Using Webb’s NIRCam and NIRSpec instruments, astronomers have obtained the deepest spectrum ever taken of a little red dot.
The post Webb Delivers Strongest-Ever Case for ‘Black Hole Stars’ Lurking in Early Universe appeared first on Sci.News: Breaking Science News.
Scientists from Goethe University, Frankfurt, studying alternatives to black holes have suggested a mathematically viable formation mechanism for one proposed alternative called a ‘Gravastar.’
Although the team behind the newly proposed gravastar formation mechanism conceded that black holes still represent the simplest and most natural solution to gravitational collapse, they also suggest that the physics behind the alternative, which doesn’t require a single point where spacetime curves infinitely, called a “singularity,” can make them “easier to accept” than black holes.
If correct, and some or all black holes are, in fact, gravastars that mimic their expected properties, the work would establish a valid formation mechanism that could rewrite decades of accepted science and open a new field of research dedicated to understanding this previously misunderstood phenomenon.
According to standard cosmology theories, black holes form when extremely massive stars stop generating energy, allowing the force of gravity to take over and collapse the remaining matter into a single point, or singularity. Unfortunately, the research team behind the new study notes that “the laws of physics break down” within the singularity, making the formation of the resulting black hole a difficult phenomenon to predict.
“How can spacetime be curved infinitely at that point, the singularity?” asks the team’s statement announcing the new approach. They also note that no information escapes a black hole, including light, making studying its inner workings effectively impossible, and opening up the possibility that “black holes are in fact entirely different objects.”
Some options have been proposed, including ‘horizonless’ black hole mimickers. The team notes that these proposed options are “mathematically consistent alternatives” that also address the physics challenges posed by traditional black holes.
Still, how these alternative objects form has remained largely unclear. The research team said this lack of a formation mechanism constitutes “a significant open problem” since understanding how they form is the “first step” to determining if they truly exist.
In the new formation model, theoretical physicists Daniel Jampolski and Theoretical Astrophysics Professor Luciano Rezzolla from Goethe University showed that the collapse of a dying star may not go far enough that it reaches the point of no return, where “the collapse to a black hole is inevitable.”
Instead, the collapse slows down near a point scientists call the Schwarzschild radius, then stops. The result is what the team termed a “miniature universe” within the collapsing matter, which they compared to the dynamics of the Big Bang, which most theorists agree formed the entire universe.
Since the universe’s expansion was driven by dark energy, the new model proposes that the dark energy within the mini-universe establishes an “equilibrium” with the counteracting force of gravity, therefore halting the collapse of the star “before a black hole can form.”
“The Big Bang of the emerging universe can unfold once the star has already collapsed almost to the point of becoming a black hole,” explained Jampolski, who discovered the black hole alternative gravastar solution in his master’s thesis while under the supervision of Professor Rezzolla.
When discussing the impact of their proposed black hole alternative formation model, Jampolski said that from a mathematical and physics standpoint, it is “easier to imagine that the Big Bang occurs only at a very late stage, when matter has already been compressed to an extreme degree, thereby giving rise to new effects.” The team also notes that the unresolved behavior of matter in this environment “leaves room for new physics.”
Although the team’s model offers a mathematically sound formation for an alternative to black holes, Rezzolla notes that the search for gravastars or other alternatives “should not suggest a skepticism towards black holes,” which, he adds, “still represent the most natural and simplest solution to the fate of gravitational collapse.”
Instead, the Goethe professor explained, his general role as a scientist and his specific discipline as a theoretical physicist make it essential that he and his colleagues “maintain an unbiased approach towards what we do not know and hence explore both the accepted wisdom and the more exotic interpretations.”
“History teaches us that it is not unusual for the latter to become the former,” the professor added.
The paper “Formation of gravastars” was published in the journal Physical Review D.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.
Using NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton satellite, astronomers identified a possible remnant of ancient stellar explosion just a few dozen light-years from Sagittarius A*, a supermassive black hole at the center of our Milky Way Galaxy.
The post Astronomers May Have Found Supernova Remnant near Milky Way’s Central Black Hole appeared first on Sci.News: Breaking Science News.
The giant planet’s bow shock isn’t just deflecting the solar wind, it’s acting as a powerful particle accelerator, firing electrons to relativistic energies of at least 1 MeV, according to a new analysis of data from NASA’s Juno spacecraft.
The post Jupiter Accelerates Electrons to Near-Light Speed, Offering Clues to Cosmic Ray Origins appeared first on Sci.News: Breaking Science News.
A Breathhh é uma extensão para o browser com ferramentas para quem se preocupa com o bem-estar e, além de sugerir pausas ao longo do dia, conta com exercícios práticos de respiração e alongamentos, bem como ferramentas de produtividade.
The post Passa horas no computador? Breathhh ajuda a fazer pausas para respirar e alongar ao longo do dia appeared first on Tek Notícias.
A stunning new image from the 8.1-m Gemini North telescope, located on the summit of Maunakea in Hawai’i, reveals the Crystal Ball Nebula in unprecedented detail: a lumpy, glowing sphere of gas sculpted by a pair of stars.
The post Gemini North Telescope Peers into Crystal Ball Nebula appeared first on Sci.News: Breaking Science News.
The Star Wars series depicted alien heroes fighting against evildoers and their planet-destroying superweapons “a long time ago in a galaxy far, far away.” But what do scientists really know about alien planets in distant galaxies beyond our own? These worlds, known as extragalactic exoplanets, are expected to exist, assuming the Milky Way is no different from other galaxies. However, we have yet to find them since other galaxies are still too far, far away for modern exoplanet-observing techniques.
Recently, a team of astronomers analyzed a stream of over 700,000 stars that the Milky Way likely absorbed from the dissolving Sagittarius dwarf galaxy. These stars are very distant, so the team investigated whether any of them host large, close-orbiting exoplanets called hot Jupiters, which are relatively easy to find.
They established a set of 3 criteria to narrow down their list of stars. First, each star should appear bright enough when observed by the Transiting Exoplanet Survey Satellite, or TESS, to ensure high-precision results from the team’s data processing software. Second, each star must have more than a 50% likelihood that it originated from the Sagittarius dwarf galaxy, based on motion and position measurements from the Gaia mission. Finally, each star should have a radius of less than twice the Sun’s, as it’s easier to find planets around smaller stars. They used these criteria to limit their candidate list to around 20,000 stars.
After selecting their candidate stars, the team analyzed publicly available TESS catalog data using the software packages eleanor and TESS-Gaia Light Curve, or TGLC. These tools allowed them to plot each star’s brightness over time, in graphs called light curves. Then, the astronomers looked for periodic brightness dips in these light curves as evidence that an exoplanet passed in front of the star. From this, they excluded several thousand additional stars with too much light interference from their surroundings, reducing their final sample size to just over 15,000 stars.
To find hot Jupiters, the team looked for brightness dips at intervals of 14 hours to 10 days, which is the typical orbital period range for hot Jupiters. Then, they used geometry to derive each exoplanet’s radius from the fraction of the starlight it blocked. They excluded candidates with dips corresponding to objects with radii at least twice that of Jupiter’s, as these are likely caused by orbiting companion stars rather than exoplanets.
Among all the stars they surveyed, the team’s strongest candidate to host a hot Jupiter was a star labeled TIC 92223525. They calculated that this star could host an exoplanet with a radius 1.76 times the size of Jupiter’s and an orbital period of 7.2 days. However, when they reviewed this star’s light curve, they found that it was likely contaminated by its neighbor, TIC 92223526. The regular brightness dips from this system of orbiting stars mimicked that of an exoplanet, creating a false positive for TIC 92223525 that was difficult to detect during initial screening. As a result, the team ultimately excluded this candidate, leaving them with no confirmed exoplanets.
The researchers drew several conclusions from their inability to find hot Jupiters in their sample of stars from the Sagittarius dwarf stream. They estimated that if more than 1% of these stars hosted hot Jupiters, it would have been highly unlikely not to detect one in a sample of over 15,000 stars. This places an upper limit of about 1% on the occurrence rate of hot Jupiters. If this estimate is accurate, then even an ideal exoplanet search team would need to examine over 11,000 stars to find an extragalactic hot Jupiter. Accounting for more realistic levels of scientific uncertainty, a future team would likely need to study at least 80,000 stars to find one.
Although this survey of the Sagittarius dwarf stream yielded null results, the team suggested that future researchers continue searching it and other star streams from different galaxies. Scientists have identified over 20 such streams in the Milky Way. Researchers studying these streams could find the first extragalactic exoplanet or provide evidence that other galaxies produce fewer hot Jupiters than our own. But let’s hope none of them find the first extragalactic Death Star!
The post Searching for planets in a galaxy far away appeared first on Sciworthy.
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