Which of the following best explains why the Sun’s luminosity gradually rises over billions of years group of answer choices?
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.
What would cause the fusion rate in the Sun to increase?
Which of the following changes would cause the fusion rate in the Sun's core to increase? An increase in the core temperature and A decrease in the core radius.
What would happen if the fusion rate in the core increased but the core could not expand?
What would happen if the fusion rate in the core of the Sun were increased but the core could not expand? The Sun's core would start to cool down and the rate of fusion would decrease.
How does energy generated by fusion makes its way to the Sun’s surface How long does it take?
Describe the processes by which energy generated by fusion makes its way to the Sun's surface. Most of the Sun's energy starts in the core. It then takes hundreds of thousands of years for the energy exit as has to travel a long way to the surface. The energy goes from the core to the radiation zone as photons.
Why does the luminosity of the Sun increase over time?
As the helium core grows, so does the hydrogen-burning shell above it, thus making the Sun ever brighter even while ominously increasing the rate at which helium is accreted onto the core. The growing core burns the Sun's hydrogen yet more rapidly, which in turn only enlarges the core more rapidly. . . .
Which of the following best explains why the Sun’s luminosity?
Which of the following best explains why the Sun's luminosity gradually rises over billions of years? The planets need more and more energy to maintain any life on them as time goes on, and therefore the Sun must bet hotter.
What would happen if the Sun’s fusion rate increased?
If the fusion rate of the Sun did increase rapidly then what would happen is that the Sun would expand, the core would become less dense and the fusion rate would fall.
What would happen if the fusion rate in the core of the Sun were increased but the core could not expand View Available hint S?
What would happen if the fusion rate in the core of the Sun were increased but the core could not expand? The Sun's core would start to heat up and the rate of fusion would increase even more.
What would happen if the rate of nuclear reaction inside the Sun’s core suddenly sped up?
If the fusion in the Sun's core sped up slightly releasing more energy, what would happen? The entire Sun would become hotter.
Why does the Sun get gradually brighter with time?
Overall, the rate-of-fusion and the volume where fusion occurs increases over time. This results in the Sun — and all sun-like stars — increasing its energy output as it ages.
How does sun fusion work?
In the core of the Sun hydrogen is being converted into helium. This is called nuclear fusion. It takes four hydrogen atoms to fuse into each helium atom. During the process some of the mass is converted into energy.
How has the Sun’s energy output changed over time?
The Sun's energy output changes over multiple time scales. The most regular pattern is an 11-year cycle of high and low activity caused by reversal of the Sun's magnetic poles. During strong cycles, the Sun's total brightness at solar maximum is about 0.1 percent higher than it is at solar minimum.
Why does the Sun’s luminosity increases and its temperature decreases at position A?
As in the first (earlier) red-giant phase, the core collapse leads to very high rates of fusion in the surrounding shells of helium and hydrogen. The high rate of energy production causes the star's luminosity to rise, accompanied by an increase in size and decrease in surface temperature.
Why does the brightness of the Sun change over time?
The Sun's magnetic fields are responsible for our star's long-term brightness variations. At its surface, they become noticeable in the form of dark regions, so-called sunspots. The Sun's magnetic fields are responsible for our star's long-term brightness variations.
How will the Sun’s luminosity change as it ages?
Throughout the subsequent billions of years, the Sun's luminosity increased gradually and will continue to increase in the future. Astronomers estimate that the Sun's luminosity will increase by about 6% every billion years.
Does the rate of nuclear fusion in the Sun change?
No, the fusion rate of the Sun is not absolutely constant in time. The Sun is gradually becoming more luminous and that luminosity is provided for almost exclusively by fusion in the core. However, the rate of increase is not large, of order 10% per billion years.
What would happen to the Sun if fusion stopped?
Second, the lack of gravitational compression in the core will cause the process of nuclear fusion to stop, since there will no longer be any force capable of fusing atomic nuclei together. So, the Sun will be left as a small (Earth-sized) ball of inert gas called a White Dwarf: it will essentially be dead.
Why does fusion only occur under conditions of extremely high temperature?
Why does fusion only occur under conditions of extremely high temperature? Protons normally repel each other, so only in a hot gas are they traveling fast enough to approach each other closely. -The threshold temperature in a star is about 10 million K for fusion to occur.
What would happen in the Sun if fusion reactions suddenly ceased?
The random-walk process, radiative diffusion, causes the photon to take millions years to reach the surface of the Sun. So if fusion in the core of the Sun suddenly stopped, the surface would continue to shine for millions of years, and therefore, the luminosity would not decrease abruptly.
What would happen in the Sun if fusion reactions suddenly ceased what would happen in the Sun if fusion reactions suddenly ceased?
If nuclear fusion reactions at the core of the Sun mysteriously 'suddenly stopped entirely', the overlying (mostly hydrogen) layers would fall toward the core due to decreased radiation pressure. The diameter would decrease.
What happens when nuclear fusion in the Sun stops?
Without nuclear fusion in the Sun's core, the Sun essentially becomes useless to us. We will no longer have a source of energy to power our planet.
Is the Sun gradually expanding?
The sun is slowly expanding and brightening, and over the next few billion years it will eventually desiccate Earth, leaving it hot, brown and uninhabitable.
Why is the Sun brighter than usual?
1) The sun seems brighter (more dazzling) if there is more scattering in the atmosphere. The sun would actually look very small to us in the sky if there were no atmosphere (it's the same angular size as the moon) and most of the brightness seen in the direction of the sun is from small deflection rayleigh scattering.
What happens during a fusion reaction on the Sun?
Nuclear Fusion reactions power the Sun and other stars. In a fusion reaction, two light nuclei merge to form a single heavier nucleus. The process releases energy because the total mass of the resulting single nucleus is less than the mass of the two original nuclei. The leftover mass becomes energy.
Why does the Sun need nuclear fusion?
Nuclear fusion, the source of all the energy so generously radiated by the Sun, does two things: it converts hydrogen into helium (or rather, makes helium nuclei from protons) and it converts mass to energy.
Why is the Sun luminosity increasing?
Since its birth 4.5 billion years ago, the Sun's luminosity has very gently increased by about 30%. This is an inevitable evolution which comes about because, as the billions of years roll by, the Sun is burning up the hydrogen in its core.
Why does the amount of energy transferred from the Sun to the Earth vary?
The atmosphere directly absorbs about 23% of incoming sunlight, and the remaining energy is transferred from the Earth's surface by evaporation (25%), convection (5%), and thermal infrared radiation (a net of 5-6%).
Why has the luminosity of the Sun gradually increased over its lifetime on the main sequence?
Since its birth 4.5 billion years ago, the Sun's luminosity has very gently increased by about 30%. This is an inevitable evolution which comes about because, as the billions of years roll by, the Sun is burning up the hydrogen in its core.
How has the Sun changed over the years?
Because the Sun continues to 'burn' hydrogen into helium in its core, the core slowly collapses and heats up, causing the outer layers of the Sun to grow larger. This has been going on since soon after the Sun was formed 4.5 billion years ago.
How has the Sun evolved over time?
The Sun has been shining for 4.6 billion years. Considerable hydrogen has been converted to helium in the core, where the burning is most rapid. The helium remains there, where it absorbs radiation more readily than hydrogen. This raises the central temperature and increases the brightness.