module 5

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.

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

by noting the wind's effects on the tails of comets

Where in the Sun does fusion of hydrogen occur?

Only in the core

Coronal Mass Ejections from the Sun have many serious effects on or near the Earth. Which of the following is NOT one of these effects?

causing huge cyclones around the equator of the Earth

Which part of the Sun's atmosphere has the lowest density (number of atoms per unit volume)?

corona

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

corona

The ten million tons of particles that escape the Sun each year in the form of the solar wind get out mainly through regions called

coronal holes

Three kinds of worlds are round in our solar system. Which of the following is NOT a type of world that is typically round?

minor planet (asteroid)

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

more than one of the above

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

nuclear fusion

Which of the following pieces of observational evidence does our modern "solar nebula" theory of the formation of the solar system NOT explain directly?

the plane of the orbit of Pluto

One of the best ways to learn more about a world is to have samples from its surface to analyze in our laboratories. From which of the following worlds do we NOT yet have a sample to analyze here on Earth?

Venus

Which of the following is NOT a product of the first step in the p-p chain of nuclear fusion?

a form of helium

According to the formula E=mc2,

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

Which of the following is NOT one of the fundamental particles that we find inside atoms?

positrons

How do astronomers know that the age of the solar system is about 4.5 billion years old?

radioactive dating of the primitive meteorites indicates they have that age (since they are left-over building blocks of the solar system)

The first technique that allowed astronomers to find exoplanets involved:

measuring changes in the radial velocity (Doppler shift) of the star caused by the pull of orbiting planets

Astronomers call the vast, rotating cloud of vapor and dust from which the solar system formed:

the solar nebula

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

the speed of light

If it takes an average of 14 billion years before any proton inside the Sun will undergo fusion, and the Sun is only about 5 billion years old, why do astronomers believe that fusion is going on there now?

there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average

Sunspots are darker than the regions of the Sun around them because

they are cooler than the material around them (although still very hot compared to Earth temperatures)

When two light elements collide to undergo nuclear fusion,

some of the energy in their mass is released

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

study the oscillations (pulsations) of the Sun's surface

Astronomers now believe that the differences in composition among the planets reflect what characteristic in the early solar system

temperature

Which of the following is not a characteristic that worlds in our solar system have in common:

that all the planets have solid surfaces on which we can see impact craters

For solid rocky worlds, a general rule is

the larger the world, the slower it cools off and the more it will keep its internal heat

How do astronomers know how strong the magnetic field of the Sun is?

the measure the Zeeman effect (the splitting of spectral lines)

The ages of stony meteorites have been measured to be roughly equal to:

the oldest ages we have measured for any bodies in the solar system

The Sun's photosphere is

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

Which of the following worlds does NOT have a ring (as far as we know)?

Venus

The most common element in the Sun is

hydrogen

The material inside the Sun is in the form of a

plasma

The strongest force we know is

the nuclear force which holds nuclei together

Which statement about the Sun's rotation is TRUE?

The Sun rotates at different rates at different latitudes on the Sun

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

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

Which of the following statements about the Sun's photosphere is NOT TRUE?

The photosphere is significantly hotter than all the layers of the Sun beneath it (further inward)

How can astronomers measure the age of a meteorite that fell from the skies?

They measure the amount still left of radioactive materials in the meteorite, and how much has turned into decay products

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)

Which of the following particles has the lowest mass?

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

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

a slow contraction

At the beginning of the solar system's history, a ready supply of proto-planets or mini-planets crashed into the developing planets and each other - something astronomers call the "era of giant impacts." How long do astronomers estimate this era lasted?

about 100 million years (0.1 billion)

Astronomers have found that the level of the Sun's activity varies over the centuries. How did they come to realize that this is so:

all of the above (historical records of the number of sunspots seen on the Sun, measuring the amount of radioactive carbon in tree rings historical records of auroral activity)

Which of the following statements about the violent events on the Sun called flares is FALSE?

astronomers think that flares are connected with sudden changes in the magnetic field of the Sun

One of the best proofs that our theory of how the solar system formed is correct is that astronomers now observe

disks around other stars which show evidence of gaps where planets may be forming

The Sun's chromosphere and corona were discovered

during total eclipses of the Sun

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

energy in the form of a gamma ray

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

Which of the following is not part of some active regions on the Sun?

granulation

One of the most perplexing issues raised by the discovery of thousands of exoplanets is the existence of "hot Jupiters" - planets with the masses and compositions of Jupiter, but orbiting closer to their stars than Mercury does in our solar system. What is our best idea currently about how such "hot Jupiters" came to be?

hot Jupiters formed further out in their star system, and then migrated inward somehow

Some of the early planetesimals that formed the solar system still survive today. Where would you find such planetesimals?

in the asteroid and Kuiper belts

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

is made entirely of hot gas

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

You are out on the beach, enjoying the warm sunshine with friends. As you glance up at the Sun (only briefly we hope), the part of the Sun that you can see directly is called its:

photosphere

One region on Earth that has become a rich source of new meteorites in recent decades (including the meteorite from Mars that got famous because some scientists claimed they had found evidence for the building blocks of life on Mars) is:

the Antarctic

What mechanisms do astronomers believe is responsible for making the Sun's outer atmosphere so much hotter than its photosphere?

the Sun's magnetic field interacting with the charged particles that make up the atmosphere

The reason that worlds like the Earth are differentiated is that

the continuing impacts on a growing protoplanet eventually melted the entire body

Which part of the Sun has the greatest density?

the core

A key difference between the protoplanets that formed in the outer solar system and those that formed in the inner solar system was that

those in the outer solar system were in a place where ice, not just rock, condensed and thus could grow larger

Among solid worlds, which type of world is most likely to have significant geological activity?

those that are the largest (and retain heat the best)

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 in a neutrino oscillation

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

two protons

How do astronomers know what the outer layers of the Sun are made of?

we take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers

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