In our previous chapter, we looked at Einstein’s theory, regarding the way which mass bends space. We talked about why a ray of light can appear to us, here on earth, as if it travels in a straight line, while it actually travels in a curve. We explained that according to the Theory of Relativity, this happens because gravity warps existence around it, along witheverything in it – be it light, ourselves and even time! In this chapter, we will elaborate on what the latter actually means. Or, in other words, we’ll try to understand what time really is, according to modern science and, more importantly, can it be cheated?
A Matter of Time
As explained in our recent post, the speed in which time flows in a certain place depends on the speed it is traveling and the intensity of the nearby matter’s gravity force bounding it. This phenomena is called time dilation and it could have a serious impact on space voyages. For example, let’s say NASA’s ground control wants to send a spaceship on a mission to deep space – far from any gravitational force – and let’s say both sides schedule a call in 80 years from now. In order for that to happen, ground control will actually have to count 81 years, while the astronauts will need to wait only 80. However, both the astronauts and the people on Earth will share the same sense of time, because it’s their entire existence that is changing. The same goes for people who are inhabiting different planets. Infact, since satellites travel at high velocities and are far from the surface, clocks on board them “tick” faster than synchronized identicalclocks on the ground. Simply because in space time itself flows faster. GPS engineers take this effect into account and program satellites’ clocks to tick slightly slower than their counterparts on Earth!
Satellites in space, aging a little slower than we do
In fact, all you workaholic professional pilots out there might be happy to hear that if you are traveling at a speed of 600 miles/hr, 12 hours per day, every day, for 50 years- you will “prolong” your life by about 5.87 minutes!
Illustration of Time Dilation. A relatively accelerated clock moves more slowly.
Blowing a Hole in Everything We Thought
So now for the real questions: If we know that space and time can be “stretched” by gravity like an elastic band, does it mean that they can be ripped as well? And if so, what does that mean?
While no one is quite sure, in order to try answering this question, let’s look at the most mysterious place we know in the universe – a black hole. A black hole is a region of space with a gravitational field so intense that practically no matter or radiation can escape it, not even light (hence its name). Black holes feed on planets, absorbing more and more mass. Some can be “small,” some can be billions of times heavier than our sun!
Illustration of a black hole from the film “Interstellar”
Black holes’ potent gravity fields have a dramatic effect on the time axis. For the sake of illustration, let’s say that a married couple approaches the proximity of a black hole in two separate spacecraft. They stop right before they reach the “event horizon” (the point of no return). Then, all of a sudden, the man feels he had enough of his marriage and dives in at full speed. So, in the eyes of his surprised woman it would appear as if the man is slowing down the closer he gets to the black hole, up until the point it will look like as if he is hovering. But, for the man, the descent will feel completely quick and normal, up until the point he disintegrates from the intense gravity. Or in the other words, as far as we know, a “hole” in the spacetime continuity means slowing time so much that it reaches almost a complete stop.
But wait! That’s not all. Some scientists go so far as to believe that some black holes stretch space SO much, that they actually punch a literal hole in it. And since every hole has two ends, the opposite end of a massive black hole could be located in a different part of space, a parallel dimension if you will (or may be simply far away.)
This also means that the other end of a black hole might appear in the form of something called a “white hole” – a sort of portal which outputs energy and mass. According to this theory, unlike black holes which are long lasting events, white holes appear spontaneously and all their matter is ejected at a single pulse. In fact, recent claims have been heard that the big bang itself, which started our universe, was such a white hole. Now another question that this theory springs to mind is when does the white hole appear? Since black holes “suck” (slow) itself, does it mean that white holes can be some sort of portal to the past, or perhaps the future?
A glimpse into the theory of the “multiverse”
While the very idea of creating a tunnel, a “wormhole” that links between two different time regions, different dimensions or even between two distant places may sound far-fetched: believe it or not, scientists are already observing certain particles which don’t play by the rules of time and space as we know them. In the Quantum world (which is in the realm of the tiniest things,) particles seem to blink in and out of existence and even appear at two different places at the same time, hinting us that such phenomena are possible. But this is a mind twist for another day… See you next time!
