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UNDER THE ICE
SCIENTISTS SUSPECT MICROSCOPIC LIFE MAY BE BLOOMING UNDER ANTARCTIC SEA ICE
If phytoplankton are lurking underneath large swaths of the Southern Ocean, is there a hidden ecosystem we're ignoring?
SCIENTISTS MAY HAVE uncovered large swaths of phytoplankton under Antarctica’s sea ice — a discovery scientists previously thought was highly unlikely. The findings were published Thursday in the journal Frontiers in Marine Science.
“I think the conventional wisdom was that this wouldn't happen in Antarctica,” Christopher Horvat, the lead author of the study, tells Inverse. Horvat is a senior lecturer at Auckland University and a visiting professor at Brown.
HERE’S THE BACKGROUND — Phytoplankton are tiny, self-feeding microorganisms that form the base of aquatic ecosystems. Many sea creatures rely on them for food. Large growths of phytoplankton — known as blooms — can happen when there’s prolonged sunlight over an area of the ocean.
Over the past 30 years, global warming has caused sea ice in the Arctic to melt at an alarming rate, making phytoplankton blooms possible there. For example, in 2011, scientists uncovered a massive under-ice bloom in the Chukchi Sea in the Arctic.
WHAT’S NEW — Researchers had little reason to suspect phytoplankton blooms were occurring under the sea ice in Antarctica’s Southern Ocean, where climate change has had little impact on sea ice thickness.
However, Horvat’s team suspected that during the summer months, sunlight peeping through openings in the usually compact sea ice may be allowing phytoplankton to grow.
Under-ice blooms cannot be observed directly from the surface or even from space, so Horvat’s team used specialized autonomous buoys — known as Argo floats — that sit under sea ice and measure chlorophyll and carbon counts, among other variables.
Using the data from the floats as well as climate models that estimate when the right light conditions for phytoplankton blooms would occur, the researchers determined that it was possible for phytoplankton blooms to occur there.
According to the findings, anywhere between three and five million kilometers of the Southern Ocean could have the right light conditions to support phytoplankton blooms, suggesting “widespread” phytoplankton blooms may be hiding beneath Antarctic sea ice.
“Historically, the assumption has been that the sea ice blocks all of the light, and so you can't have these blooms. And what we've shown is that, well, the sea ice in Antarctica is not fully compact,” Horvat says.
WHY IT MATTERS — Phytoplankton form the base of many aquatic ecosystems, so the obvious next question is whether they are supporting hidden underwater ecosystems under the Antarctic ice.
It’s not out of the question to expect a greater chance of a complex food web based on the presence of phytoplankton there, he says, but “ultimately, that's a question for a biologist.”
He’s hopeful that biologists and other experts will be able to build on his findings to answer those questions. If they did find these blooms, it wouldn’t be unprecedented. Earlier this year, New Zealand scientists found a rich trove of shrimp-like marine creatures under the Antarctic ice.
“I think the one take-home message here is that you can find things everywhere you look in some of the most surprising places,” Horvat adds.
WHAT’S NEXT — While Horvat’s research uncovered the likely existence of phytoplankton blooms through the floats, they haven’t actually seen any of them in person. So, their next step would be to find partners who can help them go under the ice using ships known as icebreakers.
“We want to go down there...and watch one of these blooms happen,” Horvat says.
SCIENCE
NASA SUCCESSFULLY LAUNCHES ARTEMIS I TOWARD THE MOON
NASA's Moon rocket has finally launched on a 25-day journey farther than Apollo ever went.
LIFTOFF! NASA’s Artemis I mission is finally underway to the Moon. There were 500 seconds between the ground and glory. On early Wednesday morning at 1:47 a.m. Eastern, Artemis I ignited its engines, initiating 8.8 million pounds of thrust in a little more than eight minutes.
The first phase of this human-grade Moonshot harnesses the momentum of the Space Launch System’s novel launch technology and the Sun’s energy upon four unfurled Orion capsule solar arrays to fly on an epic lunar journey not seen since the Apollo era.
Beginning this 26-day voyage was a challenge. Up until Artemis I’s four RS-25 engines and rocket-booster pair lit up the dark sky over NASA’s Kennedy Space Center in Cape Canaveral, Florida, Artemis I had towered taller than the Statue of Liberty for eight months at the historic facility.
The long wait included numerous delays attributed to liquid propellant leaks, minor hardware replacement, and Hurricane Ian. In the days before launch, the rocket’s mission management team agonized over whether delaminated caulk from winds of Hurricane Nicole made flying too dangerous.
Even the night and early morning of the mission saw multiple issues, with an ethernet switch delaying the launch up until about 1:38 a.m. Eastern, when the T-minus 10 countdown finally began, with a declared launch time of 01:47:44 a.m. NASA was able to hit that goal and finally launch Artemis I on a course to fly farther than any spacecraft built for humans has ever ventured.
A few minutes after launch, the solid rocket boosters on the side jettisoned, while the core engine stage cutoff occurred at 1:56 a.m. Eastern, at which point the craft entered orbit.
Once a team in Houston performs one final review, Artemis I then enters an 18-minute trans-lunar injection (TLI) burn, and begin its 280,000-mile journey away from our planet.
Today marks the first leg in its journey of 1.3 million miles.
WHAT IS ARTEMIS I’S MISSION?
Artemis I demonstrates NASA’s new deep space exploration system. Its two main components — the Space Launch System (SLS) and the Orion capsule — have undergone testing separately. Artemis I is the first integrated flight test of these two. It will evaluate the SLS’ heavy lift capabilities and dispatch the crew-capable Orion thousands of miles beyond the Moon.
NASA heritage rocket-makers have been making space vehicles for more than half a century. The Orion program has existed since 2006, and SLS since 2011 (though it had several predecessors). NASA had been developing these ideas over the last two decades, and then in 2019, Vice President Mike Pence announced the rework of these projects into the Artemis Program. This put the rocketry on a schedule, with a goal to return humans to the Moon by 2024. The first chapter of the program, Artemis I, has already accumulated a price tag of roughly $50 billion.
Artemis I is currently set as a short-class mission lasting just 25 days, 11 hours, and 36 minutes. Splashdown in the Pacific Ocean is scheduled for Sunday, December 11.
WHAT HAPPENS AFTER ARTEMIS I LAUNCHES?
The rocket will swing once around Earth, reaching a speed of almost 20,000 miles per hour, and then head towards the Moon.
On the first day, NASA will conduct a test of Artemis I’s guidance and navigation control system. The team will also perform the first of several trajectory correction burns. There are a total of four burns on the way to the Moon, which set Artemis I on a path to taking one of the most important maneuvers of the entire mission: the Outbound Powered Flyby (OPF) on the mission’s sixth day, Monday, November 21.
The OPF will bring Orion to 60-80 miles above the lunar surface, and send the future four-astronaut vehicle farther than any human-designed spacecraft has gone before. This lunar pirouette is called the Distant Retrograde Orbit (DRO).
Artemis will also release 10 cubesats. These tiny satellites will gather information about the cislunar environment, which could inform how NASA conducts and designs future human space travel.
After collecting data across its Manikin and taking a modern version of the classic Apollo image Earthrise, Artemis I will head back to Earth and maneuver into a prime reentry approach. As it careens through Earth’s atmosphere from a great distance and benchmark speed, Orion will likely register a temperature of 5,000 degrees Fahrenheit. That’s 73 percent hotter than compared to a spacecraft returning from low-Earth orbit, such as a capsule departing the International Space Station.
NASA hopes Orion’s thermal protection system will safely keep against the novel feat. If all goes well, Orion will successfully splashdown on Sunday, December 11, in the Pacific Ocean.
GRAB THE LAWN CHAIRS
ARTEMIS I LAUNCH: NASA RESCHEDULES ITS MOON LAUNCH — FOR THE FIFTH TIME
NASA is delaying the Artemis I launch until November 16 to allow time for inspections in the wake of Tropical Storm Nicole.
Brace yourselves for a bit of a shock: NASA is pushing back its Artemis I launch date yet again.
Teams at NASA’s Kennedy Space Center in Florida are battening down the hatches on Artemis I — literally. With Tropical Storm Nicole bearing down on eastern Florida, they won’t be rolling the rocket and spacecraft back into the Vehicle Assembly Building (VAB) this time, as they did in advance of Hurricane Ian back in September. Instead, Artemis I will ride out the storm on Launch Pad 39B in hopes that its teams can have it ready for its latest launch date, November 16.
Nicole is expected to make landfall as a Category 1 hurricane on the evening of Wednesday, November 9, somewhere between Melbourne and Cocoa Beach. The National Hurricane Center expects the storm’s strongest winds to fall short of what SLS can safely stand up to, which is about 85 miles per hour at a point 60 feet (18 meters) above the ground. With that in mind, NASA opted to leave Artemis on the pad to weather the storm rather than rolling it back into the VAB yet again. We can only hope there are photos because it sounds like the kind of imagery Ernest Hemingway would have come up with if he’d written science fiction.
But with the storm bearing down on Tuesday evening, NASA decided to push back the launch date by two more days, from November 14 to November 16, to allow engineers time to inspect the rocket, the spacecraft, and the launch pad afterward. The new launch attempt is set for November 16 at 1:04 a.m. EST, although if you’re writing that in your calendar, you may want to use a pencil. NASA is holding onto a backup date of November 19.
Meanwhile, eastern Floridians are boarding up windows and stocking up ice chests, and teams at Kennedy Space Center have installed a hard cover over a window on the Orion capsule’s launch aboard system, and they’re checking the launch pad for anything that could turn into flying debris in hurricane-force winds.
SPACE IS WEIRD
ASTRONOMERS GET A RARE GLIMPSE OF THE EXPOSED CORE OF A STAR
Sometimes astrophysics gets super weird.
AT FIRST GLANCE, the star Gamma Columbae — a bright blue point of light about 870 light-years away in the southern hemisphere constellation Columba — looks seems like your average celestial body. But according to a team of astrophysicists, it’s “anything else but normal.”
A recent study of the star’s surface, published in the journal Nature Astronomy, says that we’re seeing Gamma Columbae in a short, deeply weird phase of a very eventful stellar life, one that lets astronomers look directly into the star’s exposed heart.
WHAT’S NEW – The mix of chemical elements on the surface of Gamma Columbae look like the byproducts of nuclear reactions that should be buried in the depths of a massive star, not bubbling on its surface.
University of Geneva astrophysicist Georges Meynet and his colleagues observed light from the star, which had been split into the individual wavelengths that make it up — exactly like when light shines through a prism, and we see a rainbow. Each molecule absorbs and emits light at different wavelengths, so looking at the spectrum of light from an object can reveal what it’s made of. Astronomers had never studied Gamma Columbae’s surface composition in detail before, and what Meynet and his colleagues saw surprised them.
In particular, Gamma Columbae’s surface boasts much more helium and nitrogen —compared to hydrogen, carbon, and oxygen — than should be present on the surface of a star. These ratios look like the mix of elements left over from nuclear reactions in the heart of a massive star, in which certain isotopes of carbon, nitrogen, and oxygen play a role in the reactions that fuse hydrogen atoms into helium.
Meynet and his colleagues describe that material as “nuclear ashes,” and usually only a little bit of it gets mixed into the star’s outer layers, thanks to the churning currents of convection. But the spectrum of light from Gamma Columbae’s surface reveals too strong a signature to be from just a handful of nuclear ashes stirred into (what should be) the star’s hydrogen-rich outer layers.
“In order to observe this at the surface of a star, you need to remove a lot of mass above these deep layers, to uncover the core of the star,” Meynet tells Inverse.
In other words, although Gamma Columbae looks like a typical bright main-sequence star (about as normal as it gets), it’s actually “the stripped, pulsating core of a previously much more massive star,” write Meynet and his colleagues.
DIGGING INTO THE DETAILS – At the moment, Gamma Columbae is about four or five times the mass of our Sun, so it’s still not exactly small. But in its younger years, Meynet and his colleagues estimate that it probably weighed in at around twelve times the mass of our Sun. That’s based on the ratios of the chemical elements nitrogen, carbon, and oxygen visible in the light from its surface, which “nicely match” the expected makeup of the core of a twelve solar-mass star, specifically, one that’s burned up all the hydrogen in its core and is ready to transition to burning helium.
So what happened?
The explanation that best fits the observations, according to Meynet and his colleagues, is that Gamma Columbae is, or was, part of a binary star system: Two stars orbiting a common center of gravity, like Alpha Centauri A and B, or the twin suns of Tatooine if you’re a sci-fi fan. When Gamma Columbae finished its hydrogen-burning phase, its outer layers would have expanded outward (just like our Sun will do one day). That swollen envelope of gas and plasma fell prey to the gravitational pull of a smaller companion star, perhaps around three times the mass of our Sun.
Meynet says that process probably took about 10,000 years, with the companion star pulling away about 0.01 percent of the mass of our Sun from Gamma Columbae every year, until all that was left was the core of the star, stripped bare.
WHY IT MATTERS – All of that adds up to make Gamma Columbae extremely unusual. What happened to gamma Columbae doesn’t happen often, and the handful of examples that astronomers know of are all much smaller stars, about the size of our Sun. But Gamma Columbae is unusually large and bright; it’s bright enough to see with the unaided eye, in fact.
Astronomers also know of another weird group of stars called Wolf-Rayet stars. These stars were once much, much larger than Gamma Columbae, about 60 times the mass of our Sun. They blasted away their own outer layers with powerful stellar winds. But there’s no sign of that kind of stellar wind coming from Gamma Columbae. Apparently, it’s in a class by itself.
And it’s a blink-and-you-miss-it phenomenon, at least in astronomical terms. Right now, we see Gamma Columbae as the exposed core of a hydrogen-burning star, but it’s only going to be that way for another few thousand years.
“The phase in which Gamma Columbae has been observed is a short phase of its life,” says Meynet. “So that is why it’s very unique because it’s a short timescale. It is rapidly evolving now.”
First, the core will contract, falling inward under its own weight, until the pressure at its center is enough to kickstart the process of fusing helium atoms together. At that point, Gamma Columbae will become an even brighter, hotter blue star, with probably another 2 million years left to live before it dies in a spectacular supernova.
For now, though, it gives astronomers a rare chance to look directly at the heart of a star.
WHAT’S NEXT – To learn more about what’s going on inside Gamma Columbae, Meynet and his colleagues point to a technique called asteroseismology: measuring small changes in the light on a star’s surface and using that to infer things about its internal structure.
“Asteroseismology is an extraordinary technique to probe the physics of the interior of stars,” says Meynet.
The researchers also hope to learn more about the fate of Gamma Columbae’s small, hungry companion. It may be that the smaller star’s light is just lost in the bright glow of gamma Columbae, but it’s also possible that the two stars merged at some point in their history.
Depending on how much Gamma Columbae expanded, and how closely the two stars orbited their shared center point, they could have gone through what astrophysicists call a “common-envelope phase.” That means the two stars orbited each other so closely, and Gamma Columbae swelled outward so far, that the little companion star was actually inside Gamma Columbae’s outermost layers — feasting on the larger star from the inside.
If that’s what happened, then the mechanics of the whole system mean that the two stars would gradually have spiraled closer to each other — so close that it’s possible that Gamma Columbae may actually have absorbed its smaller, envelope-thieving partner. In the process, whatever material the smaller star didn’t “eat” would have been tossed out of the star system by gravity or a brief gust of stellar wind.
We told you this star was weird.
To uncover whether Gamma Columbae still has a companion star, astronomers could turn to a method that’s often used to find exoplanets. By very precisely measuring how the star’s light changes over time, they could see the star wobbling slightly back and forth on its axis. This would mean it’s being tugged ever so slightly by the gravity of something in its orbit, like an exoplanet or a small companion star.
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