Forbes contributors publish independent expert analyses and insights.

There are no rainbows in space, but the next best thing has been snapped by a new NASA spacecraft now orbiting Earth while testing its cameras.

The spacecraft, called PUNCH (Polarimeter to Unify the Corona and Heliosphere), is about to begin investigating how the sun's outer corona -- by far the hottest part of our star's atmosphere -- becomes the solar wind that causes the Northern Lights.

The PUNCH mission blasted off on a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California on March 11, 2025. Also in the rocket's fairing was NASA's SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) observatory.

PUNCH isn't a single spacecraft. It comprises four small satellites that together create a single "virtual instrument" that spans the whole PUNCH constellation. The aim is to make 3D observations of the sun's corona for at least two years.

It's hoped that by doing so, scientists will better be able to figure out how the sun's corona becomes the solar wind and so more accurately predict space weather. That's crucial because solar wind can greatly affect satellites and robotic explorers in space.

A rainbow is an optical illusion created by sunlight refracting and being reflected inside droplets of liquid in an atmosphere. That's not going to happen in space. PUNCH's "space rainbows" are unique images of what astronomers call the zodiacal light, a triangular beam of light that can be seen on the horizon a few hours before sunrise or after sunset as the false dawn or false dusk.

PUNCH's stunning polarimetric triplet images are a combination of three images (red, green and blue) of sunlight being reflected by space dust. They were created during imaging tests of three polarizers on PUNCH on April 18, 2025, with the light colorized based on its angle (polarization).

For a few weeks in late September and October, a triangular beam of light appears on the eastern horizon a few hours before sunrise before gently fading. This is the "false dawn." In March and April, the opposite happens as a triangular beam of light appears on the western horizon a few hours after sunset -- the "false dusk."

So-called zodiacal light -- literally "light from the circle of animals" -- is the glow of the solar system. Reflected sunlight from interplanetary dust around the sun between the orbits of Mars and Jupiter radiates across the (visible) optical spectrum and beyond.

It's called the zodiacal light because it appears above where the sun has just set/is about to rise, so along the ecliptic -- the path of the sun through the daytime sky. This is the plane of the solar system, and it's where you'll find the belt of constellations across the night sky that the sun moves through in a calendar year -- hence star signs. The 12 "signs" of the zodiac are all officially recognized astronomical constellations: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces. There's also a thirteenth, Ophiuchus, a huge constellation that the sun also passes through.