HW 12 -- Ch 15,16

A region in the Sun's outer atmosphere that appears darker because there is less hot gas there.

NOT chromosphere

The Sun is an enormous ball of plasma (superheated 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

Where in the Sun does fusion of hydrogen occur?

Only in the core

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

Two protons

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

a Helium nucleus

plage

a bright region of the solar surface observed in the light of some spectral line

plasma

a hot ionized gas

prominence

a large, bright, gaseous feature extending outward from the Sun's surface, often in a loop shape

According to the formula E=mc^2

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

Maunder Minimum

a period during the eighteenth century when the number of sunspots seen throughout the solar cycle was unusually low

solar flare

a sudden and temporary outburst of electromagnetic radiation from an extended region of the Sun's surface

an area on the Sun where magnetic fields are concentrated; sunspots, prominences, flares, and CMEs all tend to occur in ______________.

active region

Light radiated by atoms and ions in the ionosphere excited by charged particles from the Sun, mostly seen in the magnetic polar regions

aurora

fission

breaking up of heavier atomic nuclei

fision

building up of heavier atomic nuclei

__________ is the part of the solar atmosphere that lies immediately above the photospheric layers.

chromosphere

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

The _________ (of the Sun) is the outer (hot) atmosphere of the Sun.

corona

____________ is the phenomenon that occurs when different parts of a rotating object rotate at different rates at different latitudes

differential rotation

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

energy in the form of a gamma ray

Sunspots are large, dark features seen on the surface of the Sun caused by decreased magnetic activity.

false

The proton-proton chain is a series of thermonuclear reactions by which nuclei of hydrogen are built up into nuclei of __________.

helium

The fundamental particle that has no charge and a mass that is tiny relative to an electron; it rarely interacts with ordinary matter and comes in three different types

neutrino

When a large nucleus breaks apart into two smaller pieces, this is called

nuclear fission

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

nuclear fusion

The region of the solar (or stellar) atmosphere from which continuous radiation escapes into space.

photosphere

Particle with the same mass as an electron, but positively charged

positron

The antimatter version of an electron is called a

positron

Hydrostatic equilibrium is the balance between the weights of various layers, as in a star or Earth's atmosphere, and the _____________ that support them

pressures

Conduction

process by which heat is directly transffered

Coronal mass ejection (CME) is a solar flare in which immense quantities of coronal material, mainly _____________, is ejected at high speeds (500-1000 kilometers per second) into interplanetary space

protons and electrons

The ________________ a flow of hot, charged particles leaving the Sun

solar wind

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

Radation

the emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles that cause ionization.

Convection

the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

transition region

the region in the Sun's atmosphere where the temperature rises very rapidly from the relatively low temperatures that characterize the chromosphere to the high temperatures of the corona

granulation

the rice-grain-like structure of the solar photosphere; granulation is produced by upwelling currents of gas that are slightly hotter, and therefore brighter, than the surrounding regions, which are flowing downward into the Sun

sunspot cycle

the semiregular 11-year period with which the number of sunspots fluctuates

As originally suggested by Wolfgang Pauli, neutrinos have the following property: (Select the best answer)

they travel almost at the speed of light

helioseismology is the study of pulsations or oscillations of the Sun in order to determine the characteristics of the solar interior

true