The Parker Solar Probe has finally reached the atmosphere of the sun.
The NASA spacecraft spent more than three years winding its way by planets and creeping gradually closer to our star to learn more about the origin of the solar wind, which pushes charged particles across the solar system.
Since solar activity has a large effect on living on Earth, from generating auroras to threatening infrastructure like satellites, scientists want to know more about how the sun operates to better make predictions about space weather.
Observations from Parker’s April 28 flyby, which was the eighth time the spacecraft whizzed by the sun, show that the spacecraft managed to get inside the sun’s atmosphere, or the corona, for the first time. The results generated two science papers that NASA explored in a recent statement.
“We were fully expecting that, sooner or later, we would encounter the corona for at least a short duration of time,” Justin Kasper, lead author on a new paper about the coronal milestone published in Physical Review Letters, said in the statement. Kasper is also deputy chief technology officer at BWX Technologies and a University of Michigan professor.
The sun isn’t a solid sphere like our Earth, but it does have a zone in which the immense gravity of the star keeps in the solar material it spews through fusion.
At a particular distance from the sun, however, gravity and magnetic fields are no longer able to keep that material close. It’s from that point where the solar wind flows away from the sun, never to return. The point of no return is called the Alfvén critical surface and scientists had not been able to measure exactly where it was, before Parker reached it.
Previously, faraway pictures of the corona suggested that the critical surface was somewhere between 4.3 to 8.6 million miles (6.9 to 13.8 million kilometers) from the surface of the sun, or in relative terms, the equivalent of 10 to 20 times the radius of the sun. As it turns out, these estimates were not too far off. Parker’s data suggests it crossed the critical surface at 18.8 solar radii, or 8.1 million miles (13 million km) above the sun’s surface.
More importantly, Parker found the critical surface is not uniform, and there are “spikes and valleys” (as NASA termed it) in which the surface protrudes higher or lower from the center of the sun. The surface also likely varies with solar wind activity, which in turn depends on the sun’s 11-year solar cycle.
“Discovering where these protrusions line up with solar activity coming from the surface can help scientists learn how events on the sun affect the atmosphere and solar wind,” NASA officials wrote in the statement.
Parker could only spend a few hours in the corona due to the intense conditions there, but it did manage to go as low as 15 solar radii from the sun’s surface. In that zone, it found a “pseudostreamer,” one of the huge structures you can see from Earth during total solar eclipses.
“Passing through the pseudostreamer was like flying into the eye of a storm,” NASA said in the same statement, noting that Parker saw changes such as quieter conditions and fewer particles.
On future flybys, Parker is expected to creep even closer to the sun, coming as low as 8.86 solar radii (3.83 million miles or 6.16 million km) from the sun’s photosphere, its visible surface.
Farther away from the sun, the spacecraft has been exploring the physics of “switchbacks,” or zig-zag-shaped structures in the solar wind.
Parker’s work on this aspect of solar physics, now in press at the Astrophysical Journal, suggests that switchbacks originate at the visible surface of the sun, known as the photosphere. The switchbacks have been known for some time and were first discovered by the NASA-European Space Agency mission Ulysses, which orbited the sun’s poles in the 1990s.
While scientists at first assumed the switchbacks were confined to solar regions, Parker found the switchbacks were quite common in the solar wind in 2019. Now fresh findings, from the mission’s sixth solar flyby, suggest that switchbacks “occur in patches and have a higher percentage of helium” than other elements, NASA said.
Scientists also found that the patches line up with magnetic funnels coming from the photosphere, called supergranules. This is helpful to understanding solar physics because the funnels may be where fast particles of the solar wind originate.
“The structure of the regions with switchbacks matches up with a small magnetic funnel structure at the base of the corona,” Stuart Bale, a professor at the University of California, Berkeley, and lead author on the new switchbacks paper, said in the NASA statement. “This is what we expect from some theories, and this pinpoints a source for the solar wind itself.”
If scientists could better understand the physics of switchbacks, this may also point to why the corona is millions of degrees Fahrenheit or Celsius, which is far above the temperature of the solar surface.
“While the new findings locate where switchbacks are made, the scientists can’t yet confirm how they’re formed,” NASA added. “One theory suggests they might be created by waves of plasma that roll through the region like ocean surf. Another contends they’re made by an explosive process known as magnetic reconnection, which is thought to occur at the boundaries where the magnetic funnels come together.”
Parker Solar Probe’s next solar flyby is scheduled for late February 2022, although the spacecraft will gather observations for weeks before and after the closest approach.
Explainer-Scientists struggle to monitor Tonga volcano after massive eruption
Scientists are struggling to monitor an active volcano that erupted off the South Pacific island of Tonga at the weekend, after the explosion destroyed its sea-level crater and drowned its mass, obscuring it from satellites.
The eruption of Hunga-Tonga-Hunga-Ha’apai volcano, which sits on the seismically active Pacific Ring of Fire, sent tsunami waves across the Pacific Ocean and was heard some 2,300 kms (1,430 miles) away in New Zealand.
“The concern at the moment is how little information we have and that’s scary,” said Janine Krippner, a New Zealand-based volcanologist with the Smithsonian Global Volcanism Program.
“When the vent is below water, nothing can tell us what will happen next.”
Krippner said on-site instruments were likely destroyed in the eruption and the volcanology community was pooling together the best available data and expertise to review the explosion and predict anticipated future activity.
Saturday’s eruption was so powerful that space satellites captured not only huge clouds of ash but also an atmospheric shockwave that radiated out from the volcano at close to the speed of sound.
Photographs and videos showed grey ash clouds billowing over the South Pacific and metre-high waves surging onto the coast of Tonga.
There are no official reports of injuries or deaths in Tonga https://www.reuters.com/business/environment/impact-assessment-aid-efforts-underway-world-responds-tonga-tsunami-2022-01-16 yet but internet and telephone communications are extremely limited and outlying coastal areas remain cut off.
Experts said the volcano, which last erupted in 2014, had been puffing away for about a month before rising magma, superheated to around 1,000 degrees Celsius, met with 20-degree seawater on Saturday, causing an instantaneous and massive explosion.
The unusual “astounding” speed and force of the eruption indicated a greater force at play than simply magma meeting water, scientists said.
As the superheated magma rose quickly and met the cool seawater, so did a huge volume of volcanic gases, intensifying the explosion, said Raymond Cas, a professor of volcanology at Australia’s Monash University.
Some volcanologists are likening the eruption to the 1991 Pinatubo eruption in the Philippines, the second-largest volcanic eruption of the 20th century, which killed around 800 people.
The Tonga Geological Services agency, which was monitoring the volcano, was unreachable on Monday. Most communications to Tonga have been cut after the main undersea communications cable lost power.
American meteorologist, Chris Vagasky, studied lightning around the volcano and found it increasing to about 30,000 strikes in the days leading up to the eruption. On the day of the eruption, he detected 400,000 lightning events in just three hours, which comes down to 100 lightning events per second.
That compared with 8,000 strikes per hour during the Anak Krakatau eruption in 2018, caused part of the crater to collapse into the Sunda Strait and send a tsunami crashing into western Java, which killed hundreds of people.
Cas said it is difficult to predict follow-up activity and that the volcano’s vents could continue to release gases and other material for weeks or months.
“It wouldn’t be unusual to get a few more eruptions, though maybe not as big as Saturday,” he said. “Once the volcano is de-gassed, it will settle down.”
(Reporting by Kanupriya Kapoor; Editing by Jane Wardell and Michael Perry)
Astronauts at Risk of 'Space Anemia' | Health | thesuburban.com – The Suburban Newspaper
MONDAY, Jan. 17, 2022 (HealthDay News) — Astronauts can develop a condition called space anemia because their bodies destroy more red blood cells than normal when in space, a groundbreaking study shows.
Assessments of 14 astronauts over six months between space missions found that 54% more blood cells were destroyed while they were in space than when they were on Earth, according to findings published Jan. 14 in Nature Medicine.
“Space anemia has consistently been reported when astronauts returned to Earth since the first space missions, but we didn’t know why,” said lead author Dr. Guy Trudel of the Ottawa Hospital Research Institute in Canada. “Our study shows that upon arriving in space, more red blood cells are destroyed, and this continues for the entire duration of the astronauts’ mission.”
Before this study, it was believed that space anemia was due to fluid shifting into an astronaut’s upper body upon arrival in space.
Astronauts lose 10% of the liquid in their blood vessels this way. It was thought that their bodies rapidly destroyed 10% of their red blood cells to restore the balance, and that red blood cell control returned to normal after 10 days in space.
But this study found that red blood cell destruction is a primary effect of being in space, not just the result of fluid shifts.
On Earth, our bodies create and destroy 2 million red blood cells every second. But the astronauts in this study — both male and female — destroyed 3 million every second while in space.
Five of 13 astronauts in the study were clinically anemic when they returned to Earth. One of the 14 did not have blood drawn on landing.
The researchers also found that space anemia is reversible, with red blood cells levels progressively returning to normal three to four months after astronauts returned from space.
“Thankfully, having fewer red blood cells in space isn’t a problem when your body is weightless,” Trudel said in a hospital news release. “But when landing on Earth and potentially on other planets or moons, anemia affecting your energy, endurance and strength can threaten mission objectives. The effects of anemia are only felt once you land, and must deal with gravity again.”
The findings could be prove useful for patients who develop anemia after long illnesses that require bed rest. Bed rest has been shown to cause anemia, but how it does so is unknown.
The mechanism may be like what occurs in space anemia, according to Trudel, who plans to investigate this theory in future research.
The American Academy of Family Physicians has more on anemia.
SOURCE: The Ottawa Hospital, news release, Jan. 14, 2022
Western scientists study meteorite made famous after crashing into B.C. woman's bedroom – CBC.ca
A meteorite that ripped through a roof and landed inches from a B.C. woman’s head is believed to be around 470 million years old, Western researchers say.
Ruth Hamilton of Golden, B.C. was woken abruptly on the night of Oct. 3, when the small charcoal grey rock the size of a melon broke through her ceiling and landed between her floral pillowcases.
After coming to terms with the surreal experience, she lent the rock to Western University’s physics and astronomy department in London, Ont., where researchers are working to map its orbital journey around the sun before it arrived in Hamilton’s bedroom.
“It was very exciting getting it because any time you see a new meteorite, it’s kind of like Christmas Day,” said adjunct professor Phil McCausland, who leads the investigation.
Upon inspection, McCausland found that the meteorite is an L chondrite, one of the most commonly found types of meteorites to fall on Earth.
What’s not so common about Hamilton’s meteorite is where it originates in the sky.
“This rock has a very interesting and unusual orbit,” said McCausland.
“Chondrite meteors are thought with good evidence to have come from the early solar system, but they went through a major asteroid breakup event. So there is a big body in the asteroid belt that broke up about 470 million years ago,” he said.
“From then, a bunch of material has been delivered around the inner solar system, some of it arriving on Earth. And this, prospectively, is one of those pieces.”
McCausland said so far, the orbits of only a handful of L chondrite meteors are known.
“What happens out in space is that the cosmic rays interact with the rock and end up irradiating it, so that it has somewhat activated isotopes that decay over time,” he said. “We can detect what the decay products are that are coming out of this, the gamma rays and so on. And that gives us a handle on the orbital history of the rock.”
Afternoon Drive9:04Meteorite analysis at Western University
He added that researchers are looking to dash cam and surveillance footage, as well as local photographers who captured the fireball event, to reconstruct the rock’s flight path.
Under Canadian law, the meteor is owned by its finder – in this case, Ruth Hamilton. It’s hers to sell, donate, or keep.
Meanwhile, McCausland will ensure a sample is registered with the Meteoritical Society, where it will be available for future scientific research.
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