Question How Many Atoms are in the Observable Universe?

[Mergatroid]

I was reading this article and I came across this:
"Using cosmic microwave background radiation, we can work out how fast the universe is expanding, and because that rate is constant — which is currently scientists' best guess (although some scientists think it may be slowing down) "

Excuse me??????
"because that rate is constant"
Is the expansion of the universe not accelerating? And if not, why was this amazing fact discovered and not made into news for everyone??? Last I checked, the most recent theories say the universe is expanding and that expansion is accelerating (dark energy and all that).

"although some scientists think it may be slowing down"
Since when? This is basically exactly the opposite of what we have been taught over the last 30 or more years. Wasn't it Hubble that discovered the expansion is accelerating? Did someone prove him wrong? Don't most scientists believe it is still accelerating?

If you guys are going to change the way the universe works, you gotta let us in on it.

 

[IG2007]

Is the expansion of the universe not accelerating?

The article means that the acceleration rate (m/s/s) is constant.

"although some scientists think it may be slowing down"

And this means to say that the acceleration rate may be slowing down.

Currently, deciding the Hubble Constant (the acceleration rate of the Universe) is a hot debate among the astronomical community. Even a space.com article has said that not being able to decide the Hubble Constant is the shame of the astronomical community, because, since Edwin Hubble, we have not been able to decide the exact value of the Hubble Constant. Because, in every different direction, the Hubble Constant is different. The Hubble Constant is literally not a constant. That's the biggest confusion and topic of debate in the astronomical sphere.

 

[Lariliss]

1. Hubble's law is considered the first observational basis for the expansion of the universe, and today it serves as one of the pieces of evidence most often cited in support of the Big Bang model.
2. As the Hubble Constant is the unit of measurement used to describe the expansion of the Universe. At first Hubble measurements showed that the farther these galaxies are from Earth, the faster they appear to be moving, according to NASA.

While scientists then understood the phenomenon no matter where you are located in the cosmos, you would see the same expansion happening at the same speed.

Hubble's initial calculations have been refined over the years, together with more sensitive telescopes have been used to make the measurements that extrapolated the constant based on measurements of the cosmic microwave background — a constant background temperature in the Universe.

The uncertainties also come from the fact that there are three possible ways of the future of the Universe: it may stop expansion at a certain point, collapse back or expand to infinity. This is unresolved by scientists.

 

[Catastrophe]

Only atoms? What about WIMPs?

Dark matter might consist of an as yet unidentified subatomic particle of a type completely different from what scientists call baryonic matter – that's just ordinary matter, the stuff we see all around us – which is made of ordinary atoms built of protons and neutrons.23 Feb 2020

What is dark matter? | Astronomy Essentials | EarthSky

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