ASTR: unit 2- The Sun

Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for:

aurorae

The hottest zone in the Sun is the

core

Layers of the Sun (inside to outside)

core, radiative zone, convective zone, photosphere, chromosphere, Corona

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

corona

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

Astronomers now realize that active regions on the Sun are connected with

loops of magnetic field emerging from the surface of the Sun

When we use the light of atoms such as hydrogen and calcium to examine the Sun's outer layers, we can see bright "clouds" in the chromosphere right around the location of sunspots. These bright clouds are given the name:

plages

Which of the following is NOT one of the fundamental particles that we find inside atoms? -positrons -protons -neutrons -electrons

positrons

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

radiation

In a star like the Sun, high temperatures are required to get H (hydrogen) nuclei to fuse because they ____ one another, due to their ____ electric charges.

repel, positive

The Sun's chromosphere contains many jet-like projections that stick up into the transition region. These spikes of gas are called:

spicules

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

As you go upwards from the Sun's photosphere,

the density (number of atoms in a unit volume) decreases

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

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

A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty 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 strong nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together

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

Which of the following statements about the Sun's photosphere is NOT TRUE? -The photosphere is not a solid layer; if a spaceship (that could withstand the heat) fell through it, it wouldn't feel anything when reaching the photosphere -The photosphere is much less dense than our Earth's atmosphere -The photosphere is significantly hotter than all the layers of the Sun beneath it (further inward) -The photosphere is the layer where the Sun becomes opaque (you can't see through it)

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

Which of the following is NOT a product of the first step in the p-p chain of nuclear fusion? -a deuteron (nucleus of deuterium atom consists of a proton and a neutron) -a form of helium -a form of hydrogen

a form of helium

what order would you see these phenomena?

-Sunspots -prominences -solar flares -coronal mass ejections (CME)

The most common element in the Sun is

Hydrogen

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

Which statement about the Sun's rotation is TRUE? -The Sun does not rotate; only planets rotate -Only the atmosphere of the Sun rotates, not the main body of the Sun -The Sun rotates at different rates at different latitudes on the Sun -The Sun rotates only at the equator, where the sunspots are found; the rest of the Sun does not rotate -The Sun rotates once a day

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: -When sunspots are at a minimum, we get the largest number of flares and prominences -Every 11 years sunspots completely cover the Sun, making its surface much darker -The Sun's activity cycle shows absolutely no connection to its magnetic field -The number of sunspots gets larger and smaller over the course of 11 years

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

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

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

corona

"B" is a

coronal hole

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

energy in the form of a gamma ray

Observing the Sun in H-alpha allows astronomers to observe solar features in the Chromosphere such as the

filaments

Which of the following statements about the violent events on the Sun called flares is FALSE? -a flare can release energy equivalent to a million hydrogen bombs -the visible light we see from a flare is only a tiny fraction of the energy it releases -flares happen more often during solar maximum, and sometimes during those periods, there can be several in one day -flares originate in the upper part of the corona, in the regions called coronal holes -astronomers think that flares are connected with sudden changes in the magnetic field of the Sun

flares originate in the upper part of the corona, in the regions called coronal holes

The granulation pattern that astronomers have observed on the surface of the Sun tells us that:

hot material must be rising from the Sun's hotter interior

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 material inside the Sun is in the form of a

plasma

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

Which part of the Sun has the greatest density?

the core

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)