The solar wind is a ubiquitous feature of our solar system. This relentless high-speed flow of charged particles from the sun fills interplanetary space. On Earth, it triggers geomagnetic storms that can disrupt satellites and it causes the dazzling auroras — the northern and southern lights — at high latitudes.
However, precisely how the sun generates the solar wind has remained unclear. New observations by the Solar Orbiter spacecraft might provide an answer.
Researchers on Thursday said that the spacecraft has detected numerous relatively small jets of charged particles expelled intermittently from the corona — the sun’s outer atmosphere — at supersonic speeds for 20 to 100 seconds.
Photo: Reuters / ESA & NASA / Solar Orbiter / EUI team
The jets emanate from structures on the corona called coronal holes where the sun’s magnetic field stretches into space rather than back into the star. They are called “picoflare jets” due to their relatively small size. They arise from areas a few hundred kilometers wide — tiny when compared to the immense scale of the sun, which has a diameter of 1.4 million kilometers.
“We suggest that these jets could actually be a major source of mass and energy to sustain the solar wind,” said solar physicist Lakshmi Pradeep Chitta from the Max Planck Institute for Solar System Research in Germany, lead author of the research published in the journal Science.
The solar wind consists of plasma — ionized gas, or gas in which the atoms lose their electrons — and is mostly ionized hydrogen.
“Unlike the wind on Earth that circulates the globe, solar wind is ejected outward into interplanetary space,” Chitta said.
“Earth and the other planets in the solar system whiz through the solar wind as they orbit around the sun. Earth’s magnetic field and atmosphere act as shields and protects life by blocking harmful particles and radiation from the sun, but the solar wind continuously propagates outward from the sun and inflates a plasma bubble called the heliosphere that encompasses the planets,” Chitta added.
The heliosphere extends out to about 100 to 120 times further than Earth’s distance to the sun.
The data for the study were obtained last year by one of the three telescopes on an instrument called the Extreme Ultraviolet Imager aboard the Solar Orbiter, a sun-observing probe built by the European Space Agency and NASA that was launched in 2020. The Solar Orbiter was about 50 million kilometers from the sun at the time — about one-third of the distance separating the sun and Earth.
“This finding is important, as it sheds more light on the physical mechanism of the solar wind generation,” said solar physicist and study coauthor Andrei Zhukov of the Royal Observatory of Belgium.
The solar wind’s existence was predicted by American physicist Eugene Parker in the 1950s and was verified in the 1960s.
“Still, the origin of the solar wind remains a longstanding puzzle in astrophysics,” Chitta said. “A key challenge is to identify the dominant physical process that powers the solar wind.”
The Solar Orbiter is discovering new details about the solar wind and is expected to obtain even better data in the coming years using additional instruments and viewing the sun from other angles.
Zhukov said stellar wind is a phenomenon common to most, if not all, stars, though the physical mechanism might differ among various types of stars.
“Our understanding of the sun is much more detailed than the understanding of other stars, due to its proximity and thus the possibility to make more detailed observations,” Zhukov added.
The Bolivian government on Friday struck a deal with protesting miners, but was still grappling with blockades and demonstrations by other workers across La Paz. Other groups are still blocking access roads into the city, which is also the seat of the government. Police on Thursday prevented the miners from entering the main square by using tear gas, while the demonstrators hurled stones and explosives with slingshots. Protests against the policies of Bolivian President Rodrigo Paz have convulsed the Andean nation since early this month, and roadblocks were choking routes into La Paz throughout Friday, the national road authority said. Miners demanded that Paz
The Philippines said it has asked the country’s Supreme Court to allow it to arrest former Philippine president Rodrigo Duterte’s chief drug war enforcer to stand trial in an international tribunal. The International Criminal Court (ICC) last week unsealed an arrest warrant against Philippine Senator Ronald dela Rosa, accusing him along with Duterte and other “coperpetrators” of the “crime against humanity of murder.” Dela Rosa briefly sought refuge in the Philippine Senate last week while asking the Philippine Supreme Court to stop an ongoing attempt by government agents to arrest him. “By his own conduct, he has placed himself outside the protection of
A ship anchored off the United Arab Emirates (UAE) was seized and taken toward Iran and another — a cargo ship near Oman — sank after being attacked, authorities said on Thursday, as tensions escalated near the Strait of Hormuz. It was not immediately clear who was behind these incidents, but they happened as a senior Iranian official reiterated his country’s claim of control over the waterway and another said it had a right to seize oil tankers connected to the US. The turmoil in the strait has been a sticking point for weeks in talks between the US and Iran to
The researchers in Ireland looked at their computer screen, marveling at a medieval book tracked down in a Roman library. They flipped through its digitized pages and found their sought-after treasure: the oldest surviving English poem. “We were extremely surprised. We were speechless. We couldn’t believe our eyes when we first saw that,” said Elisabetta Magnanti, a visiting research fellow at Trinity College Dublin’s school of English. The poem was also within the main body of Latin text, she said, calling it “extraordinary.” Composed in Old English by a Northumbrian agricultural worker in the 7th century, Caedmon’s Hymn appears within some copies of
RSS