Question

part 1: how our sun changes

1. click the play button on the information panel and observe how the sun changes during its life. name the three stages of the sun’s life shown on the hertzsprung-russell diagram.

stage 1
stage 3

1. change the speed to \fast\ then click \play\ again. watch as the star progresses through its life cycle. without using numbers, describe how the temperature, brightness, and size of the sun changes as it goes through its life cycle.

1. in which stage of its life will the sun be at its brightest? when will this be (mil. year?) press the pause button or click on the point on the diagram to move the star to find the exact year.

1. in which stage of its life does the sun spend the least amount of time?

1. in which stage does the sun spend the longest time?

click on the \information\ tab. read about stars with the mass of the sun.

1. what are the sun (and all stars) doing in the main sequence stage?

1. what causes a star to turn into a red giant?

1. how will the sun become a white dwarf?

Explanation:

These questions are about the Sun's life cycle, which falls under the subfield of Physics (Astronomy) in Natural Science. The questions require knowledge of stellar evolution, Hertzsprung - Russell diagram, and the stages of a star's life. For example, question 1 asks about the three stages of the Sun's life on the HR diagram, which are typically the Main Sequence, Red Giant, and White Dwarf (or other relevant stages depending on the model). Question 6 is about what stars do in the main sequence stage, which is fusing hydrogen into helium in their cores.

Answer:

1. Stage 1: Main Sequence; Stage 2: Red Giant; Stage 3: White Dwarf (answers may vary slightly depending on the specific model or simulation used, but these are the typical main stages of the Sun's life cycle shown on an HR diagram)
2. Temperature: Generally, starts relatively stable (Main Sequence), then cools (Red Giant phase), and then heats up again (White Dwarf phase). Brightness: Increases during the Red Giant phase, is relatively stable during Main Sequence, and then decreases as a White Dwarf. Size: Relatively stable (Main Sequence), expands greatly (Red Giant), then shrinks to a very small size (White Dwarf). (Descriptions are qualitative as per the question's request)
3. The Sun will be at its brightest during the Red Giant stage. The time (in million years) would be determined by the simulation, typically around 12 billion years after its formation (but exact value depends on the simulation used).
4. The Sun spends the least amount of time in the Red Giant or the White Dwarf? No, actually, the shortest stage is typically the Red Giant branch? Wait, no, the Main Sequence is the longest, the Red Giant phase is shorter, and the White Dwarf phase is very long but in terms of the active stages, the Red Giant phase (the time when it is a Red Giant) is relatively short compared to Main Sequence. But again, depends on the simulation.
5. The Sun spends the longest time in the Main Sequence stage (about 90% of its life is in the Main Sequence).
6. In the main sequence stage, the Sun (and all stars) are fusing hydrogen into helium in their cores, which produces the energy that keeps them shining and stable against gravitational collapse.
7. A star turns into a Red Giant when it runs out of hydrogen in its core. The core then contracts, and the outer layers expand as hydrogen fusion moves to a shell around the core, causing the star to expand and cool (becoming red) and increase in brightness.
8. After the Red Giant phase, the Sun will shed its outer layers (forming a planetary nebula), and the remaining core will collapse under gravity to form a White Dwarf, which is a dense, hot, and small stellar remnant.