Only a Matter of ‘Time’: On Einstein, Negative Mass, Time Travel and Aliens | Space & Technology

Prime members enjoy Prime FREE One-Day delivery

In 1957, the astrophysicist Herman Bondi wrote a paper in which he considered the possible existence of a negative mass in Albert Einstein’s theory of gravity. A negative mass would repel a positive mass away from it. Given that, a pair of positive and negative masses could accelerate together up to the speed of light. The negative mass would push away the positive mass which in turn would pull the negative mass for the ride. The runaway pair would accelerate indefinitely, without any need for fuel or a propulsion system. Energy conservation would not be violated because the sum of the two masses is zero.

However, in a recent discussion I had with my brilliant collaborator, Mark Hertzberg, we agreed that the existence of a negative mass in nature would allow for a time machine in which one can visit the past. The reason is simple. A positive mass delays the arrival of light that passes near it, as recognized in a seminal paper by my distinguished colleague, Irwin Shapiro.

The “Shapiro time delay” near a positive mass reverses sign and turns into a “Shapiro time advance” near a negative mass. If the sender is moving sufficiently close to…


Advertisement Gaming:   Xbox  |  Xbox Bundles  |  Nintendo  |  Playstation  |  Cards   |   Manor Lords   |   Horizon Forbidden West
FTC: We use income earning affiliate links. More on Sposored links.
Terms of use and third-party services. More here.

Ad Amazon Minecraft the game, plus clothing, toys, and accessories.

Ad Amazon Gaming Laptops, clothing, games and more

Ad Amazon MUSIC Artists Merch Shop

Stay connected throughout the year with official, ongoing Microsoft podcasts.
Microsoft Podcasts Apple | Microsoft podcasts YouTube

Related Posts