A Spacecraft Has “Touched” the Sun for the First Time. Credit: NASA / Johns Hopkins APL / Ben Smith
On April 28, 2021, at 0933 UT (3:33 a.m. Eastern Daylight Time), NASA’s Parker Solar Probe reached the sun’s extended solar atmosphere, known as the corona, and spent five hours there. The spacecraft is the first to enter the outer boundaries of our sun.
The results, published in Physical Review Letters, were announced in a press conference at the American Geophysical Union Fall Meeting 2021 on December 14. The manuscript is open-access and freely available to download.
“This marks the achievement of the primary objective of the Parker mission and a new era for understanding the physics of the corona,” said Justin C. Kasper, the first author, Deputy Chief Technology Officer at BWX Technologies, and a professor at the University of Michigan. The mission is led by the Johns Hopkins University Applied Physics Laboratory (JHU/APL).
The probe made the first direct observations of what lies within the sun’s atmosphere, measuring phenomena previously only estimated.
The sun’s outer edge begins at the Alfvén critical surface: the point below which the sun and its gravitational and magnetic forces directly control the solar wind. Many scientists think that sudden reverses in the sun’s magnetic field, called switchbacks, emerge from this area.
“The concept of sending spacecraft into the magnetized atmosphere of the sun—sufficiently close that the magnetic energy is greater than both ion and electron kinetic and thermal energy—predated NASA itself,” said Kasper.
Artist’s conception of the Parker Solar Probe spacecraft approaching the Sun. Credit: NASA/Johns Hopkins APL/Steve Gribben
In 2018, NASA launched Parker Solar Probe with the goal of finally reaching the sun’s corona and making humanity’s first visit to a star.
This past April, the probe spent five hours below the Alfvén critical surface in direct contact with the sun’s plasma. Below that surface, the pressure and energy of the sun’s magnetic field was stronger than the pressure and energy of the particles. The spacecraft passed above and below the surface three separate times during its encounter. This is the first time a spacecraft has entered the solar corona and touched the atmosphere of the sun.
Surprisingly, the researchers discovered that the Alfvén critical surface is wrinkled. The data suggest that the largest and most distant wrinkle of the surface was produced by a pseudostreamer—a large magnetic structure more than 40 degrees across, found back on the innermost visible face of the sun. It is not currently known why a pseudostreamer would push the Alfvén critical surface away from the sun.
Researchers noticed far fewer switchbacks below the Alfvén critical surface than above it. The finding could mean that switchbacks do not form within the corona. Alternatively, low rates of magnetic reconnection on the sun’s surface could have pumped less mass into the observed wind stream, resulting in fewer switchbacks.
The probe also recorded some evidence of a potential power boost just inside the corona, which may point to unknown physics affecting heating and dissipation.
“We have been observing the sun and its corona for decades, and we know there is interesting physics going on there to heat and accelerate the solar wind plasma. Still, we cannot tell precisely what that physics is,” said Nour E. Raouafi, the Parker Solar Probe Project Scientist at JHU/APL. “With Parker Solar Probe now flying into the magnetically-dominated corona, we will get the long-awaited insights into the inner workings of this mysterious region.”
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The observations took place during Parker Solar Probe’s eighth encounter with the sun. All data is publicly available in the NASA PSP archive. Several previous studies predicted the probe would first pass within the sun’s boundaries in 2021.
The new findings suggest that direct observations by spacecraft have much to illuminate about the physics of coronal heating and solar wind formation. Having achieved its goal of touching the sun, Parker Solar Probe will now descend even deeper into the sun’s atmosphere and linger for longer periods of time.
According to Gary Zank, a coinvestigator on the probe‘s Solar Wind Electrons Alphas and Protons (SWEAP) instrument and a member of the National Academy of Sciences, “It is hard to overstate the significance of both the event and the observations made by Parker Solar Probe. For over 50 years, since the dawn of the space age, the heliospheric community has grappled with the unanswered problem of how the solar corona is heated to well over a million degrees to drive the solar wind. The first measurements of the sub-Alfvénic solar wind may represent the most major step forward in understanding the physics behind the acceleration of the solar wind since the formative model by Parker.”
“This event is what many heliophysicists have dreamed about for most of their careers!” Zank added.
More information:
J. C. Kasper et al, Parker Solar Probe Enters the Magnetically Dominated Solar Corona, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.127.255101
Citation:
Parker Solar Probe: A spacecraft has ‘touched’ the sun for the first time (2021, December 14)
retrieved 14 December 2021
from https://phys.org/news/2021-12-parker-solar-probe-spacecraft-sun.html
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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.
