars at this time

the leftover dense hot core of a star

white dwarf

In 2013, a small stony asteroid collided with the Earth above the Russian city of Chelyabinsk. What was the result?

A fireball briefly brighter than the Sun could be seen in the sky and smaller pieces rained down in the region

Credit for the purely mathmatical discovery of Neptune is shared by two astronomers. They are

Adams and Leverrier

The astronomer who, at the turn of the century, measured the spectra of hundreds of thousands of stars, leaving a catalog that astronomers used for the rest of the century, was

Annie Cannon

Which ancient Greek thinker suggested (long before Copernicus) that the Earth is moving around the Sun?

Aristarchus

1.4 solar masses, beyond which a star's core can not support its own mass with degeneracy pressure

Chandrasekhar Limit

The comet-hunting astronomer who made a list of over 100 nebulae and galaxies that could be mistaken for comets was

Charles Messier

The Renaissance astronomer who wrote the pioneering book that suggested the Earth probably orbits the Sun (instead of the other way around) was:

Copernicus

A progressive series of techniques that allow astronomers to stretch the maximum distances from Earth that can be measured

Cosmic Distance Ladder

A star's lines ALL appear to be moved toward the red side or blue side of the rainbow

Doppler Shift due to a star moving through space

A star's lines appear to be fatter like a bell curve and reduced in intensity

Doppler Shift due to a star's rotation

The telescope maker and astronomer whose craftsmanship was considered the highest in his era

Fraunhofer

The astronomer whose measurement of a star's actual distance from the Sun was accepted as the first accurate parallax

Fredrich Willhelm Bessel

The first person who regularly turned a telescope to astronomical observations (and published his observations) was

Galileo Galilei

The scientist who made the first telescopic survey of the Milky Way and discovered that it is composed of a huge number of individual stars was

Galileo Galilei

The four large moons of Jupiter were first discovered by

Galileo with his early telescope

Why do many people consider Isaac Newton one of the greatest scientists who ever lived

He formulated the laws that govern all motion in the universe, He combined the work of Galileo, Brahe, and Kepler into one framework, He figured out the mathematical form of a law of universal gravity, he invented a new mathmematics called calculus in order to model his laws of motion

Who was the astronomer who is the "H" in H-R diagram?

Hertzsprung

a constant in the Hubble Law that relates the velocity (red shift) of remote galaxies to their distance

Hubble constant

a rule that the radial velocity of remote galaxies are proportional to their distance from Earth

Hubble's Law

A star spectral lines appears to be very strong in the red but the blue lines seem fainter that you would expect

Interstellar Reddening

The change in color of a star because its view is blocked by grains of dust

Interstellar Reddening

the last element that can fuse in the core of a star because the reaction sucks heat away, causing the star to collapse

Iron

Why is an absorption spectrum especially useful for astronomers?

It has dark lines in it that allow astronomers to determine what elements are in the star

The scientist who formulated the three laws of planetary motion by analyzing the data on the precise location of planets in the sky was

Johannes Kepler

The largest planet in the solar system (by mass) is

Jupiter

Sunspot

Large features seen on the surface of the Sun caused by increased magnetic activity

Doppler Effect

Light and Sound waves shift depending on if the source is moving toward or away from the observer

The total power output of a star

Luminosity

A Star's mass goes up, so does its power output

Mass Luminosity Relationship

the band of light encircling the sky

Milky Way Galaxy

The astronomer who assisted Edwin Hubble at the Mount Wilson Observatory and helped him establish the expansion of the universe was

Milton Humason

The first human being to step out onto the surface of another world was

Neil Armstrong

a type of star explosion that happens in a binary star that is repeatable and does not destroy the white dwarf or its companion

Nova

the hottest burning, largest, and quickest stars to die

O type stars

Your weird cousin, who is really into astronomy, decides that the return address he uses on his letters is incomplete! To his city, state, and country, he begins to add: "North America, Earth, Solar System..." If he now wants to include the name of the Galaxy s spiral-structure feature in which the Earth is located, how should his address end?

Orion Spur

The relationship found in Cephid Variables that allows astronomers to determine their distance from Earth

Period Luminosity

The great astronomer of ancient times who summarized and improved a system of circles upon circles to explain the complicated motions of the planets (and published the system in a book now called The Almagest) is:

Ptolemy

The astrophysicist who first calculated the highest mass that a dying star can have and still be a white dwarf was

S. Chandrasekhar

The comet that broke into more than 20 pieces and then collided with Jupiter in 1994 was

Shoemaker-Levy 9

A way to group stars by the lines that appear in their spectrum

Spectral Class

A star's Hydrogen and Helium lines appear thicker that all the rest

Stark Effect

Which part of the Sun has the greatest density?

The core

Astronomers have concluded that the Sun's activity varies in an 11-year cycle. Which of the following statements about this cycle is TRUE:

The number of sunspots gets larger and smaller over the course of 11 years

local bubble

The skin of the balloon of dust around the solar system caused by outgoing solar winds

The 17th century astronomer who kept a roughly 20 year continuous record of the positions of the Sun, Moon, and planets was

Tycho Brahe

What specific event really made it possible for the three laws of planetary motion to be discovered

Tycho Brahe died and his assistant was able to get full access to his data

a type of star explosion that happens after a massive star core begins to produce iron

Type II supernova

a type of star explosion that turns a white dwarf into a neutron star and likely destroys its binary companion

Type la Supernova

Which of these worlds is the most active geologically?

Venus

A star's spectral lines appead to have oval 'wings' around the line

Zeeman Effect

An idealized object that does not reflect or scatter any radiation that hits it, but simply absorbs every bit of radiation that falls on it is called

a blackbody

When a chunk of cosmic material the size of a golf ball or a baseball hits the Earth s atmosphere it makes a

a fireball that we call a meteor or a shooting star

solar wind

a flow of charged particles leaving the Sun

A type of star cluster that contains mostly very old stars is

a globular star cluster

Plasma

a hot ionized gas (meaning the atoms have fewer or no electrons bout to them)

The Orion Nebula is

a large cloud of gas and dust illuminated by the light of newly formed stars within it

In a radio telescope, the role that the mirror plays in visible-light telescopes is played by

a large metal dish (antenna)

Prominence

a large, bright, gaseous feature that appears above the surface of the Sun and extends into space

telescope

a light bucket designed to direct as many photons as possible at a detector

According to the formula E=mc2

a little bit of mass can be converted into a substantial amount of energy

Who pays the bill for the energy generated by nuclear fusion in the Sun? In other words, where does the energy pouring out of the Sun come from ultimately?

a little bit of mass is lost in each fusion reaction and is turned into energy (the Sun is losing mass)

The largest visible-light telescopes in the world use what device to collect as much light as possible before the light is brought to a focus (to act as the light bucket )?

a mirror

What happens as an electron falls from a higher level to a lower level in an atom?

a photon is given off

coronal hole

a region in the Sun's outer atmosphere that appears darker because there is less hot gas there

The Local Bubble is

a region of low density interstellar gas extending several hundred LY around the Sun

This chapter discusses that light sometimes acts like a photon. What is a photon?

a self-contained packet of electro-magnetic energy

A star moving toward the Sun will show

a shift in the spectral lines toward the blue end (as compared to the laboratory positions of these lines)

coronal mass ejection

a solar flare in which immense quantities of coronal material is ejected at high speed into space

solar flare

a sudden and temporary outburst of electromagnetic radiation from an extended region of the Sun's surface

refractor

a telescope that bends light using a glass lense

radio telescope

a telescope that focuses electromagnetic radiation that is to low of frequency to be seen by the eyes

reflector

a telescope that uses a large mirror to bend the light to a focus

According to the fossil record, how old is the oldest evidence of life forms on the surface of the Earth

about 3.5 billion years

The brightness of stars seen at a standard distance of 10 parsecs

absolute magnitude

To go from a lower level in an atom to a higher level, an electron must

absorb a photon of energy

One way in which the ozone layer is useful for life forms on the Earth's surface is that it

absorbs ultra-violet light, preventing much of it from reaching the surface

Which of the following can astronomers learn from studying the spectrum of a star?

all of these can be learned from studying the spectrum

spectrograph

an instrument attached to a telescope that divides light into its component parts or spectrum

The brightness of stars as we see them from Earth

apparent magnitude

Planets in the habitable zone of their stars

are at a temperature where water can exist as a liquid

The laws of nature as determined by science

are constructed from many observations, hypotheses, and experiments, apply both on Earth and among the stars, and are often written in the language of mathematics (all of the above)

From a city in the U.S., where in the sky would you look to see one well known star that does not appear to turn with the all the others?

at the north celestial pole

How fast do electro-magnetic waves travel?

at the speed of visible light

What happens in the process of fluorescence?

atoms absorb ultraviolet rays and convert them to visible light as their electrons cascade to lower energy levels

Why are the largest craters we find on the Moon and Mercury so much larger than the largest craters we find on the Earth?

because the largest craters were made early in each world's history before the atmosphere thickened, and geologic activity has erased most traces of this early period on the Earth's surface

Why can a star with a mass like our Sun not fuse (produce) further elements beyond carbon and oxygen?

because they just cannot get hot/close enough for the fusion of heavier nuclei because it lacks mass and stronger gravity

Two stars that are physically associated (rotate around each other in space) are called

binary stars

Fission

breaking up of heavier atomic nuclei into lighter ones

Fusion

building up of heavier atomic nuclei from lighter ones

molecular clouds

bunched up interstellar dust that can stretch for many light years across

How did Henrietta Leavitt calibrate her period-luminosity relationship for Cepheid variable stars? In other words, how did she make the general idea into a numerical rule?

by finding cepheids in star clusters whose distance was known in another way

the central part of the Milky Way in the direction of Sagittarius

central bulge

Astronomers now understand that the dark regions or rifts visible in parts of our Galaxy that are otherwise crowded with stars are caused by

clouds with a considerable amount of dust which blocks the light of the stars behind them

The most basic function or operation of an astronomical telescope is to

collect as much light as possible and bring it to a focus

A measure of how blue or red a star appears

color index

Short-period comets like Comet Halley

come back again and again at predictable intervals

The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called:

constellations

Which part of the Earth has the greatest density?

core

Which part of the Sun's atmosphere is the hottest?

corona

the mass in the Milky Way that extends well beyond the boundary of the luminous stars to a distance of at least 200,000 light years

dark matter halo

The part of your GPS location expressed in the number of degrees north or south of the Earth's equator is equal to your latitude. The equivalent coordinate for stars is called

declination

the idea that different parts of the Galaxy turn at different rates

differential galactic rotation

The way scientists know that a hypothesis in astronomy is a reasonable description of nature is to

do experiments and observations about the predictions of the hypothesis

The fact that each type of atom has a unique pattern of electron orbits helps explain why

each type of atom shows different absorption or emission spectra

a galaxy whose shape is an ellipse and contains no observable interstellar dust

elliptical galaxy

Radiation

emission of energy as electromagnetic radiation or photons, also the name for the transmitted energy itself

In the Sun, when a positron and an electron collide, they will produce

energy in the form of a gamma ray

To leave the gravitational pull of the Earth, and explore other planets, probes must have at least

escape velocity

Of the people who stepped foot on the Moon, how many trained originally in their careers to be scientists?

exactly one

a planet orbiting a star other than the Sun

exoplanet

What method would astronomers use to find the distance to a galaxy so far away that individual stars are impossible to make out (resolve)?

finding the red¬shift and using Hubble's Law

What phase of the Moon must it be to have a lunar eclipse?

full moon

Neutrino

fundamental particle that has no charge and a mass that is tiny relative to an electron

a large cold interstellar cloud with a diameter of dozens of light years

giant molecular cloud

a cluster of stars that is old, lacks blue stars, and is found mostly above and below the disk of the Milky Way

globular cluster

round compact groups of stars

globular clusters

the outermost extent of our Galaxy, containing stars and globular clusters in a more or less spherical distribution

halo

If mid-sized stars with masses like our Sun s cannot make elements heavier than oxygen, where are heavier elements like silicon produced in the universe?

heavier elements are made in the cores of significantly more massive stars than the Sun, which can get hotter in their core and have greater gravity

cosmic rays

high energy particles from all around the milky way that strike the Earth

solar wind

high energy particles from the Sun which strike the Earth, planets and other objects in the solar system and extends out into space in a sphere.

a Jupiter sized planet that orbits close to its star

hot Jupiter

When an astronomer rambles on and on about the luminosity of a star she is studying, she is talking about

how much energy the star gives off

By far the most abundant element in the giant (jovian) planets is

hydrogen

Studies of the spectra of stars have revealed that the element that makes up the majority of the stars (75% by mass) is

hydrogen

The most common element in the Sun is

hydrogen

A main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of

ice

If you want to find stars that are just being born, where are the best places to search?

in giant molecular clouds

Where would you look for the youngest stars in the Milky Way Galaxy?

in the disk with the dust and nebula clouds

When an atom has lost one or more electrons, it is said to be

ionized

a galaxy without any clear symmetrical shape

irregular galaxy

As astronomers have learned more about the structure of the Sun, they have found that it.

is made entirely of hot gas

At the largest and most modern astronomical observatories on Earth today, which of the following regularly happens to the image formed by the telescope?

it is recorded using an electronic detector called a CCD for later analysis

How long a main sequence star remains on the main sequence in the H-R diagram depends most strongly on

its initial mass

When a star settles down to a stable existence as a main-sequence star, what characteristics determines where on the main sequence in an H-R diagram the star will fall?

its mass

Which of the following is a way that the planet Mercury is similar to the Moon?

its surface is heavily cratered

Aurora

light in the ionosphere excited by charged particles from the Sun

Astronomers now realize that active regions on the Sun are connected with

loops of magnetic field emerging from the surface of the Sun

the diagonal line on the HR diagram

main sequence

the point in the plot of a cluster of stars where some start aging into red giants

main sequence turn off

An astronomer discovers a new star and wants to measure its temperature. She would typically do this by

making a blackbody curve and finding the wavelength of the peak (maximum)

a property of binary stars determined by their period of rotation and Kepler's Laws

mass

the property of a star that determines its destiny and eventual death

mass

the ratio of total mass of a galaxy to its light output (Luminosity) which can aid in determining its distance

mass-to-light ratio

The planet Neptune was discovered by means of

mathematical calculations of how it was perturbing the motion of a neighbor planet

The lakes found in the north polar region of Titan are filled with liquid

methane

In terms of numbers, the most common life-forms on Earth today are

microscopic creatures, too small to see with our eyes

a planet of intermediate size between Earth and Neptune

mini-Neptune

According to the geocentric view, everything in the heavens had to go around the Earth, which was the center of the universe. What objects did Galileo discover with his telescope that clearly didn't go around the Earth?

moons around the planet Jupiter

Convection

movement caused within a gas or liquid by hotter less dense matter rising and colder denser matter sinking under the influence of gravity

You are on a camping trip, far away from city lights. You look up into the dark night sky, and see lots of stars, some brighter, some dimmer. All the stars you see with your unaided eye are

nearby in the Milky Way Galaxy

What phase of the Moon must it be to have a solar eclipse?

new moon

Astronomers first detected the presence of a wind of particles coming from the Sun by

noting the wind's effects on the tails of comets

loosely gathered stars born in nebula clouds in the galaxy

open clusters

The canals that late 19th and early 20th observers thought they saw on Mars turned out to be

optical illusions

the shift in distance of one object in comparison to a more distance object, useful to determine their actual distances away

parallax

Positron

particle with the same mass as an electron but positively charged

how fast binary stars rotate around each other

period of rotation

a dying star that is shedding its outer shell and looks like a planet when seen from Earth

planetary nebula

a star containing heavy elements, typically young and found in the disk of the galaxy

population I (one) star

a star with very low abundance of heavy elements, found throughout the galaxy

population II (two) star

Conduction

process by which heat is directly transmitted through a substance when there is a difference in temperature

A star's motion across the sky as seen from Earth

proper motion

balls of nebula gas that will soon become stars

proto-stars

a very young star still in the process of formation

protostar

A star's motion toward or away from Earth, determined by its Doppler Shift

radial velocity

the slowest burning and longest living type of star

red dwarf

When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum

red-shifted (shifted toward the red end of the light spectrum)

Photosphere

region of the solar atmosphere from which continuous radiation escapes into space

When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:

retrograde motion

In locating objects on the celestial sphere, we call the spacing east or west that something is from Greenwich, England its

right ascension

If you want to locate someone precisely on the surface of the Earth, you specify her exact latitude and longitude. If you want to locate a star precisely on the sky, you need to specify its exact

right ascension and declination

proton-proton chain

series of thermonuclear reactions by which nuclei of hydrogen are built up into nuclei of helium

According to the theory of plate tectonics

slow motions within the mantle of the Earth move large sections of the crust around

The combination of motions of a star that give its total motion relative to Earth

space velocity

Our Milky Way Galaxy is what type of galaxy?

spiral

a spiral shaped region characterized by relatively dense interstellar material and young stars

spiral arm

a galaxy whose shape is a flattened rotating disk with pinwheel like arms of interstellar material and young stars

spiral galaxy

An astronomer who is observing visible light from a glowing cloud of gas in space uses an instrument called a spectrometer which contains a grating with thousands of grooves on its surface. What will this instrument allow our astronomer to do?

spread out the light from into a spectrum

Two stars have the exact same luminosity, but star Y is four times dimmer looking that star X. This means that

star Y is twice as far away as star X

Large amounts of Electromagnetic Radiation caused by fusion

starlight

reddening

starlight that is blocked is often blue, making the stars behind a cloud appear to be red

The process of birth, life, and death of a star

stellar evolution

the energetic outflow of gas from a star

stellar wind

a planet larger than Earth found around another star

super Earth

the object in the center of most large galaxies so massive and compact that light cannot escape from it

suppermassive black hole

An H-R Diagram plots the luminosity of stars against their

surface temperature/ spectal class

What method was used to discover Pluto in 1929-1930?

take pairs of photographs several days apart and "blink" them

A type of star that has turned out to be extremely useful for measuring distances is

the Cepheid variables

If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?

the Earth's axis is tilted by about 23 degrees from the vertical

As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of the H-R diagram first?

the O and B type stars

Why does the Moon show phases in the course of a month?

the angle the Moon makes with the Sun changes and we see differing amounts of reflected sunlight

An astronomical unit is

the average distance between the Earth and the Sun

hydrostatic equilibrium

the balance between the weights of different layers, as in a star or Earth's atmosphere, and the pressures that support them

Astronomers believe that the center of our Galaxy has a black hole with enough mass inside to make almost 4 million Suns! How do astronomers think a black hole could acquire so much mass?

the center of our Galaxy is a much more crowded region than where the Sun is found due to strong gravity; we still see material falling toward the center and material has fallen in for billions of years

When a knowledgeable amateur astronomer tells you that she has a 14-inch telescope, what does the number 14 refer to?

the diameter of the primary lens or mirror

A light year is

the distance that light travels in one year

Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth s layers to happen?

the early Earth was so hot it was like a liquid and heavier elements sank to the middle

Which of the following is evidence for volcanic activity on Venus?

the fact that the lava plains are only 500 million or so years old, the existence of large volcanic mountains such as Sif Mons, the discovery of thousands of small volcanic cones of the surface of Venus, the pancake domes of Venus

Edwin Hubble was able to show that (with the exception of our nearest neighbors) the farther a galaxy is from us, the

the faster it is moving away from us

The Drake Equation allows astronomers to estimate

the number of probable civilizations out among the stars with which we might communicate

Corona

the outermost (hot) atmosphere of the Sun

detector

the part of a telescope that the photons strike which builds up an image over an exposure time

The Sun's photosphere is

the part of the Sun from which the light comes that we see when we look at the Sun with our eyes

Chromosphere

the part of the solar atmosphere that lies immediately above the photosphere

Baryonic Cycle

the process sort of like the evaporation of clouds on Earth where dust becomes stars becomes dust

The process by which Venus became so much hotter than the Earth is called

the runaway greenhouse effect