stars and galaxies test questions

Considering stellar motion:

The 'space' motion is the actual true 3-dimensional vector velocity

Which of the following indicate the source is RECEDING away from the observer?

The OBSERVED wavelength is 700nm and the LABORATORY wavelength is 699nm

Which of the following stars has a hotter surface than the Sun?

F9

For star A we have: Effective Surface T=10,000, dist. = 1000 pc, dia. = 10.0 × 10⁵ km. And for star B we have: Effective Surface T=5,000, dist. = 10 pc, dia. = 4.00 × 10⁶ km.

For Star B the absolute magnitude = the apparent magnitude

Hipparchus

created the basis of stellar magnitude system we use today

The Babylonians

adopted the 7 day week calendar

All atoms:

each have at least one proton in the nucleus

Which of the following characteristics can one possibly obtain information about a star by examining only the shape of a single spectral line without knowing which line it is (i.e. where it belongs in the spectrum)?

if the star is rapidly rotating

Eclipsing binaries:

only occur when their mutual orbits are viewed close to edge on.

The Doppler Effect:

...for sound waves it caused a shift to a higher pitch by waves emitted from an approaching source.

Concerning binary stars in general:

they obey Keplers laws (as modified by Newton)

If a particular star has a surface temperature of 5,000 K and an effective black body spectrum that peaks at 4 MSWUs (My Special Wavelength Units), the spectrum:

of a 20,000 K stars peaks at 1 MSWUs

Which of the following is a variable star?


A   26 Canis Majoris

B   Alpha Centauri (where Alpha is the first letter in the Greek alphabet).

C   M87

D   RR Lyrae

RR Lyrae

Choose the FALSE statement:


A   Light may appear to move slower when moving through a transparent medium such as glass or water than it does in a vacuum.

B   Magnetic fields always appear the same independent of the relative frame of reference of the observer.

C   Light is an oscillating and propagating electromagnetic field.

D   Changing magnetic fields create electric fields and vice versa.

Magnetic fields always appear the same independent of the relative frame of reference of the observer

Isaac Newton:


A   ...discovered all 3 of his Laws of Motion at the same time Galileo did.

B   ...was the first person who recognized the law of Inertia

C   ...invented the refracting (using primary lenses) telescope.

D   ... used Kepler's Laws in part to deliver his Law of Universal Gravitation.

used Keplers laws in part to deliver his law of universal gravitation

Concerning Stellar Magnitudes, which statement is FALSE (not correct). For this question: 'M' = ABSOLUTE Magnitude and 'm' = Apparent Magnitude.


A   A star at 10 pc from us would have m = M.

B   If 2 stars have the same M, they still have different m's.

C   A star with m = M + 5.0 is at distance of 100 pc.

D   If m < M the star must be farther away than 10pc.

if m<M the star must be farther away than 10pc

A binary system has equal mass stars, each with a mass 3 times that of the Sun, and a period of 6 years. If the separation between them remains constant throughout their entire revolution, then using Newton's form of Kepler's Third Law (where M is the mass) is (M₁ + M₂)p² = a³, what is the distance between the 2 stars.


A   Their mutual separation is 2 AU.

B   Their mutual separation is 4 AU.

C   Their mutual separation is 36 AU.

D   Their mutual separation is 6 AU.

Their mutual separation is 6 AU

Which of the following is a true statement?


A   Two stars with the same diameter and effective surface temperature will necessarily have the same absolute magnitude as well.

B   Aristotle was first person to detect stellar parallax.

C   A smaller diameter star can never have a number for its apparent magnitude than a larger star.

D   All G2 stars necessarily have same absolute magnitude.

Two stars with the same diameter and effective surface temperature will necessarily have the same absolute magnitude as well

If a hypothetical planet were 4 times the mass and 2 times the diameter of the Earth:


A   ...your weight would be one-half of that at the Earth's surface.

B   ...the density of the planet would be half as much as the Earth's.

C   ...the density of the planet would be the same as the Earth's density.

D   ...the density of the planet would be twice the Earth's density.

the density of the planet would be half as much as the earths

Democritus and Leucippus:


A   ...were students of Plato at the academy.

B   ...were first to argue for the general idea that everything is made of atoms.

C   ...are best known for advocating a heliocentric (Sun-centered) Universe.

D   Leucippus was Democritus' student.

were the first to argue for the general idea that everything is made of atoms

Which of the following is FALSE (NOT TRUE) regarding Galileo?


A   He discovered the Law of Inertia.

B   He was the first person to report seeing the phases of Venus.

C   He invented the reflecting telescope (with a primary mirror) where the image is viewed at right angles with respect to the observing direction.

D   He observed that the 4 brightest moons of Jupiter obeyed Kepler's Third Law.

he invented the reflecting telescope (with a primary mirror) where the image is viewed at right angles with respect to the observing direction

Which of the following quantities is necessarily conserved in a closed inertial system?


A   Volume

B   Kinetic Energy

C   Angular Momentum

D   Density

Angular momentum

One would expect to see a continuous spectrum from:


A   ...the sun.

B   ...a rainbow from sunlight.

C   ...the filament of an incandescent light bulb.

D   ...moonlight.

the filament of an incandescent light bulb

Which of the following would be the approximate limiting (minimum) resolution in arc seconds in visible light by a telescope with a diameter, d, of 1 m?(Hint: First calculate the resolution in radians, then convert to arc seconds) NOTE: For visible light wavelength , L is ~5.00 × 10^-7 m, and 1 radian ~1/5 × 10^-6 arc sec. The minimum angle that can be resolved is ~L/d.


A   0.10 arc sec

B   10.0 arc sec

C   1.0 arc sec

D   0.01 arc sec

0.10 arc sec

Concerning telescopes used for astronomy:


A   ...the Hubble telescope was placed in space primarily to avoid atmospheric effects.

B   ...the ground based visible light telescopes are primarily placed on mountain tops to avoid city lights.

C   ...all telescopes use mirrors as primary element independent of the wavelength being observed.

D   ...many visible-light telescopes still use photographic film to capture images.

The Hubble telescope was placed in space primarily to avoid atmospheric effects

On an HR diagram:


A   ...cooler stars are always plotted lower on the diagram with respect to the hotter stars.

B   ...two stars with the same Apparent magnitude are always plotted at the same level on the vertical axis.

C   ...any star that is generally below and to the left of another star must always be the smaller of the two stars.

D   ...the vertical axis can be plotted as color.

any stars that is generally below and to the left of another star must always be the smaller of the two stars

Concerning stellar evolution:


A   ...any star that is generally above and to the right of another star must always be the smaller of the two stars.

B   ...T-Tauri variables are generally thought to be examples of a Post-Main Sequence phenomena.

C   ...All stars more massive than Sun generally takes less time than the Sun did to reach the ZAMS from when they first started to contract.

D   ...all hydrogen 'burning' concludes everywhere in the star's interior once a star leaves the main

All stars more massive than the sun generally take less time than the sun did to reacher the ZAMS from when they first started to contract

Along the 'Main Sequence' (for Main Sequence stars):


A   ...All stars are generally 'burning' Helium into Carbon via the Triple Alpha process only in their central-most cores.

B   ..All stars with a surface temperature substantially greater than the Sun's have longer net Main Sequence lifetimes.

C   ..All stars with a surface temperature substantially less than the Sun's have masses that are less than the Sun's as well.

D   ...Stars have fixed locations and do not move at all until they enter the post-main sequence phase.

All stars with a surface temperature substantially greater than the Sun’s have longer net Main sequence lifetimes

Our present Theory of the Sun's main sequence evolution is in some significant way based on our knowledge of:


A   ...the history of meteoritic impacts with the Earth.

B   ...the length of the mean solar day.

C   ...the Sun's relative location in the Milky Way.

D   ...the oldest biological growth records on Earth being used to determine the relative constancy of the Sun's luminosity over the largest part of its' prior main sequence lifetime.

the oldest biological growth records on Earth being used to determine the relative constancy of the Sun’s luminosity over the largest part of its’ prior main sequence lifetime

Neutron stars:


A   ...are in ALL cases to be remnants only of prior Type 2 supernovae.

B   ...are approximately the size of the Earth.

C   ...are thought to be the explanation for pulsars.

D   ...do not collapse further because electrons are fermions and they can become degenerate.

are though to be the explanation for pulsars

Supernovae:


A   ...can result, at least sometimes, in the formation of the white Dwarf stars.

B   ...for a few seconds, have a net luminosity that outshines the rest of the visible universe combined.

C   ...emit most of their energy in the forms of neutrons.

D   ...occur in stars which are known to always be red giants (the star that becomes a supernova was a red giant just before that) for both Type I and Type II Supernovae.

for a few seconds, have a net luminosity that outshines the rest of the visible universe combined

The fundamental postulates of Special Relativity include or imply:


A   Information can never be transmitted in the form of light.

B   You can never visit any point in your Future from your present Here-Now, because it will always remain in your future.

C   Clocks appear to run slower to an observer when the observer in question is moving with respect to the clock, but not when the clock appears to be moving with respect to the observer.

D   The laws of physics do not depend upon the frame of the observer so long as th observer is in an inertial (non-accelerating) frame of reference.

The laws of physics do not depend upon the frame of the observer so long as the observer is in an inertial (non-accelerating) frame of reference.

For Black Holes:


A   Near the Event Horizon af all individual Stellar Remnant Black Holes, the tidal forces are expected to be able to tear molecules apart, meaning that no person could possibly survive a trip through that region.

B   Outside a black hole it is possible to determine only it's exact mass.

C   They are typically identified by studying the emissions from the matter being ejected from them through their event horizons.

D   They always occur at the end of a star's life when more than ~1.4 solar masses remain in the core.

Near the Event Horizon of all individual stellar remnant Black Holes, the tidal forces are expected to be able to tear molecules apart, meaning that no person could possibly survive a trip through that region

Concerning the Space Time Diagram:


A   ...as you move into your future some of what was in elsewhere can become part of your past at your new here-now, but parts of elsewhere can never become part of your future.

B   ...you can always choose to stay at here-now without moving since that clearly is slower than the speed of light.

C   ...the future and past are indistinguishable.

D   ...elsewhere is not in our universe.

as you move into your future some of what was in elsewhere can become part of your past as your new here-now, but parts of elsewhere can never become a part of your future

General Relativity:


A   ...has been used to show all of the laws of physics can be interpreted as simple geometric effects.

B   ...did not predict black holes until they were actually observed.

C   ...has never actually succeeded in making any observable predictions.

D   ...it is Einstein's theory that gravity is not a Force, but rather is due to the warping effect that the local energy density has on the geometry of the space-time.

it is Einsteins theory that gravity is not a force, but rather is due to the warping effect that the local energy density has on the geometry of the space time

The sunspot cycle:


A   ...has been recognized only since the beginning of the 20th Century.

B   ...requires about 11 years for the total true full cycle period to return to the initial state.

C   ...have almost exactly the same number of spots from one cycle to the next.

D   ...is a result of the Sun's periodic magnetic field reversals due to the winding up of the magnetic field from the effect of the Sun's differential rotation.

is a result of the Suns periodic magnetic field reversals due to the winding up of the magnetic field from the effect of the sun’s differential rotation

The Red Giant branch on the HR diagram:


A   ...includes the location of the point in a star's evolution known as the Helium Flash.

B   ...has only stars that are all burning Helium into Carbon via the Triple Alpha process somewhere inside.

C   ...contains only stars who have stopped 'burning' Hydrogen into Helium everywhere inside.

D   ...will never contain any stars that are less massive as the Sun.

includes the location of the point in a stars evolution known as the helium flash

Pre-T-tauri stars:


A   ...typically proceed through the RR-lyrae variable stage prior to reaching the main sequence.

B   ...first appear in the InfraRed wavelengths at the extreme lower left-hand edge of the HR diagram.

C   ...all known current examples in the Milky Way are Population II (low heavy element abundance) type stars.

D   ...reach net luminosities that are very high compared to the star's ZAMS luminosity.

reach net luminosities that are very high compared to the stars ZAMS luminosity

'Brown Dwarfs:'


A   ...are collapsed objects that failed to reach the Main Sequence because they don't have enough mass.

B   ...are old Main Sequence stars that are dimmer the Sun.

C   ...are plotted at the extreme lower left-hand corner of an HR diagram.

D   ...are all 'burning' hydrogen in their central-most core in the stars's interior.

are collapsed objects that failed to reach the Main sequence because they dont have enough mass

Population II stars in our galaxy:


A   ...generally are all very young stars.

B   ...have HR diagrams that are virtually identical to those of Population I stars.

C   ...contain a much smaller fraction of their total mass in elements heavier than Helium than do Population I stars.

D   ...form clusters that are much bluer than Population I star clusters.

contain a much smaller fraction of their total mass in elements heavier than Helium than do population1. stars

With regards to the Sun's atmospheric layers:


A   ...the maximum temperature that occurs in each successive layer decreases as one moves outwards from the surface of the Sun.

B   ...the chromosphere lies directly above the corona.

C   ...they each have compositions that are similar to the composition of air in this room.

D   ...the upper boundary of the photosphere is cooler than its lower boundary.

the upper boundary of the photosphere is cooler than the lower boundary

Fermions:


A   ...are all electrically charged.

B   ...do not obey the Uncertainty Principle.

C   ...do not obey the Pauli Exclusion Principle.

D   ...are the fundamental 'building blocks' of the normal matter in our universe.

are the fundamental building blocks of the normal matter in the universe

Concerning the Solar Neutrino Experiment that was done in the South Dakota mine, which of the following is true?


A   It required a deep mine so that no transmitted radio traffic produced at the surface of the Earth would confuse the detector.

B   The detector contained normal tap water as the sensitive medium for detecting neutrinos.

C   It was designed to 'detect' neutrinos coming directly from the center of the Sun.

D   It found too many neutrinos (around 3 times as many) when compared with the initial theoretical predictions.

it was designed to detect neutrinos coming directly from the center of the sun

Cepheid variable stars:


A   ...have period-luminosity relationships that make them VERY useful as distance indicators.

B   ...are current Main Sequence variable stars with very high luminosities with respect to the Sun's.

C   ...reach the dimmest point in their light curve when their atmospheres are the most expanded.

D   ...have a rapidly varying energy source in their cores which cause the variation in the luminosity.

have period luminosity relationships that make them very useful as distance indicators

During post main sequence on the Asymptotic Giant Branch (AGB):


A   ...all stars will always become extreme Population II stars kin their surface spectrum.

B   ...the remaining lifetime is far greater than the same star's main sequence lifetime had been.

C   ...all stars tend to increase their mass significantly.

D   ...elements much heavier than Helium ban be produced.

elements much heavier than helium can be produced

Fusion as a process in general:


A   ...increases the net amount of energy in the universe.

B   ...results in a net decrease in the total mass if the resulting object is more tightly bound than the sum of the independent masses of the separate objects.

C   ...is the process going on in our nuclear power reactors today.

D   ...refers to the process of breaking apart already bound objects.

results in a net decrease in the total mass if the resulting object is more tightly bound than the sum of the independent masses of the separate objects

R-Process and S-Process Nucleosynthesis beyond the Iron peak:


A   ...can both produce elements heavier than Lead, like Uranium.

B   ...will occur in all stars at some point in their lifetime.

C   ...both have to be generally endothermic (absorb energy) to produce nuclei, generally heavier than Iron because the heavier nuclei are less tightly bound per nucleon than Iron.

D   ...is ever occurring in the cores of isolated white dwarf stars.

both have to be generally endothermic (absorb energy) to produce nuclei, generally heavier than Iron because the heavier nuclei are less tightly bound per nucleon than Iron

Concerning the Sun's interior:


A   The Density is roughly constant all the way down to the core from the surface.

B   The net total luminosity emanating from the core is essentially the same as that being shined away at the Sun's surface.

C   Energy is transported principally via the convection in the region just above the core.

D   The Radiative Zone is where the bulk of the energy is produced.

the net total luminosity emanating from the core is essentially the same as that being shined away at the Sun’s surface

Type 1A Supernovae are characterized by all sharing the same properties EXCEPT:


A   ...distance.

B   ...Similar Resulting light curves.

C   ...maximum luminosity.

D   ...occurring in a close binary star system.

distance

the Sun's Atmosphere:


A   ...is broken in to 3 (three) distinct regions, the Photosphere, the Chromosphere and the Corona.

B   ...in total contributes only a small portion of the total spectrum of visible light we see.

C   ...the brightest region is the Corona.

D   ...never exceeds a maximum temperature of about 5,800 K.

is broken into 3 distinct regions, the photosphere, the chromosphere, and the corona.