I need a completely empty Earth. I need:
- a natural phenomenon,
- some local or extraterrestrial disaster,
- some intentional human action or event,
to turn the entire Earth into second, world-sized Pompeii with:
- human population reduced to zero (obligatory) and
- Earth ground burned to the very ground, in ashes (optional).
There are three fundamental conditions:
Whatever comes into your mind or you propose -- be it meteor hit, COVID-19, giant volcano eruption, alien invasion or Earth orbit shift a bit closer (too close) to the Sun, it must be absolutely quick with no option for any surviving party to do anything (like in Pompeii).
Earth must remain as a whole planet, not destroyed, not split, allowing some future alien expedition to land on its surface, somewhere in the future, and examine it (like we do now in Pompeii).
At least some dead bodies and remains of buildings must remain and be able to examined (like in Pompeii).
Some additional information:
Poisonous gases, shifted gravity, high radiation etc. is all as an option, because alien race can survive it, as long as Earth remains possible to be landed and examined.
Whether some non-human live (like plants and animals) are reborn or whether Earth soil remains death for centuries after this cataclysm, is up to you.
The event that lead to apocalypse could happen any time in human history, but I'd prefer today or very-near-future with current level of technology existing on Earth at the moment of its devastation.
Once again, the ability for Earth to remain in one piece is a crucial and fundamental element of this question. From this perspective current question is an exact opposite of this question.