The constellation of Orion, along with the great molecular cloud complex and including its brightest… [+] stars. Betelgeuse, the nearby, bright red supergiant, is the nearest supernova candidate to Earth, shown in visible light at the lower left.
Rogelio Bernal Andreo
When you take a look at the stars in the night sky, they generally appear the same regardless of time. Only a small number of stars ever appear to change on human timescales, as most stars burn through their fuel very stably, with almost no variation in their continuous brightness. The few stars that do appear to change are either intrinsically variable, members of multi-star systems, or go through an enormous evolutionary change.
When very massive stars get close to the end of their lives, they start varying by tremendous amounts, and do so with significant irregularity. At a critical moment, most of these stars will run out of the nuclear fuel holding up their cores against collapse, and the resulting implosion leads to a runaway cataclysm: a core-collapse supernova. Could Betelgeuse, whose variability intensified in a novel way over the last few days, be about to explode? Here’s what astronomers know so far.
The black hole at the center of the Milky Way should be comparable in size to the physical extent of… [+] the red giant star Betelgeuse: larger than the extent of Jupiter’s orbit around the Sun. Betelgeuse was the first star of all beyond our Sun to be resolved as more than a point of light.
A. Dupree (CfA), R. Gilliland (STScI), NASA
The last time our species witnessed a supernova from within our own galaxy with the naked human eye, the year was 1604. A new point of light in the sky suddenly appeared, brightened, and briefly outshone every single star before slowly fading away. This wasn’t the first such event, as prior supernovae had illuminated Earth’s skies like this in 1572, 1054, and 1006, among others.
But all of those supernovae occurred from stars that were thousands of light-years away, with Kepler’s 1604 explosion being traced back to a stellar remnant located some 20,000 light-years across the Milky Way. Of all the stars we see in the night sky, one bright member stands out as the most fascinating possibility as our galaxy’s next supernova: Betelgeuse, one of our sky’s 10 brightest stars, located a mere 640 light-years away.
This artist’s impression shows the supergiant star Betelgeuse as it was revealed thanks to different… [+] state-of-the-art techniques on ESO’s Very Large Telescope (VLT), which allowed two independent teams of astronomers to obtain the sharpest ever views of the supergiant star Betelgeuse. They show that the star has a vast plume of gas almost as large as our Solar System and a gigantic bubble boiling on its surface.
ESO/L. Calçada
Betelgeuse, best known as the bright red “shoulder” star in the constellation of Orion, is one of the most remarkable objects in all of astronomy. It is a red supergiant star: red because of its low surface temperatures, supergiant because its radius is so enormous that — if it were to replace the Sun in our Solar System — it would engulf the orbits of Mercury, Venus, Earth, Mars, the asteroid belt, and possibly even Jupiter! In terms of physical size, it’s approximately 900 times the radius, and 700 million times the volume, of our Sun.
Betelgeuse is so large and so close that it was the first star beyond our Sun to ever be resolved as more than a point source. But perhaps its most fascinating property is that Betelgeuse is a pulsating, variable star, meaning that its diameter and brightness both change with time.
A radio image of the very, very large star, Betelgeuse, with the extent of the optical disk… [+] overlayed. This is one of the very few stars resolvable as more than a point source as seen from Earth.
NRAO/AUI and J. Lim, C. Carilli, S.M. White, A.J. Beasley, and R.G. Marson
At approximately 20 times the mass of our Sun, there’s little doubt that Betelgeuse is headed on it was to becoming a supernova. Betelgeuse was likely formed in the great Orion molecular cloud complex very recently on cosmic scales: within the last 10 million years. It has already finished burning through all the hydrogen fuel in its core, and has gone onto the next element, helium, which it fuses into carbon.
Perhaps ironically, the core of Betelgeuse is now much smaller than when it was fusing hydrogen, as it contracted and heated up tremendously in order to begin fusing helium. The outer layers, with this increased radiation pressure, expanded and cooled tremendously. At a surface temperature of only 3500 K, barely half the temperature of our Sun’s photosphere, only 13% of Betelgeuse’s energy output is detectable to human eyes. If we could see the entire electromagnetic spectrum from our perspective, Betelgeuse would outshine every star in the Universe except our Sun.
Three of the major stars in Orion (Betelgeuse, Meissa and Bellatrix) as revealed in the infrared. In… [+] IR light, Betelgeuse (lower left) is the brightest star in the night sky.
NASA / WISE
We aren’t sure whether Betelgeuse is exclusively fusing helium in its core, or whether the interior has contracted even further and is now fusing carbon. While the helium fusion phase lasts for timescales of ~100,000 years, carbon fusion lasts for merely hundreds. Unfortunately, the only signature that would give us a surefire view of what processes are occurring in the core — neutrino emissions — are too faint to be seen from 640 light-years away.
All we can observe, when it comes to Betelgeuse at the present, is what’s occurring in its outermost layers. When we look there, what we see is remarkable: it’s constantly losing mass, pulsing, having its outermost layers expelled, and changing over time in both its apparent brightness and redness.
The nebula of expelled matter created around Betelgeuse, which, for scale, is shown in the interior… [+] red circle. This structure, resembling flames emanating from the star, forms because the behemoth is shedding its material into space. The extended emissions go beyond the equivalent of Neptune’s orbit around the Sun.
ESO/P. Kervella
Recently, in just the past few weeks, its brightness has dropped tremendously, knocking it out of the top 10 brightest stars for the first time in many years. This dimming has led many to suspect that a supernova may be imminent, but this is extremely unlikely. The story is simple, straightforward, but not known by most people, with the exception of professional astronomers.
The key takeaway is this: what’s occurring in the outer layers of a supergiant star is largely unrelated to what processes are occurring in the inner core of a supergiant star. When you examine variable stars in general, you might think that the pulsing/variability that you see is because some process that’s changing in the core is propagating to the surface, but that’s not usually the case. Instead, there are huge convective cells in the outer layers of the star, and changes there are more than capable of causing this dimming.
A century of observations of Betelgeuse, with both visual (black dots) and V-band magnitudes (green… [+] dots) shown atop one another. Although the recent dimming is unprecedented with modern photometric techniques, it’s clear that Betelgeuse has varied tremendously since humanity has been observing it with modern 20th and 21st century telescopes.
AAVSO / Lautaro Vergara
In fact, if you look beyond the previous decade and instead go back to the past century, you’ll find that Betelgeuse has been this dim many, many times in the past. If you look beyond the photosphere of the star itself, you’ll find that there are enormous radio emissions that reveal the presence of expelled gas out beyond where the orbit of Neptune is around the Sun.
Similar dimming events have occurred before, reducing the brightness of Betelgeuse below even what it currently is at. But to see a dimming event occur this rapidly and this severely really hasn’t been seen before over the past century at all. It’s unlikely to be a signature of an imminent supernova, but we have to remember that since the advent of modern astronomy, we’ve never seen a star up close in the lead-up to a supernova. Whether there’s a detonation about to happen or not, something fascinating is truly occurring.
This simulation of a red supergiant’s surface, sped up to display an entire year of evolution in… [+] just a few seconds, shows how a “normal” red supergiant evolves during a relatively quiet period with no perceptible changes to its interior processes. The enormity of its surface and the volatility of the tenuous outer layers leads to tremendous variability on short but irregular timescales.
Bernd Freytag with Susanne Höfner & Sofie Liljegren
What’s not up for debate is how truly remarkable the processes at play are here. On our Sun alone, the sized of the convective cells that we find are larger than the continent of North America, with sunspots frequently exceeding the size of Earth. On the surface of a red supergiant — thousands of times larger than our Sun — there might only be a handful of convective cells altogether, causing it to look like, according to astronomer Emily Levesque, a “wacky, giant, boiling amoeba-star,” as simulated above.
Our actual astronomical maps of Betelgeuse cannot yet attain that kind of resolution, but can still reveal the following properties of Betelgeuse:
its irregular shape,
its uneven, non-uniform temperature,
localized hot spots,
and even faint plumes of illuminated ejecta near the photosphere itself.
This orange-looking blob is actually the highest-resolution map of the photosphere of the red… [+] supergiant Betelgeuse ever constructed. The image was put together by ALMA, a large array of radio telescopes, and show many properties of Betelgeuse, including its asymmetry, plumes, and an enormous hot spot that’s approximately the size of Mars’s orbit around the Sun.
ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella
The opportunity to study a red supergiant up close, one that’s about to go supernova relatively soon (at least, on astronomical timescales), has never occurred like this before. At only 640 light-years distant, Betelgeuse could have gone supernova at any time since the 14th century and that signal would not yet have arrived here on Earth.
When that supernova does occur, however, we’re in for a real treat. The runaway fusion reaction that occurs in the final few instants of the star’s life will generate neutrinos that should lead to millions of detectable events here our terrestrial neutrino detectors. The star will brighten to the point where it will rival or possibly even exceed the brightness of the full Moon, casting brilliant shadows at night and being clearly visible during the day for more than a year.
The constellation Orion as it would appear if Betelgeuse went supernova in the very near future. The… [+] star would shine nearly as brightly as the full Moon.
Wikimedia Commons user HeNRyKus / Celestia
Unfortunately, though, the key question of exactly when Betelgeuse is going to go supernova is one that we’re not any closer to having an answer to. Until we can measure the processes occurring in the star’s core, which would require a neutrino telescope far more powerful than all the neutrino observatories on Earth combined, we cannot know which elements are being fused inside of it.
Right now, our best models are consistent with helium-burning rather than any of the heavier elements, indicating that we have at least hundreds of years — and possibly hundreds of thousands — until the inevitable supernova finally detonates. If you haven’t checked out the constellation of Orion recently, though, take a good look and notice how much dimmer red Betelgeuse is than blue Rigel, a severe departure from its past decade of appearances. A supernova may not be imminent, but is sure is fascinating to watch and hope!
More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.
That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.
“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”
The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.
Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.
Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.
Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.
Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.
Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.
“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”
The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.
North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.
Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”
Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.
Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.
For Dello, the “fingerprints of climate change” were clear.
“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”
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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.
On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.
They call it “Big Sam.”
The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.
It didn’t die alone.
“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.
She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”
“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.
The head alone, she said, is about the size of a baby elephant.
The discovery was a long time coming.
The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.
“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.
When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”
“It contains about 100 to 300 bones per square metre,” she said.
Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.
About a year ago, they found the second adult: Big Sam.
Bamforth said both dinosaurs are believed to have been the elders in the herd.
“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.
“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”
The genders of the two adults are unknown.
Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.
The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.
She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.
“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.
“It’s pretty exciting.”
This report by The Canadian Press was first published Sept. 25, 2024.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
