How is existence defined? Does nothingness (vacuum) qualify as existence?

My attempt to get answer for the post from AI platform is as follows:

The concept of a singularity, particularly in the context of black holes and the Big Bang, indeed presents challenges to our current understanding of physics. In general relativity, a singularity is a point where gravitational forces cause matter to have an infinite density and zero volume. This creates a breakdown of the laws of physics as we know them, particularly because the equations of general relativity predict that spacetime curvature becomes infinite at singularities.

When it comes to energy-mass conversion, described by Einstein's equation \(E=mc^2\), singularities suggest conditions where this relationship may not hold or where our classical understanding fails. For instance, inside a black hole, the laws of physics as we know them cease to operate normally, leading to paradoxes that challenge both general relativity and quantum mechanics.

Current theories in physics, including quantum gravity, aim to reconcile these discrepancies, but as of now, a complete understanding of singularities remains elusive. Scientists continue to explore these concepts to find a more unified theory that can adequately describe the phenomena occurring at singularities without defying the established laws of physics.

...However, the properties of light and its interactions with the vacuum can lead to intriguing effects, such as the bending of light around massive objects (gravitational lensing) and the phenomenon of vacuum polarization, where the presence of light alters the vacuum state.

In my opinion, I think the bending of light is due to the properties of photons interacting with the massive objects, because they’ve properties of mass. I don’t know if this has anything to do with the vacuum of space.

 In my opinion, vacuum doesn’t affect the speed of light, nor are photons part of the vacuum. Our understanding of existence is related to our perception of matter, and thus life as tangible components of the universe. We haven’t even touched the secrets of vacuum that exists in its own omnipresent state, facilitating every celestial motion, including that of light.

 Based on AI search:

“…while zero-point energy has not been measured directly in a straightforward manner, its existence and effects have been by experimental observations such as the Casimir effect and the Lamb shift, affirming its role in quantum mechanics.”

Just as we acknowledge the existence of an observable universe, there similarly exists an observable vacuum of space, beyond which we may attain a more precise understanding of the vacuum's nature - an infinite, intangible expanse devoid of any remnants of quantum fluctuations.

Why do I feel humans may very well be another complex form of virus with their capacity to destroy the planet 

in a long run.

Time is our making. If time was universal, we wouldn’t use light year to measure cosmic distances. Remember a year, whose origin is the complete revolution of earth around the Sun, is a local way of measuring time based on cyclical motions.