Multiple choice general knowledge science & technology

In four to five billion years, the sun's outer layers will expand as the core's hydrogen fuel is used up, contracts and heats up. What is this phase called?

  1. Yellow giant phase

  2. Red giant phase

  3. Blue giant phase

  4. White giant phase
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B Correct answer
Explanation

When the Sun exhausts the hydrogen fuel in its core (in about 4-5 billion years), it will expand dramatically, becoming a red giant. During this phase, the outer layers will expand outward (possibly engulfing inner planets) while the core contracts and heats up, eventually beginning helium fusion. After the red giant phase, it will shed its outer layers and become a white dwarf. Yellow, blue, and white giants are different stellar evolutionary stages that don't apply to the Sun.

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