The Future of Earth as a Red Giant: What Will Happen?

The Sun will eventually transition into a red giant, a phase that poses significant and potentially catastrophic changes for our planet. While the Sun will not necessarily engulf Earth, the effects will still be devastating.

Understanding the Red Giant Phase

When the Sun's hydrogen fuel is exhausted, it will expand to become a red giant. Despite the common misconception that the Sun will gain mass during this phase, its density will actually drop. The Sun's mass is also slightly different compared to its total mass, leading to changes in the orbits of the surviving planets. Mars might move a bit further from the Sun, but the core, mantle, and even the crust of the Earth will undergo significant but survivable changes.

The Fate of Earth

The future of Earth as a red giant depends on the extent of the Sun's expansion.

Expansion Beyond Earth's Orbit

If the Sun expands past Earth's orbit, our planet will face a perilous situation. The intense radiation and solar winds will cause Earth to fracture before being completely engulfed. Life as we know it will cease to exist, with the oceans boiling away and the atmosphere being blown away.

Expansions Between Venus and Earth

Even if the Sun's expansion is limited to the region between Venus and Earth, the effects will still be catastrophic. Mercury and Venus will be destroyed, and on Earth, the increased heat and radiation will lead to devastating changes. The atmosphere will be stripped away, and the planet will be plagued by intense heat and lethal radiation.

Survival and Future Possibilities

However, it is important to note that by the time the Sun becomes a red giant, humanity or whatever intelligent life forms exist on Earth will have long since evacuated the planet. Even if Earth is engulfed by the Sun, it will remain in its orbit, brushing aside the solar molecules.

During the Sun's contraction phase, Earth could once again pass through the habitable zone. Any descendants could potentially resettle the planet, making it habitable again. However, they might not be aware of the planet's critical role in their origin.

Other Galactic Consequences

It's also worth mentioning that the Milky Way's merger with Andromeda will be well underway by this time. Although the chances of Earth being hit by another celestial object are slim, the galactic collision will have significant implications for the future of the Milky Way galaxy.

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