Homework #12
The temperature at the Sun's core is about _____.
15,000,000 K
The Sun is about how far from Earth?
150,000,000 km
Approximately how long does energy take to travel from the core to the surface of the Sun?
16 million years
Light travels for about _____ to reach the Sun's surface from the Sun's core, and about ____ to reach the Earth from the Sun's surface.
16 million years; 8 minutes
Approximately how massive is the Sun as compared to the Earth?
300,000 times
According to the ideal gas law, the only way to have high pressure is by having a high density.
False
Comparison of the number of sunspots and the surface temperature of the Earth shows a correspondence right up to the present day.
False
The light produced in the Sun's core is able to pass freely through the Sun.
False
Astronomers use theory to determine the temperature of the Sun's core, because they cannot measure the core temperature directly.
True
Coronal holes are cooler parts of the corona from which the solar wind escapes.
True
One method of measuring the distance between the Earth and the Sun is by bouncing radar waves off the Sun.
True
Seismic waves observed at the surface of the Sun provide clues about the temperature and the density of the solar interior.
True
Starting from the core, the internal temperatures of the Sun decreases gradually until reaching the photosphere.
True
The Sun rotates slower near its poles than near its equator.
True
A solar prominence is essentially
a plasma confined to a magnetic tube sticking out of the surface of the Sun.
From the center out, the correct order of the parts of the Sun is
core, radiative zone, convection zone, photosphere, chromosphere, corona.
Generally speaking, activity on the surface of the Sun is primarily driven by
electromagnetism
The Sun's core is generating energy in the form of ________.
gamma rays
The Sun's composition by the % of mass is 71% ____, 27% _____, and 2% _____.
hydrogen; helium; other elements
The photosphere
is the layer of the Sun where it transitions from being opaque to transparent.
The Zeeman effect, in which energy levels of electrons are shifted and produce a corresponding split in spectral lines observed, is used to measure _________ at the Sun's surface.
magnetic field strength
One way to probe the rate of nuclear reactions in the center of the Sun is by studying ______ produced because _____________.
neutrinos; they pass out of the Sun without undergoing a random walk
In the Sun, nuclear fusion occurs
only in the core.
Which part of the Sun is covered with granules?
photosphere
Sunspots are dark because they are
slightly cooler regions, meaning they emit less light than the surrounding areas.
What holds the Sun together?
the Sun's gravity
The Sun's energy comes from __________.
the conversion of mass into energy
What is the Sun's outermost atmosphere called?
the corona
The Sun produces its energy through __________.
the fusion of hydrogen into helium
What is the visible surface of the Sun called?
the photosphere
What is the specific 3-step energy generating process in the Sun called?
the proton-proton chain
What is solar seismology?
the study of the Sun's interior by analyzing waves in the Sun's atmosphere
Which of the following gives evidence of the solar wind?
the tails of comets
If the Sun's rotation carries two sunspots around the side out of sight, you might see them again in about
two weeks
Astronomers know what the solar interior is like by
using locally-tested physics combined with observations to build a mathematical model of what the Sun should be like in its interior.
Since nuclear fusion in the Sun creates energy from matter, why doesn't it violate the law of conservation of energy?
Matter and energy are equivalent, as expressed by Einstein's equation E = mc^2.
About how long is the solar cycle (evidenced by the polarity of the Sun's magnetic field)?
??? (22 years)
The Sun is composed of about ______ and _______ plus 2% other elements.
71% hydrogen/27% helium
The _____ a period _______, that coincides with _______.
Maunder Minimum is; of low sunspot activity; the "little ice age" in the late 17th century
The ideal gas law implies that raising the temperature and density of a gas increases the pressure of the gas.
True
The magnetic fields in sunspots can be detected by the fact that some lines in the spectrum of a gas split into two or more lines by the action of magnetic fields.
True
The solar wind is created in the Sun's _______.
corona
The solar cycle is a result of the
differential rotation of the Sun.
The diameter of the Sun is determined by measuring its ____ and _____.
distance; angular size
The Sun rotates _____ at its equator than at its poles.
faster
Which is denser?
the Earth (a solid object)
Which is more massive?
the Sun (a gaseous giant)
Although the Sun's core has a density much greater than rock it is considered a gaseous object because
the Sun's high internal temperature prevent the atoms from bonding together to form a liquid or a solid.
The temperature at the ____ of the Sun's chromosphere is higher than the temperature _________.
top; at the base of the chromosphere
The Sun converts mass to energy through the proton-proton chain.
True
The average density of the Sun is about the same as that of Jupiter.
True
The mass of an entire hydrogen atom is converted into energy during the proton-proton chain.
False
How big is the Sun compared to the Earth, by diameter, approximately?
100 times bigger
About how long is the solar cycle (evidenced by sunspots)?
11 years
Why are astronomers interested in detecting neutrinos from the Sun?
Neutrinos give information about the nuclear reactions in the Sun's core.
At which observatory listed below are scientists trying to capture neutrinos?
Super Kamiokande, Japan
Why does the number of sunspots change over time?
The Sun's magnetic field changes in strength and shape with time.
How is the composition of the Sun today different than when it formed 4.6 billion years ago?
There is now more helium and less hydrogen.
Why do sunspots appear dark?
They are cooler than the surrounding gases.
What powers the Sun?
nuclear fusion of hydrogen into helium