Question

Red Giant Stars – Aldebaran. Eventually, the majority of hydrogen in the core of the main sequence stars is consumed, and the core collapses due to gravity. Very low-mass stars form white dwarf stars, whereas most other stars collapse and heat up until helium fusion begins. This fusion causes the star to expand outward several times larger than before, forming a red giant star (making the star cooler...Aldebaran is an example). When this happens to our Sun (in about 4.5 billion to 5 billion years), what will happen to Earth?

a) Earth will be pushed by the expanding Sun to maintain its orbital distance from the Sun, allowing Earth to retain the same environmental conditions that it has now.

b) Earth will experience increased temperatures but will retain its atmosphere and water.

c) Earth will lose its atmosphere and water and may/may not be completely vaporized by the Sun as it expands close to Earth’s current orbit.

Answer 1

The Earth will likely lose its atmosphere and water due to the Sun's transformation into a red giant, potentially leading to Earth's complete vaporization, although the exact fate is uncertain due to competing gravitational and tidal forces.

Step-by-step explanation:

When considering what will happen to Earth when our Sun expands into a red giant in about 4.5 billion to 5 billion years, the most likely scenario is that Earth will experience extreme environmental changes. As the Sun loses mass, its gravitational pull decreases, theoretically increasing the diameter of Earth's orbit according to Kepler's third law. However, tidal forces could lead to a reduction of Earth's orbital distance. The combined effects make it uncertain whether Earth will be completely engulfed. If Earth does avoid direct collision with the Sun's outer layers, it will still lose its atmosphere and water, making it uninhabitable. The drastic temperature increase and solar radiation will likely vaporize Earth's surface, rendering the planet devoid of life long before the potential collision.