Today, we are bringing other exciting results involving black holes and AI. We released a new paper:

"Black Hole Weather Forecasting with Deep Learning: A Pilot Study"

Work by Roberta Duarte (@import_robs), Rodrigo Nemmen (@nemmen) and João Paulo Navarro (from @NVIDIABrasil).

The authors used deep learning to simulate the dynamics of gas accreting onto a black hole, i.e., black hole weather forecasting.

They trained the model (U-Net) with frames from numerical solutions of the hydrodynamical equations.
Numerical simulations are time-consuming. A simple simulation can take as long as 7 days to finish. If we go with more complex simulations, this time may increase.

We want to investigate if deep learning can be a new method to simulate accurately in less time!
In the paper, they discussed two examples:

1- The model simulating only one system after learning only from this system
2- The model simulating an unseen system after training with several systems with different initial conditions
In the first example, they trained the model with a single system and analyzed how the model simulates by iterative predictions.

The result is that the model can simulate up to 8e4 gravitational time accurately with a speed-up of 30000x faster!
In the 2nd example, they fed the model seven different simulations with the same physics but other initial conditions. They informed the model how the initial conditions differ from one to another.

However, they hid one system to understand the generalization power of the model!
They analyzed how the model can simulate an unseen system only by looking at previous systems!

It simulated the unseen system for 4e4 gravitational time, showing that the model can generalize the black hole physics presented in the dataset!
In the second example, the model can also simulate the systems it learned from:
For more details, please check it out on arXiv: https://t.co/VBh3RQnhov

More from Science

@mugecevik is an excellent scientist and a responsible professional. She likely read the paper more carefully than most. She grasped some of its strengths and weaknesses that are not apparent from a cursory glance. Below, I will mention a few points some may have missed.
1/


The paper does NOT evaluate the effect of school closures. Instead it conflates all ‘educational settings' into a single category, which includes universities.
2/

The paper primarily evaluates data from March and April 2020. The article is not particularly clear about this limitation, but the information can be found in the hefty supplementary material.
3/


The authors applied four different regression methods (some fancier than others) to the same data. The outcomes of the different regression models are correlated (enough to reach statistical significance), but they vary a lot. (heat map on the right below).
4/


The effect of individual interventions is extremely difficult to disentangle as the authors stress themselves. There is a very large number of interventions considered and the model was run on 49 countries and 26 US States (and not >200 countries).
5/

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THE MEANING, SIGNIFICANCE AND HISTORY OF SWASTIK

The Swastik is a geometrical figure and an ancient religious icon. Swastik has been Sanatan Dharma’s symbol of auspiciousness – mangalya since time immemorial.


The name swastika comes from Sanskrit (Devanagari: स्वस्तिक, pronounced: swastik) &denotes “conducive to wellbeing or auspicious”.
The word Swastik has a definite etymological origin in Sanskrit. It is derived from the roots su – meaning “well or auspicious” & as meaning “being”.


"सु अस्ति येन तत स्वस्तिकं"
Swastik is de symbol through which everything auspicios occurs

Scholars believe word’s origin in Vedas,known as Swasti mantra;

"🕉स्वस्ति ना इन्द्रो वृधश्रवाहा
स्वस्ति ना पूषा विश्ववेदाहा
स्वस्तिनास्तरक्ष्यो अरिश्तनेमिही
स्वस्तिनो बृहस्पतिर्दधातु"


It translates to," O famed Indra, redeem us. O Pusha, the beholder of all knowledge, redeem us. Redeem us O Garudji, of limitless speed and O Bruhaspati, redeem us".

SWASTIK’s COSMIC ORIGIN

The Swastika represents the living creation in the whole Cosmos.


Hindu astronomers divide the ecliptic circle of cosmos in 27 divisions called
https://t.co/sLeuV1R2eQ this manner a cross forms in 4 directions in the celestial sky. At centre of this cross is Dhruva(Polestar). In a line from Dhruva, the stars known as Saptarishi can be observed.