Have you ever looked up at the stars and wondered if we could ever reach them? This might now be possible, as there might be a way to travel faster than the speed of light using negative energy density.

The way we would do this would be by compressing spacetime in front of the spaceship and expanding spacetime behind it. We would compress and expand spacetime by using regular matter and negative mass. Instead of attempting traveling faster than the speed of light normally, you could compress the space between points and travel at a more possible speed, as only photons can go at the speed of light since they are massless particles. All of this is possible within the laws of General Relativity.

This, of course, should mean that we should expect to go to Proxima Centauri (the closest star to Earth besides the Sun) soon. Well, here’s a problem we run into. The warp drive would work by creating a bubble of flat spacetime around the spaceship and bending spacetime around the bubble to reduce the distance needed for travel. To bend spacetime in the way that we need it to be bent, we would either need negative mass or negative energy density. Physicists aren’t really sure if negative mass really exists, so it makes negative energy density an opportunity.

Here is another problem we face. Making a 100 meter warp-drive bubble would require the mass of the entire observable universe (a lot). A way that we can reduce the energy requirements significantly would be by increasing the volume of the bubble while keeping the surface area constant. This would reduce the energy requirement to about the mass of the Sun. This is still impractical in today’s terms, but it is more plausible than using the mass of the entire observable universe.

In conclusion, we would compress spacetime in front of the spaceship and expand spacetime behind it to compress the space between to points, it is more likely that humanity will use negative energy instead of negative mass due to the lack of evidence supporting the existence of negative mass, and lastly we could increase the volume of the warp drive bubble while keeping the surface area the same to reduce the energy requirements.