I'm not the one saying this, it's NASA - and with it's publicly available research findings - plus the scientific community all over the world. Let's try and understand this. What I'm talking about is on this link
https://map.gsfc.nasa.gov/universe/uni_shape.html
What they mean is, except for a 0.4% marginal error, the universe is FLAT!!
Flat as in a sheet of paper? That's what they are saying. Flat as in, it is finite, or measurable, or has some sort of boundaries, along the z - axis, and it is infinite along the x and y axes. Though the dimensions of this z - axis, the thickness of the sheet of paper, isn't calculated yet.
How did they calculate this?
The answer is WMAP or Wilkinson Microwave Anisotropy Probe. Let's see what the WMAP means, word by word. More info on WMAP from NASA is at this link.
https://map.gsfc.nasa.gov/news/facts.html
I sure don't need to explain a probe, it's plain english. And I'm pretty sure you don't need an explanation on Wilkinson either, but just in case. He was a pioneer cosmologist, you can check his wikipedia page if you wish.
https://en.wikipedia.org/wiki/David_Todd_Wilkinson
The two terms we need to understand in WMAP are Microwave and Anisotropy.
Anisotropy: we can already see, it means something opposite to what isotropy means. So if we get the meaning of isotropy, we also get anisotropy. Now isotropy has many specific definitions in many fields including maths, physics, biology, and geography. But in all these fields it only has something to do with being uniform. As in having a uniform geometry in maths, or uniform distribution in physics, or cells showing more or less uniform characteristics every where in biology, etc.
Isotropy is about uniformity of a property in every dimension (or simply direction, or place it exists in). This makes our property uniform everywhere, and hence, independent of dimensions.
So, Anisotropy, obviously means something that is not uniform. Or by definition here, it is the changing (dependence) of some property with dimensions (or directions or places).
So what is changing here? The microwave radiation. Let me tell you a story about this.
In 1937, an engineer in bell laboratories, was studying the radio waves. While studying these, he found radio waves that were coming from space. And then people started building radio telescopes to see where they came from.
Optical telescopes were already being used, and many galaxies around us were discovered. And so was the huge gap between the galaxies, and also even larger gaps between galaxy clusters.
Using one of these telescopes - must have been a quite sensitive one in those days - two radio astronomers discovered a faint noise signal, which also showed as a faint glow, and which wasn't associated with any star or galaxy or any other object. And hence, the Cosmic Microwave Background (CMB) radiation was discovered. These two dudes got Nobel prize for this discovery.
https://en.wikipedia.org/wiki/Cosmic_microwave_background
This radiation, seemed "almost" isotropic (uniform). And it is the change in the uniformness (anisotropy) of CMB radiation, that WMAP has studied.
Don't worry about the microwave, it's just a name given to a range of frequncies in cosmic radiation.
The data that was collected from WMAP, was astonishing, and perhaps the most important data that was ever collected on the origin of the universe, And I'll post a link about it below, and hence conclude our post. More details coming soon.
Note that the fact that the universe is flat is not really what "NASA says". You have many experiments, and thus a lot of data, pointing into that direction too. The WMAP data is a fraction of them. You may be interested by the recent PLANCK results, that are more precise than the older WMAP results.
@lemouth, of course I'll read the results from planck. Thanks for the insight.
This seems very shady but what do I know I ve been wrong before like that time about Kith the flying pig.
Loads of information. Many thanks. Love it. @pratik27 Followed
Very interesting post. But i feel the need to clarify that it's actually not actually possible to definitively prove that the universe is superflat
Keep in mind that no matter how much distance you use to measure the flatness of the universe, we can ONLY speculate what the results mean for the observable universe. The issue is that the universe is larger than the observable universe. The background radiation we can perceive only defines the observable universe, as we know that the universe is expanding faster than the speed of light, we know that there is more universe beyond said radiation that we cannot observe.
Imagine you are given a section of a line that you have to determine whether or not if it is curved.
Now say that it appears to be flat. How do you know if that your apparently flat section of the line is not just a tiny section from a much much bigger circle where the relative curvature of the section appears to be negligible?
That's my 2 cents.
Of course we can't conclude anything yet, especially when there is so much with unknown properties out there, there is no way we can say that the observations we've made can apply beyond what we can observe.