Astronomical News

Coastaljames

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I saw the moon low in the night sky at about 9pm last night, and there were two 'contrail' type clouds, one north-south and one east-west, with the moon directly where they crossed each other, making a nice white cross in the sky.

Hmm, thats interesting...
 

maximus otter

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Mysterious Radio Blasts From Space

Scientists discovered that so-called "giant radio pulses" coincide with X-rays, suggesting they are hundreds of times more energetic than previously thought.


In the year 1054, skywatchers in China and Japan witnessed light from an exploding star reach Earth, creating a dazzling bright spot in the sky. More than a millennium later, scientists have now revealed amazing new details about the powerful and unexplained radio signals that eerily emanate from the remains of this ancient supernova.

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Crab Nebula. Image: NASA/ESA, J. Hester and A. Loll (Arizona State University)

For years, scientists have been baffled by extremely loud radio signals, known as giant radio pulses (GRPs), that can be traced to a special type of dead star known as a pulsar. Pulsars are compact, rapidly rotating remnants of supernovae that get their name from the clockwork pulses of radiation they emit from their poles, which have made them useful natural timepieces for astronomers who use their regular bursts to measure other celestial phenomena.

For reasons that remain unexplained, some pulsars occasionally spew out GRPs that are hundreds to thousands of times brighter than regular pulsar radio signals. Now, scientists have discovered that GRPs are many times more energetic than previously thought.

One of the most infamous sources of GRPs is the Crab Pulsar, the remnant of the supernova spotted by skywatchers in 1054, which sits inside the Crab Nebula some 6,500 light years from Earth.

https://www.vice.com/en/article/n7b...om-space-just-got-a-whole-lot-weirder-somehow

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uair01

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2104.03902.pdf (arxiv.org)

The Autodidactic Universe

We present an approach to cosmology in which the Universe learns its own physical laws. It does so by exploring a landscape of possible laws, which we express as a certain class of matrix models.

We discover maps that put each of these matrix models in correspondence with both a gauge/gravity theory and a mathematical model of a learning machine, such as a deep recurrent, cyclic neural network. This establishes a correspondence between each solution of the physical theory and a run of a neural network. This correspondence is not an equivalence, partly because gauge theories emerge from N → ∞ limits of the matrix models, whereas the same limits of the neural networks used here are not well-defined. We discuss in detail what it means to say that learning takes place in autodidactic systems, where there is no supervision.

We propose that if the neural network model can be said to learn without supervision, the same can be said for the corresponding physical theory. 1 arXiv:2104.03902v1 [hep-th] 29 Mar 2021We consider other protocols for autodidactic physical systems, such as optimization of graph variety, subset-replication using self-attention and look-ahead, geometrogenesis guided by reinforcement learning, structural learning using renormalization group techniques, and extensions. These protocols together provide a number of directions in which to explore the origin of physical laws based on putting machine learning architectures in correspondence with physical theories.
 

Sid

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2104.03902.pdf (arxiv.org)

The Autodidactic Universe

We present an approach to cosmology in which the Universe learns its own physical laws. It does so by exploring a landscape of possible laws, which we express as a certain class of matrix models.

We discover maps that put each of these matrix models in correspondence with both a gauge/gravity theory and a mathematical model of a learning machine, such as a deep recurrent, cyclic neural network. This establishes a correspondence between each solution of the physical theory and a run of a neural network. This correspondence is not an equivalence, partly because gauge theories emerge from N → ∞ limits of the matrix models, whereas the same limits of the neural networks used here are not well-defined. We discuss in detail what it means to say that learning takes place in autodidactic systems, where there is no supervision.

We propose that if the neural network model can be said to learn without supervision, the same can be said for the corresponding physical theory. 1 arXiv:2104.03902v1 [hep-th] 29 Mar 2021We consider other protocols for autodidactic physical systems, such as optimization of graph variety, subset-replication using self-attention and look-ahead, geometrogenesis guided by reinforcement learning, structural learning using renormalization group techniques, and extensions. These protocols together provide a number of directions in which to explore the origin of physical laws based on putting machine learning architectures in correspondence with physical theories.
Imagine.jpg
 

Bigphoot2

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Lyrid Meteor Shower peaking on the morning of the 22nd. Nice clear skies here at the moment so I'll be having a look (if I'm not sleeping!).
2021 Lyrid meteor shower: All you need to know
Posted by Bruce McClure and Deborah Byrd in ASTRONOMY ESSENTIALS | TONIGHT | April 20, 2021
The Lyrids are an Earth Day meteor shower, peaking on the morning of April 22. Also, try the next morning, April 23. The moon is waxing – staying out longer after dark each night – so you’ll want to watch the time of moonset carefully.

The annual Lyrid meteor shower always brings an end to the meteor drought, which happens each year between January and mid-April. There are no major meteor showers during that time, as you can see by looking at EarthSky’s meteor shower guide. The Lyrids are active each year from about April 16 to 25. In 2021, we expect the shower to peak in the predawn hours on Thursday, April 22. The following morning (April 23) might be good too, if you’re game.
etc

https://earthsky.org/astronomy-essentials/everything-you-need-to-know-lyrid-meteor-shower
 

maximus otter

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The closest black hole to Earth has been christened "The Unicorn".

Astronomers have discovered one of the smallest black holes to date, sitting just 1,500 light-years away which also makes it the closest one to Earth found so far. And they have called it "the Unicorn."

The black hole was given the nickname in part because it's so rare but also because it was discovered in the constellation Monoceros, which means unicorn, according to a release from the Ohio State University.

Though it's roughly three times the mass of our sun, the size is considered tiny for a black hole.

1619256147502.jpeg


"The Unicorn" appears to be a companion to a red giant star, which is how scientists were able to find it. Since black holes aren't visible, researchers were able to locate this one after analyzing data documenting certain changes in the companion star. After noticing something was causing the red giant's intensity and appearance to change, researchers noticed something was pulling at the star, an effect known as a tidal distortion.

https://eu.usatoday.com/story/news/...n-may-smallest-one-discovered-yet/7349740002/

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maximus otter

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Proxima Centauri shoots out humongous flare

Scientists have spotted one of the largest stellar flares ever recorded in our galaxy. The jets of plasma shot outward from the sun's nearest neighbor, the red dwarf star Proxima Centauri. The flare, which was around 100 times more powerful than any experienced in our solar system, could change the way scientists think about solar radiation and alien life.

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Stock image

Proxima Centauri is a red dwarf — the smallest, dimmest and most common type of main sequence stars in the galaxy — located approximately 4.25 light-years from Earth. Its mass is only one-eighth of the sun's, and it is orbited by two exoplanets. One of these planets, Proxima Centauri b, is considered to be Earth-like and lies within the star's habitable zone — the distance from a star that could support the development of life, according to the researchers.

On May 1, 2019, the team captured the mega flare, which shone for just 7 seconds and was mainly visible in the ultraviolet spectrum.

"The star went from normal to 14,000 times brighter when seen in ultraviolet wavelengths over the span of a few seconds," [said] Meredith MacGregor, an astrophysicist at the University of Colorado, Boulder.

https://www.space.com/proxima-centauri-emits-largest-stellar-flare.html

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maximus otter

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Scientists Spot Yet Another Unexplained Ring-Shaped Radio Structure In Space

Scientists have spotted yet another bizarre, gigantic, and unexplained circle-shaped radio structure in outer space, a discovery that contributes to “exciting times in astronomy.”


The bubble is the latest example of an Odd Radio Circle (ORC), an aptly named type of spectral ring that debuted in a 2020 paper led by Western Sydney University astrophysicist Ray Norris. Norris and his colleagues detected four of these enormous circles eerily glowing in faint radio wavelengths far beyond our galaxy.

Now, scientists led by Bärbel Koribalski, a research scientist at CSIRO's Australia Telescope National Facility, have discovered a fifth ORC that appears to span about one million light years.

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ASKAP images of the new ORC. Image: Koribalski et al. 2021

This structure, named ORC J0102–2450, also looks like it has an elliptical galaxy at its center, a feature it shares with two of the ORCs found by Norris’ team.

The team suggests that “a giant blast wave in the central galaxy” that produces “a spherical shell of radio emission” might be the progenitor of ORCs, according to the study. One possible trigger of such a large-scale spherical shock could be the merger of two supermassive black holes during a galactic collision.

https://www.vice.com/en/article/5db...xplained-ring-shaped-radio-structure-in-space

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