Astronomy: The Sun (Unit 2) Flashcards
Plasma Definition
A super-heated gas in which the particles are ionized
Using technologies such as radio and X-ray astronomy, what have scientists been able to identify about the sun?
Scientists have been able to identify 6 layers that make up the sun, arranged from the center outward
How do astronomers and astrophysicists estimate the arrangement and properties of the sun’s layers?
By combining known facts with theoretical models of the sun’s composition
What are the first three layers of the sun?
The core, radiative zone, and convection zone
What do the core, radiative zone, and convection zone form?
The sun’s inner structure
What is the sun’s core?
The core is the innermost layer where the sun’s energy is produced by fusion reactions
Where does the energy produced in the sun’s core travel to?
The energy from the core travels slowly through the dense 2nd layer, the radiative zone
What happens in the convection zone of the sun?
In the 3rd layer, the convection zone, huge currents form and bubbles of hot plasma rise to the surface
What are the sun’s outer three layers and what do they form?
The sun’s outer three layers — photosphere, chromosphere, and corona - form it’s atmosphere, the part we see from earth
In which layer of the sun does visible light appear?
The photosphere
What happens in the chromosphere?
The chromosphere, above the photosphere, emits a bright red glow as hydrogen burns off
What does the corona of the sun do?
The corona, which surrounds the sun, helps release the sun’s heat into space
When are the chromosphere and corona visible to us?
They are only visible to us during a total solar eclipse
True or False: The temperatures of each of the layers of the sun varies
True
How does the temperature of each layer of the sun vary?
The core is the hottest layer, with a temperature of 15.7 million K (28 million degrees Fahrenheit). Temperatures then decrease through the radiative and convection zones until they reach 5,800 K (10,000 degrees Fahrenheit) in the photosphere. Temperatures then rise again through the chromosphere and the corona. Scientists have yet to explain this pattern
What is the core composed of?
Plasma
How much of the sun’s radius does the radiative zone make up?
3/4
What happens in the radiative zone?
In the radiative zone, energy from the core moves outward as thermal radiation, which bounces and zig-zags as it makes its way toward the surface
What is the only visible layer of the sun from Earth without instruments?
The photosphere
Which layer of the sun may have sun spots?
The photosphere
What is the corona composed of?
Hot plasma
Why is Earth the only planet known to have complex life?
Earth is the only planet known to have complex life, since it is in the sun’s habitable zone, where the right amount of energy from the sun is available
About how old is the sun? How long with its remaining fuel last?
The sun is about 5 billion years old and has enough fuel to continue for another 5 billion years
What is evidence for the sun’s energy transfer through its layers?
The energy enters Earth’s atmosphere, the plants then capture that energy, and then the animals receive then energy by eating the plants
What is the element that fuels the sun? What is in the center of this element’s atoms?
Hydrogen is the elements that fuels the sun, and the center of each hydrogen atom is its nucleus
When is most of the sun’s energy released?
Most of the energy that the sun emits is released when a strong gravitational attraction between hydrogen nuclei squeezes the nuclei together. With enough pressure, 4 hydrogen atoms can undergo nuclear fusion and form a helium atom, with the release of tremendous amounts of stored energy and gamma rays
Where does the rest of the energy emitted by the sun come from, when not from nuclear fusion reactions in hydrogen?
Fusion reactions involving other types of atoms
When the sun’s energy is released, through what regions does it travel?
It travels through the layers of the sun, through space, then to Earth
Nuclear Fusion Definition
A reaction in which atoms combine and release large amounts of energy
In nuclear fusion, where is energy released from?
Matter
Why does nuclear fusion occur in the core of the sun?
Because it is under so much pressure
What does the magnetosphere of earth do?
Charged particles, known as solar wind, travel outward from the sun in all directions, along with its energy, and the magnetosphere protects the atmosphere from being completely stripped away by solar wind while allowing the solar energy through
Solar energy radiates in all directions from the sun’s surface in the form of what?
Solar energy radiates in all directions from the sun’s surface as “electromagnetic radiation”. It travels at the speed of light and reaches earth’s surface in 8 minutes
True or False: the surface of the sun is a very active, high energy place
True
How is the sun’s release of radiation? Is it constant? Is it uniform?
The sun’s release of radiation is constant but not always uniform. When electrically charged gases move, they produce magnetic fields that are in constant motion. Depending on the motion of the magnetic fields, sporadic intense discharges of energy and matter occur.
Aurora Definition
Lights caused by interaction between particles from the sun and Earth’s atmosphere
True or False: The surface of the sun is full of energy, electrically charged particles, and magnetic fields
True
In some regions of the sun, with particularly strong magnetic fields, what happened as the magnetic fields get tangled?
In some regions, magnetic fields are particularly strong, and they can become twisted and tangled and produce solar flares that eject electromagnetic radiation into space
Coronal Mass Ejections occur near what other space event?
Massive bubbles of radiation and particles, called coronal mass ejections (CMEs), sometimes occur near solar flares. These bubbles explode and send energy and matter shooting into space
What can strong solar flares disturb on Earth?
Radio signals
What occurs on earth due to the interaction of charged particles from CMEs and Earth’s magnetic field?
CMEs emit charged particles, which are deflected by Earth’s magnetic field, causing auroras in the North and South poles
What is the order of energy release from the sun’s core to Earth?
Fusion, Radiation, Convection, Radiation
How did Galileo Galilei contribute to the study of sun spots?
Galileo Galilei measured and recorded the distance the black dots had moved since his last observation and calculated the rate they traveled across the sun
Was Galileo the first person to observe sunspots?
Galileo was not the 1st person to observe sunspots, but in 1610 he was the first to study them through a telescope and publish his findings
What was Galileo’s occupation?
He was an Italian physicist and astronomer
What did a contemporary scientists claim about sunspots? How did Galileo prove this wrong?
A contemporary scientists claimed that sunspots were planets, that were revolving close to the sun, but Galileo proved they were just apart of the sun’s surface, using his observations
The activities visible one the surface of the sun can be explained by what?
The sun’s magnetic properties
What is most of the matter in the universe made up of ?
Plasma
What is plasma?
Plasma is matter that has been heated to such a degree that some of the electrons are stripped off their atoms, resulting in a swirling mass of charged particles
True or False: A flow of electrically charged particles can generate a magnetic field
True
How does the sun rotate, due to it being made up plasma?
Since the sun is made of plasma, it does not rotate evenly: a point on the sun’s equator takes 25 days to make a full rotation, while a point on the poles takes up to 35 days
Due to its rotation, what is happening to the plasma within the sun?
It is constantly mixed and churned
What forms due to the differential rotation of the sun?
The differential rotation of plasma results in magnetic fields that ebb and flow. This system that produces the magnetic fields of the sun is called the solar dynamo, named after the device that generates electric current via a moving magnetic field
What happens when churning magnetic fields pop out of the sun’s surface?
Often, the churning magnetic fields pop out of the sun’s surface, acting like horseshoe magnets with a positive and a negative end. These regions, called sunspots, are slightly cooler that the rest of the sun’s surface, so they appear dark in comparison
Why are the sun’s features always changing?
Due to its complex magnetic field
How is the magnetic field of Earth?
Earth has a fairly stable magnetic field, with a single pair of magnetic poles
How is the magnetic field of Earth formed?
Earth’s magnetic field is created by movement of its liquid outer core around its solid inner core
True or False: The sun sometimes has more than one North Pole
True
How is the sun’s magnetic field created?
The sun’s magnetic field is created by movement in its outer layer, the convection zone
When the sun’s magnetic field gets tangled, what happens to convection?
When the sun’s magnetic field gets tangled, convection is inhibited, creating sunspots
How do sunspots appear as pairs?
Sunspots always appear in pairs; one with a magnetic North Pole and one with a magnetic South pole
What happens as the sun’s magnetic energy builds up?
When the sun’s magnetic energy builds up, it must release it as a solar flare. A solar flare is a sudden explosion of energy from the sun’s surface
What happens when the sun has billions of tons of matter to be released from its magnetic field?
When the sun has billions of tons of matter to be released from its magnetic field, a CME is sent out. CMEs can travel at millions of miles per hour
What do models, that scientists use to show the sun’s magnetic fields, appear?
Scientists use computer-generated models in which open field lines are represented by purple and green lines and closed field lines, in the form of loops, are yellow