Science News

"Dark Matter" may finally be on its way out

- David Nabhan

Neither NASA nor any other spacefaring agency uses Einstein's equations to calculate orbits and trajectories for their satellites and crafts. Isaac Newton's less accurate computations of how gravity should cause spacecraft to careen on their journeys are far and away good enough for the relative low-velocity and comparatively minuscule realm of human space exploration at present.

That's not to say that the heightened accuracy of relativistic considerations of gravity, even in the prosaic environs of our home planet, is never required. GPS, for example, would be impossible without Einstein's field equations. The rapid-fire interaction to triangulate one's automobile on a highway at ground level with satellites some 20,000 kilometres above and moving at 14,000 kilometres per hour is one in which the mathematics and classical view of gravity of the 17th century simply won't do. The gravity well of Earth differentiates enough between its surface and orbital heights to produce time dilations which would result in wide errors in precise positioning were they not accounted for using Einstein's formulations and not Newton's.

Newton's laws are hardly wrong, but more that as the centuries passed and science matured and progressed, it came to realise that its foundational view of gravity was flawed and that it was only the mathematics that still worked properly—in the main, at least. The lesson should be that there almost certainly must be an even better way to understand gravity in the future; a further unveiling of a deeper and more complex calculus at the heart of this universal force. And that is hardly a brash assumption to be made since the more we come to learn about gravity the greater the paradoxes surrounding it become.