Here’s what real science looks like ...

Plasma and electricity in space. Failure of gravity-only cosmology. Exposing the myths of dark matter, dark energy, black holes, neutron stars, and other mathematical constructs. The electric model of stars. Predictions and confirmations of the electric comet.
BeAChooser
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Joined: Thu Oct 15, 2015 2:24 am

Here’s what real science looks like ...

Unread post by BeAChooser » Tue Mar 07, 2023 5:47 pm

https://earthsky.org/space/cosmic-burst ... r-mystery/
Has mystery of universe’s missing matter been solved?
What it boils down to is that up till now they've found only about half the ordinary matter they claimed there should be back in the late 1990s. But using fast radio bursts, they appear to have found the rest. Here's what they realized back in 2007 ...
As these bursts of radiation traverse the universe and pass through gases and the theorized WHIM, they undergo something called dispersion.

The initial mysterious cause of these FRBs lasts for less a thousandth of a second and all the wavelengths start out in a tight clump. If someone was lucky enough – or unlucky enough – to be near the spot where an FRB was produced, all the wavelengths would hit them simultaneously.

But when radio waves pass through matter, they are briefly slowed down. The longer the wavelength, the more a radio wave “feels” the matter. Think of it like wind resistance. A bigger car feels more wind resistance than a smaller car.

The “wind resistance” effect on radio waves is incredibly small, but space is big. By the time an FRB has traveled millions or billions of light-years to reach Earth, dispersion has slowed the longer wavelengths so much that they arrive nearly a second later than the shorter wavelengths.

Therein lay the potential of FRBs to weigh the universe’s baryons, an opportunity we recognized on the spot. By measuring the spread of different wavelengths within one FRB, we could calculate exactly how much matter – how many baryons – the radio waves passed through on their way to Earth.

At this point we were so close, but there was one final piece of information we needed. To precisely measure the baryon density, we needed to know where in the sky an FRB came from. If we knew the source galaxy, we would know how far the radio waves traveled. With that and the amount of dispersion they experienced, perhaps we could calculate how much matter they passed through on the way to Earth?

Unfortunately, the telescopes in 2007 weren’t good enough to pinpoint exactly which galaxy – and therefore how far away – an FRB came from.
So fast forward to today's technology and instruments ...
It was 11 years until we were able to place – or localize – our first FRB. In August 2018, our collaborative project called CRAFT began using the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope in the outback of Western Australia to look for FRBs. … snip …

ASKAP captured its first FRB one month later. Once we knew the precise part of the sky the radio waves came from, we quickly used the Keck telescope in Hawaii to identify which galaxy the FRB came from and how far away that galaxy was. The first FRB we detected came from a galaxy named DES J214425.25–405400.81 that is about 4 billion light-years away from Earth, in case you were wondering.

The technology and technique worked. We had measured the dispersion from an FRB and knew where it came from. But we needed to catch a few more of them in order to attain a statistically significant count of the baryons. So we waited and hoped space would send us some more FRBs.

By mid-July 2019, we had detected five more events, enough to perform the first search for the missing matter. Using the dispersion measures of these six FRBs, we were able to make a rough calculation of how much matter the radio waves passed through before reaching Earth.

We were overcome by both amazement and reassurance the moment we saw the data fall right on the curve predicted by the 5% estimate. We had detected the missing baryons in full, solving this cosmological riddle and putting to rest two decades of searching.
In my opinion, this is how science is supposed to work.

danda
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Joined: Tue May 26, 2020 2:33 pm

Re: Here’s what real science looks like ...

Unread post by danda » Wed Mar 08, 2023 4:13 am

It sounds like they are starting to wake up to "tired light" theories. Only took 100 years or so...

one hiccup the in methodology:
If we knew the source galaxy, we would know how far the radio waves traveled
That assumes we already know how far away the source galaxy is. Which is typically calculated via redshift. And of course folks here understand that redshift cannot be relied upon for distance measurements, and other galaxies much be closer than we've been told, etc.

Now, distance of some closer objects can be calculated using parallax. I don't remember if that works for "nearby" galaxies or not... maybe it only applies within our galaxy. But if so and the parallax and redshift agree, maybe? we can accept the distance estimate in this case.

maybe someone here can tell us if parallax is applicable to this or not.

BeAChooser
Posts: 1052
Joined: Thu Oct 15, 2015 2:24 am

Re: Here’s what real science looks like ...

Unread post by BeAChooser » Wed Mar 08, 2023 4:54 am

danda wrote: Wed Mar 08, 2023 4:13 am one hiccup the in methodology:
If we knew the source galaxy, we would know how far the radio waves traveled
That assumes we already know how far away the source galaxy is. Which is typically calculated via redshift. And of course folks here understand that redshift cannot be relied upon for distance measurements, and other galaxies much be closer than we've been told, etc.
Yes, but notice in the linked article that the farthest of their FRB sources is just 3 billion light years away. A pittance when it comes to redshift. Also there were only 8 data points. And maybe the density they arrived at in the medium doesn't match the actual density (which we're estimating too). Plus, NewScientist just published a article (https://www.newscientist.com/article/23 ... uch-of-it/) claiming there's now too much matter in galaxies. So maybe there's still room to question red shift?

Aardwolf
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Joined: Tue Jul 28, 2009 2:56 pm

Re: Here’s what real science looks like ...

Unread post by Aardwolf » Wed Mar 08, 2023 3:23 pm

danda wrote: Wed Mar 08, 2023 4:13 am It sounds like they are starting to wake up to "tired light" theories. Only took 100 years or so...

one hiccup the in methodology:
If we knew the source galaxy, we would know how far the radio waves traveled
That assumes we already know how far away the source galaxy is. Which is typically calculated via redshift. And of course folks here understand that redshift cannot be relied upon for distance measurements, and other galaxies much be closer than we've been told, etc.

Now, distance of some closer objects can be calculated using parallax. I don't remember if that works for "nearby" galaxies or not... maybe it only applies within our galaxy. But if so and the parallax and redshift agree, maybe? we can accept the distance estimate in this case.

maybe someone here can tell us if parallax is applicable to this or not.
Parallax is only viable for nearby stars, and even then you get some dubious results.

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