If you have ever seen videos of astronauts in training on the "Vomit Comet,” ridden on a particularly exciting roller-coaster or maybe even tried skydiving, you will have noticed there is something about the force of gravity that is different.
When you are in an aircraft during its takeoff run, or have been a passenger when your friend is showing off the acceleration in his or her electric car, you feel firmly pushed back in your seat.
During the acceleration of a spacecraft heading for space, passengers can feel pushed back in their seats by a force several times their weight. When falling freely, allowing gravity to accelerate you, there is no sensation of weight at all. If your spaceship has no windows, you won't be able to tell if you are floating around in the remote reaches of space or falling earthward at high speed.
That is one of the things that led Albert Einstein to decide gravity was not a force like all the others. One of the main intentions behind his General Theory of Relativity was to come up with a better idea of what gravity might be. He proposed gravity is the curvature of the fabric of space-time by massive objects. Imagine bowling balls and cannonballs sitting on a trampoline.
Since gravity plays a major role in defining the structure of the universe, Einstein applied his concept of gravity to the universe and found something he did not like. Along with many others at the time, he believed the universe as a whole is unchanging and eternal, with planets, stars and galaxies coming and going within it.
His calculations described a universe that wanted to either expand or collapse. The only time his universe would be stationary is the moment between when expansion ceases and contraction begins. He then made what he later described as the biggest mistake of his life. He fudged his calculations to fit his opinion. He added a fudge factor, which he impressively named "Cosmological Constant.” He could adjust the value of this to make his universe static.
At almost the same time, a senior Jesuit priest, Georges Lemaitre, was doing the same calculation. However, he believed the results. He concluded the universe was truly expanding, and if it was, the expansion could be tracked back in time to when everything was concentrated in one tiny lump, which he called the Primaeval Atom.
This, then, started to expand rapidly, in an event we now call the Big Bang, leading to the universe we see around us today.
In 1927, Lemaitre had a chance to present his ideas at an international science conference. When he had a chance to talk to Einstein about them, the Great Man said to Lemaitre "Your calculations are correct, but your grasp of physics is abominable."
This rude and crushing response might very well have been due to Einstein having years of work questioned, and maybe a consequence of too much fame and adulation.
Astronomer Edwin Hubble had been comparing the speeds galaxies are receding from us with their measured distances, and in 1929 he presented his results. The universe is expanding, and the farther away a galaxy lies, the faster it is receding. This result independently suggested there was a point in the past when it was all confined to one small lump. Lemaitre was right. Einstein would have been right too if he had not added his fudge factor.
In the light of these observations, Einstein publicly apologized to Lemaitre and the two men became friends. There is a moral to this story, think carefully about the results of your calculations before fudging them to give the result you want.
• Venus shines very brightly in the west after sunset. Mars, much less bright, and reddish, is a little higher in the sky.
• Saturn, golden coloured and moderately bright, lies low in the dawn glow.
• The Moon will be new on May 19.
Ken Tapping is an astronomer with the National Research Council's Dominion Radio Astrophysical Observatory near Penticton.
This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.