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Category: physics – Page 93

Astronomers are currently pushing the frontiers of astronomy. At this very moment, observatories like the James Webb Space Telescope (JWST) are visualizing the earliest stars and galaxies in the universe, which formed during a period known as the “Cosmic Dark Ages.” This period was previously inaccessible to telescopes because the universe was permeated by clouds of neutral hydrogen.

As a result, the only light is visible today as relic radiation from the Big Bang—the (CMB)—or as the 21 cm spectral line created by the reionization of hydrogen (aka the Hydrogen Line).

Now that the veil of the Dark Ages is being slowly pulled away, scientists are contemplating the next frontier in astronomy and cosmology by observing “primordial ” created by the Big Bang. In recent news, it was announced that the National Science Foundation (NSF) had awarded $3.7 million to the University of Chicago, the first part of a grant that could reach up to $21.4 million. The purpose of this grant is to fund the development of next-generation telescopes that will map the CMB and the gravitational waves created in the immediate aftermath of the Big Bang.

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This particular burst, called GRB 230307A, was likely created when two neutron stars — the incredibly dense remnants of stars after a supernova — merged in a galaxy about one billion light-years away. In addition to releasing the gamma-ray burst, the merger created a kilonova, a rare explosion that occurs when a neutron star merges with another neutron star or a black hole, according to a study published Wednesday in the journal Nature.

The Space Telescope Science Institute in Baltimore is the mission operations center for the telescope. It launched last in 2021 from French Guiana.

“There are only a mere handful of known kilonovas, and this is the first time we have been able to look at the aftermath of a kilonova with the James Webb Space Telescope,” said lead study author Andrew Levan, astrophysics professor at Radboud University in the Netherlands. Levan was also part of the team that made the first detection of a kilonova in 2013.

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Dutch-born Christiaan Huygens is probably one of the most famous physicists you’ve never heard of. His work in the late 17th century straddled both the intangible and tangible realms of our Universe: the nature of light, and the mechanics of moving objects.

Among his many contributions, Huygens proposed a wave theory of light that would give rise to physical optics, which deals with the interference, diffraction, and polarization of light. He also invented the first pendulum clock; the most accurate timekeeper for almost 300 years, right through the Industrial Revolution.

Little has been made of the connections between these two seemingly disparate fields of optics and classical mechanics – until now.

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Researchers have developed a new computer simulation of the early universe that closely aligns with observations made by the James Webb Space Telescope (JWST).

Initial JWST observations hinted that something may be amiss in our understanding of early galaxy formation. The first galaxies studied by JWST appeared to be brighter and more massive than theoretical expectations.

The findings, published in The Open Journal of Astrophysics, by researchers at Maynooth University, Ireland, with collaborators from US-based Georgia Institute of Technology, show that observations made by JWST do not contradict theoretical expectations. The so-called “Renaissance simulations” used by the team are a series of highly sophisticated computer simulations of galaxy formation in the early universe.

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The astrophysicists, from Trinity and the Breakthrough Listen team and Onsala Space Observatory in Sweden, are scanning the universe for “technosignatures” emanating from distant planets that would provide support for the existence of intelligent, alien life.

Using the Irish LOFAR telescope and its counterpart in Onsala, Sweden, the team—led by Professor Evan Keane, Associate Professor of Radio Astronomy in Trinity’s School of Physics, and Head of the Irish LOFAR Telescope—plans to monitor millions of star systems.

Scientists have been searching for extraterrestrial radio signals for well over 60 years. Many of these have been carried out using single observatories which limits the ability to identify signals from the haze of terrestrial interference on Earth. Much of the effort has focused on frequencies above 1 GHz because the single-dish telescopes employed operate at these frequencies.

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Modern computer models—for example for complex, potent AI applications—push traditional digital computer processes to their limits. New types of computing architecture, which emulate the working principles of biological neural networks, hold the promise of faster, more energy-efficient data processing.

A team of researchers has now developed a so-called event-based architecture, using photonic processors with which data are transported and processed by means of light. In a similar way to the brain, this makes possible the continuous adaptation of the connections within the neural network. This changeable connections are the basis for learning processes.

For the purposes of the study, a team working at Collaborative Research Center 1,459 (Intelligent Matter)—headed by physicists Prof. Wolfram Pernice and Prof. Martin Salinga and computer specialist Prof. Benjamin Risse, all from the University of Münster—joined forces with researchers from the Universities of Exeter and Oxford in the UK. The study has been published in the journal Science Advances.

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The simulated universe theory implies that our universe, with all its galaxies, planets and life forms, is a meticulously programmed computer simulation. In this scenario, the physical laws governing our reality are simply algorithms. The experiences we have are generated by the computational processes of an immensely advanced system.

While inherently speculative, the simulated theory has gained attention from scientists and philosophers due to its intriguing implications. The idea has made its mark in popular culture, across movies, TV shows and books—including the 1999 film “The Matrix.”

The earliest records of the concept that reality is an illusion are from ancient Greece. There, the question “What is the nature of our reality?” posed by Plato (427 BC) and others, gave birth to idealism. Idealist ancient thinkers such as Plato considered mind and spirit as the abiding reality. Matter, they argued, was just a manifestation or illusion.

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Researchers from the University of Southampton, together with colleagues from the universities of Cambridge and Barcelona, have shown it’s theoretically possible for black holes to exist in perfectly balanced pairs—held in equilibrium by a cosmological force—mimicking a single black hole.

Black holes are massive astronomical objects that have such a strong gravitational pull that nothing, not even light, can escape. They are incredibly dense. A black hole could pack the mass of the Earth into a space the size of a pea.

Conventional theories about , based on Einstein’s theory of General Relativity, typically explain how static or spinning black holes can exist on their own, isolated in space. Black holes in pairs would eventually be thwarted by gravity attracting and colliding them together.

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Whenever light interacts with matter, light appears to slow down. This is not a new observation and standard wave mechanics can describe most of these daily phenomena.

For example, when light is incident on an interface, the standard wave equation is satisfied on both sides. To analytically solve such a problem, one would first find what the wave looks like at either side of the interface, and then employ electromagnetic boundary conditions to link the two sides together. This is called a piecewise continuous solution.

However, at the boundary, the must experience an acceleration. So far, this has not been accounted for.

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Researchers have developed a potentially revolutionary superlens technique that once seemed impossible to see things four times smaller than even the most modern microscopes have seen before. Known as the ‘diffraction limit’ because the diffraction of light waves at the tiniest levels has prevented microscopes from seeing things smaller than those waves, this barrier once seemed unbreakable.

Many have tried to peer below this optical barrier using a technique that researchers in the field term ‘superlensing, including making customized lenses out of novel materials. But all have gathered too much light. Now, a team of physicists from the University of Sydney says they have discovered a viable path that peeks beyond the diffraction limit by a factor of four times, allowing researchers to see things smaller than ever seen before. And the way they did, it is like nothing anyone else has tried.

Breaking the Diffraction Limit by ‘Superlensing’ without a Superlens.

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