Illustration by Mayank Chhaya
It would be grand of me to say that I grasp the concept of spacetime, although I do have an instinctive feel for it. We all do at the elemental level. It is just that articulating it is beyond most of us.
In the interest of simplicity let me break it down the best I can. In our classical understanding there are three spatial dimensions of length, width and height which together make a three dimensional perspective. Time was considered a separate independent dimension until it was joined with space and together they came to be known as spacetime. This is the best I can/will do for a blog that is free.
With that out of the way, let me bring in the latest research by physicist Robert Nemiroff of Michigan Technological University (MTU) that seems to confirm something even more befuddling. Albert Einstein maintained that spacetime is smooth and not foamy as postulated by some. Those who took the contrary view had argued that, “Spacetime is made up of a froth of particles and possibly even black holes that pop in and out of existence over infinitesimally small moments at the so-called Planck-length scale, which is less than a trillionth of a trillionth the diameter of a hydrogen atom.” The direct quotes are from a statement released by Dr. Nemiroff.
It has been very difficult to prove given the extremely minute scales required to test whether spacetime is foamy or smooth. However, photons shot by a gamma-ray burst, which originated seven billion light-years from us, were captured by NASA’s Gamma Ray Space Telescope in May, 2009. It is by studying three photons that Dr. Nemiroff and his team have been able to establish that spacetime is smooth.
The photons hit the NASA telescope a mere millisecond apart. If spacetime was foamy, seven billion light-years is a long enough distance for these photons to be pushed around and scattered such that they would arrive at different intervals. The fact that there was a virtual dead heat is interpreted by Dr. Nemiroff and others to mean that spacetime is smooth enough to let the photons slide through without significantly changing their speeds. It is that interpretation that proves Einstein right.
Being a scientist Dr. Nemiroff would not assert his findings with religious certitude. "If foaminess exists at all, we think it must be at a scale far smaller than the Planck length, indicating that other physics might be involved," he says.
"There is a possibility of a statistical fluke, or that spacetime foam interacts with light differently than we imagined," Nemiroff said.
However, it is possible to confirm his findings with more such studies. The first results seem to indicate spacetime being smooth rather than frothy. The MTU press release has taken care to explain it in a language that even drunkards by the gutter would understand. It says, “Spacetime may be less like foamy quantum beer and more like smooth Einsteinian whiskey.”
Being a teetotaler I would have preferred a different description. However, being a pretend physicist I understood the more scientific explanation.
So if you are a photon it is possible to slide through the universe without getting your buttocks bruised. Now, that I understand.
