The claim that scientists know it is impossible to create a warp drive or faster-than-light (FTL) technology without trying is not entirely accurate. In science, it is generally challenging to definitively prove that something is impossible without testing it directly or providing strong theoretical evidence based on existing scientific knowledge.
The current understanding of physics, as described by Einstein's theory of relativity, suggests that objects with mass cannot travel at or faster than the speed of light in a vacuum. This theory has been extensively tested and validated through various experiments and observations. According to the theory, as an object with mass approaches the speed of light, its energy and momentum increase without bound, requiring an infinite amount of energy to reach or exceed the speed of light. This is known as the relativistic mass increase.
Warp drives, which are often depicted in science fiction, involve manipulating spacetime to create a warp bubble or a distortion in the fabric of space. This concept relies on the hypothetical concept of "exotic matter" with negative energy density to achieve the necessary spacetime curvature. However, the existence and properties of such exotic matter are still purely speculative, and we have no evidence or understanding of how it could be created or manipulated.
While the current understanding of physics does not support the feasibility of warp drives or FTL travel, it is essential to note that our understanding of the universe is continually evolving. Future scientific advancements, discoveries, or paradigm shifts could potentially lead to new insights and breakthroughs that challenge our current knowledge. Therefore, scientists cannot definitively state that such technologies are impossible without further exploration and experimentation.