cosmic microwave background

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If you study a map of the Cosmic Microwave Background, or CMB, you may notice a large deep blue splotch on the lower right.

This is the cold spot.

Is this feature a statistical fluke, the signature of vast supervoids, or even the imprint of another universe? Is that giant cold spot in the cosmic microwave background really evidence of a collision with another universe? That's what all the media hype is saying, which means it's time for another space time journal club to sort it out.

Today we're going to talk about a fascinating new publication by Mackenzie et al.

2017 titled Evidence Against a Super Void Causing the CMB Cold Spot.

First, the name.

Evidence against a supervoid.

And so you normally, by assuming this sort of, we assume in this, you have a flat lambda cold dark matter model, and then you get a value for H naught for that model.

If you were to change the model, you would get a slightly different value of H naught, but the CMB supports this sort of flat lambda CDM cosmology.

So they use that.

Now the problem is that these two values are now measured very precisely, but they don't agree at a fairly high significance level.

actually it'd be nice to really see, could we ever constrain a kind of shape for it?

But this is, I guess, a way of checking the systematics on that local universe.

So, you know, then we have to say, okay, well, there's a reason that the CMB is not the same as the local universe.

And it isn't because the local universe measurement is wrong.

More data has to be gathered.

And once the CMB was understood, it was pretty resound like, like, yeah, okay, this looks to be this very, very, um, very, very precisely matches the expectation out of this, uh, out of this, uh, big bang cosmological model.

We would expect to see, uh, this, this, uh, this artifact and it would be stretched to precisely this, uh, this temperature.

So, uh, and the, the, uh, the, the, the, uh, the, and it's a tropic, uh, uh, aspect of it too.

So they need this story.

And they need the story so bad... that they try to tell the story from within the history of science, but they're lying every time when they do that.

Once they got to CMB, okay, Big Bang cosmology is very, very clear.

And again, none of it substantiates any of their propaganda.

This moment known as decoupling is a defining milestone releasing an immense flood of radiation that will travel across the cosmos for eternity.

These photons, unimpeded at last, form what we now observe as the Cosmic Microwave Background, or CMB, the universe's oldest light, a fossilized afterglow from 380,000 years after the Big Bang.

The CMB is our cosmic blueprint, an invaluable relic that carries the secrets of the early universe, revealing subtle temperature variations that would one day shape galaxies, stars, and clusters.

It stands as a testament to the universe's origins, helping scientists decode its age, composition, and even its fate.

By now, at around 380,000 years old, the universe has become transparent but not yet illuminated.

And yet, there is one frame of reference that in some ways is a little more preferred, or at least special, than all of the others.

It's the frame of reference of the cosmic microwave background radiation, the CMB.

The CMB is the leftover heat glow from the hot, dense early universe.

In all directions, it appears to be the same temperature, around 2.7 Kelvin, and hence, the same microwave wavelength.

Actually, when we look at the CMB from our moving platform of planet Earth, we don't see a perfectly even temperature.

This motion is due to the sun's orbit around the Milky Way and the Milky Way falling to the great attractor.

More on that last one soon.

That motion causes the CMB to be Doppler shifted.