A new NASA mission to map the solar wind has returned some of its first images from its position in low Earth orbit.
The Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission launched on 11 March 2025, and its early glimpses of the Solar System and the space beyond are both eerie and fascinating.
Each of PUNCH’s four satellites carries an imaging instrument – one narrow-field and three wide-field, to capture different aspects of the solar atmosphere as it transitions into the solar wind and blows through the Solar System.
The aspect captured by the narrow-field imager (NFI) is perhaps the eeriest of all. This instrument is a type of coronagraph, which includes an attachment called an occulter that sits in the middle of the field of view and blocks out the Sun’s disk. This allows fine details of the solar atmosphere, or corona, to be seen, in the same way details of the corona can be seen during a solar eclipse.
In the image from PUNCH’s NFI, the occulter is not quite fully aligned with the Sun, which means some of the Sun’s light leaks through the image in interesting ways. Around the edge of the occulter, a bright ring of diffracted light can be seen, while a larger halo of light bouncing off the occulter dominates the image. Within this halo floats the new Moon, fully illuminated by the Sun’s light reflecting off Earth.
The visuals from the wide-field imagers (WFIs) are just as fascinating, all of them showing constellations and star clusters, with the Pleiades making an appearance in all three. From WFI-2, we get this gloriously rainbow-tinted image of the stars.
Although we can’t see those hues with our own eyes, they do represent something real. The spacecraft is equipped with a filter that allows it to determine how light is polarized, its waves aligned in a particular orientation. When light travels through and bounces off matter, it can become polarized.
WFI-2 used its filters to detect the polarization of sunlight scattering off the interplanetary dust that orbits the Sun on the plane of the Solar System. This scattering creates a phenomenon known as zodiacal light that can be seen in dark night skies most strongly around the annual equinoxes.
The hues and saturations indicate the direction and strength of the polarization of zodiacal light in WFI-2’s image.
The images from WFI-1 and WFI-3 are pretty similar to each other, showing zodiacal light stretching upwards, from slightly different angles. The Hyades, a V-shaped cluster of stars, and the Pleiades, a cluster resembling a scoop, can be seen at the top middle and slightly down and to the right in the WF-1 image.
Meanwhile, in the WF-3 image, the Pleiades cluster appears at nine o’clock, with the constellation of Cassiopeia at the top.
All four images, NASA says, provide confirmation that all the instruments are working as they should. Now, the ground team will be working on calibration, after which the true science work will commence.
If we’re lucky, though, even this early phase of the mission will yield some observations that help us understand how the Sun generates the wind that carves out the Solar System’s bubble in the Milky Way galaxy.
