Circa 2020
It was an old idea of Stephen Hawking’s: Unseen “primordial” black holes might be the hidden dark matter. A new series of studies has shown how the theory can work.
The thing is, it could be—and a University of Michigan physicist is using quantum computing and machine learning to better understand the idea, called holographic duality.
A study by the University of Bonn: Observations fit poorly with the Standard Model of Cosmology.
The Standard Model of Cosmology describes how the universe came into being according to the view of most physicists. Researchers at the University of Bonn have now studied the evolution of galaxies within this model, finding considerable discrepancies with actual observations. The University of St. Andrews in Scotland and Charles University in the Czech Republic were also involved in the study. The results have now been published in the Astrophysical Journal.
Most galaxies visible from Earth resemble a flat disk with a thickened center. They are therefore similar to the sports equipment of a discus thrower. According to the Standard Model of Cosmology, however, such disks should form rather rarely. This is because in the model, every galaxy is surrounded by a halo of dark matter. This halo is invisible, but exerts a strong gravitational pull on nearby galaxies due to its mass. “That’s why we keep seeing galaxies merging with each other in the model universe,” explains Prof. Dr. Pavel Kroupa of the Helmholtz Institute for Radiation and Nuclear Physics at the University of Bonn.
It’s hard to spot a black hole.
There are two different approaches to such detection. In “X-ray binary stars” — in which a star and a black hole orbit a shared center while producing X-rays — a black hole’s gravitational field can pull material from its companion. The material circles the black hole, heating up by friction as it does so.
The hot material glows brightly in X-ray light, making the black hole visible, before being sucked into the black hole and disappearing. You can also detect pairs of black holes as they merge together, spiraling inwards and emitting a brief flash of gravitational waves, which are ripples in spacetime.
Continue reading “Scientists may have just found an invisible black hole — should you be worried?” »
Astronomers found that parts of the galaxy where stars are born were being protected from these powerful outflows thanks to its structure.
The nature of dark matter continues to perplex astronomers. As the search for dark matter particles continues to turn up nothing, it’s tempting to throw out the dark matter model altogether, but indirect evidence for the stuff continues to be strong. So what is it? One team has an idea, and they’ve published the results of their first search.
The conditions of dark matter mean that it can’t be regular matter. Regular matter (atoms, molecules, and the like) easily absorbs and emits light. Even if dark matter were clouds of molecules so cold they emitted almost no light, they would still be visible by the light they absorb. They would appear like dark nebula commonly seen near the galactic plane. But there aren’t nearly enough of them to account for the effects of dark matter we observe. We’ve also ruled out neutrinos. They don’t interact strongly with light, but neutrinos are a form of “hot” dark matter since neutrinos move at nearly the speed of light. We know that most dark matter must be sluggish, and therefore “cold.” So if dark matter is out there, it must be something else.
In this latest work, the authors argue that dark matter could be made of particles known as scalar bosons. All known matter can be placed in two large categories known as fermions and bosons. Which category a particle is in depends on a quantum property known as spin. Fermions such as electrons and quarks have fractional spin such as 1/2 or 3/2. Bosons such as photons have an integer spin such as 1 or 0. Any particle with a spin of 0 is a scalar boson.
Machine learning can work wonders, but it’s only one tool among many.
Artificial intelligence is among the most poorly understood technologies of the modern era. To many, AI exists as both a tangible but ill-defined reality of the here and now and an unrealized dream of the future, a marvel of human ingenuity, as exciting as it is opaque.
It’s this indistinct picture of both what the technology is and what it can do that might engender a look of uncertainty on someone’s face when asked the question, “Can AI solve climate change?” “Well,” we think, “it must be able to do *something*,” while entirely unsure of just how algorithms are meant to pull us back from the ecological brink.
Continue reading “Astronomers spot a wandering black hole in empty space for the first time” »
https://www.youtube.com/watch?v=mRvbSIVjkhM
Professor Stephen Hawking might have died before the James Webb Space Telescope finally launched. Still, due to the vast space legacy of the late physicist, many hours of the new space telescope will be dedicated to proving some of his theories! One of such theories is the very last one Hawking worked on before his death, in which he argued about a multiverse theory that implies an exact copy of you existed in a parallel universe! What is the multiverse theory, and will the James Webb Space Telescope finally prove Stephen Hawking’s multiverse theory?
Stephen Hawking died in 2018, missing the launch of the James Webb Space Telescope by more than three and a half years. That was thanks to multiple delays that pushed the launch date from between 2007 and 2011. It also gulped about 10 billion dollars, about ten times the initial budget. However, following a successful launch and deployment of its components, this powerful space telescope will undergo several months of calibrating and testing before settling down to work.
Thanks to the large 6.5 meter giant mirror that had to be folded during launch, the telescope will be able to peer into the atmospheres of planets outside our Solar System and peek through massive clouds of dust to watch the birth of new stars and planetary systems. JWST will be able to gather and reflect light from the early Universe. The Universe is thought to be around 13.8 billion years old, and JWST will be able to observe light from the earliest stars and galaxies, close to the Big Bang!
The JWST is an infrared telescope, meaning it uses infrared radiation to detect objects in space. It is able to observe celestial bodies, such as stars, nebulae, and planets that are too cool or too faint to be observed in visible light, that is, what is visible to the human eye. According to NASA, infrared radiation can also pass through gas and dust, which appear opaque to the human eye. This is different from the world-famous Hubble Telescope, which sees visible light, ultraviolet radiation, and near-infrared radiation. In order for the instruments aboard to work, they need to be kept at extremely cold temperatures,-370 degrees Fahrenheit or lower. The large sunshield protects the telescope from the heat of the sun and keeps the instruments cold.
According to a report conducted by an independent review board in 2018, there were 344 “single-point failures,” or steps that needed to work for the mission to succeed! However, the telescope was tucked inside the nose of an Ariane 5 rocket and launched safely from the European Space Agency’s Spaceport in French Guiana in December last year! It separated from the rocket after the launch and began unfolding. According to NASA, about 30 minutes after the launch, the first deployment took place as the solar panels unfolded so the telescope could get power from the sun!
Because of JWST’s capabilities, many astronomers are vying for time with the telescope. The Space Telescope Science Institute, which oversees science operations on Hubble and JWST, had sent out a call to astronomers for proposals on how they’d like to use James Webb, with 6,000 hours of observation time up for grabs! The lucky ones have now received approvals for their projects, and we look forward to the wealth of knowledge they will enrich us with! There is plenty of time for the JWST to unlock the deep secrets of the Universe, with about 20 years of operation guaranteed by the amount of fuel aboard the space telescope.
With the JWST safely delivered to its location about one million miles away from the earth, is it time to confirm one of Hawking’s most intriguing theories, the multiverse concept? The theory is special because it was the last one published by the professor! In fact, that final research from the sharp mind was submitted for publication just ten days before his death!
In the paper, titled “A smooth exit from eternal inflation?” which he co-authored with Thomas Hertog, a physicist at the Catholic University of Leuven in Belgium, Hawking laid out a theory on the origin of the Universe that might settle a few lingering questions. However, despite being his last work, the paper was actually a final look at one of his earliest theories. In fact, if the JWST eventually helps prove the existence of the multiverse, it will make the scientists behind it likely candidates for a Nobel Prize! However, since Nobel Prizes cannot be awarded posthumously, Hawking would be ineligible to receive it.
A team of astronomers noted a binary pair of black holes that may be on the verge of merging. The event could provide an unprecedented observing opportunity.
