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Ancient soil once stored at UB shows Greenland melted recently … and could melt again

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A new study that analyzes ancient soil once stored at the University at Buffalo is causing a worrisome rethinking of the history of Greenland’s ice sheet and reveals its fragile nature today.

Joshua Brown, University of Vermont

Release Date: July 21, 2023

BUFFALO, N.Y. — Until recently, geologists believed that Greenland was a fortress of ice, mostly unmelted for millions of years. But, two years ago, using soil once buried a mile beneath the island’s ice sheet and later stored at the University at Buffalo, a team of scientists showed that it likely melted less than one million years ago.

Now, further analysis of the sediment has created a starker picture: Greenland was a green land only 416,000 years ago.

The team’s new study — published July 21 in the journal Science and co-authored by Elizabeth Thomas, associate professor of geology in the UB College of Arts and Sciences — presents direct evidence that the sediment was deposited by flowing water in an ice-free environment during a moderate warming period from 424,000 to 374,000 years ago.

“It’s really the first bulletproof evidence that much of the Greenland ice sheet vanished when it got warm,” says University of Vermont geoscientist Paul Bierman, who co-led the study with lead author Drew Christ, a postdoctoral geoscientist who worked in Bierman’s lab.

Elizabeth Thomas, Univeristy at Buffalo associate professor of geology, conducted chemical analysis that enabled the team to understand the types of plants that were on site. Credit: Douglas Levere/University at Buffalo

Understanding Greenland’s past is critical for predicting how its giant ice sheet will respond to climate warming in the future. The new study provides strong and precise evidence that Greenland is more sensitive to climate change than previously understood — and at grave risk of irreversibly melting off.

Since about 23 feet of sea level rise is tied up in Greenland’s ice, every coastal region in the world is at risk.

Under ice

Camp Century was a U.S. Army base on Greenland in the 1960s. It was the site of a secret operation, called Project Iceworm, to hide nuclear missiles under the ice near the Soviet Union.

The missile mission was a bust, but the science team did complete first-of-its-kind research, including drilling a nearly mile-deep ice core. The Camp Century scientists were focused on the ice itself, so they took little interest in the 12 feet of sediment gathered from beneath their ice core.

Engineers with the Cold Regions Research and Engineering Laboratory capture part of an ice core at Camp Century, Greenland, circa 1966. Credit: U.S. Army Corps of Engineers

Then, in a bizarre story, the ice core was moved in the 1970s from a military freezer to UB by then-UB geology professor, Chester “Chet” Langway, who was one of the leads of the Camp Century drilling expedition. He kept the ice core at a building on Ridge Lea Road in Amherst that housed UB’s Department of Geology while the North Campus was being built.

When retiring from UB in the 1990s, Langway gave the ice core to colleagues in Denmark. There it was lost for decades — until it was found again when the cores were being moved to a new freezer in 2017.

In 2019, Christ looked at the sediment through his microscope and found leaves and moss. That suggested that the area had been free of ice in the recent geologic past — and that a vegetated landscape stood where today stands an ice sheet two miles thick and three times the size of Texas.

The team, including Christ and UB’s Thomas, published their findings in 2021 in the Proceedings of the National Academy of Sciences.

Other scientists, working in central Greenland, have gathered data showing the ice there melted at least once in the last 1.1 million years — but no one knew exactly when.

Into the light

For this latest study, the team examined the Camp Century sediment for what is called a “luminescence signal.”

When bits of rock and sand are exposed to sunlight, any previous luminescence signal is zeroed out. When reburied in the darkness under rock or ice over time, minerals of quartz and feldspar in the sediment accumulate freed electrons in their crystals.

At the Utah State University lab of study co-author Tammy Rittenour, pieces of the ice core sediment were exposed to blue-green or infrared light, releasing the trapped electrons. The number of released electrons forms a kind of clock, revealing with precision the last time these sediments were exposed to the sun.

A sediment sample from the Camp Century core site. Credit: Drew Christ/University of Vermont

This powerful new data was combined with insight from Bierman’s University of Vermont lab, which studied the quartz from the Camp Century core. Ratios of beryllium and other isotopes inside the quartz – which build up when exposed to the sky and hit by cosmic rays — demonstrate how long rocks at the surface were exposed vs. buried under layers of ice.

This data helped the scientists show that, 400,000 years ago, the Camp Century sediment was exposed to the sky less than 14,000 years before it was deposited under the ice, narrowing down the time window when that portion of Greenland must have been ice-free.

Thomas conducted chemical analysis that enabled the team to understand the types of plants that were on site. The team is doing similar analyses to understand what the temperature and water cycle were like when those chemicals were produced.

Sea level

The team’s new study, combined with their earlier work, is causing a worrisome rethinking of the history of Greenland’s ice sheet and reveals its fragile nature today.

The last time the ice sheet melted, the team’s models show, it caused at least five feet of sea level rise. Temperatures during that time, an interglacial called Marine Isotope Stage 11, were similar to or slightly warmer than today, and atmospheric carbon dioxide was at least a third less than it is today.

“Forward modeling the rates of melt, and the response to high carbon dioxide, we are looking at meters of sea level rise, probably tens of meters,” Rittenour says. “And then look at the elevation of New York City, Boston, Miami, Amsterdam. Look at Bangladesh, India and Africa—most global population centers are near sea level.”

“Four-hundred-thousand years ago there were no cities on the coast,” Bierman adds, “and now there are cities on the coast.”

The research was supported by the National Science Foundation.

Media Contact Information

Tom Dinki
News Content Manager
Physical sciences, economic development
Tel: 716-645-4584
tfdinki@buffalo.edu

 

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Las Vegas Aces Rookie Kate Martin Suffers Ankle Injury in Game Against Chicago Sky

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Las Vegas Aces rookie Kate Martin had to be helped off the floor and taken to the locker room after suffering an apparent ankle injury in the first quarter of Tuesday night’s game against the Chicago Sky.

Late in the first quarter, Martin was pushing the ball up the court when she appeared to twist her ankle and lost her balance. The rookie was in serious pain, lying on the floor before eventually being helped off. Her entire team came out in support, and although she managed to put some pressure on the leg, she was taken to the locker room for further evaluation.

Martin returned to the team’s bench late in the second quarter but was ruled out for the remainder of the game.

“Kate Martin is awesome. Kate Martin picks up things so quickly, she’s an amazing sponge,” Aces guard Kelsey Plum said of the rookie during the preseason. “I think (coach) Becky (Hammon) nicknamed her Kate ‘Money’ Martin. I think that’s gonna stick. And when I say ‘money,’ it’s not just about scoring and stuff, she’s just in the right place at the right time. She just makes people better. And that’s what Becky values, that’s what our coaching staff values and that’s why she’s gonna be a great asset to our team.”

Las Vegas selected Martin in the second round of the 2024 WNBA Draft. She was coming off the best season of her collegiate career at Iowa, where she averaged 13.1 points, 6.8 rebounds, and 2.3 assists per game during the 2023-24 campaign. Martin’s integration into the Aces organization has been seamless, with her quickly earning the respect and admiration of her teammates and coaches.

The team and fans alike are hoping for a speedy recovery for Martin, whose contributions have been vital to the Aces’ performance this season.

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Asteroid Apophis will visit Earth in 2029, and this European satellite will be along for the ride

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The European Space Agency is fast-tracking a new mission called Ramses, which will fly to near-Earth asteroid 99942 Apophis and join the space rock in 2029 when it comes very close to our planet — closer even than the region where geosynchronous satellites sit.

Ramses is short for Rapid Apophis Mission for Space Safety and, as its name suggests, is the next phase in humanity’s efforts to learn more about near-Earth asteroids (NEOs) and how we might deflect them should one ever be discovered on a collision course with planet Earth.

In order to launch in time to rendezvous with Apophis in February 2029, scientists at the European Space Agency have been given permission to start planning Ramses even before the multinational space agency officially adopts the mission. The sanctioning and appropriation of funding for the Ramses mission will hopefully take place at ESA’s Ministerial Council meeting (involving representatives from each of ESA’s member states) in November of 2025. To arrive at Apophis in February 2029, launch would have to take place in April 2028, the agency says.

This is a big deal because large asteroids don’t come this close to Earth very often. It is thus scientifically precious that, on April 13, 2029, Apophis will pass within 19,794 miles (31,860 kilometers) of Earth. For comparison, geosynchronous orbit is 22,236 miles (35,786 km) above Earth’s surface. Such close fly-bys by asteroids hundreds of meters across (Apophis is about 1,230 feet, or 375 meters, across) only occur on average once every 5,000 to 10,000 years. Miss this one, and we’ve got a long time to wait for the next.

When Apophis was discovered in 2004, it was for a short time the most dangerous asteroid known, being classified as having the potential to impact with Earth possibly in 2029, 2036, or 2068. Should an asteroid of its size strike Earth, it could gouge out a crater several kilometers across and devastate a country with shock waves, flash heating and earth tremors. If it crashed down in the ocean, it could send a towering tsunami to devastate coastlines in multiple countries.

Over time, as our knowledge of Apophis’ orbit became more refined, however, the risk of impact  greatly went down. Radar observations of the asteroid in March of 2021 reduced the uncertainty in Apophis’ orbit from hundreds of kilometers to just a few kilometers, finally removing any lingering worries about an impact — at least for the next 100 years. (Beyond 100 years, asteroid orbits can become too unpredictable to plot with any accuracy, but there’s currently no suggestion that an impact will occur after 100 years.) So, Earth is expected to be perfectly safe in 2029 when Apophis comes through. Still, scientists want to see how Apophis responds by coming so close to Earth and entering our planet’s gravitational field.

“There is still so much we have yet to learn about asteroids but, until now, we have had to travel deep into the solar system to study them and perform experiments ourselves to interact with their surface,” said Patrick Michel, who is the Director of Research at CNRS at Observatoire de la Côte d’Azur in Nice, France, in a statement. “Nature is bringing one to us and conducting the experiment itself. All we need to do is watch as Apophis is stretched and squeezed by strong tidal forces that may trigger landslides and other disturbances and reveal new material from beneath the surface.”

The Goldstone radar’s imagery of asteroid 99942 Apophis as it made its closest approach to Earth, in March 2021. (Image credit: NASA/JPL–Caltech/NSF/AUI/GBO)

By arriving at Apophis before the asteroid’s close encounter with Earth, and sticking with it throughout the flyby and beyond, Ramses will be in prime position to conduct before-and-after surveys to see how Apophis reacts to Earth. By looking for disturbances Earth’s gravitational tidal forces trigger on the asteroid’s surface, Ramses will be able to learn about Apophis’ internal structure, density, porosity and composition, all of which are characteristics that we would need to first understand before considering how best to deflect a similar asteroid were one ever found to be on a collision course with our world.

Besides assisting in protecting Earth, learning about Apophis will give scientists further insights into how similar asteroids formed in the early solar system, and, in the process, how  planets (including Earth) formed out of the same material.

One way we already know Earth will affect Apophis is by changing its orbit. Currently, Apophis is categorized as an Aten-type asteroid, which is what we call the class of near-Earth objects that have a shorter orbit around the sun than Earth does. Apophis currently gets as far as 0.92 astronomical units (137.6 million km, or 85.5 million miles) from the sun. However, our planet will give Apophis a gravitational nudge that will enlarge its orbit to 1.1 astronomical units (164.6 million km, or 102 million miles), such that its orbital period becomes longer than Earth’s.

It will then be classed as an Apollo-type asteroid.

Ramses won’t be alone in tracking Apophis. NASA has repurposed their OSIRIS-REx mission, which returned a sample from another near-Earth asteroid, 101955 Bennu, in 2023. However, the spacecraft, renamed OSIRIS-APEX (Apophis Explorer), won’t arrive at the asteroid until April 23, 2029, ten days after the close encounter with Earth. OSIRIS-APEX will initially perform a flyby of Apophis at a distance of about 2,500 miles (4,000 km) from the object, then return in June that year to settle into orbit around Apophis for an 18-month mission.

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Furthermore, the European Space Agency still plans on launching its Hera spacecraft in October 2024 to follow-up on the DART mission to the double asteroid Didymos and Dimorphos. DART impacted the latter in a test of kinetic impactor capabilities for potentially changing a hazardous asteroid’s orbit around our planet. Hera will survey the binary asteroid system and observe the crater made by DART’s sacrifice to gain a better understanding of Dimorphos’ structure and composition post-impact, so that we can place the results in context.

The more near-Earth asteroids like Dimorphos and Apophis that we study, the greater that context becomes. Perhaps, one day, the understanding that we have gained from these missions will indeed save our planet.

 

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McMaster Astronomy grad student takes a star turn in Killarney Provincial Park

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Astronomy PhD candidate Veronika Dornan served as the astronomer in residence at Killarney Provincial Park. She’ll be back again in October when the nights are longer (and bug free). Dornan has delivered dozens of talks and shows at the W.J. McCallion Planetarium and in the community. (Photos by Veronika Dornan)

Veronika Dornan followed up the April 8 total solar eclipse with another awe-inspiring celestial moment.

This time, the astronomy PhD candidate wasn’t cheering alongside thousands of people at McMaster — she was alone with a telescope in the heart of Killarney Provincial Park just before midnight.

Dornan had the park’s telescope pointed at one of the hundreds of globular star clusters that make up the Milky Way. She was seeing light from thousands of stars that had travelled more than 10,000 years to reach the Earth.

This time there was no cheering: All she could say was a quiet “wow”.

Dornan drove five hours north to spend a week at Killarney Park as the astronomer in residence. part of an outreach program run by the park in collaboration with the Allan I. Carswell Observatory at York University.

Dornan applied because the program combines her two favourite things — astronomy and the great outdoors. While she’s a lifelong camper, hiker and canoeist, it was her first trip to Killarney.

Bruce Waters, who’s taught astronomy to the public since 1981 and co-founded Stars over Killarney, warned Dornan that once she went to the park, she wouldn’t want to go anywhere else.

The park lived up to the hype. Everywhere she looked was like a painting, something “a certain Group of Seven had already thought many times over.”

The dome telescopes at Killarney Provincial Park.

She spent her days hiking the Granite Ridge, Crack and Chikanishing trails and kayaking on George Lake.  At night, she went stargazing with campers — or at least tried to. The weather didn’t cooperate most evenings — instead of looking through the park’s two domed telescopes, Dornan improvised and gave talks in the amphitheatre beneath cloudy skies.

Dornan has delivered dozens of talks over the years in McMaster’s W.J. McCallion Planetarium and out in the community, but “it’s a bit more complicated when you’re talking about the stars while at the same time fighting for your life against swarms of bugs.”

When the campers called it a night and the clouds parted, Dornan spent hours observing the stars. “I seriously messed up my sleep schedule.”

She also gave astrophotography a try during her residency, capturing images of the Ring Nebula and the Great Hercules Cluster.

A star cluster image by Veronika Dornan

“People assume astronomers take their own photos. I needed quite a lot of guidance for how to take the images. It took a while to fiddle with the image properties, but I got my images.”

Dornan’s been invited back for another week-long residency in bug-free October, when longer nights offer more opportunities to explore and photograph the final frontier.

She’s aiming to defend her PhD thesis early next summer, then build a career that continues to combine research and outreach.

“Research leads to new discoveries which gives you exciting things to talk about. And if you’re not connecting with the public then what’s the point of doing research?”

 

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