Science
Antarctica's Denman Glacier is sinking into the world's deepest canyon – msnNOW
Video by GeoBeats
The glaciers of Antarctica are melting at unprecedented rates, and a giant canyon in the continent’s rocky underbelly could make matters much worse.
In a study published March 23 in the journal Geophysical Research Letters, researchers used more than 20 years of satellite data to monitor the ice in Denman Glacier — a 12-mile wide (20 kilometers) stream of ice in East Antarctica — along with the bedrock beneath it. The researchers found that, not only did Denman’s western flank retreat nearly 3 miles (5 km) between 1996 and 2018, but that a deep canyon below the glacier may be causing the glacier to melt faster than it can possibly recover.
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Denman trough (dark blue strip) sinks some 11,000 feet (3,500 meters) below sea level, and could soon become the burial plot of a massive, dying glacier.
Denman Glacier’s western flank flows over the deepest known land canyon on Earth, plunging at least 11,000 feet (3,500 meters) below sea level. Right now, that canyon (known as the Denman trough) is mostly cut off from the sea thanks to all the glacial ice piled inside and atop the ravine. However, as the glacier’s edge continues to retreat farther and farther down the slope, warm ocean water will pour into the canyon, battering bigger and bigger sections of the glacier and gradually turning the Denman trough into a giant bowl of meltwater with nowhere else to go.
This scenario, the researchers wrote, could kick off a runaway feedback loop of melt that ultimately returns all of Denman Glacier’s ice to the sea — risking nearly 5 feet (1.5 m) of global sea level rise.
“Because of the shape of the ground beneath Denman’s western side, there is potential for rapid and irreversible retreat, and that means substantial increases in global sea levels in the future,” lead study author Virginia Brancato, a postdoctoral fellow with NASA’s Jet Propulsion Laboratory, said in a statement.
Losing frozen ground
© Provided by Live Science
This map shows Denman Glacier’s grounding line retreating between 1996 (the black line) and 2018 (yellow line). The large dip in the bedrock represents Denman trough, a canyon reaching a maximum depth of 11,000 feet (3,500 meters) below sea level. The glacier’s grounding line has already begun creeping down the canyon’s wall. (Image credit: AGU/ Brancato et. al)
Glaciers are giant slabs of ice sitting atop continental bedrock. Most glaciers in Antarctica, including Denman, end in large ice shelves or “tongues” that jut away from the land and into the open ocean, where their edges slowly snap into pieces and form new icebergs. The point where a glacier first leaves the bedrock and begins to float in the water is called the grounding line. The location of this line is key to a glacier’s stability; when warm ocean water melts away exposed glacial ice, the grounding line retreats farther and farther back, making nearby ice sheets less stable and more prone to melting and cracking.
In the new study, researchers used satellite data from the German Aerospace Center and the Italian Space Agency to measure how far Denman Glacier’s grounding line retreated in the 22 years between 1996 and 2018, and how much mass the glacier lost in melted ice. They saw extensive melting — Denman lost more than 268 billion tons (2.43 metric tons) of ice in those two decades — and an alarming rate of retreat on one side of the glacier only.
While there was little retreat on Denman’s eastern flank (where a rocky ridge stabilizes the grounding line), the glacier’s western flank shot back by nearly 3 miles (5 km), plunging partway down the slope of the massive Denman trough.
If current global warming trends continue, that trough could spell doom for Denman glacier, the researchers wrote. As the glacier’s grounding line continues to sink farther down the canyon (which already sits below sea level), warm ocean water will batter larger and larger chunks of the glacier’s edge, causing it to melt even faster and make the precarious ice shelf above even more vulnerable to collapse.
If that happens, it’s likely that Denman Glacier will undergo a “rapid and irreversible retreat” with “major consequences” for sea level rise, the researchers wrote in the study. This possibility should be a wake-up call to scientists who previously considered melt in East Antarctica a relatively benign threat compared to the rapidly melting Pine Island and Thwaites glaciers in West Antarctica, the authors concluded.
“The ice in West Antarctica has been melting faster in recent years, but the sheer size of Denman Glacier means that its potential impact on long-term sea level rise is just as significant,” study co-author Eric Rignot, a professor of Earth system science at the University of California, Irvine, said in the statement.
Originally published on Live Science.
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CAPE CANAVERAL, Fla. (AP) – NASA has finally heard back from Voyager 1 again in a way that makes sense.
The most distant spacecraft from Earth stopped sending back understandable data last November. Flight controllers traced the blank communication to a bad computer chip and rearranged the spacecraft’s coding to work around the trouble.
NASA’s Jet Propulsion Laboratory in Southern California declared success after receiving good engineering updates late last week. The team is still working to restore transmission of the science data.
It takes 22 1/2 hours to send a signal to Voyager 1, more than 15 billion miles (24 billion kilometers) away in interstellar space. The signal travel time is double that for a round trip.
Contact was never lost, rather it was like making a phone call where you can’t hear the person on the other end, a JPL spokeswoman said Tuesday.
Launched in 1977 to study Jupiter and Saturn, Voyager 1 has been exploring interstellar space – the space between star systems – since 2012. Its twin, Voyager 2, is 12.6 billion miles (20 billion kilometers) away and still working fine.
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SpaceX sent yet another batch of its Starlink internet satellites skyward today (April 23).
A Falcon 9 rocket topped with 23 Starlink spacecraft lifted off from Florida’s Cape Canaveral Space Force Station today at 6:17 p.m. EDT (2217 GMT).
The Falcon 9’s first stage came back to Earth for a vertical landing about 8.5 minutes after launch as planned. It touched down on the SpaceX droneship Just Read the Instructions, which was stationed in the Atlantic Ocean.
It was the ninth launch and landing for this particular booster, according to a SpaceX mission description. Five of its previous eight liftoffs were Starlink missions.
The Falcon 9’s upper stage will continue carrying the 23 Starlink satellites toward low Earth orbit (LEO) today, deploying them about 65 minutes after liftoff.
This evening’s launch was the 41st of the year for SpaceX, and the 28th of 2024 dedicated to building out the huge and ever-growing Starlink megaconstellation. There are nearly 5,800 operational Starlink satellites in LEO at the moment, according to astrophysicist and satellite tracker Jonathan McDowell.
The Starlink launch ended up being the first half of a spaceflight doubleheader: A Rocket Lab Electron vehicle launched two satellites, including a NASA solar-sailing technology demonstrator, from New Zealand today at 6:33 p.m. EDT (2233 GMT).
Editor’s note: This story was updated at 6:30 p.m. ET on April 23 with news of successful launch and first-stage landing.
Science
Exploring ecological networks in a digital world | News | Vancouver Island University | Canada – Vancouver Island University News
Getting to know Samantha Letourneau
By day, Samantha Letourneau is Vancouver Island University’s Canada Learning Bond project lead and Volunteer Tutor Coordinator. She’s also a musician and dancer and for the past two years, she’s been collaborating with Swedish artist Mårten Spångberg, thanks to funding obtained through Crimson Coast Dance, to create a digital art installation that goes live on Friday, April 26. A launch event takes place at Black Rabbit restaurant in the Old City Quarter that night. Samantha is also hosting a creative process workshop on April 27 and 28.
Can you share a bit about your background as an artist and how you got into it?
I have been working in art for a very long time, as a musician and dancer as well as an art administrator and program coordinator. I started music at the age of 11 and dance came later in my life in my early 20s. I always wanted to do dance, but I grew up in a small community in Yellowknife and at that time the only dance classes available were highland dancing, which I was not very interested in.
In my early 20s while living in Vancouver, I took classes in contemporary dance and was fortunate to land a small part in the Karen Jameison Dance company for a piece called The River. The River was about rivers and connection between the reality of a real and physical outdoor river and the different reality of “the river within.” It was both a piece of art and outreach for the community. It included working with the S’pak’wus Slu’lum Dancers of the Squamish Nation. Somewhat ground-breaking for 1998.
From there I was hooked and wanted to do more in dance. I studied a lot and took many classes. Fast forward to now, I have been involved with productions and performances with Crimson Coast Dance for more than 15 years and greatly appreciate the talent and innovation that Artistic Director Holly Bright has brought to this community. She is amazing and very supportive of artists in Nanaimo.
How did this international exchange come about?
The Nordic/Nanaimo exchange is one of the innovative projects Holly created. At the height of the pandemic, funded by BC Arts Council and Made In BC, Crimson Coast Dance embarked on a project that explored the ways in which Nanaimo artists could participate in online exchanges.
Two artists in Nanaimo – myself and Genevieve Johnson – were introduced to artists from Europe and supported through this international exchange. My collaborator, Mårten Spångberg, is a Swedish artist living and working in Berlin. An extension of that exchange is funded by Canada Council for the Arts – Digital Now.
What brought Mårten and myself together – and I quote Mårten here – is “questions around climate change, ecology and the influence contemporary society has on its environments. We are not interested in making art about the ecological crises or informing our audience about the urgency that climate change implies, but instead through our research develop work that in itself proposes, practices and engages in alternative ecologies.”
We share an understanding that art is a unique place, in the sense of practice, activation, performance and event, through which alternative ecologies can emerge and be probed and analyzed.
Tell us about the launch event.
We are launching the digital art installation that Mårten and I created on April 26 at The Attic at Black Rabbit Restaurant. The event is free to attend but people must sign up as seating is limited. I produced video art with soundscapes that I recorded mixing field recordings with voice and instrumentation. Marten explores text, imagery and AI.
My focus is on the evolving and ongoing process of how we communicate with each other and to nature within a digital context.
During our collaboration, Mårten and I talked about networks, though not just the expansive digital network of the internet but of nature. We shared thoughts on mycelium, a network of fungal threads or hyphae, that lately has received much attention on the importance of its function for the environment, including human beings.
Building off this concept, ideas of digital and ecological landscapes being connected emerged. From this we worked both collaboratively and individually to produce material for this digital project. Mårten will be there via Zoom as well and we will talk about this two-year process and the work we created together.
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