Hubble Detects Ghostly Glow Surrounding Our Solar System

A survey of the residual light in the night sky has uncovered an eerie, omnipresent glow spread throughout the Solar System, thought to be caused by sunlight reflected from cometary dust.

Over its thirty-plus years of operations, astronomers have become accustomed to subtracting the background light from the Solar System from Hubble’s images. They are interested in the faint, discrete objects that are other stars and galaxies. But the SKYSURF team realised that Hubble’s images would be an excellent set of survey data to measure the Solar System’s background light.

The SKYSURF programme used 200,000 images from the NASA/ESA Hubble Space Telescope to look for any residual background light in the sky. This would be any leftover light after subtracting the glow from planets, stars, galaxies, and from dust in the plane of our solar system (called zodiacal light). The excess that they found was extremely faint – equivalent to the steady glow of 10 fireflies spread across the entire sky.

The researchers say that one possible explanation for this residual glow is that our inner solar system contains a tenuous sphere of dust from comets that are falling into the solar system from all directions, and that the glow is sunlight reflecting off this dust. If real, this dust shell could be a new addition to the known architecture of the solar system.

[Image Description: Illustration shows a simple diagram of the Solar System with white speckling representing comet dust. The Sun is represented as a fuzzy yellow sphere at the center. It is surrounded by four concentric ovals labeled 'Planetary Orbits', which represent the orbital paths of Jupiter, Saturn, Uranus, and Neptune, as viewed from an oblique angle to the orbital plane.]