Tag: stars

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Astronomers’ Search for Vanishing Stars Fails

Universe Today

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On July 19, 1952, Palomar Observatory was undertaking a photographic survey of the night sky. Part of the project was to take multiple images of the same region of sky, to help identify things such as asteroids. At around 8:52 that evening a photographic plate captured the light of three stars clustered together. At a magnitude of 15, they were reasonably bright in the image. At 9:45 pm the same region of sky was captured again, but this time the three stars were nowhere to be seen. In less than an hour they had completely vanished.

Stars don’t just vanish. They can explode, or experience a brief period of brightness, but they don’t vanish. And yet, the photographic proof was there. The three stars are clearly in the first image, and clearly not in the second. The assumption then is that they must have suddenly dimmed, but even that is hard to accept. Later observations found no evidence of the stars to dimmer than magnitude 24. This means they likely dimmed by a factor of 10,000 or more. What could possibly cause the stars to dim by such an astounding amount so quickly?
One idea is that they are not three stars, but one. Perhaps a star happened to brighten for a short time, such as a fast radio burst from a magnetar. While this happened, perhaps a stellar-mass black hole passed between it and us, causing the flare to gravitationally lens as three images for a brief time. The problem with this idea is that such an event would be exceedingly rare, but other photographic images taken during the 1950s show similar rapid disappearances of multiple stars. In some cases, the stars are separated by minutes of arc, which would be difficult to produce by gravitational lensing.
Another idea is that they weren’t stars at all. The three bright points are within 10 arcseconds of each other. If they were three individual objects, then something must have triggered their brightening. Given the timespan of about 50 minutes, causality and the speed of light would require they were no more than 6 AU apart. This means they would have to be no more than 2 light-years away. They could have been Oort Cloud objects where some event caused them to brighten around the same time. Later observations couldn’t find them because they had since drifted on along their orbits.
A third idea is that they weren’t objects at all. Palomar Observatory isn’t too far from the New Mexico deserts where nuclear weapons testing occurred. Radioactive dust from the tests could have contaminated the photographic plates, creating bright spots on some images and not others. Given similar vanishings seen on other photographic plates of the 1950s, this seems quite possible.
At this point, we can’t be sure. What we really need is to capture a few of these events in modern sky surveys, where we can quickly go back and make additional observations. For now, it’s a mystery waiting to be solved (https://arxiv.org/pdf/2310.09035.pdf).

AR #117

Secrets of the Stars

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Webb Finds Most Distant Star Ever Detected

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NASA’s James Webb Space Telescope has followed up on observations by the Hubble Space Telescope of the farthest star ever detected in the very distant universe, within the first billion years after the big bang. Webb’s NIRCam (Near-Infrared Camera) instrument reveals the star to be a massive B-type star more than twice as hot as our Sun, and about a million times more luminous.

The star, which the research team has dubbed Earendel, is located in the Sunrise Arc galaxy and is detectable only due to the combined power of human technology and nature via an effect called gravitational lensing. Both Hubble and Webb were able to detect Earendel due to its lucky alignment behind a wrinkle in space-time created by the massive galaxy cluster WHL0137-08. The galaxy cluster, located between us and Earendel, is so massive that it warps the fabric of space itself, which produces a magnifying effect, allowing astronomers to look through the cluster like a magnifying glass.  

While other features in the galaxy appear multiple times due to the gravitational lensing, Earendel only appears as a single point of light even in Webb’s high-resolution infrared imaging. Based on this, astronomers determine the object is magnified by a factor of at least 4,000, and thus is extremely small – the most distant star ever detected, observed 1 billion years after the big bang. The previous record-holder for the most distant star was detected by Hubble and observed around 4 billion years after the big bang. Another research team using Webb recently identified a gravitationally lensed star they nicknamed Quyllur, a red giant star observed 3 billion years after the big bang.
Stars as massive as Earendel often have companions. Astronomers did not expect Webb to reveal any companions of Earendel since they would be so close together and indistinguishable on the sky. However, based solely on the colors of Earendel, astronomers think they see hints of a cooler, redder companion star. This light has been stretched by the expansion of the universe to wavelengths longer than Hubble’s instruments can detect, and so was only detectable with Webb.

Since Hubble’s discovery of Earendel, Webb has detected other very distant stars using this technique, though none quite as far as Earendel. The discoveries have opened a new realm of the universe to stellar physics, and new subject matter to scientists studying the early universe, where once galaxies were the smallest detectable cosmic objects. The research team has cautious hope that this could be a step toward the eventual detection of one of the very first generation of stars, composed only of the raw ingredients of the universe created in the big bang – hydrogen and helium. 

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

AR #57

Project Stardust

by William Henry

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The Pole Shift Paradigm

by J. Douglas Kenyon

Our compasses may already be tracking the forces at work, but the good news is: Earth’s North and South magnetic poles are NOT about to swap positions—at least not any time soon. That is the conclusion of a new study published in June in the journal PNAS, Proceedings of the National Academy of Sciences of America (https://www.pnas.org/doi/full/10.1073/pnas.2200749119). Spotlighted in the study is something called the ‘South Atlantic Anomaly’ which some scientists have warned could signal an immanent and catastrophic reversal of the poles of Earth’s magnetic field that protects us from cosmic rays and space rocks.

While geographic pole shifts, as envisioned by the likes of Edgar Cayce, Charles Hapgood and others, are rejected by establishment science, no one denies that Earth’s magnetic pole is on the move. Triggered, it is believed, by molten iron at Earth’s core, the magnetic pole is distinct from the geographic pole which is determined by planetary rotation. Academic experts have predicted, in fact, that within fifty years, the north magnetic pole could shift far enough for Alaska to lose its famed northern lights (Aurora Borealis) to more southerly latitudes in Siberia and Europe.


Still, just as many worry about the dangers of catastrophic global warming, or the possibility of being hit by a space bolide (asteroid or comet), others are on the watch for a ‘pole shift,’ and they are not the first to worry about such a thing. As early as the 1950s maverick cartographer Charles Hapgood wrote that an advanced pre-diluvian civilization, possibly Atlantis, was destroyed by a sudden shift in the angle of Earth’s polar axis.


Also relevant may be Hapgood’s notion that significant periodic shifts in the planet’s geographic poles are at least one cause of what we call ice ages, where vast regions move quickly from temperate to cold areas and vice versa. Hapgood believed that the rapidity of this process accounts for the fact that undigested summer plants are found in the stomachs of mammoths frozen in Siberia. Incidentally many of Hapgood’s conclusions about pole shift were endorsed by Albert Einstein.


Harvard climate scientist professor Peter Huybers has used computer models to demonstrate that tiny shifts in Earth’s axis cause glaciers to either advance or retreat in cycles lasting either 10,000 or 40,000 years. In a 2011 paper published in the journal Nature, Huybers explained two cycles of tilt change, ‘obliquity’ and ‘precession’. When they align correctly, ice melts. When they oppose each other, glaciers advance.


Serbian geophysicist Milutin Milankovitch first argued the point a century ago. According to Milankovitch, Earth’s axis completes one full cycle of ‘precession’ approximately every 26,000 years. At the same time the elliptical orbit rotates more slowly. Milankovitch believed the combined effect of the two precessions leads to a 21,000-year period between the astronomical seasons and the orbit.


‘Precession’ is the cycle behind the so-called astrological ‘ages’ where the constellation which appears at sunrise, seems, over time, to shift slowly backward through the zodiac, at about two thousand years per astrological sign. By this reckoning we are now entering the age of Aquarius. Many modern alternative scholars, as well as ancient sages, have suggested that this ‘precession of the equinoxes’ tracks the rise and fall of civilizations.


Could pole shift have been behind enormous ancient catastrophic events, and should we be concerned about the possibility of history repeating itself? In Atlantis Rising Magazine #81, John White, author of the 1988 bestselling book, Pole Shift, wrote about what he called the “Doomsday Fallacy.”


“There are no problems,” he wrote, “there are only situations. Problems don’t exist in nature. Only situations exist, only sets of circumstances. It is the human mind which projects attitudes and values onto those situations and then labels them as problems. But that label doesn’t describe what nature is doing. It describes the state of mind of the human who labeled the situation.”

 

AR #127

POLE SHIFT AND THE PYRAMIDS

 

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Stars that Spin, and a Mysterious Galactic Signal

Australian Researchers have found an alternative explanation for a mysterious gamma-ray signal coming from the center of the galaxy, which was long claimed as a signature of dark matter. 

Gamma-rays are the form of electromagnetic radiation with the shortest wavelength and highest energy.  
Co-author of the study Associate Professor Roland Crocker at Australian National University said this particular gamma-ray signal—known as the Galactic Centre Excess—may actually come from a specific type of rapidly-rotating neutron star, the super-dense stellar remnants of some stars much more massive than our sun.  
The Galactic Centre Excess is an unexpected concentration of gamma-rays emerging from the center of our galaxy that has long puzzled astronomers.   


“Our work does not throw any doubt on the existence of the signal, but offers another potential source,” Associate Professor Crocker said. 


“It is based on millisecond pulsars — neutron stars that spin really quickly — around 100 times a second. 
“Scientists have previously detected gamma-ray emissions from individual millisecond pulsars in the neighborhood of the solar system, so we know these objects emit gamma-rays. Our model demonstrates that the integrated emission from a whole population of such stars, around 100,000 in number, would produce a signal entirely compatible with the Galactic Centre Excess.”  


The discovery may mean scientists have to re-think where they look for clues about dark matter. 

 

AR #122

“Mega Engineering in the Stars,”

by Robert M. Schoch, Ph.D.

 

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Could Binary Stars Host Alien Life?

Astronomers Want to Know

Nearly half of Sun-size stars are binary. According to researchers, planetary systems around binary stars may be very different from those around single stars. This points to new targets in the search for extraterrestrial life forms.

Since the only known planet with life, the Earth, orbits the Sun, planetary systems around stars of similar size are obvious targets for astronomers trying to locate extraterrestrial life. Nearly every second star in that category is a binary star. A new result from research at University of Copenhagen indicate that planetary systems are formed in a very different way around binary stars than around single stars such as the Sun.


“The result is exciting since the search for extraterrestrial life will be equipped with several new, extremely powerful instruments within the coming years. This enhances the significance of understanding how planets are formed around different types of stars. Such results may pinpoint places which would be especially interesting to probe for the existence of life,” says Professor Jes Kristian Jørgensen, Niels Bohr Institute, University of Copenhagen, heading the project.


The results from the project, which also has participation of astronomers from Taiwan and USA, are published in the distinguished journal Nature.


The new discovery has been made based on observations made by the ALMA telescopes in Chile of a young binary star about 1,000 lightyears from Earth. The binary star system, NGC 1333-IRAS2A, is surrounded by a disc consisting of gas and dust. The observations can only provide researchers with a snapshot from a point in the evolution of the binary star system. However, the team has complemented the observations with computer simulations reaching both backwards and forwards in time.


“The observations allow us to zoom in on the stars and study how dust and gas move towards the disc. The simulations will tell us which physics are at play, and how the stars have evolved up till the snapshot we observe, and their future evolution,” explains Postdoc Rajika L. Kuruwita, Niels Bohr Institute, second author of the Nature article.
Notably, the movement of gas and dust does not follow a continuous pattern. At some points in time – typically for relatively shorts periods of ten to one hundred years every thousand years – the movement becomes very strong. The binary star becomes ten to one hundred times brighter, until it returns to its regular state.


Presumably, the cyclic pattern can be explained by the duality of the binary star. The two stars encircle each other, and at given intervals their joint gravity will affect the surrounding gas and dust disc in a way which causes huge amounts of material to fall towards the star.


“The falling material will trigger a significant heating. The heat will make the star much brighter than usual,” says Rajika L. Kuruwita, adding:

“These bursts will tear the gas and dust disc apart. While the disc will build up again, the bursts may still influence the structure of the later planetary system.”

 

AR #93

“Sun’s Lost Twin Thought to Be Sirius”

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The Pleiades and the Very Long March of Time

Astronomy professor Ray Norris at Western Sydney University in Australia believes that he can explain a piece of ancient star lore found in cultures as far apart as Australia and Greece. In his forthcoming book Advancing Cultural Astronomy, Norris recounts legends of the Pleiades, also known as the “seven sisters.” The constellation appears in the northern sky at the beginning of winter.

Today, only six stars appear to the naked eye. The seventh star, is  so tightly aligned with one of the other stars as to be virtually invisible, yet equivalent myths regarding the missing star can be found in Europe, Africa, Asia, Indonesian, native American, and indigenous Australian. All these cultures speak of seven stars and have similar stories to account for the missing seventh. The seventh star, says Norris, was once clearly separate but has now moved so close to its neighbor, as to be indistinguishable to observers. The separation, says Norris, has not been visible for a hundred thousand years, and from that, he concludes that the myths telling the story must also date that far back. You can read his article on line: https://theconversation.com/the-worlds-oldest-story-astronomers-say-global-myths-about-seven-sisters-stars-may-reach-back-100-000-years-151568.

Myths of the “seven Sisters” are not the only clues referencing very ancient times to the Pleiades. The Nebra sky disk dating, to 1600 BC, is thought to depict the Pleiades. In the 1990s researcher Frank Edge reported that he had identified a celestial formation incorporated into cave drawings at Lascaux, France as the Pleiades. A series of black dots placed over the most prominent Bull in the famed hall of the bulls was, said Edge, the Pleiades. A few years later, the BBC mentioned the Lascaux’s design, but gave credit for the discovery to Dr. Michael Rappenglueck, a German professor from the University of Munich. “A prehistoric map of the night sky has been discovered on the walls of the famous painted caves at Lascaux in central France,” reported the BBC, and went on to describe the “map” as believed to date back 16,500 years.

In 2018, a University of Edinburg study of artworks at sites across Europe, including Lascaux, concluded that ancient cave art does not, as once thought, simply depict wild animals. Instead, the analysis showed, the animal symbols represented star constellations in the night sky, and were used to represent dates and to mark events such as comet strikes. As far back as 40,000 years ago, humans kept track of time using knowledge of how the position of the stars slowly changes over thousands of years. The findings suggest that long before the Greeks, ancient people understood the precession of the equinoxes.

The ‘precession of the equinoxes’ is the astronomical phenomenon that gives us the so-called astrological ages, as the point of the Spring equinox appears to move slowly backward through the zodiac at the rate of one sign (i.e., ‘the age of Aquarius’) every 2150 years. This is said to be due to a slow wobble of the Earth’s axis that takes almost 26,000 years to circle the zodiac. Detection of any such movement, it is clear, would require centuries of close, disciplined, and continuous observation—something which, orthodox science maintains, would have been beyond the capability of any primitive ancient society. ‘Precession,’ according to mainstream academic science was discovered by the Greek astronomer Hipparchus between 190 and 120 BC, and not everyone accepts that even Hipparchus knew about the precession.

If you could show that long before the Greeks, ‘primitive people’ knew about ‘precession,’ you could make a very strong case for the existence of advanced science in pre-history, something that orthodoxy has consistently denied. Nevertheless, groundbreaking recent research on very ancient cave paintings, makes exactly the point—that indeed, ancient people had an advanced knowledge of astronomy.

The research was published in 2018 in Athens Journal of History. Dr Martin Sweatman, of the University of Edinburgh’s School of Engineering, who led the study, said: “Early cave art shows that people had advanced knowledge of the night sky within the last ice age. Intellectually, they were hardly any different to us today.” (https://www.ed.ac.uk/news/2018/cave-paintings-reveal-use-of-complex-astronomy)