Unruh Radiation from hovering?

Question

I know that masses on their own don't produce Unruh radiation outside of black holes which produce a similar effect known as Hawking radiation. However, what if some observer hovers above the Earth and fires the rocket engines to prevent from going closer to the surface?Does that create Unruh radiation or no or would the Unruh radiation be affected by Earth's gravitational field and would some of the Unruh particles from acceleration fall onto the Earth? What if an observer is on an asteroid that is hovered above the Earth using rocket boosters, would the entire asteroid experience Unruh radiation or just the observer?

Answer 1

No, one does not observe Unruh radiation when hovering close to a planet or star. The existence of Unruh and Hawking radiations is closely related to the existence of a horizon, which is not present in the case of a planet or similar body. Due to the absence of the horizon, the quantum state of the quantum fields ends up not being a thermal state for stationary observers (this state is known as the Boulware vacuum).