Approximately 7 billion years from now, the Sun will likely engulf the Earth after its red giant phase.
Here's a more detailed breakdown of the events leading to this:
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The Sun's Evolution: The Sun, a main-sequence star, will eventually exhaust the hydrogen fuel in its core. This will cause the core to contract and heat up, while the outer layers expand significantly.
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Red Giant Phase: The Sun will transition into a red giant. During this phase, its luminosity will increase dramatically, and its outer layers will expand outwards, potentially reaching the orbit of Mars.
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Earth's Fate: As the Sun expands, Earth's orbit will be affected. Tidal interactions with the Sun's outer atmosphere will cause Earth's orbit to decay. The drag exerted by the Sun's chromosphere will further reduce Earth's orbital radius. Although mass loss from the Sun might initially cause the Earth to spiral outward, these other effects will dominate.
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Engulfment: Ultimately, these factors are expected to lead to Earth being engulfed by the Sun in approximately 7.59 billion years. The exact timing and details depend on complex stellar evolution models, but the general consensus is that Earth's survival beyond the Sun's red giant phase is highly improbable.
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What Comes After? After engulfing the inner planets, the Sun will eventually shed its outer layers, forming a planetary nebula, and its core will become a white dwarf.
In summary, while the timeline involves complex astrophysical processes, the most likely outcome is that the Sun's expansion will engulf Earth in about 7 billion years.
