According to findings by physicists at Goethe University in Frankfurt, a gravastar could resemble a matryoshka doll. Credit: Daniel Jampolski and Luciano Rezzolla
Einstein’s inexhaustible field equations continue to predict strange stellar objects, and the latest one is a doozy – so strap on your helmet, inside which is another helmet, enclosing yet another helmet. This headset is modeled after a strange solution to the field equations described below, as well as an interesting neural study involving human speech in reverberant environments and predictions for the Atlantic Ocean over the next 20 million years .
Ordinary specimen
We all want to find dinosaur remains in soft tissue. For example, if permafrost loss is absolutely necessary to benefit the fossil fuel industry, we should at least extract a whole frozen triceratops from it, right? In 1931, diggers in the Italian Alps discovered a fossil footprint of a Tridentinosaurus antiquus; within the outline of its body is a dark material that has long been interpreted as a fossilized imprint of skin remains.
But researchers at the University of Cork recently conducted the first detailed analysis of the fossil and came to the disappointingly damp conclusion that the dark material is a painted coating. The use of varnishes or lacquers to preserve fossilized specimens was once a common practice. However, the analysis also revealed osteoderms, tiny bony scales, on the specimen’s back.
Unusual object
In 1916, German physicist Karl Schwarzchild proposed a solution to Einstein’s equations of general relativity so scandalous that Albert Einstein closed his doors and called the police: a black hole contained a singularity so gravitationally dense that it traveled through space -time like the Kool. -Help the man. The world of physics erupted in disbelief. Einstein sought to use his own equations to prove that black holes were impossible.
But eventually things calmed down and physicists turned to designing big bombs and wearing wide-brimmed hats. In 2001, physicists Pawel Mazur and Emil Mottola published another solution to Einstein’s equations proposing a new object: gravitational condensate stars, or gravastars.
Gravistars are as heavy as black holes and exert similar gravity; however, they do not have an event horizon or singularity. The interior of a gravastar contains exotic energy that exerts negative pressure against the gravitational forces compressing the object, and its surface is an extremely thin skin of ordinary matter.
Now, two physicists from Goethe University Frankfurt have proposed another solution to the field equations that describes a gravastar inside another gravastar: they call it a “nestar” and say it’s like a Russian matryoshka doll. Their solution allows for a series of nested gravastars because each successive gravastar is in self-gravitating equilibrium.
The authors write: “Although these ultra-compact objects are certainly very exotic, some of the solutions found offer an interesting alternative to a black hole by having an origin without a singularity, an interior full of matter, a surface of time-like matter and a compactness C → (1/2)–“.
Hungry Coat
What will you be doing in 20 million years? It might be possible to visit the Atlantic coastline between now and then if you’re not afraid of all the earthquakes that occur along the East Coast. Using computer modeling, researchers at the University of Lisbon predict that the subduction zone beneath the Strait of Gibraltar will eventually transform into an Atlantic subduction system similar to the “Ring of Fire” around the Pacific Ocean.
Their model does not rely on the formation of a new subduction system, which would require breaking the tectonic plates – they are far too difficult to break without, I don’t know, crushing them with a giant asteroid – but rather on the migration from Gibraltar. Strait subduction zone further inland from the Atlantic. And then, in geological terms, the Atlantic will “shut down” and begin to die, just as the Mediterranean Sea is panting.
Notably, the study, which relies on supercomputer processing, would have been impossible a few years ago. The Gibraltar subduction zone has been in a dormant period for about 1 million years, but when it wakes up, according to the model, it will migrate and eat breakfast (the oceanic lithosphere), a process of recycling the crust under the Eastern Atlantic into the Earth’s mantle.
Reverberations eradicated
Humans are extremely good at distinguishing speech from its own echoes in environments like canyons and parking lots, even though the echoes distort the sound of the original speech. And if you want to train an AI system to separate speech from its own echoes, you learn from the master: the slimy human brain. Researchers at Zhejiang University conducted a study using magnetoencephalography to record human neural activity while volunteers listened to a story with and without echo.
They compared these neural signals to computer models that simulate the brain’s adaptation to the echo or separate the echo from the original speech. Simulation of neural adaptation did not fully capture the observed brain responses; however, the simulation of speech/echo separation closely matched the brain activity of the study participants.
The results suggest that “auditory stream segregation” accounts for human abilities such as distinguishing words from a specific speaker in a noisy environment like a restaurant, as well as distinguishing speech in a reverberant space.
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Quote: Saturday Quotes: Einstein Revisited (Again); geological forecasts of the Atlantic; how the brain manages echoes (February 17, 2024) retrieved on February 18, 2024 from
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