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Huge stars might have formed in the first million years of the universe if there was enough matter clumped together, according to a computer model

This modern UFO case has been declared to be one of the most compelling ever.

The James Webb Space Telescope (JWST) continues to make amazing discoveries. This time in the constellation of Pictor where, in the Beta Pictoris system a massive collision of asteroids. The system is young and only just beginning its evolutionary journey with planets only now starting to form. Just recently, observations from JWST have shown significant energy changes emitted by dust grains in the system compared to observations made 20 years ago. Dust production was thought to be ongoing but the results showed the data captured 20 years ago may have been a one-off event that has since faded suggesting perhaps, an asteroid strike!

Beta Pictoris is a young star located 63 light years away in the constellation Pictor. It has become well known for its fabulous circumstellar disk of gas and dust out of which a new system of planets is forming. It has been the subject of many a study because not only does it provide an ideal opportunity to study planetary formation but one of those planets Beta Pictoris b has already been detected. 

Beta Pictoris is located about 60 light-years away towards the constellation of Pictor (the Painter’s Easel) and is one of the best-known examples of a star surrounded by a dusty debris disc. Earlier observations showed a warp of the disc, a secondary inclined disc and comets falling onto the star, all indirect, but tell-tale signs that strongly suggested the presence of a massive planet. Observations done with the NACO instrument on ESO’s Very Large Telescope in 2003, 2008 and 2009, have proven the presence of a planet around Beta Pictoris. It is located at a distance between 8 and 15 times the Earth-Sun separation — or Astronomical Units — which is about the distance Saturn is from the Sun. The planet has a mass of about nine Jupiter masses and the right mass and location to explain the observed warp in the inner parts of the disc. This image, based on data from the Digitized Sky Survey 2, shows a region of approximately 1.7 x 2.3 degrees around Beta Pictoris. Credit: ESO/Sky Survey II

Wind the clock back 20 years and the Spitzer infra-red observatory was observing Beta Pictoris. It was looking for heat being emitted by crystalline silicate minerals which are often found around young stars and on celestial bodies. Back in 2004-2005 no traces were seen suggesting a collision occurred among asteroids destroying them and turning their bodies into find dust particles, smaller even than grains of sand and even powdered sugar. 

Radiation was detected at the 17 and 24 micron wavelengths by Spitzer, the result of significant amounts of dust. Using JWST, the team studied radiation from dust particles around Beta Pictoris and were able to compare with these Spitzer findings. They were able to identify the composition and size of particles in the same area around Beta Pictoris  that was studied by Spitzer. They found a significant reduction in radiation at the same wavelengths from 20 years ago. 

The Spitzer Space Telescope observatory trails behind Earth as it orbits the Sun. Credit: NASA/JPL-Caltech

According to Christine Chen, lead astronomer from the John Hopkins University ‘With Webb’s new data, the explanation we have is that, in fact, we witnessed the aftermath of an infrequent, cataclysmic event between large asteroid-sized bodies, marking a complete change in our understanding of this star system.’

By tracking the distribution of particles across the circumstellar disk, the team found that the dust seems to have been dispersed outward by radiation from the hot young star. Previously with observations from Spitzer, dust surrounded the star which was heated up by its thermal radiation making it a strong thermal emitter. This is no longer the case as that dust has moved, cooled and no longer emits those thermal features. 

The discovery has adjusted our view of planetary system formation. Previous theories suggested that small bodies would accumulate and replenish the dust steadily over time. Instead, JWST has shown that the dust is not always replenished with time but that it takes a cataclysmic asteroid impact to seed new planetary systems with new dust. The team estimate the asteroid that was pulverised was about 100,000 times the size of the asteroid that killed the dinosaurs!

Source : WEBB TELESCOPE REVEALS ASTEROID COLLISION IN NEIGHBORING STAR SYSTEM

The post Webb Sees Asteroids Collide in Another Star System appeared first on Universe Today.

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We often assume that religious beliefs are no different in kind from ordinary factual beliefs―that believing in the existence of God or of supernatural entities that hear our prayers is akin to believing that May comes before June. Neuroscientist and philosopher Neil Van Leeuwen shows that, in fact, these two forms of belief are strikingly different. Our brains do not process religious beliefs like they do beliefs concerning mundane reality; instead, empirical findings show that religious beliefs function like the imaginings that guide make-believe play.

Van Leeuwen argues that religious belief―which he terms religious “credence”―is best understood as a form of imagination that people use to define the identity of their group and express the values they hold sacred. When a person pretends, they navigate the world by consulting two maps: the first represents mundane reality, and the second superimposes the features of the imagined world atop the first. Drawing on psychological, linguistic, and anthropological evidence, Van Leeuwen posits that religious communities operate in much the same way, consulting a factual-belief map that represents ordinary objects and events and a religious-credence map that accords these objects and events imagined sacred and supernatural significance.

It is hardly controversial to suggest that religion has a social function, but Religion as Make-Believe breaks new ground by theorizing the underlying cognitive mechanisms. Once we recognize that our minds process factual and religious beliefs in fundamentally different ways, we can gain deeper understanding of the complex individual and group psychology of religious faith.

Neil Van Leeuwen is Associate Professor of Philosophy and Neuroscience at Georgia State University and a recipient of the European Commission’s Marie Curie Fellowship. His research has been featured in The New York Times and The Atlantic and on NPR. His new book is Religion as Make-Believe: A Theory of Belief, Imagination and Group Identity.

Shermer and Van Leeuwen discuss:

• His own personal religious journey (or lack thereof)
• What is “make-believe” and “pretend play”?
• Believe vs. make-believe
• “I think” vs. “I believe”
• Beliefs and imagination: “many religious beliefs are imaginings of the sort that guide make-believe play, though they are imaginings that become central to the religious actor’s identity and guide symbolic actions that express sacred values.”
• Factual belief vs. religious credence
• Four principles of factual belief:
  • If you factually believe it, you can’t help believing it.
  • Factual beliefs guide actin across the bard.
  • Factual beliefs guide inferences in imagination
  • Factual beliefs respond to evidence.
• Tanya Luhrmann’s How God Becomes Real: Kindling the Presence of Invisible Others
• Ben Alderson-Day: Presence: The Strange Science and True Stories of the Unseen Other
• What does it mean to “take God seriously”?
• General religious credences vs. personal religious credences
• Willing suspension of disbelief
• Group identity
• Sacred values
• The Puzzle of Religious Rationality:
  • Solution 1: Religious belief as delusion
  • Solution 2: People are gullible
  • Solution 3: Religious belief as rational
  • Solution 4: Displaced content (Gould’s NMA)
  • Solution 5: Murky contents (God is 3 persons in 1)
  • Solution 6: No content
  • Solution 7: Belief in belief (Dennett)
  • Solution 8: Weak belief
  • Solution 9: A distinct cognitive attitude
• What is “that still small voice” we all hear in our heads?
• When people say they “hear the voice of God” what does that mean?
• Normal “voices within” vs. hallucinations and psychoses
• Psychiatrist Milton Rokeach’s book The Three Christs of Ypsilanti
• Anomalous psychological experiences
• Sleep paralysis and other cognitive anomalies
• Belief in angels and demons
• Sensed presences
• Empirical truths, religious truths, mythic truths
• How people come to religious belief vs. how they leave religion
• Witches and witchcraft.

If you enjoy the podcast, please show your support by making a $5 or $10 monthly donation.

Scientists have grown 'mini-guts' in the lab to help understand Crohn's disease, showing that 'switches' that modify DNA in gut cells play an important role in the disease and how it presents in patients. The researchers say these mini-guts could in future be used to identify the best treatment for an individual patient, allowing for more precise and personalized treatments.

Dark Matter is Nature’s poltergeist. We can see its effects, but we can’t see it, and we don’t know what it is. It’s as if Nature is playing tricks on us, hiding most of its mass and confounding our efforts to determine what it is.

It’s all part of the Universe’s “missing mass” problem. Actually, it’s our problem. The Universe is what it is. It’s our understanding of the Universe, mass, and gravity that’s the problem. And a solution is proving to be elusive.

Whatever the missing mass is or whatever causes the effects we observe, we have a placeholder name for it: dark matter. And it makes up 85% of the matter in the Universe.

Could dark matter be primordial black holes? Could it be axions? How about WIMPS? Are dark photons its force carrier? There’s lots of theoretical thought but no conclusion.

New research in the Monthly Notices of the Royal Astronomical Society says that our hunt for dark matter may be off-track. Instead of looking for a type of particle, the solution might lie in a type of topological defect found throughout the Universe that has its roots in the Universe’s early stages.

The new research is in a paper titled “The binding of cosmological structures by massless topological defects.” The author is Richard Lieu, a distinguished professor of physics and astronomy at the University of Alabama at Huntsville.

“There is then no need to perpetuate this seemingly endless search for dark matter.”

Dr. Richard Lieu, Professor, University of Alabama, Huntsville

As the paper’s title makes clear, dark matter has a binding effect on structures like galaxies. Astronomers know that galaxies don’t have enough measurable mass to hold themselves together. By measuring the mass of the stars and gas in galaxies, it became clear that the visible components of the galaxies don’t provide enough mass to hold themselves together. They should simply dissipate into their constituent stars and clouds of gas.

But galaxies don’t dissipate, and scientists have concluded that something is missing. Professor Lieu has another idea.

“My own inspiration came from my pursuit for another solution to the gravitational field equations of general relativity — the simplified version of which, applicable to the conditions of galaxies and clusters of galaxies, is known as the Poisson equation — which gives a finite gravitation force in the absence of any detectable mass,” said Lieu. “This initiative is in turn driven by my frustration with the status quo, namely the notion of dark matter’s existence despite the lack of any direct evidence for a whole century.”

An entire century is a long time in the age of modern science. It’s not surprising that Nature has the power to confound us, but it is somewhat surprising that very little progress has been made on the problem. Scientists have made great progress in understanding how dark matter influences the Universe’s large-scale structure, an impressive feat, but haven’t figured out what it is.

“The nature of dark matter (DM), defined specifically in this letter as an unknown component of the cosmic substratum responsible for the extra gravitational field that binds galaxies and clusters of galaxies, has been an enigma for more than a century,” Dr. Lieu writes in his paper.

Lieu’s work leans on phase transitions in the Universe. These are episodes when the state of matter in the Universe changes. Not locally but across the entire cosmos. One example is when the Universe cooled enough to allow the strong force to bind quarks into protons and neutrons.

Dr. Lieu contends that topological defects could have formed during one of these phase transitions. These defects can take the shape of shell-like compact regions where matter density is much higher. When arranged in concentric rings, these defects behave like gravity but don’t have mass.

“It is unclear presently what precise form of phase transition in the universe could give rise to topological defects of this sort,” Lieu says. “Topological effects are very compact regions of space with a very high density of matter, usually in the form of linear structures known as cosmic strings, although 2-D structures such as spherical shells are also possible. The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers — which is all one could measure, mass-wise — is exactly zero, but when a star lies on this shell it experiences a large gravitational force pulling it towards the center of the shell.”

So, despite our inability to measure the mass, it’s there, and other objects respond to it. Mass warps space-time and affects even massless photons. That fact underlies our ability to use gravitational lensing. We use the mass of galaxy clusters in gravitational lensing. A set of spherical shells, as Lieu talks about, could cause the same effect.

This illustration shows the gravitational lensing phenomenon. Astronomers use it to study very distant and very faint objects. Note that the scale has been greatly exaggerated in this diagram. In reality, the distant galaxy is much further away and much smaller. Image Credit: NASA, ESA & L. Calcada

“Gravitational bending of light by a set of concentric singular shells comprising a galaxy or cluster is due to a ray of light being deflected slightly inwards — that is, towards the center of the large-scale structure, or the set of shells — as it passes through one shell,” Lieu notes. “The sum total effect of passage through many shells is a finite and measurable total deflection which mimics the presence of a large amount of dark matter in much the same way as the velocity of stellar orbits.”

Since astronomers measure galaxy and galaxy cluster masses by measuring the light they deflect and the way they affect the orbit of stars, astronomers could be measuring topological defects rather than particles that comprise dark matter.

“Both the deflection of light and stellar orbital velocities is the only means by which one gauges the strength of the gravitational field in a large-scale structure, be it a galaxy or a cluster of galaxies,” Dr. Lieu says. “The contention of my paper is that at least the shells it posits are massless. There is then no need to perpetuate this seemingly endless search for dark matter.”

In 2022, researchers discovered a giant arc in the sky. It spans 1 Gigaparsec and is nearly symmetrical. It’s one of several large-scale structures that seems to go against the Standard Model and the Cosmological Principle it’s based on.

These are three separate data images of the Giant Arc discovered in 2022. The paper provides details. Image Credit: Lopez et al. 2022, 10.1093/mnras/stac2204

“The observation of giant arcs and rings could lend further support to the proposed alternative to the DM model,” Lieu writes in his paper. He also points out that the shells he proposes needn’t be a complete sphere.

If these shells exist, their alignment would also govern the formation and shape of galaxies and clusters. Future research will determine exactly how these shells form. “This paper does not attempt to tackle the problem of structure formation,” Lieu says. In fact, Lieu acknowledges that there’s currently no way to even observe how they might form.

“A contentious point is whether the shells were initially planes or even straight strings, but angular momentum winds them up. There is also the question of how to confirm or refute the proposed shells by dedicated observations,” Lieu says.

An experienced scientist, Lieu knows the limits of what he’s proposing.

“Of course, the availability of a second solution, even if it is highly suggestive, is not by itself sufficient to discredit the dark matter hypothesis — it could be an interesting mathematical exercise at best,” Lieu concludes. “But it is the first proof that gravity can exist without mass.”

The post If Gravity Can Exist Without Mass, That Could Explain Dark Matter appeared first on Universe Today.

Astronomers have discovered a rare hypervelocity L subdwarf star racing through the Milky Way. More remarkably, this star may be on a trajectory that causes it to leave the Milky Way altogether.

Peering deeply into the cosmos, NASA's James Webb Space Telescope is giving scientists their first detailed glimpse of supernovae from a time when our universe was just a small fraction of its current age. A team using Webb data has identified 10 times more supernovae in the early universe than were previously known. A few of the newfound exploding stars are the most distant examples of their type, including those used to measure the universe's expansion rate.

If a material absorbs light, it will heat up. That heat must go somewhere, and the ability to control where and how much heat is emitted can protect or even hide such devices as satellites. An international team of researchers has published a novel method for controlling this thermal emission in Science.

If a material absorbs light, it will heat up. That heat must go somewhere, and the ability to control where and how much heat is emitted can protect or even hide such devices as satellites. An international team of researchers has published a novel method for controlling this thermal emission in Science.

A newly developed radiotracer can generate high quality and readily interpretable images of cardiac amyloidosis, a condition referred to as the 'Alzheimer's disease of the heart.' As the first amyloid-specific and pan-amyloid binding radiotracer designed for planar and SPECT/CT imaging, 99mTc-p5+14 could play an important role in early detection and treatment of cardiac amyloidosis.

Nightmare material or truly man's best friend? A team of researchers equipped a dog-like quadruped robot with a mechanized arm that takes air samples from potentially treacherous situations, such as an abandoned building or fire. The robot dog walks samples to a person who screens them for potentially hazardous compounds.

Nightmare material or truly man's best friend? A team of researchers equipped a dog-like quadruped robot with a mechanized arm that takes air samples from potentially treacherous situations, such as an abandoned building or fire. The robot dog walks samples to a person who screens them for potentially hazardous compounds.

Researchers have developed -- and shared -- a process for creating brain cortical organoids -- essentially miniature artificial brains with functioning neural networks.

Researchers have developed -- and shared -- a process for creating brain cortical organoids -- essentially miniature artificial brains with functioning neural networks.

A framework based on advanced AI techniques can solve complex, computationally intensive problems faster and in a more more scalable way than state-of-the-art methods, according to a new study.

Astronomers have used new data from NASA's Hubble Space Telescope and the retired SOFIA (Stratospheric Observatory for Infrared Astronomy) as well as archival data from other missions to revisit one of the strangest binary star systems in our galaxy -- 40 years after it burst onto the scene as a bright and long-lived nova. A nova is a star that suddenly increases its brightness tremendously and then fades away to its former obscurity, usually in a few months or years.

Researchers have demonstrated the first chip-based 3D printer, a tiny device that emits reconfigurable beams of visible light into a well of resin that rapidly cures into a solid shape. The advance could enable a 3D printer small enough to fit in the palm of a person's hand.

Researchers have demonstrated the first chip-based 3D printer, a tiny device that emits reconfigurable beams of visible light into a well of resin that rapidly cures into a solid shape. The advance could enable a 3D printer small enough to fit in the palm of a person's hand.

Observing the earliest stars is one of the holy Grails of astronomy. Now, a team at the University of Hong Kong led by astronomer Jane Lixin Dai is proposing a new method for detecting them. If it works, the approach promises to open a window on the origin of the cosmos itself.

The earliest stars in the Universe formed very soon after the Big Bang. Astronomers call them “Population III” (or Pop III) stars. They’re different from the Sun and other stars in the modern cosmos for a variety of reasons. They formed mainly from the hydrogen and helium in the newborn cosmos. From there, they grew to outrageous sizes and masses very quickly. That growth had a price. Those stars had very short lives because they blew through their core fuels very quickly. However, fusion at their cores and the circumstances of their deaths created the first elements heavier than hydrogen and helium. Those new elements seeded the next generations of stars.

Population III stars were the Universe’s first stars. They were extremely massive, luminous stars, and many of them exploded as supernovae. Image Credit: DALL-E

So, why can’t we detect these early stellar behemoths? For one thing, they existed too far away, too early in history, and their light is very faint. That’s not to say they are undetectable. Astronomers just need advanced methods and technology to spot them.

How to “See” the First Stars

Professor Dai’s team just published a study that suggests a connection between these first stars and nearby black holes. In short, they looked at what happens when a Pop III star interacts with a black hole. Essentially, it gets torn to shreds and gobbled up. For example, the supermassive one at the heart of our Milky Way Galaxy—called Sagittarius A*— does this. It has a regular habit of ripping apart stars that wander too close. When such a tidal disruption event (TDE) happens, it releases huge amounts of radiation. If the same thing happens in another galaxy—no matter how far away—the light from the event is detectable. As it turns out these tidal disruption event flares have interesting and unique properties used to infer the existence of the ancient Pop III stars.

The alien star S0-6 is spiraling toward Sagittarius A*, the Milky Way’s central supermassive black hole. S0-6 likely came from another galaxy and it may get gobbled up or torn up by interactions with the supermassive black hole. Courtesy: Miyagi University of Education/NAOJ.

“As the energetic photons travel from a very faraway distance, the timescale of the flare will be stretched due to the expansion of the Universe. These TDE flares will rise and decay over a very long period of time, which sets them apart from the TDEs of solar-type stars in the nearby Universe,” said Dai.

In addition, the expansion of the Universe stretches the wavelengths of light from the flares, according to Dai’s colleague, Rudrani Kar Chowdhury. “The optical and ultraviolet light emitted by the TDE will be transferred to infrared emissions when reaching the Earth,” Chowdhury said. Those emissions are exactly the kind of light new generations of telescopes are built to observe.

Searching for First Stars with Advanced Telescopes

This detection method is right up the alley of the JWST and the upcoming Nancy Grace Roman telescopes. Both are optimized to sense dim, distant objects via infrared wavelengths. They should be able to search out the stretched light from those long-gone Pop III stars unfortunate enough to encounter a black hole. In particular, the Roman telescope will use its wide-field instrument to gather the faint infrared light from stars born at the earliest epochs of cosmic time.

Artist’s impression of the Nancy Grace Roman space telescope (formerly WFIRST). Credit: NASA/GSFC

Astronomers generally accept that these first stars formed perhaps as early as a hundred million years after the Big Bang. That’s when overly dense regions filled with hydrogen and helium began to experience gravitational collapse. The stars that formed in those first birth crèches were purely hydrogen and helium—in other words, they were “metal-free”. They lived perhaps a few million years before exploding as cataclysmic supernovae. (By comparison, the Sun has existed for some 4.5 billion years and has another few billion years left before it becomes a red giant and then a white dwarf.) The heavier elements created inside those first stars got blasted out to space, enriching the nearby molecular clouds with infusions of carbon, oxygen, nitrogen, and other elements. Some of the largest first stars could have collapsed directly to form black holes.

Finding these first stars and their emitted light (particularly from possible interactions with early black holes) will give astronomers amazing insight into conditions in the early Universe. Even though those stars are long gone, JWST, Roman, and other telescopes can look back in time and see their dim, infrared light. If Dai’s method works, those telescopes could be responsible for the discovery of tens of Pop III stars each year.

For More Information

HKU Astrophysicists Discover a Novel Method for Hunting the First Stars
Detecting Population III Stars through Tidal Disruption Events in the Era of JWST and RomanNancy Grace Roman Space Telescope

The post A New Way to Search for the First Stars in the Universe appeared first on Universe Today.