A few days ago, I was surfing through science and astronomy topics on Medium.

I stumbled upon a discussion about space propulsion — specifically, whether a spacecraft could move without carrying fuel. The idea came from Professor Avi Loeb, who was exploring something that sounded simple at first: using the vacuum itself.

At that point, I wasn’t thinking about faster-than-light travel.

Just… a different kind of push.

The vacuum, apparently, is not empty.

There is a real effect — the Casimir effect — where two plates placed very close together feel a tiny force pulling them inward. Not because something is pushing them, but because something is missing between them.

Fewer fluctuations. Less energy.

It’s small. Extremely small. But it’s measurable.

And that’s where something started to feel… off.

Because if that region has less energy than its surroundings, then through mass-energy equivalence, it behaves like it has negative mass.