Astronomy: The Sun Review Flashcards

Questions and Answers

What is the temperature of the Sun's core?

15 million K (27 million degrees Fahrenheit)

What is the temperature at the surface of the Sun?

5780 K (9900 degrees Fahrenheit)

What is the Sun composed of?

71% hydrogen, 27% helium, 2% heavier elements

What is the most abundant element in the Sun?

Hydrogen Signup and view all the answers

Why are there only small amounts of elements heavier than helium in the Sun?

The Sun is massive enough to hold large amounts of hydrogen and helium, leaving smaller percentages for heavier elements. Signup and view all the answers

What is the photosphere?

The outer layer of the Sun that we see Signup and view all the answers

What is the purpose of the photosphere?

It helps the Sun to retain its heat thereby reducing how much of its fuel it uses. Signup and view all the answers

How does density change as you move towards the core of the Sun?

Density increases Signup and view all the answers

How does temperature change as you move towards the core of the Sun?

Temperature increases Signup and view all the answers

What are the three zones of the Sun?

Core, radiative zone, and convection zone Signup and view all the answers

How is energy moved in the core of the Sun?

Through nuclear fusion reactions Signup and view all the answers

What causes light to slow down as it moves from the core to the surface of the Sun?

Constant absorption and re-emission by atoms Signup and view all the answers

How long does it take for light to reach the surface of the Sun?

About 1 million years Signup and view all the answers

What is granulation in the Sun?

Narrow darker zones in the convection zone Signup and view all the answers

Why do granules appear darker?

They are cooler than the surrounding areas Signup and view all the answers

What is the chromosphere?

The lower atmosphere of the Sun Signup and view all the answers

What is the temperature of the chromosphere?

Ranges from 4500 K to 50,000 K Signup and view all the answers

When is the chromosphere seen and what does it look like?

During a total solar eclipse as a thin red zone around the Sun Signup and view all the answers

What are spicules?

Thin columns of hot gas within the chromosphere Signup and view all the answers

What is the corona?

The outermost layer of the Sun's atmosphere Signup and view all the answers

What is the temperature of the corona?

About 1 million K Signup and view all the answers

What are coronal holes?

Huge regions of cooler gas where gas escapes into space Signup and view all the answers

What is hydrostatic equilibrium?

The force that balances the outward push of the Sun with the inward gravitational force Signup and view all the answers

What is the pressure in the core of the Sun?

About 150 g/cm^3 Signup and view all the answers

What powers the core of the Sun?

Nuclear fusion Signup and view all the answers

What is nuclear fusion?

When atoms fuse together to release energy Signup and view all the answers

What kinds of temperatures do you need for fusion?

Very high temperatures (occurs at only the core) Signup and view all the answers

What are solar neutrinos?

Electron neutrinos produced in the Sun as a result of nuclear fusion Signup and view all the answers

Why are solar neutrinos hard to detect?

They have no charge or mass and tend to pass through matter without interacting Signup and view all the answers

What are sunspots?

Large, dark regions on the surface of the Sun Signup and view all the answers

How long do sunspots last?

From a few days to over a month Signup and view all the answers

What are the temperatures of sunspots?

About 4500 K Signup and view all the answers

How are sunspots used to measure the rotation of the Sun?

By tracking their movement across the surface Signup and view all the answers

Why are sunspots cooler than the rest of the Sun?

They are areas of reduced temperature due to magnetic activity Signup and view all the answers

What causes sunspots?

Magnetic activity within the Sun Signup and view all the answers

Study Notes

Sun's Core and Surface Temperature

The core temperature of the Sun reaches approximately 15 million K (27 million degrees Fahrenheit).
The surface temperature is about 5780 K (9900 degrees Fahrenheit).

Composition of the Sun

Composed of approximately 71% hydrogen, 27% helium, and 2% heavier elements.
Hydrogen is the most abundant element.
Heavier elements are scarce due to the Sun's mass supporting primarily hydrogen and helium.

Photosphere

The photosphere is the visible outer layer of the Sun.
It functions to retain heat, reducing fuel consumption.
Density and temperature both increase towards the Sun's core.

Energy Zones in the Sun

The Sun consists of three zones: core, radiative zone, and convection zone.
The core, where nuclear fusion occurs, is the hottest zone.
The radiative zone promotes energy movement through photon emission by capturing ions.
The convection zone features rising and falling hot plasma.
Energy transitions from the core to the surface take around 1 million years, slowing due to constant absorption and re-emission.

Granulation

Granulation consists of narrow darker zones within the convection zone, representing cooler areas.
Bright areas depict hot gases rising from the interior.

Chromosphere

The chromosphere is the lower atmosphere of the Sun, visible as a thin red layer during a total solar eclipse.
Temperature ranges from 4500 K to 50,000 K at about 2000 km height.
Spicules are thin columns of hot gas observed within this layer.

Corona

The corona is the outermost solar layer, reaching temperatures around 1 million K.
Coronal holes are cooler regions where gas escapes into space, only visible during a total solar eclipse.

Hydrostatic Equilibrium

Hydrostatic equilibrium balances the Sun's outward pressure with inward gravitational forces.
The core pressure is approximately 150 g/cm³ and is driven by nuclear fusion.

Nuclear Fusion

Nuclear fusion involves the fusing of atoms to release energy and requires extremely high temperatures, typically occurring only in the core.
Fusion primarily transforms hydrogen (1 proton) into helium (2 protons and 2 neutrons).

Solar Neutrinos

Solar neutrinos are electron neutrinos produced during nuclear fusion in the Sun.
Their detection is challenging due to their lack of charge and mass, leading them to pass through matter unimpeded.
Fewer neutrinos are observed than expected, suggesting either gaps in solar understanding or unknown neutrino properties.

Sunspots

Sunspots are large, dark regions lasting from days to over a month, cooler at about 4500 K.
Their existence is linked to the Sun's rotation; sunspots appear and disappear in relation to solar rotation.
Sunspots form due to magnetic activity that inhibits convection, resulting in cooler temperatures compared to surrounding areas.

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Description

Test your knowledge about the Sun with these review flashcards. Learn about its core temperature, surface temperature, composition, and more. This quiz will help reinforce your understanding of solar physics and the Sun's characteristics.