according to modern science, approximately how old is the sun?

according to modern science, approximately how old is the sun?


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Asked by 2 years ago
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In the late 1800s, Kelvin and Helmholtz suggested that the Sun stayed hot due to gravitational contraction. What was the major drawback to this idea?It predicted that the Sun could shine for about 25 million years, but geologists had already found that Earth is much older than this.
When is/was gravitational contraction an important energy generation mechanism for the Sun?It was important when the Sun was forming from a shrinking interstellar cloud of gas.
What do we mean when we say that the Sun is in gravitational equilibrium?There is a balance within the Sun between the outward push of pressure and the inward pull of gravity.
What do we mean when we say that the Sun is in energy balance?The amount of energy released by fusion in the Sun's core equals the amount of energy radiated from the Sun's surface into space.
Which of the following is the best answer to the question, "Why does the Sun shine?"As the Sun was forming, gravitational contraction increased the Sun's temperature until the core become hot enough for nuclear fusion, which ever since has generated the heat that makes the Sun shine.
How does the Sun's mass compare to Earth's mass?The Sun's mass is about 300,000 times the mass of the Earth.
Which of the following best describes why the Sun emits most of its energy in the form of visible light?Like all objects, the Sun emits thermal radiation with a spectrum that depends on its temperature, and the Sun's surface temperature is just right for emitting mostly visible light.
The Sun's surface seethes and churns with a bubbling pattern. Why?We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the surface.
Which of the following correctly compares the Sun's energy generation process to the energy generation process in human-built nuclear power plants?The Sun generates energy by fusing small nuclei into larger ones, while our power plants generate energy by the fission (splitting) of large nuclei.
Every second, the Sun converts about 600 million tons of hydrogen into 596 million tons of helium. The remaining 4 million tons of mass is _________.converted to an amount of energy equal to 4 million tons times the speed of light squared
Which of the following best explains why nuclear fusion requires bringing nuclei extremely close together?Nuclei normally repel because they are all positively charged and can be made to stick only when brought close enough for the strong force to take hold.
If the Sun's core suddenly shrank a little bit, what would happen in the Sun?The core would heat up, fusion rates would increase, the core would re-expand.
Why does the Sun emit neutrinos?Fusion in the Sun's core creates neutrinos.
If the Sun suddenly stopped emitting neutrinos, what might we infer (after checking that our neutrino detectors were still operational)?Fusion reactions in the Sun have ceased within the past few minutes.
Which of the following best explains why the Sun's luminosity gradually rises over billions of years?Fusion gradually decreases the number of independent particles in the core, allowing gravity to compress and heat the core, which in turn increases the fusion rate and the Sun's luminosity.
Why do sunspots appear dark in pictures of the Sun?They actually are fairly bright, but appear dark against the even brighter background of the surrounding photosphere.
How can we best observe the Sun's chromosphere and corona?The chromosphere is best observed with ultraviolet telescopes and the corona is best observed with X-ray telescopes.
The intricate patterns visible in an X-ray image of the Sun generally show _________.extremely hot plasma flowing along magnetic field lines
How can we measure the strength of magnetic fields on the Sun?By looking for the splitting of spectral lines in the Sun's spectrum.
Satellites in low-Earth orbits are more likely to crash to Earth when the sunspot cycle is near solar maximum because _________.Earth's upper atmosphere tends to expand during solar maximum, exerting drag on satellites in low orbits
Which of the following choices is not a way by which we can study the inside of the Sun?We can send a space probe into the Sun's photosphere.
A computer accessory salesman attempts to convince you to purchase a "solar neutrino" shield for your new computer. (It's even "on sale" !) Why do you turn down this excellent offer?Neutrinos rarely, if ever, interact with your computer.
According to modern science, approximately how old is the Sun?4 1/2 billion years
The Sun will exhaust its nuclear fuel in about ______.5 billion years
Which of the following correctly describes how the process of gravitational contraction can make a star hot?When a star contracts in size, gravitational potential energy is converted to thermal energy.
What two physical processes balance each other to create the condition known as gravitational equilibrium in stars?gravitational force and outward pressure
The source of energy that keeps the Sun shining today is _________.nuclear fusion
Energy balance in the Sun refers to a balance between _________.the rate at which fusion generates energy in the Sun's core and the rate at which the Sun's surface radiates energy into space
When we say that the Sun is a ball of plasma, we mean that _________.the Sun consists of gas in which many or most of the atoms are ionized (missing electrons)
What is the Sun made of (by mass)?70% hydrogen, 28% helium, 2% other elements
From center outward, which of the following lists the "layers" of the Sun in the correct order?Core, radiation zone, convection zone, photosphere, chromosphere, corona
What are the appropriate units for the Sun's luminosity?watts
The Sun's surface, as we see it with our eyes, is called the _________.photosphere
The Sun's average surface (photosphere) temperature is about ______.5,800 K
What is the solar wind?a stream of charged particles flowing outward from the surface of the Sun
The fundamental nuclear reaction occurring in the core of the Sun is _________.nuclear fusion of hydrogen into helium
The proton-proton chain is _________.the specific set of nuclear reactions through which the Sun fuses hydrogen into helium
The overall result of the proton-proton chain is:4 H becomes 1 He + energy
To estimate the central temperature of the Sun, scientists _________.use computer models to predict interior conditions
Why are neutrinos so difficult to detect?They have a tendency to pass through just about any material without any interactions.
The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about _________.a few hundred thousand years ago
What happens to energy in the Sun's convection zone?Energy is transported outward by the rising of hot plasma and sinking of cooler plasma.
What do sunspots, solar prominences, and solar flares all have in common?They are all strongly influenced by magnetic fields on the Sun.
Which of the following is not a characteristic of the 11-year sunspot cycle?The sunspot cycle is very steady, so that each 11-year cycle is nearly identical to every other 11-year cycle.
How is the sunspot cycle directly relevant to us here on Earth?Coronal mass ejections and other activity associated with the sunspot cycle can disrupt radio communications and knock out sensitive electronic equipment.
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