Question

When will Earth's atmosphere disappear?

Answer 1

All the life on earth that uses oxygen would die and probably the oceans would evaporate - possibly a very minor amount might persist, but it would likely freeze, without the atmosphere to temper solar radiation. A few types of bacteria might survive - the weirder ones that don’t use oxygen.

Earth itself, however, would continue to spin, have volcanic eruptions, earthquakes and so forth.