by The remaining light from the young universe is seriously flawed, and we don’t know how to fix it. It is the cold spot. It’s too big and too cold. Astronomers aren’t sure what it is, but they mostly agree it’s worth investigating.
The IS cosmic microwave background (CMB) when our Earth was only 380,000 years old. At the time, our cosmos was about a million times smaller than it is today and the temperature was over 10,000 kelvins (17,500 degrees Fahrenheit, or 9,700 degrees Celsius), meaning that all the gas was plasma. As the universe expanded, it cooled, and the plasma became neutral. In the process, it released a flood of white-hot light. Over billions of years, that light has cooled and stretched to a temperature of about 3 kelvins (minus 454 F, or minus 270 C), placing that radiation firmly in the microwave band of the electromagnetic spectrum.
The CMB is almost completely uniform, but there are small temperature differences of up to about 1 part per million, and these imperfections, which look like splotches of different shapes and sizes, are the sharpest part about it. We cannot predict exactly what the fluctuations will be, which exact spots will be cold and which spots will be warm. That is because the light we are seeing is coming from a part of the universe that has now been removed from observable sight.
Related: The 1st light to flood the universe can help unravel the history of the cosmos. This is how.
This means that we have to rely on statistics to understand the CMB. We cannot say what splotches will appear; we can only use physics to understand the average size of splotches and how hot or cold they might be, on average.
The cold spot
Almost everything with the CMB is fine and dandy. We understand where the splotches come from, and over the years, we’ve built increasingly refined telescopes and telescopes. satellites to get a better look. Indeed, the detection and measurement of the CMB is one of the greatest success stories in science.
And then the spot is cold.
Now there are many cold spots in the CMB. But there is one – the cold spot – that stands out. It even stands out visually. If you look at a map of the CMB — where the entire sphere of the sky is compressed into a strange, vaguely oval shape — it’s down and slightly to the right. In the sky, it is towards the constellation Eridanus.
The cold scene is strangely cold. Depending on how you define the edge of the spot, it’s about 70 microkelvins cooler than average, compared to the run-of-the-mill cold spot that’s only 18 microkelvins cooler than average. In its deepest parts, it is 140 millikelvin cooler than average.
It’s also big – about 5 steps across, which doesn’t seem like much, but that’s about 10 full moons lined up side by side. The average presence on the CMB is less than 1 degree. So it’s not only cold weird but also big weird.
Now this is where things get tricky. It is easy to spot the cold spot. Astronomers first saw it NASA‘s Wilkinson MICROWAVE Anisotropy Anisotropy in the early 2000s, and the European Space AgencyThe ‘Planck’ satellite confirmed the existence of the cold spot. So it was just a quirk of the instrument, a measurement error or some other weird interference – it’s real.
This leads to another question: Do we care?
We cannot say for sure what splotches will appear on the CMB; we only receive statistical information. There’s been a lot of back and forth on this, but the general consensus is that, yes, we shouldn’t reasonably expect the cold spot to be this big and cold just by random chance, based on our understanding of the physics. the earlier universe, it is too much offline.
Yes, large and cold spots should appear randomly from time to time, but we have a less than 1% chance of seeing one out of pure random chance (and it could be much lower, depending who you ask). So while we could say we were really lucky and found a cool place, it rarely requires more attention.
So it’s not a measurement error, and it’s probably not random chance. So what is it?
The heated debate
Your favorite explanation for the strange nature of the cold spot is that it is due to a vast cosmic vacuum that sits between us and the CMB in that direction. Cosmic voids are large patches of almost nothing. But despite everything, they affect the CMB light, and that’s because the voids are emerging.
When light from the CMB first enters a vacuum, it gains some energy as it passes from a high-density environment to a low-density environment. In a truly static Universe, the light would lose an equivalent amount of energy when it left the other side. But because the voids are changing, when the light first comes in, the void may be quite small and shallow, and gradual. time he leaves, the void is great and deep.
This results in an overall loss of energy of the CMB light crossing the vacuum – a process known as the coherent Sachs-Wolfe effect.
So a giant vacuum could explain the cold spot, but there’s one problem: We’re not sure if there really is a giant vacuum in that direction. We have maps and surveys of galaxies in that part of the sky, but they are all somehow incomplete; they do not capture every galaxy, or exceed the total volume of the supposed void. So, this, too, has gone back and forth significantly in the literature, with some groups claiming that they recognize too much emptiness and others saying that there is nothing special about it.
Furthermore, even if there were a supervacuum in that direction, it is not clear that it would produce a strong enough effect to create the cold spot we see.
This ambiguity leaves room for some out-of-the-box proposals, like the idea that the cold spot is a remnant crossing point between our universe and the neighboring universe. But that hypothesis does not even explain all the properties of the cold spot.
Related stories:
—The ‘wiggles’ of energy waves over Earth could hold the history of the universe
—Listen to the void: Why any cosmic thing has so much to say
—History of the universe: Big Bang to date in 10 easy steps
Does the cold spot invalidate the Big bang? Definitely not. Is it worth looking into? Almost certainly. Will we ever understand what it is? Maybe not.
That’s how science is. It’s never perfect, and there’s always a little thorn in the side of some theory. Sometimes, those thorns blossom to reveal new types of TK, sometimes those thorns are just consuming and scientists are slowly chipping away at it, and sometimes they just sit there, not fully resolved, not fully answered, but they don’t rise never to the level they need. attention
Either way is fine by me. Why? Because nothing is perfect in this universe, it is not worth our description.
