Quiz 3-4 Flashcards
How big is the Sun compared to the Earth?
The diameter of the Sun is about 109 times the diameter of Earth
How much mass does the Sun have compared to the Earth?
300,000 times the mass of Earth
What is the Sun made of?
70% Hydrogen, 28% Helium, 2% heavier elements
Describe how the temperature and density of the Sun change from the center to the visible surface of the Sun.
tba
What keeps the Sun from collapsing under its own gravity?
Gravitational equilibrium: When the outward push of pressure balances the inward pull of gravity. The Sun’s outward push against gravity comes from the internal gas pressure. The Sun’s internal pressure precisely balances gravity at every point within it, thereby keeping the Sun stable in size. Because the weight of overlying layers is greater as we look deeper into the Sun, the pressure must increase with depth. Deep in the Sun’s core, the pressure makes the gas hot and dense enough to sustain nuclear fusion. The energy released by fusion, in turn, heats the gas and maintains the pressure that keeps the Sun in balance against the inward pull of gravity.
What is nuclear fusion and why are high temperatures needed for hydrogen fusion to occur?
Nuclear fusion is the process in which light-weight atomic nuclei smash together and stick (or fuse) to make heavier nuclei. High temperatures are needed because the hotter the temperature, the faster the speed of the of nuclei. At high speeds, nuclei come close enough (collide) for the strong force to bind them together.
How long does it take for a photon to escape the radiation zone in the Sun? Why?
About a million years because energy gradually leaks out of the radiation zone in the form of randomly bouncing photons (radiative diffusion).
What is the solar corona?
The outermost layer of the Sun’s atmosphere which extends several million kilometers above the visible surface of the Sun.
What is the solar wind? What effect does it have on comets?
A flow of charged particles from the surface of the Sun. The solar wind helps shape the magnetospheres of planets and blows back the material that forms the plasma tails of comets.
How does the sun rotate? How does this rotation affect the sun’s magnetic field lines?
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What is a sunspot and how does it form?
Sunspots are dark, cooler regions in the visible surface of the sun. They occur where tightly wound magnetic fields poke nearly straight out from the solar interior. These tight magnetic field line suppress convection within the sunspot and prevent surrounding plasma from entering the sunspot. With hot plasma unable to enter the region, the sunspot plasma becomes cooler than the rest of the photosphere.
What do solar prominences, solar flares, and sunspots have in common?
tba
What is a coronal mass ejection (CME) and how is the Earth protected from them?
CME is when billions of tons of hot gas are blasted into space at hundreds of miles per second. The Earth is protected from them by its magnetosphere (a region around a planet occupied by its magnetic field).
What is the aurora borealis? How is it formed?
When the magnetosphere is overloaded by the flow of charged particles from the Sun, they may cascade toward Earth, producing aurorae.
What is the name of the cells in your eyes that allow you to perceive colors? How many types are there, and which colors are each of them most sensitive to?
tba
