NASA’s sun-touching Parker Solar probe has flown close enough to our star to spot the fine details of the solar wind — including its origin, “coronal holes” in the sun’s atmosphere.
Armed with this information, scientists may now be able to better predict solar storms that can supercharge auroras over our planet but can also disrupt communication and power infrastructure and pose a threat to satellites, spacecraft and even astronauts.
The Parker Solar Probe tracked the solar wind — a stream of charged particles flowing continuously from the sun — back to where it is generated, a new study reports. This allowed researchers to see characteristics of the solar wind that are lost as it exits the sun’s outer atmosphere, or corona, and before it reaches Earth as a relatively uniform stream.
The spacecraft saw that the streams of high-energy particles that make up the solar wind match so-called “supergranulation flows” within coronal holes. This discovery pointed to these regions as the source of the “fast” solar wind, which is seen over the poles of the sun and can reach speeds as great as 1.7 million mph (2.7 million kph), around 1,000 times faster than the top speed of a jet fighter.
Coronal holes are believed to form in areas where magnetic field lines emerge from the sun’s surface but do not loop back there. This causes open field lines that spread to fill the space around the sun.
During quiet periods of our star’s 11-year activity cycle, coronal holes are usually found at the poles of the sun. This means that the solar wind that emerges from coronal holes isn’t usually directed toward Earth. But when the sun becomes more active and its magnetic field “flips,” switching poles, coronal holes become more widespread, and these powerful streams of charged particles can be directed at our planet. That knowledge, and these new results, could aid the prediction of potentially disruptive solar storms, study team members said.
“Winds carry lots of information from the sun to Earth, so understanding the mechanism behind the sun’s wind is important for practical reasons on Earth,” team co-leader and University of Maryland-College Park professor James Drake said in a statement. “That’s going to affect our ability to understand how the sun releases energy and drives geomagnetic storms, which are a threat to our communication networks.”
A sun shower
The coronal holes operate like a showerhead, spraying jets of charged particles from evenly spaced “bright spots” where magnetic fields extend out from the sun’s surface, team members said. This gives rise to funnels that can be around 18,000 miles (29,000 kilometers) wide, seen on Earth as bright “jetlets” within coronal holes.
The team thinks that when magnetic fields with opposite directions pass each other in these funnels, magnetic field lines break and then reconnect. It is this process, called magnetic reconnection, that is responsible for flinging out the charged particles that we see as solar wind.
The scientists determined this because the speed of some of the observed particles is up to 10 times greater than the average for the solar wind — something only possible with a powerful phenomenon like magnetic reconnection. Such speeds aren’t possible for particles simply surfing along on plasma, team members said.
“The photosphere is covered by convection cells, like in a boiling pot of water, and the larger-scale convection flow is called supergranulation,” research co-leader Stuart Bale, a physics professor at the University of California, Berkeley, said in the same statement. (The photosphere is the sun’s surface.)
“Where these supergranulation cells meet and go downward, they drag the magnetic field in their path into this downward kind of funnel,” Bale added. “The magnetic field becomes very intensified there because it’s just jammed. It’s kind of a scoop of the magnetic field going down into a drain.”
Bale added that it is the spatial separation of these little drains or funnels that the team saw when they looked at data gathered as the Parker Solar Probe made its close approaches to the sun.
“The big conclusion is that it’s magnetic reconnection within these funnel structures that’s providing the energy source of the fast solar wind,” Bale said. “It doesn’t just come from everywhere in a coronal hole; it’s substructured within coronal holes to these supergranulation cells. It comes from these little bundles of magnetic energy that are associated with the convection flows. Our results, we think, are strong evidence that it’s reconnection that’s doing that.”
Getting up close and personal to find the origin of the fast solar wind
Studying the fine detail of the solar wind isn’t possible from Earth because, by the time it has traveled 93 million miles (150 million km) to reach our planet and strike its magnetic field, the stream has become a homogenous flow of magnetic fields and charged particles like protons, electrons and helium nuclei.
The Parker Solar Probe launched on Aug. 12, 2018. As of March 17, 2023, the spacecraft had made 15 close approaches to the sun, coming as close as 3.8 million miles (6.1 million km) and racing past the star at speeds as great as 365,000 mph (587,000 kph). Thus, Parker gets close enough to see solar wind details before they are lost.
“Once you get below that altitude, 25 or 30 solar radii [around 11 million to 13 million miles] or so, there’s a lot less evolution of the solar wind, and it’s more structured — you see more of the imprints of what was on the sun,” Bale said.
In 2021, the spacecraft passed within about 5.2 million miles (8.4 million km) of the solar surface and raced through jets of material rather than mere turbulence. The team traced those jets back to bunched-up magnetic fields and supergranulation cells on the photosphere.
What the team wasn’t sure of back then, however, was if those charged particles were being accelerated by the slingshot-like action of magnetic reconnection or if they were surfing on waves of hot plasma from the sun. The high energy status of the particles told the team that the former mechanism was responsible for accelerating the charged particles, which also got a boost from turbulence in the plasma called Alfvén waves.
“Our interpretation is that these jets of reconnection outflow excite Alfvén waves as they propagate out,” Bale said. “That’s an observation that’s well known from Earth’s magnetotail, as well, where you have similar kinds of processes.”
Further data from the Parker Solar Probe, as it comes to within around 4 million miles (6.4 million km) of the sun during future close approaches, could help the team confirm their theory. But this could be complicated by the fact that the sun is about to enter solar maximum — a period of chaotic and intense activity.
“There was some consternation at the beginning of the solar probe mission that we’re going to launch this thing right into the quietest, most dull part of the solar cycle,” Bale said. “But I think without that, we would never have understood this. It would have been just too messy. I think we’re lucky that we launched it in the solar minimum.”
The team’s research is detailed in a paper published online today (June 7) in thejournal Nature.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
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.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
