Astronomy Unit 7: The Sun

True/False: The balance of gravity pulling outward at the same time pressure is pushing in is known as gravitational equilibrium

False--it's the opposite

Given that the Sun is estimated to be about 5 billion years old, scientists estimate that we are about halfway through its lifetime. This means that the Sun's lifetime is expected to be what length of time?

10 billion years

What is a solar eclipse?

A solar eclipse happens when the Moon is between the Sun and the Earth, and it blocks the light, so the Sun appears black. There are two types of solar eclipses: a full eclipse (the Moon completely blocks the Sun), and a partial or annular eclipse (the Moon partially blocks the Sun). Solar eclipses only happen when the Moon and Sun share the same longitude.

As the Sun ages, what will happen to life here on Earth? Why?

As the Sun ages, it will become a red giant; its core will become denser and hotter, creating carbon from helium nuclei. Then the Sun will shed its outer layers, cool down, and fade, becoming a white dwarf star. The planets of the Solar System will move away from the Sun as it ages. However, scientific evidence suggests that Earth will be consumed by the Sun, when it becomes a red giant. If that scenario does not happen, the Earth will become uninhabitable due to the Sun's rising temperature, resulting in Earth being too hot to maintain liquid water.

True/False: The Sun is composed entirely of oxygen and helium

False

True/False: The Sun is divided into 3 regions

False

True/False: The Sun's radius is about 100 times the radius of the Milky Way

False

True/False: The chromosphere is the lowest layer of the Sun's atmosphere

False

How does the Sun manage to maintain an environment in its core that is conducive to nuclear fusion?

Gravitational equilibrium helps maintain the environment in the Sun's core that is conducive to nuclear fusion. The Sun's gravitational equilibrium balances the gravity pulling inward and the pressure pushing outward. It keeps the Sun's size, denseness, and hotness stable, thus making nuclear fusion possible. Then nuclear fusion creates energy that pushes outward, balancing the gravity pulling inward. Even if more or less energy were released in the Sun's core, gravitational equilibrium would eventually balance the forces and allow nuclear fusion to presume at its normal rate.

The sunspot cycle is a pattern of solar activity where the average number of sunspots gradually _______________ and ________________

Increases, decreases

About 4 million tons of ____________ are converted to energy in the Sun's core every second

Matter

What is nuclear fusion? What role does nuclear fusion play in the Sun?

Nuclear fusion is when two atomic nuclei combine and form one nucleus. Nuclear fusion generates all of the Sun's energy. Inward pulling by the Sun's gravity is counteracted by outward pushing by the Sun's nuclear fusion; this balance keeps the sun from collapsing or exploding.

How can solar weather affect our lives on Earth?

Solar weather can affect life on Earth through solar flares and coronal mass ejections. The X-rays emitted during solar flares can affect radio communications, some can cause radio blackouts. Coronal mass ejections can cause geomagnetic storms in the Earth's magnetosphere. These storms can cause power outages and damage to satellites and radio communication. However, coronal mass ejections can also cause the Northern Lights to appear during geomagnetic storms. Solar weather can cause beautiful sights, but expensive damages to technology.

How are sunspots and solar flares similar? How are they different?

Sunspots are small, cool, dark spots that can be seen in the Sun's photosphere; they can last for a few weeks. Solar flares are extremely hot explosions into the Sun's atmosphere; the human eye can not see them. Solar flares have three stages, which can last a few seconds to a few hours. Both sunspots and solar flares occur in the areas above and below the Sun's equator; they are caused by active regions in the Sun's magnetic fields.

What does the Sun orbit?

The center of the Milky Way

The photosphere is the what?

The lowest layer of the Sun's atmosphere

What is the proton-proton chain reaction? Describe this process.

The proton-proton chain reaction is the process in which energy is created from nuclear fusion. First, two hydrogen nuclei (protons) combine (one of the hydrogen nuclei is converted into a neutron), forming a deuterium nucleus. The deuterium nucleus and an additional proton combine, creating a helium-3 nucleus. Then two helium-3 nuclei combine, forming a helium-4 nucleus. This whole process converts hydrogen atoms into less dense helium atoms. The loss in density results in left-over mass which is converted into energy. This energy is released from the Sun's surface, providing sunlight.

What are the 6 regions of the Sun?

There are six regions of the Sun. The inner regions include the core, radiative zone, and convective zone. The outer regions include the visible surface (photosphere), chromosphere, and corona.

True/False: The Sun is the centermost star of our solar system

True

True/False: The Sun orbits the center of the Milky Way

True

True/False: The core of the Sun is the interior or center part of this star

True

When the Sun is in its maximum solar cycle, what occurs?

Up to 3 CMEs are created in one day

Imagine that you are traveling in a spaceship to the center of the Sun. What would you experience and see in each of the Sun's regions?

While traveling in a spaceship to the center of the Sun, I would notice that it is divided into six regions. From outer to inner, the Sun's regions include the corona, chromosphere, photosphere, convective zone, radiative zone, and the core. At the corona, which is the outer layer of the Sun's atmosphere, I would notice that it is hotter than the surface of the Sun. I might find coronal holes, through which streams of solar wind flow into space. At the chromosphere, which is the inner layer of the Sun's atmosphere, I would notice that its name (which means color) is appropriate because it looks bright red during a solar eclipse. At the photosphere, which is the glowing surface of the Sun, I would notice that it is made of plasma, not solid matter. I would be surprised to discover that the photosphere is cooler than the Sun's atmosphere. I might see sunspots, which are disturbances of magnetic fields in the photosphere. Sunspots are dark in color because their temperatures are cooler than the surface. I might also see solar flares, which are explosions that occur in magnetically active areas around sunspots. At the convective zone, I would notice the Sun's energy transfer outward through convection. There would be a temperature difference, getting hotter the further down I travel. This temperature difference would cause energy to circulate, similar to water boiling. At the radiative zone, I would notice the Sun's energy transfer outward through radiation. And finally, at the core, I would notice extreme temperatures being produced through nuclear fusion. Traveling through the sun would allow me to witness how the Sun's light and heat originates in the core and makes its way toward the surface and eventually into space.