“There may be a new element for the solar system’s content that has been hypothesized but not yet quantitatively measured.”
Someone forgot to turn off the lights.
After painstakingly analyzing 200,000 images captured by the Hubble Space Telescope, astronomers have detected a residual “ghost glow” that stains the sky almost pitch black.
Their calculations are part of an ongoing project called SKYSURF and have just been described in a series of articles. Astronomy Journal and Astronomical Journal LettersIt explains the well-documented zodiacal light emanating from planets, stars, galaxies, and interplanetary dust – and they’re pretty sure the glow isn’t coming from these sources.
The remaining background brightness itself extremely faint – NASA defines this as the equivalent of ten fireflies radiating their light across the entire sky – but it’s still there, radiating uniformly into the near pitch blackness of space. In other words, this is a real anomaly, and this has piqued the interest of scientists.
The most likely candidate, according to astronomers, could be a spherical dust structure derived from comets that crashed into the system, lurking in a previously unexplained way in our solar system. Sunlight reflected from the dust then causes it to glow.
In 2021, NASA’s New Horizons spacecraft detected a similar excess, even fainter and still unexplained light, but the glow appeared to come from a more distant source.
“If our analysis is correct, there is another dust component between us and the distance New Horizons is measuring,” Tim Carleton, an astronomer at Arizona State University (ASU), said in a NASA statement.
“This means that this is some kind of extra light coming from inside our solar system,” he added. “There may be a new element for the solar system’s content that has been hypothesized but not yet quantitatively measured.”
According to ASU astronomer Rogier Windhorst, an experienced user of the space telescope, detecting the flare would not have been possible without the hard-working and loyal Hubble. Photons of light in the sky are literally overlooked, Windhorst says, as most astronomers try to observe distant objects.
“But these sky photons contain important information that can be inferred thanks to Hubble’s unique ability to measure faint luminosity levels with high precision over its thirty-year lifespan,” Windhorst said in a statement.
James Webb may be stealing the thunder these days, but you can never count Hubble. With the intriguing glow now revealed, perhaps other telescopes and observatories will soon join the mystery to uncover the origin of this cosmic nightlight.
More on Hubble observations: NASA Publishes Hubble Images of the Star Explosion