Astronomy Chp 9

What are the three steps of the proton to proton chain?

1. Two protons combine and form a deuteron, and release a positron and a neutrino. 2. The deuteron combines with another proton to create helium-3. The positron annihilates with an electron and produces gamma rays. The neutrino escapes into space. 3. Two helium-3 nuclei combine to form helium-4 and two protons.

What percentage of the Sun's mass is not hydrogen or helium?

1.9%

about how long does it take for the sunspot cycle to complete?

11 years

What is the solar constant value?

1400 W/m^2

How long is the solar cycle?

22 years

What is the solar constant value?

3.86x10^26 W

How massive is the Sun compared to Earth?

300,000 times more massive

What are the ingredients and the end result of the proton-proton chain? Why is energy released in the process?

4 hydrogen to one helium. Energy is released because mass is missing and E=Mc^2

How far is Alpha Centauri from Earth?

4.3 light years away

What percent of Sun's energy reaches the Earth?

50-70 percent

What is the thickness of the photosphere?

500 km

What is Sun's accepted surface temperature?

6000 K

How hot is the solar surface? The solar core?

6000K, 15 million K

What is the radius of the Sun?

700,000 km

How far is the Sun from Earth?

8 light minutes away

What is the next nearest star to Earth, other than the sun?

Alpha Centauri

What is nuclear fusion?

Combining of light nuclei into heavier ones produces a great amount of energy

List the zones of the Sun from inside to out.

Core, radiation zone, convection zone, photosphere, chromosphere, transition zone, corona

When can the corona be seen?

During an eclipse

What is the law of conservation of mass and energy? How is it relevant to nuclear fusion in the Sun?

Energy is neither created nor destroyed, but transformed. The sun's gravitational energy increases pressure as the catalyst for fusion, which releases a large amount of energy.

Describe how energy from the solar core eventually reaches earth.

It's generated at the core, it goes through the radiation zone as radiation energy, then it's released through the convection zone as rising hot gas then it leaves the photosphere as thermal radiation

Why are observations of solar neutrinos important to post astronomers and physicists?

The amount, type, and rate of production of neutrinos give a story of how the sun produces energy by fusion. This is at the core, where no other method can let scientists measure.

Why do we see the photosphere?

The gas is opaque

Why are X-ray telescopes used to observe the corona?

The high heat of the corona radiates at very high frequencies, primarily x-ray.

Why does the Sun appear to have a sharp edge?

The photosphere is thin compared to other regions.

Describe the solar corona

Thin upper atmosphere of the sun. Its gas escapes the sun's gravity, because of its heat. Flows outward as "solar wind"

What fuels the Sun's enormous energy output?

a balance between gravity and nuclear fusion

How often does the sun complete rotation?

a month

What is a coronal mass ejection?

a part of coronal gas that is thrown into space from the sun

What is nuclear fusion?

a process in which two or more atomic nuclei combine and release energy

What are flares?

an explosion on the sun's surface that sweeps across an active region in a matter of minutes.

Where does the sun spin fastest?

at the equator

How is helioseismology used to model the Sun?

by measuring the waves and vibrations on the Sun's surface, we are able to find physical properties of the Sun's internal makeup and its internal rotation

How is the suns luminosity measured?

by multiplying the solar constant by the total surface area of our imaginary sphere= 4 x 10^26 W

What is the cause of sunspots, flares, and prominences?

changes in the magnetic field.

What element is the Sun consuming for fuel and what element is the result?

consuming hydrogen, result is helium

In which way of energy transport is there physical movement of gas?

convection

What are sunspots?

cooler regions of the photospheric gas

Where does nuclear fusion occur?

core

What are the low-density regions of the sun?

coronal holes

What method showed astronomers about the sun's vibration?

doppler shift of spectral lines

What is the physical nature of sunspots?

earth-sized regions of magnetism

True or false: The sun contains solid material?

false

What evidence to we have for solar convection?

granulation

What is the result of the motion of the convection zone?

granulation

What other type of wave can solar activity disrupt?

high-frequency radio communication, due to a large solar flare

What are the two most abundant elements in the sun?

hydrogen and helium

What would we observe on Earth if the Sun's internal energy suddenly shut off? How long do you think it would take for the Sun's light to begin to fade?

idk

If nuclei repel, how do two protons fuse into something heavier?

if they collide at a high enough speed, one proton can momentarily plow deep into the other, coming into the range of strong nuclear force

In what way do sunspots typically appear?

in pairs

What happens to mass during a fusion reaction?

it decreases

What happens to the sun's magnetic field after a cycle completes?

it reverses

What are prominences?

loops or sheets of glowing gas ejected from an active region of the solar surface

What is the sun powered by?

nuclear fusion

What two layers of the sun do absorption lines give us information about?

photosphere and chromosphere

What color does the chromosphere have when viewed?

pink

What mode of heat transfer carries solar energy from the surface of the photosphere to here?

radiation

What are active regions?

sites of explosive events due to the photosphere erupting

What generally happens in the proton-proton chain?

six protons (and two electrons) are converted to two protons, one helium-4 unless, and two neutrinos.

What cause the Northern and Southern lights?

solar activity inducing large currents in the Earth's magnetic field

What flows away from the Sun and permeates the entire solar system?

solar wind

What is the solar wind, and how is it related to the Sun's outer atmosphere?

solar wind is the outflow of charged particles from the corona, it permeates the solar system

Describe the solar constant

the amount of solar energy received per square meter of area every second at the Earth's distance from the Sun

How does density move through the sun?

the center is the most dense, the outward layers are the least dense

What part of the sun emits x-rays?

the corona

nuclear fusion is an example of what?

the law of conservation of mass and energy

Why is the coronal temperature so high?

the magnetic field activity just above the photosphere

Why do sunspots not take part in convection?

the magnetic field interacts with ionized gas and locks the spot in place

What is the part of the sun that emits the radiation we see?

the photosphere

What does the term solar interior refer to?

the radiation and convection zones

What is helioseismology?

the study of vibrations of the solar surface caused by pressure waves in the interior.

What is luminosity?

the total amount of energy radiated form the solar surface per second.

What do atomic nuclei do when they come into contact?

they repel

How can the Sun's rotation be measured?

timing sunspots and other surface features as they cross the solar disk

True or False: the umbra of a sunspot is still glowing

true

How do sunspots occur?

when a loop of solar magnetic field pops up from the photosphere and makes a loop above the surface

What is hydrostatic equilibrium?

when gas pressure's outward push exactly counteracts gravity's inward pull.

How can sunspots be seen with the naked eye?

when the setting sun is so obscured by dust in the air that it is so dimmed and can be seen