KEY POINTS
- NASA’s Parker Solar Probe
has taken the closest ever images to the Sun, captured just 3.8 million
miles from the solar surface.
- The new close-up images
show features in the solar wind, the constant stream of electrically
charged subatomic particles released by the Sun that rage across the solar
system at speeds exceeding 1 million miles an hour.
- These images, and other
data, are helping scientists understand the mysteries of the solar wind,
which is essential to understanding its effects at Earth.
On its record-breaking pass by the Sun
late last year, NASA’s Parker Solar Probe captured stunning new images from
within the Sun’s atmosphere. These newly released images — taken closer to the
Sun than we’ve ever been before — are helping scientists better understand the
Sun’s influence across the solar system, including events that can affect
Earth.
“Parker Solar Probe has once again
transported us into the dynamic atmosphere of our closest star,” said Nicky
Fox, associate administrator, Science Mission Directorate at NASA Headquarters
in Washington. “We are witnessing where space weather threats to Earth begin,
with our eyes, not just with models. This new data will help us vastly improve
our space weather predictions to ensure the safety of our astronauts and the
protection of our technology here on Earth and throughout the solar system.”
Parker Solar Probe started its
closest approach to the Sun on Dec. 24, 2024, flying just 3.8 million miles
from the solar surface. As it skimmed through the Sun’s outer atmosphere,
called the corona, in the days around the perihelion, it collected data
with an array of scientific instruments, including the Wide-Field Imager for
Solar Probe, or WISPR.
Parker Solar Probe has revolutionized our understanding of the solar
wind thanks to the spacecraft’s many passes through the Sun’s outer atmosphere.
Credit: NASA's Goddard Space Flight Center/Joy Ng
The new WISPR images reveal the corona
and solar wind, a constant stream of electrically charged particles from the
Sun that rage across the solar system. The solar wind expands throughout of the
solar system with wide-ranging effects. Together with outbursts of material and
magnetic currents from the Sun, it helps generate auroras, strip planetary
atmospheres, and induce electric currents that can overwhelm power grids and
affect communications at Earth. Understanding the impact of solar wind starts
with understanding its origins at the Sun.
The WISPR images give scientists a
closer look at what happens to the solar wind shortly after it is released from
the corona. The images show the important boundary where the Sun’s magnetic
field direction switches from northward to southward, called the heliospheric
current sheet. It also captures the collision of multiple coronal mass
ejections, or CMEs — large outbursts of charged particles that are a key driver
of space weather — for the first time in high resolution.
“In these images, we’re seeing the CMEs
basically piling up on top of one another,” said Angelos Vourlidas, the WISPR
instrument scientist at the Johns Hopkins Applied Physics Laboratory, which
designed, built, and operates the spacecraft in Laurel, Maryland. “We’re using
this to figure out how the CMEs merge together, which can be important for
space weather.”
This video, made from images taken by Parker Solar
Probe’s WISPR instrument during its record-breaking flyby of the Sun on Dec.
25, 2024, shows the solar wind racing out from the Sun’s outer atmosphere, the
corona.
NASA/Johns Hopkins APL/Naval Research Lab
When CMEs collide, their trajectory can change, making it harder to predict
where they’ll end up. Their merger can also accelerate charged particles and
mix magnetic fields, which makes the CMEs’ effects potentially more dangerous
to astronauts and satellites in space and technology on the ground. Parker
Solar Probe’s close-up view helps scientists better prepare for such space
weather effects at Earth and beyond.
Zooming in on Solar Wind’s Origins
The solar wind was first theorized
by preeminent heliophysicist Eugene Parker in 1958. His theories about the
solar wind, which were met with criticism at the time, revolutionized how we
see our solar system. Prior to Parker Solar Probe’s launch in 2018, NASA and
its international partners led missions like Mariner
2, Helios, Ulysses, Wind, and ACE that helped scientists understand the origins of
the solar wind — but from a distance. Parker Solar Probe, named in honor of the
late scientist, is filling in the gaps of our understanding much closer to the
Sun.
At Earth, the solar wind is mostly
a consistent breeze, but Parker Solar Probe found it’s anything but at the Sun.
When the spacecraft reached within 14.7 million miles from the Sun, it
encountered zig-zagging magnetic fields — a feature known as switchbacks. Using
Parker Solar Probe’s data, scientists discovered that these switchbacks, which came in clumps, were more common than expected.
When Parker Solar Probe first
crossed into the corona about 8 million miles from the Sun’s surface in 2021,
it noticed the boundary of the corona was uneven and more complex than previously thought.
As it got even closer, Parker Solar
Probe helped scientists pinpoint the origin of switchbacks at patches on the
visible surface of the Sun where magnetic funnels form. In 2024 scientists announced that the fast solar wind — one of two main classes of the solar wind
— is in part powered by these switchbacks, adding to a 50-year-old mystery.
However, it would take a closer
view to understand the slow solar wind, which travels at just 220 miles per
second, half the speed of the fast solar wind.
“The big unknown has been: how is
the solar wind generated, and how does it manage to escape the Sun’s immense
gravitational pull?” said Nour Rawafi, the project scientist for Parker Solar
Probe at the Johns Hopkins Applied Physics Laboratory. “Understanding this
continuous flow of particles, particularly the slow solar
wind, is a major challenge, especially given the diversity in the
properties of these streams — but with Parker Solar Probe, we’re closer than
ever to uncovering their origins and how they evolve.”
Understanding Slow Solar Wind
The slow solar wind, which is twice as dense and more variable than fast solar wind, is important to study because its interplay with the fast solar wind can create moderately strong solar storm conditions at Earth sometimes rivaling those from CMEs.
This artist’s concept shows a representative state of
Earth’s magnetic bubble immersed in the slow solar wind, which averages some
180 to 300 miles per second.
NASA's Goddard Space Flight Center Conceptual Image
Lab
Prior to Parker Solar Probe, distant observations suggested there are
actually two varieties of slow solar wind, distinguished by the orientation or
variability of their magnetic fields. One type of slow solar wind, called
Alfvénic, has small-scale switchbacks. The second type, called non-Alfvénic,
doesn’t show these variations in its magnetic field.
As it spiraled closer to the Sun,
Parker Solar Probe confirmed there are indeed two types. Its close-up views are
also helping scientists differentiate the origins of the two types, which
scientists believe are unique. The non-Alfvénic wind may come off features
called helmet streamers — large loops connecting active regions where some
particles can heat up enough to escape — whereas Alfvénic wind might originate
near coronal holes, or dark, cool regions in the corona.
In its current orbit, bringing the
spacecraft just 3.8 million miles from the Sun, Parker Solar Probe will
continue to gather additional data during its upcoming passes through the
corona to help scientists confirm the slow solar wind’s origins. The next pass
comes Sept. 15, 2025.
“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.
By Mara Johnson-Groh
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Source: NASA’s Parker Solar Probe Snaps Closest-Ever Images to Sun - NASA Science
