benk99nenm312 said:
That's dissapointing then, because on the show, and you can watch for yourself, they say that they have actually done this. They told a straight up lie.
It was probably an unfortunate confluence of the scientists attempting to explain what was going on and the editors who know that the public sees scientists who properly qualify their statements as using 'weasel words'.
benk99nenm312 said:
How exactly does one measure the angles formed by this triangle? WIth what instruments or hypothesis? (This is something I don't know a lot about. I would like to rectify that.
)
Well, I tried to explain it in the above post, but perhaps I'll try again.
First, when we observe the CMB, we see a series of hot and cold spots. If we look at the average angular size of these hot and cold spots on the sky, we get a very specific angle (around 2 degrees). Since we are observing the universe at a very young era, this 2 degree separation represents a very large physical separation. We make use of other information, both from the CMB and other experiments, combine it with theories about how the early universe behaves, in order to get a handle on the true physical separation that this 2 degree angular separation represents.
The basic idea is that in the very early universe, quantum fluctuations set up minuscule oscillations in the matter that was around at that time. As the expansion slowed down from inflation, these oscillations became sound waves that traveled through the plasma of the early universe, and they bunched up at what is known as the "sound horizon": the total distance a sound wave could travel since inflation ended. So the physical size of these fluctuations depends upon two things: the speed of sound in the fluid of the early universe, and how much time passed between inflation and the emission of the CMB. These two things, in turn, depend upon the contents of the universe (though fortunately for us, dark energy has little to no impact, so we only have to make use of the much more well-understood normal matter, radiation, and dark matter for these calculations).
So, with just the CMB, then, we have a superb picture as to the angle, as viewed from Earth, of the average separation between these hot and cold spots. The CMB itself also provides us with a pretty accurate picture of the physical distance at the emission of the CMB. That's two parts: the nearby angle, and the length of the far side of the triangle. Not enough to say the universe is flat, but it's a start.
Nearby experiments correlating the nearby properties of the universe with the CMB give us a third piece of information about this abstract triangle: the length of the sides of the triangle that stretch from us to the CMB. They also help to further constrain the contents of the universe, giving us an even clearer picture as to the length of the far side. Put all together, the dimensions of this abstract triangle tell us that the universe is very, very flat.
