i have news for (most of) you.
The Universe is expanding!
That might not be all that exciting news for many and some may even deride it as not conforming with how they view the Universe we all share – clearly the Universe just ‘is’. Anyone can see that – right??
Well, i’m afraid the evidence is pretty much irrefutable as far as those who study the phenomenon goes and those of us who don’t are just going to have to accept it the way we had to when they told us the world wasn’t actually flat and the center of the Universe either.
What i find particularly startling about this news is that it not only shows that science is right about the formation of the Universe – where all the matter we can (and that we can’t) see in the Universe was once jammed into an almost infinitely small, superhot, super-energetic point that ‘exploded’ (The Big Bang) and has continued to expand and cool, thus forming all matter and energy as we know it to be today, but even more weirdly and seemingly non-sensically, the very space that this explosion is ‘filling’ into is itself expanding – even faster than the actual explosion did.
That might need some restating because to most of us it defies all undestanding and logic.
Basically, when we look up into a clear night sky, away from the light pollution of a major city or town, we see stars in our own galaxy. Roughly there are at least 200 billion or so, possibly up to double that number.
If the sky is really clear we can maybe see some faint tiny smudges that are the closest known galaxies to our own, some smaller and some very much larger than ours. These galaxies are so far apart they measure the distance to them in light years or the distance light itself can travel in one whole year – roughly some ten thousand billion kilometers (just under 6 thousand billion miles). The Andromeda Galaxy is around 2 million light years from our Milky Way and is one of our ‘close’ (Universally speaking) neighbours.
It does not matter in which direction you or powerful radio-telescopes look, it is possible to see billions upon billions of glaxies vanishing out into the vast distances of our Universe and the space that comprises it.
Astronomers have known for many decades that all galaxies are moving away from one another as a result of their momentum gained from the Big Bang, when all energy and matter was once at one point and exploded ‘out’ in all directions to create (not fill – there simply was nothing to ‘fill'; there was not even time itself before the expanding matter and energy began it’s travel outwards) the Universe as we have come to know it.
This is not the ‘news’ i mentioned, however.
What science has now shown is that not only are the galaxies moving apart because of their initial movement away from a single point, but that there is a force which adds to this and which is causing the very space and time between the galaxies to ‘expand’ also!
In fact, this force has actually caused the Universe to expand more than the force of the Big Bang explosion has to date and, while it has been decreasing in strength since the very beginning of the Universe almost 14 billion years ago, it is only now about equal to the force of the momentum galaxies obtained because of the Big Bang.
The weirdness of this is, that even though no known matter can travel faster than the speed of light in our Universe and that our Universe is known to be 13.7 billion years old, the size of the ‘observable’ Universe we know today is thought to be a minimum of 78 billion light years, quite possibly it may turn out to be even larger.
In the time the Universe is known to have existed for no matter could possibly have separated by this big a distance. And yet it has.
The only possible answer that astronomers and cosmologists and physicists can deduce is that at the same time the matter in our galaxies are flying away from each other, the very ‘nothingness’ in which they are flying through is itself expanding.
The whole space in which our Universe exists is being stretched and has since the beginning of time. Not only that but the rate at which it has been stretched has not been constant but has speeded up and is now slowing down.
If the concept is a little difficult to wrap your mind around it is a little like an olive pizza dough base! :-) Imagine a bunch of rubbery olives tightly squeezed together, mixed in with some elastic stretchy dough into a very tightly packed ball. Suddenly the ball is ‘released’ by whatever was sticking it together under pressure ( the Big Bang) and the dough and olives start rapidly spreading apart from all of its other parts into a giant ( flat in this case for simplicity) uncooked pizza.
Here the olives are equivalent to the galaxies that formed once the ‘ball’ cooled down enough to allow matter to form, while the dough represents known space. The weird part is that there seems to be unseen ‘hands’ pulling twirling and stretching the dough ( which pulls apart the olives from one another) into a larger and larger size than the force of the doughs expansion is capable of doing on it’s own! ( It is likely that these ‘hands’ are actually a repulsive force of every particle in the pizza acting in a manner which opposes the drawing-back together force of normal gravity on the Universe’s (pizza’s) mass).
Did that help any? ;-)
Curiously, this effect is only detectable at the intergalactic level – there is no measurable effect within a solar system such as ours – or even within our galaxy. It seems to stay a constant size, while the space between us and Andromeda is getting bigger – and at a rate faster than the two galaxies are actually travelling away from one another in ‘normal’ space.
That is news that both fascinates and boggles my mind.
Thought experiment: if you could create a million light year long ruler and could put it far out in space and observe it for a few million years would it expand along with the empty space it was located in? Would a ‘fixed’ object ‘grow’ in size? Or stay the same?
If it stays the same but the space it is in expands then comparatively, the ruler would then be seen to ‘shrink’??
Given that we cannot actually see ’empty’ space expand, our shrinking ruler would then seem to show any galaxies in the vicinity were actually moving apart faster than they actually were since the ruler is occupying an increasingly smaller proportion of the space between galaxies and yet is thought to be of constant size?
(This is like measuring the distance an object travels first with a yard long ruler and then later with a foot long ruler and believing the two rulers to be the same. The later measurement is going to show a much greater distance (ruler length) travelled than if we measured both distances with the same length ruler).
What weirdness could be determined concerning velocities measured in similar manner could get quite confusing if, as Einstein showed, time is actually so linked to space that it too is expanding at an intergalactic level.
But i’ll leave that weirdness for another day. :-)