Today I Learned

[LCSphysicist]

LORENZ gauge! LORENZ, not Lorentz!
Unbelievable. Now i see the world with different eyes.

 

[Oldman too]

TIL, A SMBH can reverse it's magnetic field.
https://arxiv.org/pdf/2203.07446.pdf

 

[Rive]

TIL that my keyboard actually has four extra buttons which I've never noticed before.

I just had to tear apart the thing for it's first ever thorough cleaning for this revelation...

 

[DaveC426913]

TIL that my keyboard actually has four extra buttons which I've never noticed before.

I just had to tear apart the thing for it's first ever thorough cleaning for this revelation...

What?? Were they, like, molars waiting to erupt??
You have Wisdom Keys?

 

[fresh_42]

What?? Were they, like, molars waiting to erupt??
You have Wisdom Keys?

My guess is: Annie Key, Lost Key, Stuck Key, and Boss Key.

 

[Hornbein]

TIL, A SMBH can reverse it's magnetic field.
https://arxiv.org/pdf/2203.07446.pdf

According to the no-hair theorem a black hole doesn't have a magnetic field. The paper says an Active Galactic Nucleus reversed its field. So I'd say that it's all the junk in the accretion "disk" that reversed.

 

[collinsmark]

According to the no-hair theorem a black hole doesn't have a magnetic field. The paper says an Active Galactic Nucleus reversed its field. So I'd say that it's all the junk in the accretion "disk" that reversed.

Right. The accretion disk and the complicated mechanism that forms the jets of highly accelerated material that shoot out from either side, perpendicular to the disk.

(For clarity, I would highly doubt the accretion disk itself changed its direction of rotation. That would be a bit much. But the mechanism for the jet formation has been long thought to be powered by magnetic field interactions, and its not a trivial subject. There's a lot going on there.)

 

[Rive]

You have Wisdom Keys?

Kind of

Somebody just made the power buttons look like LEDs.
And since I've never used them, they just lingered there, unnoticed

 

[mfb]

LORENZ gauge! LORENZ, not Lorentz!
Unbelievable. Now i see the world with different eyes.

It's fine, there is the Lorentz-Lorenz equation!

 

[Ibix]

Buena suerte, tio.

 

[BillTre]

TIL there will be a double Nova show (two hours!) on PBS today, on the recent (last few years) findings on the meteor impact that ended the Age of the Dinosaurs. David Attenborough is the narrator.
It has my interest.

 

[Tom.G]

TIL there will be a double Nova show (two hours!) on PBS today, on the recent (last few years) findings on the meteor impact that ended the Age of the Dinosaurs. David Attenborough is the narrator.
It has my interest.

Is there a link to watch it on-line? (no TV here)

 

[BillTre]

There are probably PBS outlets with it if your are PBS site enabled (a member).
Here (https://www.pbs.org/video/dinosaur-apocalypse-the-last-day-h80ueb/) is one for me in Oregon. Don't know if you need to be a member to get there since I am a member and my computer automates these things. I found it with Google (Dinosaur Nova).

 

[BillTre]

It may be available through on-line services also.

 

[Tom.G]

The link in your post works fine, Thanks!

 

[pinball1970]

Kind of

Somebody just made the power buttons look like LEDs.
And since I've never used them, they just lingered there, unnoticed

I checked my keyboard after reading your post and there are three keys on there I have never used. No idea what they do, still don't but work got in the way so I didn't get round to checking.

 

[pinball1970]

TIL it's here already! It came round fast!

Event Horizon guys have a cool image to show us and it is going to be better than the black hole image in 2019.

The word 'groundbreaking' is used. That sounds like a deal.

I posted in Astrophysics with a link so you can watch it live.

https://www.physicsforums.com/threa...n-project-team-announcement-12th-may.1014741/

 

[Oldman too]

According to the no-hair theorem a black hole doesn't have a magnetic field. The paper says an Active Galactic Nucleus reversed its field. So I'd say that it's all the junk in the accretion "disk" that reversed.

Hi, sorry if the wording on my related post wasn't perfectly clear. It was made on my 42 wedding anniversary, about two margaritas into the celebration.
I'd like to clarify a couple of important points about the SMBH-reversal that I referenced. I wasn't implying that the accretion disc had reversed rotation, although MAD is referenced, I'm not certain that they are stating that's the disk's state either. What I was mentioning, is the magnetic field reversed as depicted in the attached image. Pages 17-18 of the arxiv paper are particularly useful information.
This is another way of viewing things, https://phys.org/news/2022-05-surging-distant-galaxy-black-holes.html

 

[berkeman]

TIL that professional baseball players now have "sliding mitts" to protect their precious soft handsies whild sliding. No callouses needed...

https://www.catchershome.com/sliding-mitt-for-baseball/

 

[MevsEinstein]

Today I learned a bit about elliptic curves.

 

[mfb]

Today I learned a bit about elliptic curves.

And I'll make a guess why: Andreas Enge found the smallest prime number with 50001 digits, which is the largest number confirmed to be prime using elliptic curves: 10^50,000 + 65,859.

 

[nsaspook]

TIL The origin of "gps told me to turn into a river".

 

[pinball1970]

TIL The origin of "gps told me to turn into a river".

Is that 'Tomorrow's world?'

 

[BillTre]

TIL (from a NY Times article) of an allergy to mammalian meat that can develop in people that get bit by the Lone Star Tick (identifiable by the white spot on its back). The tick is expanding its range due to climate change.

“The spatial distribution of the species has definitely increased by at least 30 to 50 percent in the last half a century,” said Ram Raghavan, an assistant professor in epidemiology and disease ecology at the University of Missouri, who has mapped the lone star tick’s spread. According to his research, the ticks are expected to continue to shift and expand their range; both to the north and west.

The allergy:

Alpha-gal syndrome is triggered by a complex sugar called galactose-alpha-1, 3-galactose, or alpha-gal, for short. The sugar is found in most mammals, but not in fish, reptiles, birds or humans. When the lone star tick feeds, alpha-gal is spread through its saliva, exposing the host’s immune system to the sugar. For some people, this triggers an overactive immune response the next time they encounter it.

 

[Ibix]

Today I learned that black herons do something called "canopy feeding" where they put their wings out in circles like umbrellas so that they don't look so bird-shaped to their prey looking up from the water.

Wikipedia has a pic.

 

[pinball1970]

TIL Some detail regarding the Titanic disaster enquiry via an interesting documentary, it is on youtube in its entirety.

I have seen a few of these but this focuses a little bit more on the combination of technical reasons that led to the disaster.

The ship design, materials, safety procedures, human errors etc

I checked to see if it was still the worst and it was not unfortunately. I have no recollection of the Dona Paz

https://en.wikipedia.org/wiki/List_...ss of the,the largest peacetime loss recorded.

 

[Jonathan Scott]

Today I learned that black herons do something called "canopy feeding" where they put their wings out in circles like umbrellas so that they don't look so bird-shaped to their prey looking up from the water.

Wikipedia has a pic.

That presumably works partly by creating a shady spot which fish are likely to move into and partly by making it easier for the bird to see the fish by reducing reflections of the sky.

 

[DaveC426913]

...making it easier for the bird to see the fish by reducing reflections of the sky.

This seems the most plausible.

 

[fresh_42]

Today I learned that black herons do something called "canopy feeding" where they put their wings out in circles like umbrellas so that they don't look so bird-shaped to their prey looking up from the water.

Wikipedia has a pic.

This behavior defined its German name: "bell-heron".

 

[sbrothy]

Today I learned that turtles can breathe using their butt.