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How we spotted a potential new planet around the sun's neighbouring star – The Conversation UK

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Most exoplanets, bodies orbiting stars other than the sun, are too far away for us to be able to send probes to. So it’s no wonder that the discovery of a possible habitable planet around the sun’s nearest neighbour star, Proxima Centauri, a few years ago generated a lot of excitement. Now we have spotted what we think is a second planet around this star.

Our study, published in Science Advances, suggests this planet could have a mass about half that of the planet Neptune. Dubbed Proxima Centauri c (abbreviated to Proxima c), it has an orbit about 1.5 times greater than the Earth’s orbit around the sun.

The star Proxima Centauri is the smallest star in a triple system in the constellation of Centaurus. Since it is the star in closest proximity to our sun, it is usually referred to as Proxima. It wasn’t discovered until 1915 by the Scottish astronomer Robert Innes because it is too faint to see with the naked eye. Like most stars, Proxima Centauri is a cool, small object known as a “red dwarf” star. It is about eight times less massive than the sun and has about half its temperature.

The previously discovered planet Proxima b is (most likely) a rocky planet orbiting the star within its habitable zone. However, Proxima c orbits relatively far from its cool star and is therefore unlikely to be habitable. If it doesn’t have an atmosphere, it most likely has a temperature below -200°C.

Proxima b was found by analysing the star’s spectra – light broken down by wavelength to provide a “fingerprint” showing what an object is made of. Small shifts in this starlight can be used to work out tiny movements of the star in response to an orbiting planet’s gravitational pull. This is called the radial velocity technique. The first signal was weak. But further observations were made and existing ones reanalysed to verify the planet’s existence.

The history of detecting and understanding exoplanets has been driven forward by a wide variety of techniques. Exoplanets were discovered for the first time in 1992, from radio observations of a pulsar, the collapsed core of giant star.

Efforts significantly grew in 1995 after the announcement of a planet in orbit around the sun-like star 51 Pegasi using the radial velocity technique. This discovery was subsequently awarded part of the 2019 Nobel prize in Physics. There have always been concerns, however, that apparent planetary signals might be caused by stellar activity. It was not until after 2000, and the discovery of the exoplanets with a variety of techniques, that the existence of exoplanets became widely accepted.

New discovery

Our detection of the new planet, Proxima c, used the same radial velocity technique as that used for the Nobel Prize-winning work, but the signal is 40 times weaker on a 400 times longer timescale. This made it a very challenging discovery. Just like our sun, Proxima has spots caused by regions of intense magnetic activity which are moving in and out of view, changing in intensity on a variety of timescales. These features need to be considered when searching for any planetary signals.

This picture combines a view of the southern skies over the La Silla observatory in Chile with images of the stars Proxima Centauri (lower-right) and the double star Alpha Centauri AB (lower-left).
Y. Beletsky (LCO)/ESO/ESA/NASA/M. Zamani

The sun’s spots, probably created by a build up of plasma, lead to magnetic field flips approximately every 11 years. For the sun this timescale is fairly consistent, but the number of sunspots remain infuriatingly difficult to predict. Unlike the sun, which has been carefully monitored for centuries, we know far less about Proxima Centauri, so it’s plausible that an activity cycle of its star could mimic a planetary signal. Further observations can, however, strengthen the evidence for its existence.

The ideal way to verify its existence would be with a direct image. However, for exoplanets this is exceedingly difficult because they are generally too close to their stars to be seen from Earth with current technology – they drown in the star’s light. But Proxima is a cool, dim star, making the contrast between star and its planets significantly easier. What’s more, the distance and orbit of Proxima c means you should be able to see them both in the sky using large telescopes on Earth.

The signal reported from Proxima c was found with the La Silla Observatory in Chile, an optical telescope with a diameter of 3.6m. The diameter of the Extremely Large Telescope, currently under construction on a nearby mountain, will be 39m and might detect Proxima c with a number of its instruments.

Can we go there?

Proxima c is an ideal planet for follow-up studies compared to other planets discovered around more distant stars. To confirm its existence and characterise its properties will require state-of-the-art technology. That said, Proxima c should provide a benchmark example for how similar or different exoplanets really are from the planets in our solar system.

Since Proxima is the closest star to our sun, one might think it would be easier to just travel there. However, at 4.2 light years, it is still immensely distant for humans. If the distance between the Earth and the sun were 1cm, Proxima is 11km away. That said, an exciting project called Breakthrough Starshot is planning to send a microchip starship to the triple-star system that includes Proxima. Such a microchip starship might be propelled by lasers and reach the system a few decades from now.

Ultimately, the discovery of multiple signals from the very closest star shows that planets are more common than stars. Proxima represents an excellent location for understanding the closest exoplanets and developing new technologies to better understand the universe we live in.

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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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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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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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.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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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.”

The Canadian Press. All rights reserved.

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