NASA’s Parker Solar Probe has captured its closest-ever images of the Sun, taken just 3.8 million miles (6.1 million kilometres) away during a flyby on December 24, 2024.
The spacecraft delivered remarkable visuals of the solar corona, the Sun’s outer atmosphere, offering fresh insight into the solar wind — the steady stream of charged particles flowing outward from the Sun.
This solar wind plays a key role in space weather, fuelling natural phenomena like auroras while also posing risks to satellites, communications systems, and even Earth’s power grids, according to Live Science.
Scientists are especially focused on understanding the “slow” solar wind, which is denser and more unstable than its faster counterpart. The latest data from Parker is helping to unravel why it behaves so differently.
For decades, researchers have struggled with two major questions: how the solar wind forms, and how it escapes the Sun’s powerful gravitational pull.
“The big unknown has been: how is the solar wind generated, and how does it manage to escape the Sun’s immense gravitational pull?” explained Nour Rawafi, project scientist for the Parker Solar Probe at Johns Hopkins Applied Physics Laboratory.
“Understanding this continuous flow of particles, particularly the slow solar wind, is a major challenge.”
The Parker Solar Probe’s latest pass was able to confirm a key hypothesis: the slow solar wind consists of two distinct types — Alfvénic and non-Alfvénic.
The images are helping scientists pinpoint the origins of these streams, suggesting Alfvénic winds may emerge from coronal holes in cooler regions, while non-Alfvénic winds could be released from hot magnetic loops called helmet streamers.
“We don’t have a final consensus yet, but we have a whole lot of new intriguing data,” said Adam Szabo, Parker Solar Probe mission scientist at Nasa’s Goddard Space Flight Centre in Greenbelt, Maryland, in the statement.
The Parker Solar Probe, which was launched in 2018, is the first spacecraft to have entered the sun’s corona. It is equipped with advanced scientific instrumentation, including the Wide Field Imager for Solar Probe (WISPR), the unmanned probe endures extreme temperatures and radiation to collect data.
The probe will continue its mission and is expected to next pass its perihelion — the closest point to the sun’s surface — on September 15.
NASA’s Parker Solar Probe has confirmed a key theory about the Sun’s behaviour during its most recent flyby, revealing that the slow solar wind is made up of two distinct types: Alfvénic and non-Alfvénic streams.
The latest images are helping researchers trace the origins of these flows. Early findings suggest that Alfvénic winds may come from coronal holes — cooler, less dense regions of the Sun’s outer atmosphere. By contrast, non-Alfvénic winds appear to be released from hot, magnetic loops known as helmet streamers.
“We don’t have a final consensus yet, but we have a whole lot of new intriguing data,” said Adam Szabo, Parker Solar Probe mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Launched in 2018, Parker Solar Probe is the first spacecraft to venture into the Sun’s corona. Outfitted with cutting-edge tools such as the Wide Field Imager for Solar Probe (WISPR), the unmanned craft withstands blistering heat and intense radiation to capture these observations.
The probe’s mission is ongoing. Its next close approach to the Sun, known as perihelion, is scheduled for September 15.