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How We'll Someday Be Able To See Past the Cosmic Microwave Background
StartsWithABang writes: When it comes to the farthest thing we can see in the Universe, that's the Cosmic Microwave Background, or the leftover glow from the Big Bang, emitted when the Universe was a mere 380,000 years old. But what, exactly, does this mean? Does it mean that we're seeing the "edge" of the Universe? Does it mean that there's nothing to see, farther back beyond it? Does it mean that, as time goes on, we're going to be able to see farther back in time and space? The answers are no, no, and yes, respectively. If we want to see farther than ever before, we've got two options: either wait for more time to pass, or get moving and build that cosmic neutrino background detector.
So how do they know that the "background" microwaves are from the edge of the universe? I thought that the primordial microwaves are scattered throughout the universe, so what we see when we look in some direction is the sum of all the background microwaves coming from that direction.
If we're actually seeing the edge, doesn't that shoot down the idea that the universe doesn't actually have an edge, and everywhere appears to be at the "center" of the universe? How was this idea disproved? I seem to have missed the discovery of an actual edge, somehow.
The cmb is simply the first light that was able to freely travel through space. There is no actual 'edge' but there is always the apparent virtual edge beyond which you cannot see. It's easiest to think of it as space being infinite in size but finite in age. Light needs to travel to your eye to see so the farthest you can see is simply the age of the universe x the speed of light. As the universe cooled right after the Big Bang, initially light could not directly pass through all the hot plasma, only after it cooled and became transparent to visible light did light spread out in significant amounts. The heavily red shifted version of this light is the cmb we see today. Your own two eyes see a slightly different virtual 'edge' as every point in the universe looks as if it is the center.
It took about 380k years for the universe to become transparent to light neutrinos pass through ionized material easily and the surface of last scattering is nearly as old as the Big Bang. It's a very old concept but has been researched lately as each kind of neutrino would have a slightly different background. The article is just random click bait there is nothing new or interesting about it really.