Astronomy Mid-term Part 2 (chapters 16, 6, 7)

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

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

Your friend, a graduate student in astronomy, is giving you a special tour of the local observatory. You notice that you are viewing the image from the big telescope from underneath the primary mirror; the beam of light has come through a small hole in the main mirror to an eyepiece below. This telescope uses what focusing arrangement?

Cassegrain focus

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

Galileo Galilei

Which of the following statements about jovian planets is NOT CORRECT?

Jovians (being larger) rotate significantly more slowly than terrestrials

A planet in our solar system whose composition resembles that of our Sun is

Jupiter

Which of the following is NOT a terrestrial planet? (mars, earth, jupiter, venus, mercury)

Jupiter

In a bad late-night science fiction film, a villain is using a large collection of rare radioactive atoms as energy for a weapon to threaten the good guys. The atoms have a half-life of 1 hour. The villain has 4 kilograms of the radioactive material now, and he needs a minimum of 1 kg for his weapon to work. After how much time will the weapon no longer be a threat?

Just a little after 2 hours

The planet closest to the Sun in the solar system is

Mercury

You are the captain of an interplanetary tour ship and a wealthy tourist from Texas asks you to take him to see only the "largest darn planets" in the solar system. Which of the following would you NOT include in your tour?

Mercury

Today we realize that the source of energy for the Sun is a process called

Nuclear fusion

The Sun is an enormous ball of gas. Left to itself, a ball of so many atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing?

Nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced

The first trans-Neptunian object astronomers found (in 1930) is called

Pluto

which of the following is a way for astronomers to learn more about the interior of the Sun?

Study the oscillations (pulsations) witnessed on the Sun's surface

Which of the following best describes the first set of experiments, using chlorine traps, that were searching for electron neutrinos from the Sun?

The chlorine experiments found only between 1/3 the number of electron neutrinos arriving from the Sun that our models predicted should be coming.

In an earlier era, some scientists suggested that the energy of the sun comes from meteorites falling into it and converting their falling motion into heat. Which of the following is part of the argument that shows that this mechanism will not work?

The meteorites would eventually increase the mass of the Sun and change the orbits of the planets.

The largest refracting telescope in the world, financed by a Chicago millionaire in the 1890's, is at the

Yerkes Observatory

Which of the following is NOT a product of the first step in the p-p chain of nuclear fusion? *a form of hydrogen *a positron *a neutrino *a deuteron *a form of helium

a form of helium

At the end of the p-p chain of nuclear fusion in the Sun, hydrogen nuclei have been converted into

a helium nucleus

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

a large metal dish (antenna)

According to the formula E=mc2,

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

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

a mirror

Which of the following particles has the lowest mass? *a neutrino *a proton *a neutron *an electron *the nucleus of a hydrogen atom

a neutrino

Which of the following, produced at the core of the Sun, will take the shortest time to emerge from the Sun's photosphere (surface)?

a neutrino

What type of telescope can be used routinely on the surface of the Earth during the DAY?

a radio telescope

Physicists Kelvin and Helmholtz in the last century proposed that the source of the Sun's energy could be

a slow contraction

Which of the following places is most likely NOT to be differentiated?

a small asteroid

Radioactive dating techniques have revealed that our Earth and Moon are approximately how old?

about 4.5 billion years

The size of the device that collects radiation (such as light) is called a telescope's

aperture

When chemists say that a planet's upper regions are reduced, they mean that these regions

are dominated by the element hydrogen and its compounds

The smaller objects in the solar system made of rock and metal (most of which orbit between Jupiter and Mars) are called

asteroids

Why do telescopes have to have a good motorized drive system to move them quickly and smoothly?

because the Earth is rotating, with the telescope attached to it

Why do astronomers prefer to put infrared telescopes on high-flying airplanes or on satellites in space?

because the water vapor in the lower atmosphere is very good at absorbing/blocking infrared

The most important function of an astronomical telescope is to

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

The smaller objects in the solar system composed mainly of ices (frozen gases) that usually orbit far from the Sun are called

comets

A new technique called adaptive optics allows astronomers to

compensate for changes in the Earth's atmosphere and achieve better resolution

When great currents of hot material rise inside the Sun (and cooler material sinks downward), energy is being transferred by a process known as ...

convection

What is one way that astronomers have actually gotten an idea of the age of the surface of terrestrial planets other than the Earth?

counting craters

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

energy in the form of a gamma ray

The Chandra Observatory orbiting the Earth is designed to

examine sources of cosmic x-rays

If the "fuel" for nuclear fusion is nuclei of hydrogen, and the Earth's oceans are filled with hydrogen atoms in water all being jostled together, why isn't there a lot of fusion happening in our oceans?

for hydrogen nuclei to fuse, they must get very close to each other, which the nuclei in the oceans cannot do

Generally planets and moons in our solar system are named after

gods and goddesses from mythology

In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its

half-life

During the process of differentiation

heavier materials sink to the centers of molten planets

Which of the following statements about helioseismology experiments is FALSE/FACTUALLY INCORRECT? *the pulsations these experiments measure take about an hour to emerge from the Sun's interior *small changes in the velocity of the waves of pulsation coming from inside the Sun help astronomers figure out the structure of the Sun's interior *Helioseismology measures waves that are set up by the motion of neutrinos from the core of the Sun *a typical pulsation takes about 5 minutes to complete a full cycle from maximum to minimum speed and back again *Helioseismology allows astronomers to look under a sunspot and see how it works

helioseismology measures waves that are set up by the motion of neutrinos from the core of the Sun

If you were to take a large sample of the four giant planets, the most common element you would find in them is

hydrogen

In studying the surfaces of solid bodies in the solar system, astronomers have learned that the number of craters (per unit are)

is roughly proportional to the age of the surface we are examining

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

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

What happens to the positron created during the p-p chain of nuclear reactions inside the Sun?

it quickly collides with an electron and turns into gamma-ray energy

The inner planets are made mostly of rock and metal because

it was so hot where the inner planets formed that the lighter materials evaporated

When the James Webb Space Telescope is finally launched, what will be its distinguishing characteristic (what about it will really help astronomers)?

it will have the largest mirror aperture ever put into space for observing faint objects

In general the further planets are from the Sun, the cooler they are. What other factor can have a significant influence on a planet's surface temperature?

its atmosphere

Which of the following is NOT an experiment that is searching for neutrinos coming from the Sun? *looking for radioactive argon atoms in a tank of cleaning fluid deep in an underground mine *looking for changes in the Doppler shift of lines in the atmosphere *looking for radioactive gallium in a vast quantity of ordinary gallium *looking with sensitive light meters in a giant vat of pure water deep underground in Japan all of these are ways to search for neutrinos

looking for changes in the Doppler shift of lines in the atmosphere of the Sun

The Global Oscillations Network Group (GONG) Project is engaged in

measuring the pulsations of the Sun from stations around the world

On which planet (besides the Earth) do we still see a high level of geological activity on the surface today?

none of these

When a large nucleus breaks apart (or is broken apart) into two smaller pieces, this is called

nuclear fission

Aa very wealthy donor decides to give a large sum of money to your college or university to build the world's largest visible-light telescope. From an astronomical perspective, where would be the best location to put such a telescope?

on a tall, dry mountain peak

The rate at which a collection of the same radioactive atoms will decay depends on

only on internal processes within the atoms; nothing external matters

Today the chemistry of the terrestrial planets does not include a lot of free hydrogen. Chemists call the chemistry in places like the Earth

oxidized

The material that would eventually make all the major bodies in our solar system first gathered together as smaller pieces which astronomers call

planetesimals

The material inside the Sun is in the form of a

plasma

The antimatter version of an electron is called a

positron

Which of the following is NOT one of the fundamental particles that we find inside atoms *protons *neutrons *Positrons *electrons *all four are found in most atoms

positrons

When energy is first produced by fusion deep in the core of the star, that energy moves outward mostly by what process?

radiation

The earliest telescopes used by astronomers were

refractors

All the planets (without exception)

revolve around the Sun in the same direction

When two light elements collide to undergo nuclear fusion

some of the energy in their mass is released

To break up light into the component colors that it contains, astronomers use a device called

spectrometer

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

spread out the light into a spectrum

One method of observation that can help astronomers sort out how the planets formed in our solar system is

studying circumstellar disks of material around many other stars

Astronomical observatories have been available since ancient times, and many cultures set aside special sites for astronomical observations. The thing modern observatories have that was missing from these older observatories until about 1610 was

telescopes

Which of the following major telescopes WAS NOT launched in space? *the Hubble Space Telescope *the Compton Gamma-ray Observatory *the International Ultraviolet Explorer *the Keck Telescope the Roentgensatellite (ROSAT) x-ray telescope

the Keck Telescope

In the far future, a visiting tourist from another planetary system asks to see the most massive object in our solar system. Where would you take him/her/it?

the Sun

Which part of the Sun has the greatest density?

the core

A friend (who does not have the new awareness which you have gained from this course) suggests that the mechanism that keeps the Sun shining as brightly as it does is the burning of coal. You brilliantly challenge his theory! Your challenge comes in several related steps; which of the following is one of those steps?

the dating of radioactive rocks show that the Earth and thus the Sun are billions of years old

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

the diameter of the primary lens or mirror

In the four terrestrial planets, the densest heaviest materials are at the center and not evenly distributed throughout the planet. Scientists interpret this observation to mean that

the four terrestrial planets must once have been hot enough to be molten (like a liquid)

What was the major problem with the Hubble Space Telescope when it was first launched into orbit?

the mirror's shape was slightly wrong, so all the light did not come to a single focus

On Earth, we can get the age of various parts of our planet by finding rocks that contain radioactive atoms. From which other world do we have a good number of rocks to do this kind of age analysis?

the moon

A future interplanetary tourist whose parents kept him too warm as a baby asks for your help to find a "really cold place" in the solar system. Which of the following would be the coldest place to take him?

the moons of Neptune

The strongest force we know of in physics is

the nuclear force which holds nuclei together

A friend of yours who has not taken any science courses hears you talking about the generation of nuclear energy and makes the following observations: "The whole idea of the atomic nucleus is ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument?

the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together

Our best evidence and theoretical calculations indicate that the solar system began with a giant spinning system of gas and dust that scientists call

the solar nebula

In the formula E=mc2, the letter c stands for

the speed of light

An astronomer is studying galaxies of stars that are very far away and thus look extremely faint (using visible light). What kind of telescope should she and her graduate students apply for time on?

the telescope with the biggest aperture possible

Which of the following characteristics do all four terrestrial planets have in common?

they all have solid surfaces with signs of geological activity on them

When astronomers do radar astronomy, they

they bounce a radar beam off the surface of solid objects in our solar system

When the twin Keck telescopes were built in the 1990s what distinguished them from telescopes of the time?

they used a mirror assembly that was made of 36 smaller hexagonal mirrors working together

On which of the planets (other than Earth) could a human being step out of a spacecraft and survive without any protective gear (special suit, oxygen tanks, etc)?

this is a bad idea, she will die

Astronomers and physicists now believe they know what is happening to the missing neutrinos from the Sun (the neutrinos that our theories say should be emerging from the Sun, but our experiments in that underground mine could not find). These neutrinos are

turning into a different type of neutrino

The process of fusion that keeps our Sun shining begins with which building blocks?

two protons

Of the following planets, which does NOT have a satellite (moon)?

venus

Radio telescopes of modest size can't make out as much detail (have a lower resolution ) than visible light telescopes. How do astronomers overcome this limitation?

we can connect several radio telescopes some distance apart together electronically to give us the resolution of a larger telescope.

What is the most important reason that astronomers have learned more about our planetary system in the last 30-40 years than all of history before then?

we have been able to send spacecraft to gather information about planets and moons up close

Which of the following statements about antimatter is true?

when a particle of matter and the corresponding particle of antimatter meet, they become pure energy