Explorations (An Introduction to Astronomy)

Sun's Gravity

Sun's Gravity

The enormous force that crushes matter in the Sun's interior and prevents its collapse.

High Temperature

Necessary for the Sun to replenish its energy by consuming itself.

Gaseous State

The Sun remains gaseous due to high temperatures that vaporize most molecular bonds.

Photosphere

The visible surface of the Sun that helps retain heat and reduces fuel consumption.

Radiative Zone

The layer near the Sun's core where energy moves outward by radiation carried by photons.

Convection Zone

The layer where energy is transported through rising and sinking gases, creating granulation.

Chromosphere

The lower atmosphere of the Sun, characterized by spicules and a red color from hydrogen emission.

Corona

The outer atmosphere of the Sun, with high temperatures and low density, containing hot streamers along magnetic fields.

Hydrostatic Equilibrium

The balance between the inward force of gravity and the outward pressure from atomic motion in the Sun.

Nuclear Fusion

The process that powers the Sun, where hydrogen nuclei fuse to form helium under high temperatures.

Proton-Proton Chain

The series of reactions in nuclear fusion that convert hydrogen into helium and release energy.

Solar Neutrinos

Particles released during fusion that indicate the rate of hydrogen conversion into helium and help deduce core conditions.

Solar Seismology

The study of waves in the Sun's atmosphere to analyze its interior structure and dynamics.

Solar Magnetic Fields

Strong magnetic fields generated by the rotation of hot ionized gas within the Sun.

Sunspots

Dark regions on the Sun's surface that are cooler and indicate concentrated magnetic fields.

Prominences

Large plumes of glowing gas that extend from the lower chromosphere into the corona, cooler than surrounding gas.

Solar Flares

Brief eruptions of hot gas in the chromosphere, linked to magnetic field dynamics.

Coronal Mass Ejections (CMEs)

Large clouds of plasma ejected from the Sun's corona due to magnetic field reorganization.

Solar Wind

A flow of mainly hydrogen and helium that escapes the Sun due to high temperatures in the corona.

Solar Cycle

The periodic variation in the number of sunspots, influenced by the Sun's differential rotation and magnetic field dynamics.

• why magnetic fields grow so concentrated in sunspots?

• tight connection between magnetic fileds and gas.

• draws surrounding gas toward it, cause magnetic field is frozen into gas, magnetic filed is dragged inward and grows more concentrated.

CMEs usually occur when

magnetic field lines in the Sun's corona become twisted and tangled due to the Sun's rotation and other dynamic processes.

How big is the SUn compared to the Earth?

About 333,000 weighs times the weight of Earth 

How Can we measure the SUn’s size, mass, and temperature?

Through theory and measurement. Combination of observations, physics, and math calculations. Temperature can be found by using color and Wien’s law.

1. What is the Sun made of? How do we know this?

1. The Sun is made out of various gases. Most prominent of which are Hydrogen, Helium, and other heavy elements. This can be found through spectroscopy. 

1. What holds the Sun together?

Gravity

1. Why doesn’t the Sun collapse?

1. The Hydrostatic equilibrium holds the Sun together. It’s a balance of inward force(Sun’s own gravity) and an outward force (rapid motion of its atoms aka pressure). The balance of inward pull of gravity and the outward push of pressure. 

1. Why must the interior of the Sun be so hot?

1. Because if the interior of the Sun is not hot enough, the Sun would shrink and collapse on its own gravity. The Sun is powered through nuclear fusion which requires a high temperature. 

1. How does energy get to the Sun’s surface from its core?

1. The energy takes a complex route. From the core through radiation(constant emission and absorption) to the surface to the convection zone through convection currents and movement of hot plasma carry the energy to the surface.

1. What visible evidence do we have that the Sun has a convection zone?

1. The granulation on its surface. 

1. What are the photosphere, chromosphere, and corona? Which of these layers is hottest? How do we know this?

1. Photosphere: the lowest atmosphere of the sun(the visible surface of the sun). Chromosphere: Second layer of the atmosphere above the photosphere, and contains millions of spicules. Corona: the outermost layer of the atmosphere, and the hottest layer. 

1. How is solar energy generated? In what form does it leave the core?

1. Solar energy is generated through the process of nuclear fusion. It leaves the core of the Sun as photons?

1. Explain the “solar neutrino problem,” and how its resolution was a good example of the scientific process.

1.  The “solar neutrino problem” was a major puzzle in astrophysics that arose when early experiments to detect neutrinos from the Sun found far fewer neutrinos than theoretical models predicted. 

1. What is solar seismology? What does it tell us about the Sun?

1. Solar seismology is studying the Sun’s interior by analyzing waves in the Sun's atmosphere.can measure the density and rotations deep within the sun from the pattern and speed of waves in the atmosphere.

1. What is meant by solar activity?

1. Solar phenomenon caused by its magnetic field, prominences, sunspots, and flares

1. What role does magnetic activity play in solar activity? 

1. It drives the formation of sunspots and triggers solar flares and coronal mass ejections. 

1. Why do sunspots appear dark?

1. Because that region is cooler than the surrounding area. 

1. How do prominence and a flare differ?

1. Prominences are huge plumes of glowing gas that jut from the lower chromosphere into the corona, they’re stable loops and constant. Solar flares are sudden, intense bursts of radiation and energy, extremely hot plasma. Prominences doesn’t travel through space but solar flares do. 

1. How do we know there are magnetic fields in the Sun?

1. It’s confirmed through various methods like the Zeeman Effect, and solar flares. 

1. What is the period between maximum sunspot numbers? How does this differ from the full solar cycle?

1. Solar cycle lasts about 11 years. The maximum sunspot is half so around 5 to 6 years. 

1. What is the Maunder minimum? Why is it of interest?

Period of less number of sunspots. Because it correlates with periods of little ice ages. Helps with the prediction and understanding of the natural changing climate of the earth. 

1. The Sun is supported against the crushing force of its own gravity by 

   a. Magnetic forces 

   b. Its rapid rotation 

   c. The force exerted by escaping neutrinos

   d .Gas pressure 

   e. The antigravity of its positrons.

d

1. The Sun produces its energy from

   a. fusion of neutrinos into helium.

   b.     fusion of positrons into hydrogen.

   c.     disintegration of helium into hydrogen.

   d.     fusion of hydrogen into helium.

   e.    electric currents generated in its core.

d.

1. According to the ideal gas law, if the temperature of a gas is made 4 times higher, which of the following is a possible result? (More than one answer may be correct.)

   a.  Its pressure increases by 4 times and its density remains the same.

   b.     Its density increases by 4 times and its pressure remains the same.

   c.     Its pressure and density both double.

   d.    Its pressure increases by 4 times while its density decreases by 4 times.

   e.    Its pressure and density both decrease by 2 times.

a.

1. During the daytime, about a trillion solar neutrinos per second pass through you. At night, the number is

   1.  zero.

   2.  about half as much.

   3.  about the same.

   4.  much, much smaller.

2.

1. The primary method astronomers use to measure oscillations on the surface of the Sun is by

   1.  comparing telescopic images.

   2.     magnetograms from measuring Zeeman splitting of spectral lines.

   3.     measuring the Doppler shift of absorption lines from the surface.

   4.     X-ray and ultraviolet i

3.

1. Sunspots are dark because

   1. they are cool relative to the gas around them.

   2.     they contain 10 times as much iron as surrounding regions.

   3.     nuclear reactions occur in them more slowly than in the surrounding gas.

   4.     clouds in the cool corona block our view of the hot photosphere.

   5.     the gas within them is too hot to emit any light.

1.

1. Differential rotation results in

   1.   the solar wind

   2.     a wound-up magnetic field.

   3.     the Maunder minimum.

   4.     the Sun's generation of energy.

   5.     All of the above.

2.

1. About how many years elapse between times of maximum solar activity?

   1. (a) 3

   2.  5

   3. 11

   4.  33

   5.  105

3.