How do we know that there are other planatary systems?

The angular separation of the Moon, as seen from the earth is:

angle = Diameter/distance = 1737 km x 2 / 384,000 km = 0.009 radians or about 0.51 degrees (There are 180/π degrees per radian.). If you were sitting on the Moon looking at Earth, what would its angular separation appear to be (in radians or degrees)? (The radius of the earth is 6,378 km). 

hint: this is a math problem 

Charon of comparable, but smaller size, mutual center of mass motion of their orbits. Retrograde orbits

1)Trajectory of Pluto is out of plan of ecliptic, sometimes inside Neptune's orbit

2)Made of icy material

How do we know the Earth's magnetic field has been reversing every million years or so?

(this was an extra credit question)

A star has a parallax of 0.0025 arc seconds.  What star do you think this might be?

(hint math problem)

d = 1/p = 1/.0025 = 400 pc away

[answer was (b) Alnilam (400 pc away)]

The more luminous one is three times further away.

B = L/4πR²

                                    9 L =   L

                                4π R^{2_{1 =}} 4π R^2₂

                                         R_{1 =} √9

                                  R₂ = 3

There is an eclipsing binary star system where the ratio of the orbital velocities, based on the Doppler shift, is one, that is both stars are moving with the same orbital speed.  If the period of the orbits are 36.5 days, and the radius of their orbits is 1 AU, how massive are the stars.  This is an easy problem. Remember how many days there are in the year!

Both stars are 50 solar masses each

                   P = 36.5/365 = 0.1 y

                m_a TM_b = A^{3 =}    1

                              P² = (.1)²

                                         ⁼ 1/.01 = 100

                        M_a+M_b = ˜b/˜a = 1

                 so, M_a = 50    M_b = 50

What is special about iron in stellar evolution?

M > 3 M_solar

Sin is a "G" star. They are much hotter

O B A E G K M

It takes 8.3 minutes for light to travel from the Sun to the Earth, a distance of 1 AU.  If Pluto is 40 AU from the sun, how long does it take to travel from the Sun to Pluto?

332 minutes

Will the North Star (Polaris) always be the North Star?

No, since the Earth precesses on its axis one about every 24,000 years.

Most planets in the solar system orbit close to the:

The ecliptic

How long does it take the moon to rotate once on its axis?

About 28 days, the same as it takes to orbit the Earth.

At what time of the month can you see the far side of the moon?

it can't be seen from Earth.

The Copernican revolution involved what?

The widespread realtization that the solar system was helio-, not geo-centric.

What bright stars are presently overhead at night, as mentioned by your teacher in class?

Deneb, Altair, and Vega

What differentiates a Newtonian and Cassigrain telescope?

A Cassigrain telescope has hole in the primary mirror for the eye peice.

Assume your eye's pupil has a diameter of about 0.01m (1 x 10^-2 m).  if you looked at the full moon through a 1 m telescope, how much more intense would the moon's image be compared to that seen with the naked eye? (Hint: this is a LGP Problem!)

10,000 times brighter

Why is a refractive telescope not used for high resolution astronomical observations?

Because of the chromatic aberrations.

What does the absorption spectrum tell you about a star?

The chemical composition of the star's atmosphere.

In a telscope where the blurring effects of atmosphere turbulence are corrected for in real time, what is being utilized?

Adaptive optics

How can you get higher resolution from radio telescopes? 

Link together different radio telescopes that are far apart in an array like the VLA and the VBLA.

The brightest (most dominant) wavelength of light coming from the star is λ = 656 nm, How hot is the star?

About 4,400 K

A mysterious gas cloud is emitting radiation only at a wavelength of 1 m.  What kind of telescope would you use to resolve the shape of the cloud?

A radio telescope.

The array of four 8.4 m telescopes (called the VLT) is where?

Atacama, Chile

Astronomers refer to a very still and clear atmosphere as:

Good seeing

What special event in the yearly cycle of the Earth's orbit around the sun recently occured?

Autumnal equinox

The perimeter of the Sun and Moon as seen from Earth, covers an angle (the so-called angular distance) of about

1/2^o

A star has a magnitude of 7 in brightness.  Is it too dim to see with the naked eye?

Yes

If a star at Right Ascension + 12 hours and Declination + 90 degrees, who would be best able to see it?

a) someone near the north pole.

b) someone in New Zealand.

c) someone near the south pole.

Someone near the north pole.

In the Ptolemaic model of the Universe, planets moved uniformly in small circles called

Epicycles

Sidereal time refers to

The motion of an object with respect to the stars

Who of the following is given most of the credit for the idea of a heliocentric solar system?

Copernicus

Kepler was the first to show the planets move:

In elliptical orbits around the Sun

The closer a planet, asteroid, or comet is to the Sun in its orbit, the faster it moves.  This is described by

Kepler's laws

A discovery Galileo made with his telescope that contrdicted Ptolemy's theory was:

The phases of Venus

We can follow the sun and moon rises over a period of several months, where we observe that:

The Moon and the Sun do not rise at the same place on the horizon as the season progresses.

What Mars Rover is still wandering around, sending pictures back to us?

Opportunity

We discussed NASAs Phoenix Mission. What is its purpose?

The explore the presence of water in the far northern hemisphere of Mars.

A strange planet Zed orbits the sun at a distance of 8 AU.  How long is the year on Zed?

About 22.6 years

We did a demonstration in class that showed the force of gravity.  What did it involve?

A Cavendish balance

What planets always appear close to the Sun?

Venus and Mercury

What really confused early austronomers who thought we had a geocentric system?

The retrograde of the planets.

How far apart are two points on the Earth's orbit over the period of 6 months?

2 AU

Why don't we have eclipses twice a month?

Because of the tilt of the Moon's orbit at 5 degrees with respect to the ecliptic.

if you want to try to see planets at night, you would:

Look along the line of the ecliptic

What part(s) of the electromagnetic spectrum cannot most easily enter the earth's atmosphere?

Gamma and x-rays

The cracks on the surface of Mercury are called

Scarps

Features on what planet are called shield volcanoes that never actually erupt?

Venus

The surface of Mars has a layer of:

Permafrost

The roughest terrain on Mars is mostly

In its Southern Hemisphere

Why does Earth have so much oxygen in its atmosphere while Mars and Venus don't?

When life starts, oranisms released oxygen from the rocks.

The surface of Venus is about 850 degrees Fahrenheit primarily because of

The strong greenhouse effect due to the dense atmosphere

The main mechanism of controlling CO₂ in Mars' atmosphere is:

absorption into the planets' rocks

The greenhouse effect on Mars is:

a) is cuasing Mars to heat almost to the Earths' ambient temperature.

b) has been steadily declining.

c) is causing more CO₂ to enter its atmosphere.

has been steadily declining

Mars' atmosphere might be restored to livable conditions by:

Terraforming by humans

Could some of the negative things destroying the Earth's atmosphere actually help restore Mars' atmosphere?

yes, even the greenhouse effect

When different parts of a planet or star that has no solid surface rotate at different rates, we refer to this as:

differential rotation

In addition to the Great Red Spot, astronomers have also observed on Jupiter:

white ovals and brown ovals. 

What kind of measurement tells us something about the interior rotation of the Jovian planets?

a)radio waves that originate from their magnetospheres

b) sound waves that can be seen with the Doppler effect

c) Holes in the zonal flow that allows us to look a the solid core of the "gas balls". 

b) Radio waves that originate from their magnetospheres

what can we say about Jupiter, Saturn and Neptune?

they all radiate more energy than they receive from the Sun

The densities of the Galilean moons, which, along with Jupiter, are sometimes called a mini planetary system

decrease the density from Jupiter

Neptune's largest moon is

Triton

Features of the rings of Saturn include?

The Cassini Division and the Encke gap

Waht is the approximate distance in planetary rasii for an object of similar density to be ripped apart (i.e. the Roche limit)?

2.5 planetary radii

How were the rings of Uranus first observed?

a) by the mission messenger

b) by stellar occultation

c) when the Shoemaker Levy commit smashed into them

d) during an unexpected 90 degree flip of Uranus' rotation direction

b) By stellar occultation

If Pluto isn't a planet, what is it?

It most likely from the Kuiper belt, hence a KBO like 2003 UB313

A star's luminosity is

the total amount of energy radiated from its surface per second

The mathematical and physical description that best describes the Sun's structure is

the standard solar model

The effect of the solar convection zone can be observed on the Sun's surface in the form of

granulatation

Open magnetic field lines in low density regions of the corona lead to

Solar wind

How many protons does it take to make a helium nucleus in the proton-proton chain reaction?

4

6

2

3

5

6

If a one kilogram melon were to be completely turned into energy, how much energy would it produce?

9 x 10 ¹⁶ joules

Approximately how many 100 watt light bulbs would represent the "solar constant" of power that we receive here on Earth from the sun per meter square of surface?

1 million

10

1000

less than 1

10

the solar neutrino problem refers to what?

the observation that only about 1/3 of the expected neutrino flux from the sun was initially observed, for instance by Davis.

The star Altair has a parallax of 0.20 seconds of arc.  How far away is it?

20 light years

20 parsecs

5 parsecs

5 parsecs

We see the apparent magnitufe of a star from its observed brightness.  How is the absolute magnitude of a star defined?

O B A F G K M refers to:

the spectral classes of stars

There are curtain relationships between the properities of stars, including the

radius-luminosity-temperature relationship

Name 2 main regions where stars appear away from the main sequence in the H-R diagram

the white dwarf and red giant regions

for stellar distance measurements, the first 3 methods that we have learned about are:

radar, parallax and spectural parallax

If 2 binary stars cannot be individually seen, but their orbital motion can be determined from other methods using different wavelengths of light, they are called

spectroscopic binaries

If 2 binary stars have orbits that lie in the plan of our vision, then they are called

eclipsing binaries

If 2 binary stars can be individually seen, and their orbital motion can be determined, they are called:

visual binaries

the source of new star formation is

interstellar medium

Light passing through interstellar clouds on its way to Earth appaers to us be what color

red

Hot O and B stars within a nebular region can lead to the appearance of

emission nebulae

Often, the sites of future star formation are

In large molecular cloud complexes

What is one of the most useful tools for astronomers to observe interstellar clouds?

the 21 cm line from hydrogen

Before a new star settles down onto the main sequence, it is called a

a) red giant

b) white dward

c) T-tauri star

d) blue giant

T-tauri star

if a new star has a mass of less han 0.08 solar masses, what will happen?

It will never be able to undergo a fusion reaction at its core, and will remain a brown drawf

If you obsrve a star cluster that is composed of very old stars, is nearly spherical in shape, and resides in the halo of a galaxy, astronomers would call it a

globular cluster (not global)

When our sun has created a lot of helium from hydrogen fusion, the helium will

When our sun eventually leaves the main seuence, it will first become a

red subgiant (not giant)

When our Sun finally runs out of nuclear fuel, it will implode, resulting in

a planetary nebula with a which dwarf in the center

Since the Sun is not in a binary star system, it is very unlikely that the remains of the sun after it dies could produce a

nova

A red shift  Z greater than 100 would refer to what period?

the very early period of the universe associated with the cosmic background radiation

Name 2 types of stars or other objects that make good "standard candles" for distance determination in distant star clusters and galaxies

Type Ia supernova and Cepheid variable stars

the Hubble constant is about 71 km/s/Mpc, and the corresponding age of the Universe is about 13.7 Billion years old.  If the Hubble constant were 142 km/s/Mpc, how old would the universe be?

What 3 objects were in near conjunction recently in the Western sky?

The Moon, Jupiter and Venus

if you want to communicate with extra terrestrials, what kind of device would best transmit a frequency that would get through the atmospheric "water hole" where also the CBR and galactic radio emissions are minimal?

cell phone

Which of the following elements would be considered "primordial", i.e. originating directly from the big bang?

hydrogen and helium

If the universe were infinit, and infinitely old, and if the stars and galaxies did not move then,

the sky would appear uniformly bright at night

for stars relatively close to us (up to 200pc or so) what is the best way to determine their distance?

Parallax

Some of the most common types of galactic shapes are:

elliptical, spiral, irregular and barred

The wavelength of the light associated with the cosmic background radiation:

corresponds to a temperature of about 3 K

The distribution of galaxies in the universe appears to be

homogenous, but with regions of high concentrations (walls) and other regions with low concentration (voids)

Hubble's law states that

The further away a galaxy is (from us), the faster its recession velocity is

If the light from a distant sar appears as multiple images, or is highly distorted into arcs, what might be the cause?

The light might be gravitationally lensed due to passing near dark matter.

If a very bright light far outside our Milky Way appears suddenly in the sky, and then dims over the periods of weeks, what have you observed?

probably a supernova

what is the significance of the Cosmological constant?

It is the "anti-gravity" term in Einstein's theory that makes the expansion of the universe accelerate

A good analogy to describe the expansion of the universe and the Hubble flow is:

a rising loaf of raisen bread

Star A has a red shift of 0.06 and Star B has a red shift of 1.6.  We can therefore say that:

Star B is much further away than Star A

How might spiral galaxies arise?

If 2 elliptical galaxies were to collide, but not head on, this could produce a spiral galaxy

In the GUT theory, what is described?

There was a unification of the four forces of nature (in the original singularity prior to the big bang), which started to differentiate during the inflationary period.  Gravity splits off first.

What is the signature of a pulsar?

Blips in the received radio signals usually occurring at second or even millisecond intervals

The centers of quasars are typically

Active Galactic Nuclei (AGNs)

What kind of data indicates that galaxies are shrouded in dark matter?

The galactic rotation curves

At large look back times, we are viewing

a) galaxies when the Universe was much younger

b) much older

c) aging globular cluster that contain only red giants

a) much younger

Seyfert Galaxies are

Are galaxies in the early universe, but they do not have spiral arms

In a global cluster, one might expect to see

a larger proportion of white dwarfs due to the advanced age of the cluster

Structures that contain a hundred thousand to a million times the mass of the sun, which are fundamental building blocks of new star formation in our galaxy, are:

giant molecular clouds

If we want to detect the presence of atomic hydrogen in space, we

tune our radio telescope to the 21cm band

If it appeared that the universe would eventually quite expanding, and begin to collapse, we would say that

the universe is well above the critical density (a closed universe).

If the number of stars N in some galaxy is 1 x 10¹¹ , the fraction of stars with planets F_p is 0.01, the fraction of planets with a life zone N_LZ is 0.01, the fraction of planets that can support life F_L is 0.01, the fraction of life that develops intelligence F_I  is 0.01, and the fraction of stars that survive long enough to support life F_S is 0.01, than how many solar systems in this galaxy probably have intelligent life?

Ten: 1 x 10¹¹ *.01*.01*.01*.01*.01 = 10

The turn off point of a star cluster plotted on an HR diagram tells you

the age of the star cluster

Exoplanets can be detected by

live curves

wobble of the host star

actual infrared photos recently

all of the above

only a and b 

all of the above

If Pluto is not a planet, then it might be

a trans-Neptunian object or Kuiper belt object

What galaxies are in the Local Group?

a) Andromeda

b) Milky Way

c) The Virgo Cluster

All of the above

Only a and b

only a and b

If ther was no "Horizon Problem", which might astronomers say

that the universe is clearly differnt in its large scale galactic structure in the northern vs. the southern direction

What are typical values of luminosity in AGNs? (note W= watt = Js)

Greater than 10³⁷ W, which means that they consume on average one sun's mass every couple of years

What is special about eh emission spectra coming from AGNs?

What is special about the energy output of an AGN?

It is highly variable, indicating that the emission source is very compact (less than a parsec in size)

What do AGNs "look" like?

they usually have jets and accretion disks, with a black hole in the center

the emission lines of AGNs have what appearance?

They are very broad, indicating that their source is undergoing rapid internal motion (in more than one direction).

Einstein's general theory of relativity predicts:

 all 3

that the semi-major axis of the elliptical orbit of Mercury around the Sun precesses with time

that light that is emitted from a massive object will be red-shifted

that the path of light from a distant start passing close the surface of the sun will bent towards the sun as it passes the sun

which of these stars is the brightest in the sky?

Rigil Kentaurus

Gacrux

Sirius

Sirius

Which of these stars will have the shortest life span?

Spica

Alpha Centauri B

Aldebaran

Spica

What is the parallax of the farthest star in the table?

0.0001 arcseconds (d = 1/900.1pc - .001 arcsec

which star is a spectral type that would be similar to the Suns'?

Rigil Kentaurus (its a G type star)

which of these stars would most likely be a red giant?

Alpha Centauri B

Sirius

Canopus

Betelgeuse

Formalhaut

Betelgeuse

What type of star is HR 8799?

A5V

What is special about the objects discovered orbiting HR 8799 compared with exoplanets discovered from the "wobble" Doppler method?

they are relatively far (between 20 and 70 AU) from HR8799

What telescopes were used to image the objects orbitting HR8799?

Both the Germini and Keck telescopes were used

Waht main conclusions were reached in this paper about HR 8799

That three directly imaged co-moving companions of HR 8799 are planetary and not brown dwarf objects

What kind of techniques did the astronomers use to detect  the objects orbiting HR8799?

A combination of adaptive optics ("AO") and angular differential imaging ("ADI") among other special imaging methods.

constellations

the plane of the Sun's apparent path around the celestial sphere and/or the plane of the Earth's orbit around the sun is called:

The ecliptic

why don't we have eclipses of the sun and moon once a month?

moon's orbit is about 5 degrees out of the ecliptic plane

When is the far side of the moon visible?

only during a trip to Mars or Venus, depending on the time of the month

The Copernican revolution involved what?

The widespread realization that the solar system was helio- not geo-centric

What bright red giant star has your teacher mentioned on several occasions seen in the west after dark?

Arccturus

What differentiates a Refractive and a Reflective telescope?

A reflective telescope mirror does not produce chromatic aberrations

What wavelengths of light easily get through the Earth's atmosphere?

Visible and Radio

When a continuous bean of radiation passes through a cool gas, and then a spectrometer, what might you see in the spectrum produced?

Absorption lines

In a telescope where the blurring effects of atmosphereic turbulence are corrected for in real time, what is being utilized?

Adaptive optics

We find that the brightest (most dominant) wavelength of light coming from a star is 290nm. How hot is the star?

T = 2,900,000/290

10,000K

How can you tell if a star at very large distaances from us is moving?

From the doppler shift in the position of the star's spectral absorption lines

which types of planets have the highest mass density?

The Terrestrial planets

What types of asteroids are 60 degrees ahead or behind in Jupiter's orbit?

The Trojan Asteroids

Where do you think that comets originate?

In the Oort cloud (spelled right)

When do meteor showers usually occur?

When Earth's orbit crosses a comet path

If a star is at Right Ascension = 13 hours and Declination + 89 degrees, who would be best able to see it?

someone near the north pole

Describe 3 different ways we can detect extrasolar planets.

wobble

occulation

actually see planet circling brown dwarf

What is thought to have happened to the extra panetesimals left over from Planetary formation?

Hod did the Solar system further clean up?

they were ejected into the Oort cloud and Kuiper belt by gravitational interactions with the Jovian planets

The solar wind blew the remaining nebular gas out of the solar system

What part of the Earth's atmosphere is where we lived and where the "weather" is?

The troposphere

How did geologists determine the core structures (liquid and solid) of the Earth

using analysis of P and S waves emitted by earth quakes

How is the San Andreas Fault Line different from the spreading fault line in Iceland and the compressing fault lines in the andes and Himalayas?

Transform faults in opposite directions

How do we think the large maria (also "mare") on the Moon were formed?

From lava filled huge impact craters

How do you think the moon was formed?

it was the result of a Mars-sized object impacting the Earth, were material was redistributed and differentiated, thereby creading the Earth-Moon system.

A Kuiper Belt object FSU#1 is obsrved to orbit the suna to 100 AU.  How long in Earth years is a year on FSU #1?

P² = A³ = (100)³ = 10⁶

P = √ 10⁶ = 10³ = 1000 y

About 1000 years

their orbits are inside Earth's orbit

Channel 6 broadcasts its TV audio on FM 87.7 (87.7 MHz).  Waht is the wavelength of the radio signal?

P ˜ σ T⁴

T⁴ (2T)⁴

2⁴ = 16

About 16 times more

The discovery of the phases of Venus was made by Galileo using a telescope. The fact that Venus had all phases, including new and full, as well as quarters, proved that the heliocentric model of the solar system was the only one that could explain these phases correctly.  Moreover, this model also explained the peculiar phenomena of retrograde which had baffled astronomers previously, and which Ptolemy had tried to explain using epicycles.

Peculiar velocities refer to what?

they are the velocities of galaxies that deviate from the "Hubble Flow".

In the 30s, chaps named Zwicky and smith both examined closely 2 relatively nearby clusters, the Coma cluster and the Virgo cluster.  They looked at the individual galaxies making up the clusters individually, and the velocities of the clusters.  Waht they found was that the velocities of the galaxies were about a factor of 10 to 100 larger than they expected.  What might this mean?

Basically, this meant that there must be dark matter in addition to this visible matter that was causing the attraction.

If a star is about 2 parsecs away, waht parallax angle in arc seconds does this correspond to?

(teacher said that should be an easy one)

0.50 seconds

Ω > 1, closed universe

(not flat or open)

Density waves refer to what apsect of Galaxies?

the structure of the spiral arms and star formation

Name 2 types of stars or other objects that make good "standard candles" for distance determination in distant star clusters

Type Ia Super Nova

Cepheid variable starts

the Hubble constant is about 71 km/s/Mpc, and the corresponding age of the Universe is about 14 Billion years old.  If the Hubble constant were 142 km/s/Mpc, how old would the universe be?

About 7 billion years old.

If 1/71 is 14, than 1/142 is 7

What is MACHO

Massive Compact Halo Objects

What is WIMP?

Weakly interacting massive particles

What would be an example of hot dark matter?

neutrino

An astronomer tells you that Quasar A has a red shift = 1, and the Quasar B has a red shift off 5.  Which Galaxy existed closer to the time of the big bang?

Quasar B

Waht might be gravitationally pulling on the Local Group?

The Great Attractor

What event does the cosmic background radiation represent?

The recombination era when atoms formed, and light could finally escape from the Big Bang Cloud

In an AGN, the apparent motion of matter that is faster than light is called:

Superluminal motion

Astronomers are starting to take string and superstring theories seriously.  Circle all of the items that describe these string-like objects

They may have eleven dimensions

They help to describe how all the forces in nature might be unified at times less than the Planck time (10^-43 seconds).

Strings might contribute to the dark matter and gravitational lensing

The different vibrations of strings can correspond to different fundamental particles like the quark, electron, neutrino, etc.

The future of the universe can be thought of as these eras.  Describe the nature of the universe in each case: (last section of chapter 18).

1. Stelliferous era:

2. Degenerate era:

3. Black hole era:

4. Dark era:

1. A universe of stars like we have now

2. Dead stars, white and brown dwarfs

3. Black holes have "eaten most of the dead stars"

4. Black holes evaporate, leaving low energy photons

    roaming through the vacuum.

We discussed the analogy of the rising loaf of raisin bread with the expansion of the universe.  this analogy indicates that: 

That the "fabric of space and time" is expanding with the galaxies fixed to it.

At least 8! 9 or 10 or maybe even more if you include the KBOs.

Two.  demos and phobos

Is the magnetic field of Venus big or small?

None

What is a KBO?

Kuiper Belt Object

Yes

Can we see the transit of Mars across the sun?

NO

Is Neptune denser than Mercury?

NO.  the average density is less than Mercury 

What are the 2 general types of variable stars used for distance determinations?

RR Lyraes and Cepheids

What did we expect to find at the very center of our galaxy?

a supermassive black hole in the region of SGR A*

Hubble Law imples that

the greater the distance to a galaxy, the faster it is moving away from us. 

If the light from a galaxy fluctuates in brightness very rapidly, the region producsing the radiation must be

very compact

Quasar spectra

are strong redshifted

Charged particles spiraling around magnetic field lines can produce

synchrotron radiation

A typical active galactic nucleus (AGN) "eats" about how much mass in a year?

almost a solar mass worth

Inferring the distance to the galaxy through a measurement of its rotation rate is called?

the Tully-Fisher method

Galaxies that look like normal spiral galaxies, but have extremely bright galactic nuclei are called

Syfert galaxies

More than ___ percent of the mass in the universe is dark?

90%

A close encounter or collision between two galaxies may result in

a burst of star formation

The Virgo Cluster, the Local Group and some other local galaxy clusters form the

the Local Super Cluster

The galactic distances used to measure the acceleration of the univrse are determined by observation of

exploding white dwarfs

The inflation theory solves the cosmological

the horizon problem

The chemical elements that form the basic molecules needed for life are found

commonly through the cosmos

At large look back times, we are

Viewing galaxies whent the Universe was much younger 

Gravitational lensing

causes the light from distance stars to be bent or focused by unseen massive objects in its path

The centers of quasars are typically

Active Galactic Nuclei (AGN)

What is the signature of a pulsar?

Periodic blips in the received radio signals usually occuring at short intervals

Where do Quasars fit into the big bang scenario?

they are the result of protogalaxies which formed less than a billion years after the big bang.

What are the things an astronomer needs to know about distant galaxies in order to create a Hubble plot and get the Hubble constant?

The recession velocity and distance of each galaxy.

In the big bang, what best describes the inflationary expansion era?

Three dimensional graph paper expanding and carrying the matter with it.

A good analogy to describe the sebsequent expansion of the universe and the Hubble flow is:

A rising load of raisan bread.

Name 2 types of stars or other objects that make good "standard candles" for distance determination in distant star clusters and galaxies.

Type 1a supernova and Cepheid variable stars

To estimate the number of other civilizations like ours in the Muly Way, we

can use the Drake equation to estimate the total probability

In class, the Prof. referred to teh large scale galactic structure of the universe as:

Foam

The ultimate way to measure distance in the universe is to use

Hubble's law

A red shift z = 1000 would referr to what period?

the very early period of the universe associated with the cosmic background radiation

What are typical values of luminosity of AGNs?

(note W = watt = J/s)

Greater than 10³⁷ W, which means that they consume an average one sun's mass every couple of years.

What is special about the emission spectra coming from AGNs?

They have non-stellar, emission, unlike the normal black-body radiation due to heat alone

What is special about the energy output of an AGN?

It is highly variable, indicating that the emission source is very compact (less than a parsec in size).

What do AGNs "look" like?

they usually have jets and accretion disks, with a black hole at the center

the emission lines of AGNs have what appearance?

They are very broad, indicating that there source is undergoing rapid internal motion (in more than one direction)

It takes 8.3 minutes for light to travel from the Sun to the Earth.  If a new KBO object is found at 100 AU from the sun, how long does it take light to travel from the Sun to this new object?

833 minutes

How long does it take the moon to rotate once on its axis?

About 28 days, the same as it takes to orbit the Earth

How long does it take the Sun to rotate once on its axis?

About one month

What is the most important parameter that determines a star's evolution?

it's mass