Hot, Fresh Dark Matter research

[Tinker Grey]

I fully confess that I don't grasp the import of what Dr. Becky is reporting. What's fascinating from an enthusiastic sideline observer is the sheer joy of both the scientists in this video. You can watch the excitement as Dr Becky reports on research released in just the last week on DES (Dark Energy Survey).

You also get to watch listen to the implicit use of the scientific method and statistical analysis of whether they might be correct.

There is joy in being uncertain. There is joy in discovery. There is joy in the possibility of being wrong. There is hopefulness in the possibility of being right.

This is good stuff.

[somewhat sexist stuff]
This is vaguely sexist in the sense the I express some surprise. Maybe a little less sexist in that all of this makes me hopeful.

What we have here is a woman who is vastly more mathematically competent than most the men I know, myself included. Fully STEM engaged. Enthusiastic. Unabashed, non-apologetically science geek.

THEN, she consults an expert. A woman from a different culture equally competent, enthusiastic, hopeful, etc.

FINALLY, half the human race isn't excluded from contributing to science.

[slightly more sexist]
It doesn't that both women are attractive (to me.)
[slightly less sexist]
Among the "hottest" things for me is a person who is not ashamed to be intellectual, smart, etc.
[/slightly less sexist]
[/slightly more sexist]

[/somewhat sexist stuff]

 

[AV1611VET]

I've said before that I think the Bible speaks of dark matter.

2 Peter 2:4 For if God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved unto judgment;

It would take powerful, powerful chains to hold these guys down!

 

[public hermit]

The data set is both "annoying and tantalizing," lol.

 

[SelfSim]

There is joy in being uncertain. There is joy in discovery. There is joy in the possibility of being wrong. There is hopefulness in the possibility of being right.

This is good stuff.
..
This is vaguely sexist in the sense the I express some surprise. Maybe a little less sexist in that all of this makes me hopeful.

What we have here is a woman who is vastly more mathematically competent than most the men I know, myself included. Fully STEM engaged. Enthusiastic. Unabashed, non-apologetically science geek.

THEN, she consults an expert. A woman from a different culture equally competent, enthusiastic, hopeful, etc.

FINALLY, half the human race isn't excluded from contributing to science.

Nicely expressed .. I agree with everything you say there .. Good one!
Cheers

PS: Oh .. and they're both cute .. and young .. the latter which, of course, means I notice that I'm getting old ..

 

[FrumiousBandersnatch]

I fully confess that I don't grasp the import of what Dr. Becky is reporting. What's fascinating from an enthusiastic sideline observer is the sheer joy of both the scientists in this video. You can watch the excitement as Dr Becky reports on research released in just the last week on DES (Dark Energy Survey).

You also get to watch listen to the implicit use of the scientific method and statistical analysis of whether they might be correct.

There is joy in being uncertain. There is joy in discovery. There is joy in the possibility of being wrong. There is hopefulness in the possibility of being right.

This is good stuff.

[somewhat sexist stuff]
This is vaguely sexist in the sense the I express some surprise. Maybe a little less sexist in that all of this makes me hopeful.

What we have here is a woman who is vastly more mathematically competent than most the men I know, myself included. Fully STEM engaged. Enthusiastic. Unabashed, non-apologetically science geek.

THEN, she consults an expert. A woman from a different culture equally competent, enthusiastic, hopeful, etc.

FINALLY, half the human race isn't excluded from contributing to science.

[slightly more sexist]
It doesn't that both women are attractive (to me.)
[slightly less sexist]
Among the "hottest" things for me is a person who is not ashamed to be intellectual, smart, etc.
[/slightly less sexist]
[/slightly more sexist]

[/somewhat sexist stuff]

I love Dr. Becky's videos, they're a breath of fresh air; so enthusiastic.

There are a few of her responding to science fiction films - critiquing the science - that are quite entertaining.

 

[public hermit]

Can anyone explain how this new data set puts Einstein's theory of general relativity into question? Actually, she was clear that the new S8 value is not different enough to be statistically significant. At any rate, can anyone explain, in stupid Public Hermit terms, what she's talking about? Is it just that dark matter is distributed more smoothly than was thought? Does it just warrant a tweak to existing theories, or wholesale reconstruction?

 

[Tinker Grey]

Here's a follow up conversation between Dr. Becky and Dr. Alexandra Amon ~ 20 min. Perhaps it will answer your question, @public hermit; I cannot.

 

[sjastro]

Here is a primer on the mysterious S₈ mentioned in the video but not explained.
Let’s start with the power spectrum of the cosmic radiation background.

The information is based on the Planck data.
The major peak near 1º and the two smaller peaks are acoustic peaks and represent regions of over density of the CMB where there is a concentration of baryonic and dark matter.
These regions of over density are from which structures such as galaxy structures formed later on.
These over density peaks correspond to a scale of 8 h⁻¹ Mpc where h = (Hₒ/100 km s⁻¹ Mpc⁻¹) where Hₒ is Hubble’s constant.
σ₈ is defined as this scale.

S₈ = σ₈√(Ωm/0.3) where Ωm is the matter density parameter composed of plasma and dark matter.
The cosmic radiation background is from an era before stars and galaxies had formed.

The Dark Energy survey is based on cosmic shear and galaxy clustering which involves the weak lensing of galaxies of a much younger Universe.
Distances to galaxies are measured in terms of redshift.
Consider the simplest case of a pair of galaxies with dark matter.
Two types of distortion occur, a transverse distortion σ and radial distortion π.
The transverse distortion is σ is straightforward and can be measured directly; the radial distortion is more problematical as it depends directly on z which is purely a radial measurement.
If there is a gravitational attraction between galaxies, the galaxies exhibit a peculiar velocity which needs to be factored in as a correction for z.
When z is corrected the radial distortion can be determined.

In redshift space a correlation function ξ(σ,π) is defined and ξ(√(σ²+π²) is the spherical average for a large number of galaxy pairs in a survey.
From this theoretical contour maps can be derived for different parameters.

These maps generate large scale structure simulations involving adjustable parameters such as w, h, Ωm and σ₈.
When compared to actual galaxy pair numbers in the Deep Sky survey the best model gives a value of S₈ = 0.775 compared to Planck's S₈ = 0.827.

Hopefully it will make some sense of the abstract for the Dark energy survey.

We present the first cosmology results from large-scale structure in the Dark Energy Survey (DES) spanning 5000 deg². We perform an analysis combining three two-point correlation functions (3×2pt): (i) cosmic shear using 100 million source galaxies, (ii) galaxy clustering, and (iii) the cross-correlation of source galaxy shear with lens galaxy positions. The analysis was designed to mitigate confirmation or observer bias; we describe specific changes made to the lens galaxy sample following unblinding of the results. We model the data within the flat ΛCDM and wCDM cosmological models. We find consistent cosmological results between the three two-point correlation functions; their combination yields clustering amplitude S8=0.776 (+0.017/-0.017) and matter density Ωm=0.339 (+0.032/-0.031) in ΛCDM, mean with 68% confidence limits; S8=0.775 (+0.026/-0.024) , Ωm=0.352 (+0.035/-0.041), and dark energy equation-of-state parameter w=−0.98 (+0.32/-0.20) in wCDM. This combination of DES data is consistent with the prediction of the model favored by the Planck 2018 cosmic microwave background (CMB) primary anisotropy data, which is quantified with a probability-to-exceed p=0.13 to 0.48. When combining DES 3×2pt data with available baryon acoustic oscillation, redshift-space distortion, and type Ia supernovae data, we find p=0.34. Combining all of these data sets with Planck CMB lensing yields joint parameter constraints of S8=0.812 (+0.008/-0.008), Ωm=0.306 (+0.004/-0.005), h=0.680 (+0.004/-0.003) and ∑mν<0.13eV(95%CL) in ΛCDM; S8=0.812 (+0.008/-0.008), Ωm=0.302 (+.006/-0.006), h=0.687 (+0.006/-0.007), and w=−1.031 (+0.030/-0.027) in wCDM. (abridged).

Dark Energy Survey Year 3 Results: Cosmological Constraints from...

 

[sjastro]

Perhaps off topic but on the subject of female astrophysicists.
Physics World interviewed Luz Angela Garcia who had to contend with the stereotype nonsense that astronomy and physics were the preserve for smart men.
From a light bulb solar system to the cosmological constant: a journey to becoming a cosmologist – Physics World

 

[FrumiousBandersnatch]

Perhaps off topic but on the subject of female astrophysicists.
Physics World interviewed Luz Angela Garcia who had to contend with the stereotype nonsense that astronomy and physics were the preserve for smart men.
From a light bulb solar system to the cosmological constant: a journey to becoming a cosmologist – Physics World

I like her comment: “It was very cool indeed. Every time I tried to explain something, I was getting some additional insight”.

 

[HitchSlap]

I fully confess that I don't grasp the import of what Dr. Becky is reporting. What's fascinating from an enthusiastic sideline observer is the sheer joy of both the scientists in this video. You can watch the excitement as Dr Becky reports on research released in just the last week on DES (Dark Energy Survey).

You also get to watch listen to the implicit use of the scientific method and statistical analysis of whether they might be correct.

There is joy in being uncertain. There is joy in discovery. There is joy in the possibility of being wrong. There is hopefulness in the possibility of being right.

This is good stuff.

[somewhat sexist stuff]
This is vaguely sexist in the sense the I express some surprise. Maybe a little less sexist in that all of this makes me hopeful.

What we have here is a woman who is vastly more mathematically competent than most the men I know, myself included. Fully STEM engaged. Enthusiastic. Unabashed, non-apologetically science geek.

THEN, she consults an expert. A woman from a different culture equally competent, enthusiastic, hopeful, etc.

FINALLY, half the human race isn't excluded from contributing to science.

[slightly more sexist]
It doesn't that both women are attractive (to me.)
[slightly less sexist]
Among the "hottest" things for me is a person who is not ashamed to be intellectual, smart, etc.
[/slightly less sexist]
[/slightly more sexist]

[/somewhat sexist stuff]

Thanks for sharing this Tinker! Very interesting and exciting. Happy to see women so involved and engaged in science.

 

[HitchSlap]

I like her comment: “It was very cool indeed. Every time I tried to explain something, I was getting some additional insight”.

Quite a different approach to the tired creationist response to things, ‘eh.

 

[HitchSlap]

I've said before that I think the Bible speaks of dark matter.

2 Peter 2:4 For if God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved unto judgment;

It would take powerful, powerful chains to hold these guys down!

Does it ever get tiring to have to always propose banal ad hoc explanations from an archaic book. Do you really find this satisfying on an intellectual level? Or do you write these pathetic responses to help assuage your own doubts? I sincerely pity you, that your religion keeps you from being able to celebrate human experience and knowledge.

 

[AV1611VET]

Quite a different approach to the tired creationist response to things, ‘eh.

You'd like us to change, wouldn't you?

Christians at Antioch: Oh, look, JEHOVAH did it.

700 AD: Oh, wait, Allah did it.

1850: Hold on, Brahma did it.

1920: Hold the fort, the Big Bang did it.

That would go over real well, wouldn't it?

 

[AV1611VET]

Quite a different approach to the tired creationist response to things, ‘eh.

You'd like us to change, wouldn't you?

Christians at Antioch: Oh, look, JEHOVAH did it.

700 AD: Oh, wait, Allah did it.

1850: Hold on, Brahma did it.

1920: Hold the fort, the Big Bang did it.

That would go over real well, wouldn't it?

Does it ever get tiring to have to always propose banal ad hoc explanations from an archaic book. Do you really find this satisfying on an intellectual level? Or do you write these pathetic responses to help assuage your own doubts? I sincerely pity you, that your religion keeps you from being able to celebrate human experience and knowledge.

Thanks for the QED.

 

[Ophiolite]

Thanks for the QED

I notice you've been relying on this line quite a lot recently. Be advised it is not working, except -perhaps -for yourself, which I suppose is the point. But in that case it is rather self indulgent.

 

[sjastro]

Another Physics World article about under represented groups in physics with a major focus again on women.
Towards a new equality narrative to encourage under-represented groups into physics – Physics World
Not all is bad news, creationists have a next to zero representation.

 

[Sif]

Here's a video by Anton Petrov on Dark Matter studies

I like watching Dr. Becky and Anton and enjoy their explanations.