Astronomy Ch 5: ALL OFFICIAL HOMEWORK QUESTIONS

When an atom absorbs a photon containing energy, any of the following can happen except which?

An electron moves from an upper energy level to a lower one.

What is a CCD?

An electronic imaging detector

The _______ ________ of the Hubble Space Telescope is better for shorter (bluer) wavelengths of light than for longer (redder) wavelengths of light

Angular resolution

At least these wavelengths, it is necassary to build telescopes with a very large light collecting________ to obtain maps of sufficient sensitivity to faint cosmic signals

Areas

The effect of a cool, dilute gas between an observer and a continuous hot source is that_____

Dark absorption lines will appear in the spectrum

If our eyes were ONLY sensitive to X-ray, how would the world appear?

Dark because x-rays light does not reach the earth's surface.

In the _____ ______ a red shift of spectral lines shows us the source is recording from us

Doppler Affect

The observed spectral lines of a star are all shifted towards the red end of the spectrum This is an example of..

Doppler Effect

The ingredients of a typical comet's nucleus are most likely..?

Dust and rocky particles trapped in methane, ammonia, and water ice

Radio waves go through? and can be done on earth

Dust and the earth's atmosphere

Pluto is different from the outer planets in all of the following ways except which one?

Its surface temperature is very cold.

These planets have rings around the equators and at least 8 moons

Jovian

What type of planet is this? -accreted from ice planetesmals -formed in regions cold enough for freezing water -formed in region of the solar system w. lower orbital speeds -large moonds formed surrounding disks of material -ejected icy planestimals that are not oort comets

Jovian

Which planet contains a mass = to all planets combined

Jupiter

Which planet has a ring system?

Jupiter Uranus Neptune Saturn

Jovian planets;

Jupiter, Saturn, Uranus, and Neptune.

Name of temperature scale that places 0 at a point where all atomic and molecular motion ceases?

Kelvin

The___ ___ extends about beyond the orbit to about 2 times the distance of Neptune from the sun

Kuiper Belt

What are two advantages of large scopes over smaller ones?

LARGE TELESCOPE CAN COLLECT MORE LIGHT AND HAS BETTER RESOLUTION

You could more easily resolve a close double star with a blue filter than with a red one.

True

this design combines the radiation from two diffeent telescopes to greatly enhance resolution cia computer syntheiss

interferometer

The twin 10-m Keck telescopes can work together to obtain better angular resolution through a technique known as __________.

interferometry

When an atom loses an electron, it becomes

ionized

Neptune

is about 30 times as far from the Sun as our planet

Jupiter

is the jovian planet that orbits closest to the sun

Venus

is the planet with the highest average surface temperature

one advantage of the hubble space telescope over ground based ones is that

it can bettr focus X-ray images

Grass (that is healthy) looks green because

it reflects green light and absorbs other colors.

what is the resolution of a telescope

its ability to distinguish two adjacent objects close together in the sky

a major advantage of newtonian reflector over a refractor is

its compact size

A major advantage of Newtonian reflector over a refractor is

its compact size.

Uranus

jas a rotational axis that is tilted so much it lies nearly in the plane of its orbit

The main reason that most professional research telescopes are reflectors is that

large mirrors are easier to build than large lenses.

what are two advantages of large scopes over small ones

large telescopes have more light grasp and better resolution

A 10-meter telescope has a larger __________-_________ _____ than a 4-meter telescope.

light-collecting area

How many atoms fit across the period at the end of this sentence?

millions

Compared to terrestrial planets, jovian planets are __________.

more massive and lower in average density

Click "show" for the emission line spectrum, then click "choose gases" and study the emission line spectrum for neon. The neon "OPEN" sign appears reddish-orange because __________.

neon atoms emit many more yellow and red photons than blue and violet photons

which design has a convex primary mirror and a flat seconadary mirror, with the eyepiece located on the top side of the telescope tube

newtonian reflector

Radio telescopes would not represent a good choice for astronomical study of which of the following types of object?

ordinary stars

which method od astornomical measurement is the precise measurment of brigthness

photometry

The ____ focus reflector needs only a single optical surface to form images.

prime

The Arecibo radio telescope is laid out like which optical telescope design?

prime focus reflector

Which type of telescope has the simplest light path?

prime focus reflector

the Arecibo radio telescope is laid out like whic optical telescope design

prime focus reflector

this design involves only one optical surface , a concave mirror

prime focus reflector

what type of telescope is the SUBARU

prime focus reflector

which type of telescope has the simplest light path

prime focus reflector

green light has a shorter wavelength than orange lit, in a 5 inch telescope green light will

provide better angular resolution than orange light

Green light has a shorter wavelength than orange light. In a 5 inch telescope, green light will

provide better angular resolution than orange light.

In what part of the electromagnetic spectrum do the biggest telescopes on Earth operate?

radio

which of the following is a problem inherent in all large radio telescopes

radio waves have long wavelentghs so radio telescopes have poor rsolution

Compared to optical telescopes, radio telescopes are built large because

radio waves have very long wavelengths

Rank the forms of light from left to right in order of increasing energy. To rank items as equivalent, overlap them.

radio waves, infrared, visible light, ultraviolet, x-rays, gamma rays

Rank the forms of light from left to right in order of increasing frequency. To rank items as equivalent, overlap them.

radio waves, infrared, visible light, ultraviolet, x-rays, gamma rays

From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation?

radio, infrared, visible light, ultraviolet, X rays, gamma rays

If telescope mirrors could be made of odd sizes, the one with the most light-gathering power would be

rectangle with two 1- sides and two 2- sides.

The primary reason professional observatories are built on the highest mountaintops is to

reduce atmospheric blurring

We can see each other in the classroom right now because we

reflect visible light.

the process occuringwhen photons bounce off a polished surface is called

reflection

Galileo's telescope designs using lenses were examples of _________ ________.

refracting telescopes

The twinkling of starlight and the focusing of images by lenses are both due to ____ of light.

refraction

the tendency of a wave to bend as it passes from one transparent medium to another is called

refraction

which design is subject to chromatic aberration

refractor

The ability of a telescope to separate two closely spaced stars is called _____.

resolution

it is diffraction that limits the ____ of a telescope of a given objective diameter

resolution

it is diffraction that limits the _____ of a telescopes objective

resolution

Compared with radio telescopes, optical telescopes can

resolve finer detail

which of these devices helps correct coma in fast reflectors

schmidt corrector plate

The light-gathering power of a telescope varies with the ____ of the diameter of the lens or the mirror.

size

Which of the following best describes Pluto in terms of the general characteristics of terrestrial and jovian planets?

size and solid surface similar to terrestrial planets; distance similar to jovian planets

The image shown in Figure 5.10 in the textbook ("Resolution") is sharpest when the ratio of wavelength to telescope size is

small

Terrestrial Planets

solid, rocky surface, located within the inner solar system, small size

the name of the new infrared orbiting obervatory is the

spitzer space telescope

diffraction is the tendency if light to...

spread around corners

Astronomical observations at these wavelengths can be obtained even during ______.

storms

Which of the following studies is best suited to a timing experiment?

studying whether a particular star's brightness is steady or variable

During the time that a comet passes through the inner solar system, the comet can appear quite bright because____?

sunlight reflects off the comet's tail and coma

what is the resolving power of a telescope

the ability to distinguish adjacent objects in the sky

When multiple radio telescopes are used for interferometry, resolving power is most improved by increasing

the distance between telescopes

The wavelength of a wave is

the distance between two adjacent peaks of the wave.

what problem is adaptive optics designed to correct

the effects of atmosphereic turbulence

the long period of comets are believed to come from

the oort cloud

Which of the following could not be determined by an observation that uses only spectroscopy?

the size of a distant galaxy

the amount of diffraction on a telescope creates depends upon

the wavelength and the diameter f the telescope objective

the amount of diffraction and thus the resolution of the scope depends upon

the wavelength used and the size of the main telescope objective lens or mirror

The amount of diffraction and thus the resolution of the telescope depends upon

the wavelength used and the size of the main telescope objective lens or mirror.

what is true of rario telecopes

they ahve poorer angular resolution than a reflector

The most important advantage of CCDs over film is that

they record much more light in a given exposure time.

the most important advantage of ccd over film is that

they record much more light ina given exposure time

compared to optical telescopes, radios telescopes are built larger becase

theyre less expensive to make than optical telescopes

Which of the following is not a good reason to place observatories on remote mountain tops?

to be able to observe at radio wavelengths

what is the primary purpose of an astornomical telescope

to collect alot of light and bring it into a focus

What is the purpose of adaptive optics?

to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground

What problem does adaptive optics correct?

turbulence in the Earth's atmosphere that creates twinkling

what problem does adaptive optics correct

turbulence in the erath's atmosphere which creates twinkling

which of the follwoing gratly improves the angular resolution of radio maps

use of interferometer

If the ____ is good, the atmosphere is stable, and image quality is sharp.

visibility

Which of the following forms of light can be observed with telescopes at sea level?

visible light, radio waves

in which part of the electromagentic spectrum have astronomers unable to get any information

we now can cces information in all speccrtal lines

Produced by hot high density light source

Continuous spectrum

What is the resolution of a telescope?

Its ability to distinguish two adjacent objects close together in the sky.

A Newtonian reflector needs no secondary mirror.

False

A convex lens is thinnest in its center; it refracts light to a focus, while a convex mirror reflects it to the focus instead.

False

A telescope with and 8-inch mirror will collect twice as much light as one with a 4-inch mirror.

False

Absorption of light passing through the glass is a bigger problem for Cassegrain reflectors than achromatic refractors.

False

All modern large optical telescopes are refractors.

False

Chromatic aberration affects reflector telescopes.

False

Galaxies look the same whether viewed in visible or X-ray wavelengths.

False

Galileo is credited with designing the first reflector telescope.

False

Gamma-ray telescopes employ the same basic design that optical instruments use.

False

Hubble Space Telescope is still the largest scope ever built.

False

In the future, adaptive optics will greatly enhance the resolution of the Hubble Space Telescope.

False

Like radio and optical astronomy, infrared astronomy is easily done with ground-based telescopes.

False

Optical interferometry is more in use than radio interferometry.

False

Photography with film is still the preferred way of capturing fine detail in the faintest, most distant galaxies.

False

Radio astronomy can only be done from up in space, due to our ionosphere.

False

The Compton GRO was the first telescope used for our exploration of high-energy astronomy.

False

The Earth's atmosphere is the major factor limiting the use of ground-based radio telescopes.

False

The Hubble Space Telescope gives us its best resolution with X-rays.

False

The Keck telescopes contain the largest single mirrors ever constructed.

False

The main advantage to using the HST is the increased amount of "night time" viewing it affords.

False

The mirrors for X-ray telescopes are same shape as those of optical reflectors.

False

The primary purpose of any telescope is to produce an enormously magnified image of the field of view.

False

The simplest scope design, by Isaac Newton, uses only a primary mirror.

False

The term seeing is used to describe how faint an object can be detected by a telescope.

False

primary purpose of an astronomical telescope is to magnify the images of distant objects, making them appear closer.

False

It is impossible to overcome the atmospheric blurring experienced by ground-based optical telescopes. T/F

False. Active and/or adaptive optics can be used to compensate for much of the distortion of light due to atmospheric turbulence.

CCD cameras and photographic film have roughly the same efficiency for collecting light. T/F

False. Although CCD cameras have replaced photogenic film in most applications, film is still used or some specialized applications.

Advantage of the Hubble Telescope over ground

It reduces atmospheric blurring

As a rotating gas cloud contracts...?

It spins faster

Which light can be observed with telescopes at sea level?

Radio and Visible

Chromatic Aberration in lenses is a result of which wave property of light?

Refraction

Radio telescopes have poorer angulation over a...?

Refractor the same mass

A telescope that uses a lens and no mirrors is a..?

Refrator

It is diffraction that limits the ____ of a telescope of a given objective diameter.

Resolution

Jovian planets have..?

Rings around their equators

The name of new Infrared Orbiting Observatory

SPITZER SPACE TELESCOPE

Diffraction is the tendency of light to:

SPREAD AROUND CORNERS

A change in amplitude is a change in.?

Saturation

What are the names of the Jovian planets

Saturn, Jupiter, Uranus, Neptune

Waves can be transferred though...?

Solid, liquid, gas, and a magnetic feild

_____________ separate the various colors of light, allowing astronomers to determine stellar composition and may other stellar properties.

Spectrographs

As a solar nebula contracts it...?

Spins faster due to conservation of angular motion

Why do stars appear to twinkle? What do astronomers use to overcome this twinkle?

Stars appear to twinkle because of the instability of the Earth's atmosphere; astronomers use adaptive optics to overcome this effect.

Astronomical observations at these wavelengths can be obtained during__________

Storms

The amount of diffraction a telescope creates depends upon:

THE WAVELENGTH AND THE DIAMETER OF THE TELESCOPE OBJECTIVE

The most important advantage of CCDs over film is that

THEY RECORD MUCH MORE LIGHT IN A GIVEN EXPOSURE TIME

What is the primary purpose of an astronomical telescope?

TO COLLECT A LOT OF LIGHT AND BRING IT INTO FOCUS

What problem does adaptive optics correct?

TURBULENCE IN THE EARTH'S ATMOSPHERE WHICH CREATES TWINKLING

Which of the following statements best describes the two principal advantages of telescopes over eyes?

Telescopes can collect far more light with far better angular resolution.

These are all properties of what type of planets? -high density -closeness to the sun -rocky terrain

Terrestial

A telescope design that uses a lens and no mirrors is a refractor.

True

All optical telescopes will bring the light from a star to a focus.

True

All radio telescopes are reflectors in design.

True

An object having a temperature of 300 would be best observed with an infrared telescope.

True

As a rule, larger telescopes can detect fainter objects.

True

CCD detectors gather light 0 - 20 times faster than most sensitive photographic film.

True

Due to our ozone layer, ultraviolet astronomy must be done from space.

True

In addition to visible light, Hubble can do some work in the infrared and ultraviolet portions of the spectrum.

True

Mt. Palomar's 200" Gale telescope is the largest reflector now in service.

True

One reason for building telescopes on mountain tops is that they improve seeing by reducing the amount of air above the observer.

True

Optical telescopes are usually used only at night, but radio telescopes can be used day or night.

True

Radio telescopes are large in part to improve their angular resolution, which is poor because of the long wavelengths at which they are used to observe the skies.

True

Radio telescopes have poorer angular resolution than optical telescopes because radio waves a much longer wavelength than optical waves.

True

Radio telescopes have poorer angular resolution than optical telescopes because radio waves have a much longer wavelength than optical waves.

True

Stars do not twinkle; the instability of the atmosphere causes this effect.

True

The 400" Keck reflector can see objects 100 times fainter than the 40" Yerkes lens.

True

The Cassegrain reflector needs a primary concave main mirror and a smaller, convex secondary mirror to reflect light back through a hole in the primary.

True

The Schmidt corrector plate largely cures spherical aberration, giving a wide, flat field of view.

True

The light-gathering ability of a telescope is most dependent on the diameter of its primary objective.

True

The opacity of the atmosphere is partially corrected via adaptive optics.

True

The simplest reflector telescope design is the prime focus reflector.

True

What is image processing?

Computer processing of electronic images to correct for defects and remove noise

In design, most radio telescopes, like Arecibo, are ____.

...

0 degrees K lies at

0 Kelvin

Based on the frequency with which we see comets from Earth, astronomers estimate the total number of comets in the solar system to be

1 trillion

a mountain top is an esentially good site for infrared telescopes since

1)closer to celestial objects 2)less air means better seeing 3)cold wwather helps sensitivity of infrared detectors 4)above most carbod dioxide and vapor water

why are most large telescopes reflectors, not refractors

1)large mirros need 1 surface, achromats need 4 surfaces 2)reflectors do not suffer from chromatic aberration 3)large lenses are harder to cast as oppose to mirrors 4) large lenses deform under their own weight, mirror can be suposrted

The large reflector, the 10m Keck, gathers ____ times more light than the 1.0 m Yerkes refractor.

100

a telescope with a 60 mm objective lens collects how many times as much light as doe syour eys 6 mm exit pupil

10x

How much more light would a 2-m-diameter telescope gather in a certain amount of time at a given wavelength compared with one that is 50 cm in diameter?

16 times

An atom of the element iron has an atomic number of 26 and an atomic weight of 56. If it is neutral, how many protons, neutrons, and electrons does it have?

26 protons, 30 neutrons, 26 electrons

Speed of light

300,000 km/s

The angular resolution of an 8inch telescope is _____ times greater than a 2inch telescope

4

What is the light gathering power of an 8 inch telescope compared to a 4 inch telescope

4 times better

What is the light-gathering power of an 8 inch telescope compared to a 4 inch telescope?

4 times better

Approximate age of the solar system

4.6 billion years old

the angular resolution of an 8 inch diameter telescope is ____ greater than that of a 2 inch diameter telescope

4x

what is the light-gathering power of an 8 inch telescope compared to a 4-inch telescope

4x better

The trojan asteroids are found

60 degrees infront of or behind jupiter

The # if electrons determines whether..

An atom carries a charge as an ion or is neutral

What is a CCD, and how does it work? Why is it replacing film?

A CCD is a charge coupled device. It consists of a grid of thousands of light-sensitive pixels that build up a digital image that can be stored on computer as light strikes it, and it can also be sent over a computer network. CCDs are more sensitive to faint light than film.

What is "seeing"?

A MEASUREMENT OF THE IMAGE QUALITY DUE TO AIR STABILITY

A meteoRITE is..?

A chunk of space debris that has stuck in the ground

As a comet rounds the sun what does it leave?

A cometary dust tail behind, Bluish ionish

The nucleus of a comet is typically

A few km in size and a very low density

Most astronomers now believe the demise of dinosaurs 65 million years ago was caused by...?

A large Asteroid impacting the yucatan penisula

What is the asteroid belt?

A large groupd of asteroids w/ orbits located between mars and jupiter

A newtonian reflector needs..?

A secondary mirror

The oort cloud is believed to be

A spherical cloud of cometary nuclei far beyond the kuiper belt

A meteor is..?

A streak of light in the atmosphere

What is the source of material of a meteror shower

Comets

Produced by a hot, high density light source shinning through a cool, low-density medium

Absorption Spectrum

What kind of spectrum does the sun have?

Absorption spectrum

Rapid modifications are made to tilt and the location of the element of a telescope to correct the effects of atmospheric and instrumental distortion

Active Optics

What do all of these have in common? -comet nuclei -Polar caps of mars -kuiper belt objects -most jovian satellites

All icy composition

All terrestial planets lie within the...?

Asteroid belt

These distinguish _____ -compositions similar to that of the terrestial planets - typically orbit the sun @ appx 3 AU

Asteroids

Which objects are composed of material mostly unchanged since the formation of the solar system?

Asteroids and Comets

How do asteroids differ from comets?

Asteroids are rocky bodies and are denser than the comets, which are made of icy material.

At the wavelengths, it is to build telescopes with very large light collection _____ to obtain sufficient detail

Baselines

Anything that perfectly absorbs or radiates waves of all wavelengths

Black Body

In ____ Model of the atom, an electron can only exist in specific, well defined energy levels

Bohr

The dwarf planet Eris was discovered in 2005, orbiting the Sun at an average distance about twice that of Pluto. In which of the following ways do Pluto and Eris differ from the terrestrial and jovian planets in our solar system?

Both Pluto and Eris are smaller than any of the terrestrial planets.Both Pluto and Eris travel in more elliptical orbits than any of the terrestrial or jovian planets. Both Pluto and Eris are less massive than any of the terrestrial or jovian planets.

To a large degree, the ____ has replaced photographic film for astronomical imaging.

CCD

Which of the following is a principal advantage of CCDs over photographic film?

CCDs capture a much higher percentage of the incoming photons than does film.

These gather light 10-20 times faster than the most sensitive photography film

CDC detector

Which of the following is currently supplying high resolution x-ray images from space?

CHANDRA

What problem do refractor telescopes have that reflects don't?

CHROMATIC ABERRATION

What type of telescope focus is behind a central hole in the main mirror?

Cassegrain

The largest asteroid and probably the only one to be spherical "world" is..?

Ceres

Which of the following is currently supplying high resolution X-ray images from space?

Chandra

Type of Distortion in which there is a failure of lens to focus all colors to the same convergence point

Chromatic Aberration

Assuming that other planetary systems form in the same way as our solar system formed, where would you expect to find terrestial planets?

Closer together and jovian would be further apart

A change in frequency is a change in....

Color

A _____ consists of dust nd gas released from a comet as it is heated by the sun

Coma

The bight spherical part of a coma observed when it is close to the sun is the_____

Coma

These distinguish a _________ -form a coma when near sun -most located either in kuiper belt or oort cloud -visible in the sky as a fuzzy patch of liht that rises and sets with the stars

Comet

This has an icy composition

Comet

The Spitzer Space Telescope (SST) is stationed far from Earth because

Earth is a heat source and the telescope must be kept very cool.

What is the main reason that ultraviolet astronomy must be done in space?

Earth's atmosphere absorbs most ultraviolet wavelengths

What is the main reason ultraviolet astronomy must be done from space?

Earth's atmosphere absorbs most ultraviolet wavelengths.

An _____ _____ results from an electron falling from higher to lower energy orbital around its nucleus

Emission lines

The spectral lines of each element are distinctive to that element whether we are looking at...

Emission lines or absorption lines

Produced by hot, low density source

Emission spectrum

The shorter the wavelength, the greater its______

Energy

In non-ionized hydrogen for instance, what does a higher orbital state have more of than a lower orbital state?

Energy.

A comet entering the inner solar system from afar will..?

Enter coma and later on form a tail

Many observatories are placed on top of mountains so they will be closer to the objects they are observing. T/F

False. An observatory on a tall mountain is above much of the atmosphere. Atmospheric effects are a primary reason why Earth-based telescopes cannot achieve their diffraction-limited resolution.

Reflecting telescopes usually suffer from chromatic aberration. T/F

False. Chromatic aberration is associated with refracting telescopes

Gamma-Ray telescopes are hard to make because they require large lenses or mirrors for focusing in order to make images. T/F

False. Gamma-ray telescopes work by absorbing high-energy photons, not by reflecting or refracting them.

The primary purpose of a telescope is to provide a magnified image of the stars. T/F

False. Magnification is secondary. Almost all stars appear as only points of light through even the most powerful telescopes. Light-gathering power and resolving power are the most important properties of astronomical telescopes.

One challenge in building large radio telescopes is getting the large surfaces smooth enough to act as mirrors. T/F

False. Since radio waves have fairly long wavelengths, centimeters to meters, the reflector surfaces do not have to be extremely smooth.

The Hubble Space Telescope is the largest optical telescope ever built. T/F

False. The HST owes its image quality (after correction for an error in the primary mirror) to the lack of atmospheric blurring.

A telescope with a 2-m diameter primary mirror would be more affected by diffraction than one with a 1-m-diameter mirror. T/F

False. The diffraction limit on resolution would actually be better (smaller) for the larger telescope.

An optical telescope of a given size would have better resolution in orange light than in blue light. T/F

False. The diffraction limit to resolution would be larger, producing worse resolution, in orange light than in blue light for a given telescope.

Terrestial planets have how many moons?

Few to none

Most energetic photon

Gamma-rays

The element 1st found in the sun's spectrum, then in earth's 30 years later is..?

Helium

The ____ Space telescope still gives us the highest resolution optical images.

Hubble

In astronomy, an interferometer can be used to

IMPROVE THE ANGULAR RESOLUTION OF RADIO TELESCOPES

Radio dishes are large in order to:

INCREASE THEIR ANGULAR RESOLUTION AND COLLECT THE VERY WEAK RADIO PHOTONS

These two photos were taken at the same time and same location near San Jose, California. The one on the left was taken using visible light. Considering the properties of the other parts of the electromagnetic spectrum, which type of radiation do you think was able to penetrate the dust and smog to obtain the image on the right?

INFRARED

What is the resolution of a telescope?

ITS ABILITY TO DISTINGUISH TWO ADJACENT OBJECTS CLOSER TOGETHER IN THE SKY

How do radio interferometers greatly enhance resolution in radio wavelengths?

In interferometry, two or more radio telescopes are used to observe the same exact object at the same time and at the same exact wavelength. This greatly enhances the resolution in radio wavelengths.

Primary advantage of techniques of radio interfermotry is..?

Increase in resolving power

Radio astronomers have pioneered use of multiple telescopes working in concept that can produce maps of radio emssions as detailed as optical images. These arrays of multiple telescopes are known as____?

Inferometers

Tessterial planets

Inner planets: Mars, mercury, earth, and Venus

How does the Sun's mass compare with that of the planets?

It is a thousand times more massive than all the planets combined.

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?

It is closer to the stars.

What do we mean by the diffraction limit of a telescope?

It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.

If we double the diameter of a telescopes mirror, what happens to the light gathering ability?

It quadruples

Which of the following is NOT a reason to use a reflecting telescope rather than a refractor?

Lenses are harder to focus than mirrors

The orbit of most comets

Lie almost entirely beyond the orbit of neptune

Objects in the kuiper belt.....?

Lie beyond neptune and close to the ecliptic

Large mirrors have larger..?

Light Collection

Which planet, other than Earth, has visible water ice on it?

Mars

Properties in a star cannot provide the...

Mass

The most metal-rich terrestrial planet is

Mercury

Order of planets closet to farthest from sun

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

These distinguish_____ -visible in the sky as bright streak of light only a sew seconds -Dust particles entering earth's atmosphere @high speed

Meteor

Particles ejected from a comet can cause a ____ ____ on earth

Meteor shower

Barringer Carter in Arizona is an example of..?

Meteorite impact

Mercury and Venus do not have..?

Moons

In general the spectral lines of molecules are..?

More complex than those of atoms

Compared to terrestial planets Jovian planets are____

More massive and less dense

Observations at wavelengths other than optical and radio need to be conducted by what telescopes

Most absorptions at wavelengths other than optical and for radio need to be conducted by space based telescopes

Earth

Most of the surface of ___ is covered with liquid water.

Which of the following statements is not an observed pattern of motion in our solar system?

Most planets orbit at the same speed.

What are meteorites made out of?

Mostly Rock

Do all planets orbit the sun in the same plane as earth?

NOOOO

Pluto is one of the largest of1000 of kuiper bodies found beyond..?

Neptune

Optical telescopes are used during...? And Radio are used during..??

Night Day

A comet's_______ is the frozen portion of it

Nucleus

Jovian Planets

Numerous orbiting moons, extensive ring systems, low average density, primarily composed of hydrogen helium and hydrogen compounds

What type of planet is this? -accreted from planestesmal of rock and metal -surfaces dramatically altered during the heavy bombardment

Terrestial

A comet's plasma tail always points directly away from the sun because...?

Of pressure exerted by the fast-moving charges particles in solar wind

The most distant objects in our solar system are..?

Oort Cloud

About a trillion comets are thought to be located far, far beyond pluto in the....?

Oort cloud

These are properties that suggest long-period comets originate from ____ _____ -orbits highly elliptical -orbital period is 200+ years -many have large inclination relative to the ecliptic plane

Oort cloud

What type of single telescope currently in operation has the highest angular resolution?

Optical

The Hubble telescope provides the best resolution for...?

Optical and ultraviolet wavelength

Radio telescopes would not represent a good choice for astronomical study for______?

Ordinary Stars

Which method of astronomical measurement is the precise measurement of brightness?

PHOTOMETRY

This design involves only one optical surface, a concave mirror. What is it?

PRIME FOCUS REFLECTOR

Which type of telescope has the simplest light path?

PRIME FOCUS REFLECTOR

Moving through space the vibrating electrical and magnetic fields of a light wave must move _______ to each other

Perpendicular

These two photos show the same region of space. One of them is taken in visible light. Note that stars are obscured in Photo 2 but are much easier to see in Photo 1. Considering the properties of the different bands of the electromagnetic spectrum, which spectral region do you think was used to take each photo?

Photo 1 is infrared; Photo 2 is visible

Why do astronomers need different telescope designs to observe across the electromagnetic spectrum?

Photons of different energy behave differently and require different collection strategies.

The orbit is almost circular with low eccentircities

Planetary orbit

Which of the following is not a pattern of motion in our solar system?

Planets all rotate in the same direction.

A comet's ____ ____ stretches away from the sun

Plasmic tail

The broader the spectral lines the higher the _______ of the gas creating it

Pressure

Green light has a shorter wavelength than orange light. In a 5 inch telescope green will...?

Provide more angular resolution than orange light

Compared to optical telescopes, radio telescopes are built large because

RADIO PHOTONS DON'T CARRY MUCH ENERGY

Which of the following is the problem inherent in all large radio telescopes?

RADIO WAVES HAVE LONG WAVELENGTHS,SO RADIO TELESCOPES HAVE POOR RESOLUTION

The process occurring when photons bounce off a polished surface is called:

REFLECTION

The tendency of a wave to bend as it passes from one transparent to another is called

REFRACTION

Large arrays of widely separated radio telescopes can achieve very good resolution. What is the primary reason that such good resolutions cannot be achieved by individual radio telescopes operating independently

Radio dishes larger than a few tens of meters across are difficult to build, limiting their individual resolutions to several times worse than the largest optical mirrors.

What are some advantages of radio telescopes over optical telescopes?

Radio telescopes can be used during the day and on cloudy nights. They are also not affected by atmospheric distortion.

Radio telescopes have poorer angular resolution than optical telescopes because..?

Radio wavelengths are larger than optical waves

Rank the forms of light from left to right in order of increasing speed. To rank items as equivalent, overlap them.

Rank the forms of light from left to right in order of increasing speed. To rank items as equivalent, overlap them. (all the same)

What is meant in astronomy by the phrase "active optics"?

Rapid modifications are made to the tilt and location of the elements of a telescope to correct for the effects of atmospheric and instrumental distortion.

A star cooler than the sun would appear...

Red

Listed following are distinguishing characteristics and examples of reflecting and refracting telescopes. Match these to the appropriate category.

Reflecting Telescopes: most commonly used by professional astronomers today, The Hubble Space Telescope, world's largest telescope Refracting Telescopes: The world's largest is 1-meter in diameter, Galileo's telescopes, very large telescopes become "top- heavy", incoming light passes through glass

The large research observatories on Mauna Kea use giant ________ __________.

Reflecting telescopes

A telescope becomes larger and larger, astronomers favor_____

Reflecting telescopes because large lenses and mirrors sag under their own weight and it's easier to support a mirror along its entire back side than it is to support a lens only around the edge

As telescopes become larger and larger, astronomers favor

Reflecting telescopes, in part because large lenses and mirrors sag under their own weight, and it is easier to support a mirror along its entire back side than it is to support a lens only around its edge

Reasons to use a reflecting telescope over a refractor

Reflecting the lens doesnt sink Lens must have 2 precision surfaces a mirror only needs one Lenses=Chromatic aberration Lenses absorb light

Discuss several advantages of reflector over refractor telescopes.

Reflectors are less expensive than refractors of similar size. Reflectors are free of chromatic aberration. The eyepiece position on a reflector is generally better place on a reflector. Reflectors can also be made much larger than refractors.

Assuming that other planetary systems form in the same way as our solar system formed, where would you expect to find terrestrial planets?

Terrestrial planets will likely be located nearer the planetary system's star than any jovian planets.

Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic weight?

The atomic number is 79, and the atomic weight is 197.

What is meant by the "diffraction limited resolution" of a telescope?

The best possible angular resolution that can be obtained by a telescope of a given size if all other sources of blurring are eliminated

The reflector needs a concave main mirror and a similar, convex mirror to reflect light back through a hole in the primary

The cassegrain

Iron meterorites are believed to come from

The core of differentiates asteroids now broken up.

The use of infrared telescopes includes..?

The detector and telescope must be cooled to a very low temperature

Which of the following statements about the use of infrared telescopes is true?

The detector and telescope must be cooled to very low temperatures.

The light gathering ability of a telescope is most dependent on the...?

The diameter of its primary objective

Relative to the comet the direction of the ion tail tells us..?

The direction of the sun

An x-ray telescope in Antarctica would not work well because

The earths atmosphere

Astronomers use the term "seeing" to describe which of the following?

The effects of atmospheric turbulence

When an electron goes from higher energy level down to a ground state, how does the light emit?

The electron absorbed moves up to the higher level **Electromagnetic radiation

Which of the following statements about light focusing is not true?

The focal plane of a reflecting telescope is always located within a few inches of the primary mirror.

Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. If it is doubly ionized, what is the charge of the gold ion and how many electrons remain in the ion?

The gold ion has a charge of +2 and 77 electrons.

Stars dont twinkle because...?

The instability of the atmosphere

The definition of density is...?

The mass per unit of volume

The thickest lenses deflect and bend light

The most

Mars

The only rocky planet to have more than one moon

Mercury

The planet that orbits closet to the sun

Saturn

The planet with the lowest average density

What is meant by the "prime focus" of a telescope?

The point at which the incoming light is focused to produce an image, where analysis instruments and imaging cameras can be placed

The arecibo radio telescope is laid out like this optical design

The prime focus Reflector

The product of the light collecting arc and the exposure time that determines...

The total amount of light collected from a distant object

We can learn a lot about the properties of a star by studying its spectrum. All of the following statements are true except one. Which one?

The total amount of light in the spectrum tells us the star's radius.

Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes?

The two stars will look like a single point of light.

The # of protons identifies..?

The type of element

The amount of diffraction and the resolution of the telescope depends upon...?

The wavelength used and the size of the main telescope objective lens or mirror

Which of the following observations indicates that conditions on Mars may have been suitable for life in the past?

There are dried-up riverbeds on Mars.

Which of the following is an advantage the Hubble Space Telescope has over ground-based telescopes?

There is no blurring due to the atmosphere

Explain three advantages the Hubble Space Telescope has over all ground-based telescopes.

There is no interference of the Earth's atmosphere. It is able to capture clearer images. It can capture more light from distant objects than ground-based telescopes.

Which of the following is not a characteristic of the inner planets?

They all have substantial atmospheres.

Which of the following is always true about images captured with X-ray telescopes?

They are always displayed in false color.

Name two advantages of larger telescopes over smaller ones.

They have a greater collecting area, and they have a finer angular resolution.

What is true of radio telescopes?

They have poorer angular resolution than a refractor of the same size.

Which of the following is not a characteristic of the outer planets?

They have very few, if any, satellites.

The most important advantage over CCD's over time is

They record much more light in a given exposure time

What happens to the absorption and/or emission spectrum lines of an object moving away from earth@ high Speed?

They will be shifted toward the red end of the spectrum

The primary reason professional observatories are built on the highest mountains is..?

To reduce atmospheric blurring

Radio waves can penetrate dusty regions of interstellar space because they are relatively unaffected by this intervening matter. T/F

True. Many parts of interstellar space (including the center of our Galaxy) cannot be seen at optical wavelengths, but are easily detectable in the radio region.

Both the Keck and VLT observatories are designed to permit interferometry to be used. T/F

True. Although the technique of interferometry was pioneered using radio telescopes, it is now being extended to the infrared, and perhaps eventually optical regions. See Section 5.6 in your textbook.

Radio telescopes often position their detectors at prime focus. T/F

True. Section 5.5 of the text and the online image archive for Chapter 5 contain many pictures showing such arrangements.

Ultraviolet and X-ray telescopes can be used only above Earth's atmosphere. T/F

True. The atmosphere is opaque to electromagnetic radiation higher in frequency (i.e., shorter in wavelength) than the near ultraviolet, so UV and X-ray astronomy must be conducted from space. Gamma rays, however, can be observed from the ground—not directly, but by observing the results of their interactions with the atmosphere.

The biggest telescopes in use today are reflectors, not refractors. T/F

True. The largest telescopes in all wavelength regions from radio to X-rays are all reflectors.

Cassegrain-style telescopes are characterized by a hole in the objective mirror. T/F

True. The resulting folded optical path is used in many commercial amateur and professional telescope designs.

The amount of light collected by a telescope is proportional to its area. T/F

True. This is the reason that astronomers need larger telescopes to study fainter objects.

Radio observations may be made in the daytime as well as at night. T/F

True. Yes. Although the Sun is a radio source, it does not interfere unduly with daytime use of radio telescopes.

Radio telescopes using very long baseline interferometry have produced images with resolutions similar to those of images produced with optical telescopes. T/F

True. As far as resolving power is concerned, the effective diameter of an interferometer is the distance between its outermost dishes.

One scheme for improving telescopic images involves collecting data from a part of the sky where there are no known sources of radiation. T/F

True. The data collected would consist of background noise. This data can be used in computer processing of images taken with the telescope to improve the quality of the image.

Which planet is approximately halfway between pluto and the sun?

Uranus

Which planet is approximately halfway between Pluto's orbit and the Sun?

Uranus, the seventh planet from the Sun

The planet closest in size to Earth is

Venus

Which planet has the highest average surface temperature, and why?

Venus, because of its dense carbon dioxide atmosphere

The shortest wavelength (color)

Violet

Surface zone light observations

Visible (optics) and radio

Electromagnetic radiation penetrates the atmosphere of earth at what portions of the electromagnetic spectrum

Visible, some Infarared and some radio

In which part of the electromagnetic spectrum have astronomers been unable to get any information?

WE NOW CAN ACCESS INFORMATION AT ALL SPECTRAL LENGTHS

the shortest electromagnetic wavelength?

X-ray

Grazing incidence optics are critical to focusing ____.

X-rays.

A mountain top is an especially good site for infrared telescopes since:

YOU ARE ABOVE MOST OF THE CARBON DIOXIDE AND WATER VAPOR IN THE ATMOSPHERE

The radiation our eyes are most sensitive to is the color..?

Yellow-green at 550 nm

A hydrogen atom consists of an electron and a a. proton b. neutron c. neutrino d. lepton

a

One of the research objectives of the ATLAS experiment at the LHC is a. to determine what happened in the first few seconds after the Big Bang b. to help us to understand what exactly happened during the creation of the earth c. to create a gigantic black hole d. all of the above sponsor

a

Please refer to page 6. The constellation labeled as "2" is called A. Ursa Major B. UrsaMinor C. Orion D. Lyra

a

Please refer to page 6. The constellation labeled as "5" is called A. Andromeda B. Orion C. Cassiopea D. Lyra

a

Please refer to page 6. The point B on the sketch of an ellipse is called A. Perihelion B. Aphelion C. Eccentricity D. Node

a

The Large Hadron Collider, just completed in Geneva, is getting ready to collide two beams of protons at energy of 14 TeV. The word "hadron" refers to a. protons and similar particles b. electrons and similar particles c. a company which has contracted the LHC d. a name of the major sponsor

a

Tycho Brahe's contribution to Kepler's Laws of Planetary Motion were A. his detailed and accurate observations of the planet's position B. his observations of Jupiter's moons C. a mathematical explanation of epicycles D. a precise lunar calendar

a

What is the name of the effect when an electromagnetic wave is bent as it passes from one material into another? a. refraction b. reflection c. deflection d. diffraction

a

Which of the following statements about light is FALSE? a. The speed of light is lower for radio than for X-rays. b. Nothing moves faster than light. c. The speed of light is equal to 3·108 m/s. d. The speed of light is equal to three hundred thousand kilometres per second.

a

Why are molecular lines more complex than elemental spectral lines? A. Molecules can vibrate and rotate as well B. Molecules are heavier than atoms C. Molecules are the basis of life D. Most of the universe is made of molecules, not individual atoms

a

what is "seeing"

a measurement of the image quality due to air stability

What is a compound?

a molecule containing two or more elements

What is an artificial star?

a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations

Study the graph of the intensity of light versus wavelength for continuous spectra, observing how it changes with the temperature of the light bulb. Recall that one of the laws of thermal radiation states that a higher-temperature object emits photons with higher average energy (Wien's law). This law is illustrated by the fact that for a higher temperature object, the graph peaks at __________.

a shorter wavelength

All optical telescopes will bring the light from

a star to focus

Estimate the angular resolution of the 8.1 m Gemini North telescope in red light. A. 0.10' B. 0.02" C. 0.10" D. 0.20"

b

When used in a single instrument to greatly enhance its resolution, the four separate mirrors of the VLT act as a(n) _____.

interferometer

____ optics deform the shape of the mirror to compensate for the turbulence in the atmosphere and yield a close to diffraction-limited range.

adaptive

____ optics greatly reduces the effect of atmospheric turbulence by deforming the shape of the mirror by computer control.

adaptive

What type of visible light spectrum does the Sun produce?

an absorption line spectrum

If you heat a gas so that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels the gas produces

an emission line spectrum.

When light reflects off an object, what is the relation between the angle of incidence and the angle of reflection?

angle of incidence = angle of reflection

How long, approximately, would a radar signal take to complete a round-trip between Earth and Mars when the two planets are 1.3 AU apart? A. 650 seconds B. 1300 seconds C. 43 minutes D. 87 minutes

b

If a light source is approaching you at a speed very close to the speed of light, it will appear a. redder than it is b. bluer than it is c. brighter than it is d. fainter than it is

b

In order from low to high frequency, which of the following lists is correct? a. gamma-rays, X-rays, ultraviolet, visible, infrared, microwave, radio b. radio, microwave, infrared, visible, ultraviolet, X-rays, gamma-rays c. gamma-rays, X-rays, ultraviolet, visible, infrared, radio, microwave d. radio, microwave, ultraviolet, visible, infrared, X-rays, gamma-rays

b

Please refer to page 6. The brightest star in constellation "3" is called A. Vega B. Polaris C. Alpheratz D. Betelgeuse

b

Please refer to page 6. The constellation labeled as "3" is called A. Ursa Major B. UrsaMinor C. Orion D. Andromeda

b

The Orion Nebula, M-42, is a hot, thin cloud of glowing gas, so its spectrum is: A. a continuum, strongest in the color red. B. a few bright lines against a dark background C. a few dark line in the continuum. D. not in the visible portion of the spectrum.

b

What are constellations? a. Groups of galaxies gravitationally bound and close together in the sky b. Groups of stars making an apparent pattern in the celestial sphere c. Groups of stars gravitationally bound and appearing close together in the sky d. Ancient story boards, useless to modern astronomers

b

The absorption line spectrum shows what we see when we look at a hot light source (such as a star or light bulb) directly behind a cooler cloud of gas. Suppose instead that we are looking at the gas cloud but the light source is off to the side instead of directly behind it. In that case, the spectrum would __________.

be an emission spectrum

compared to a 5 inch prime focus reflector a 5 inch newtonian refractor will

be easier to build

What causes stars to twinkle?

bending of light rays by turbulent layers in the atmosphere

Where are most of the known asteroids found?

between the orbits of Mars and Jupiter

The kuiper belt is found where in the solar system?

beyond the orbit of neptune

Please refer to page 6. The constellation labeled as "4" is called A. Andromeda B. Orion C. Cassiopea D. Lyra

c

The orbital period of the asteroid Ceres is 4.7 Earth years. What is its semi-major axis? A. 8.8 × 106 m B. 2.209 × 108 km C. 4.2 × 108 km D. 13.4 × 104 AU

c

The wavelength of the red hydrogen line is A. 364.8 nm B. 486.1nm C. 656.3 nm D. 1.36 × 105 angstroms

c

There are no x-ray telescopes on Earth because A. they are too expensive to build B. no one has yet invented an x-ray telescope that works C. x-rays don't penetrate Earth's atmosphere D. there are no astronomical objects that emit x-rays

c

Which of the following are the jovian planets? a. Jupiter, Saturn, Uranus, Neptune, and Pluto. b. Jupiter only. c. Jupiter, Saturn, Uranus, and Neptune. d. Mars, Jupiter, Saturn, Uranus, and Neptune

c

A mirror must be ____ in shape to focus the transmitted light.

concave

A lens must be _____ in shape to focus the transmitted light.

convex

what type of telescope is the hubble space telescope

cassegrain

the convex secondary mirror in this deisgn focuses light down a hole cut in the concave primary mirror

cassegrain reflector

which of the following is currently supplying high resolution x-ray images from space

chandra

The separation of red and blue light in a single-lens telescopes is called ____ aberration.

chromatic

What problem do refractor telescopes have that reflectors don't?

chromatic aberration

refractor telescopes suffer from this separation of light into its component colors

chromatic aberration

what ptoblem do refractor telescope have that reflectors dont

chromatic aberration

Adding a secondary concave lens of carefully chosen different glass to the primary lens on a refractor allows

chromatic aberration to be reduced.

An advantage a reflector has over a refractor is the elimination of _____.

chromatic aberration.

The primary purpose of a telescope is to

collect a large amount of light and bring it into focus.

the primary purpose of a telescope is to

collect a large amount of light and bring it to a focus

16. According to Wein's Law, if the Sun's surface temperature of 5800 K were doubled: A. the Sun would look much redder than it does now. B. the Sun would now radiate four times more total energy into space. C. most of the Sun's radiation would be in the form of the heat, not light. D. the peak of its energy would now fall in the ultraviolet part of the spectrum.

d

According to Kepler's third law, the square of the planet's period in years is a. equal to its perihelion distance from the Sun in A.U b. inversely proportional to its mass in kilograms c. equal to the fourth power of its average temperature in degrees Kelvins d. proportional to the cube of its semimajor axis in A.U

d

At which of these Kelvin temperatures would a blackbody radiate mostly at visible wavelengths: A. 6 K B. 60 K C. 600 K D. 6000 K

d

Increasing the temperature of a blackbody by a factor of 3 will increase its energy by a factor of A. 3 B. 9 C. 12 D. 81

d

Please see page 6. The aphelion distance of Mars from the Sun is approximately A. 0.31 AU B. 0.47 AU C. 1.38 AU D. 1.67 AU

d

What causes seasonal variations on Earth? A. wobble of Earth's rotation axis B. global warming and cooling C. variations in distance of Earth from the Sun D. tilt of the Earth's rotational axis with respect to its orbital axis

d

What is "seeing"? A. a measure of the quality of the telescope's optics B. a measure of the transparency of the scope's objective lens C. a measurement of the sharpness of vision of the astronomer's eyes D. a measurement of the image quality due to air stability

d

Which of the choices below correctly lists things in order from largest to smallest? a. Local Group, Solar System, Milky Way, Universe b. Local Group, Milky Way, Solar System, Universe c. Universe, Milky Way, Local Group, Solar System d. Universe, Local Group, Milky Way, Solar System

d

Which of these bodies is misplaced? a. Mercury = 0.4 AU b. Venus = 0.72 AU c. Earth = 1.0 AU d. Jupiter = 12.5 AU

d

If our eyes were sensitive only to X rays, the world would appear __________.

dark because X-ray light does not reach Earth's surface

Telescopes operating at this wavelength must be cooled to observe faint astronomical objects.

extreme infrared

Order the following in order of increasing efficiency of detecting photons of visible light.

eye, photographic film, CCD

The angular resolution of an 8 inch diameter telescope is ____ times greater than that of a 2 inch diameter telescope.

four

We divide the electromagnetic spectrum into six major categories of light, listed below. Rank these forms of light from left to right in order of increasing wavelength. To rank items as equivalent, overlap them.

gamma rays, x-rays, ultraviolet, visible light, infrared, radio waves

Using ____ incidence optics, the Chandra is the X-ray equivalent of the Hubble Space Telescope.

grazing

The Chandra X-Ray observatory focuses X rays with _________ _________ mirrors.

grazing incidence

the design of moder x-ray telescopes depends on

grazing incidence optics

The design of modern X-ray telescopes depends on

grazing incidence optics.

the chandra x-ray telescope must use

grazingincidence optics to focus the short wavelentghs

Process of accretion

growth of an object by the accumulation of matter

Compared to a 5 inch prime focus reflector, a 5 inch Newtonian reflector will

have the same light gathering power

Which of the following objects is not a close approximation of a thermal emitter?

hot, thin air

What are the main constituents of the jovian planets?

hydrogen and helium

in astronomy an interferometer can be sued to

improve the angular resolution of radio telescopes

In astronomy, an interferometer can be used to

improve the angular resolution of radio telescopes.

Where does nuclear fusion occur in the Sun?

in its core

One advantage of the Hubble Space telescope over ground based ones is that

in orbit, it can operate close to its diffraction limit at visible wavelengths.

If you had only one telescope and wanted to take both visible-light and ultraviolet pictures of stars, where should you locate your telescope?

in space

radio dishes are large in order to

increase their angular resolution and collect the very weak radio photons

In general, as a telescope's diameter increases, its angular resolution _____.

increases

The best way to study young stars hidden behind interstellar dust clouds would be to use

infrared light