A new analysis of Hubble data has settled it: There is a lot of light in space around the solar system.
Not a lot of extra light, for sure. Just a subtle, ghostly glow, a faint excess that could not be accounted for in a census of all light-emitting beings.
All of the stars and galaxies surrounding the solar system — and zodiacal light, also known as solar system-wide dust — none of these can explain what astronomers now call “ghost light.”
After analyzing 200,000 Hubble images and taking thousands of measurements in a project called skysurfthe international collaboration confirms that excess light is real.
Moreover, they cannot fully explain it. There are possibilities, but none have been confirmed. Not now anyway.
The strongest possibility? A dusty element in the solar system that we haven’t yet directly detected: tiny particles of dust and ice from a group of comets travel inland from the dark reaches of the solar system, reflecting sunlight and generating a diffuse global glow.
This source will be a little closer to us than Extra light detected by the New Horizons space probewhich found excess light in the space beyond Pluto, outside the solar system.
“If our analysis is correct, then there is another dust element between us and the distance New Horizons made the measurements. And that means that this is some kind of additional light that comes from within our solar system,” he said. says astronomer Tim Carlton from Arizona State University.
“Because our measure of residual light is higher than New Horizons, we believe it is a local phenomenon not far from the solar system. They may be a new solar system contents hypothesized but not quantitatively measured yet.”
There are a lot of bright things floating around the universe: planets, stars, galaxies, and even gas and dust. And in general, the bright things are the things we want to look at. So detecting ambient light in interstitial spaces – the space between planets, interstellar and between galaxies – is challenging.
However, when we look, we sometimes find that things are not what we expect them to be.
For example, something we cannot explain is produced at the center of the galaxy High power light. Voyager found an increase in brightness associated with hydrogen at the boundaries of the solar system. Discover New Horizons. Things look strangely glowy there.
The purpose of SKYSURF was to fully characterize the sky’s brightness.
“More than 95 percent of the photons in the images from the Hubble archives come from distances of less than 3 billion miles from Earth. Since the very early days of Hubble, most Hubble users have ignored these sky photons, because they are interested in the faint discrete objects in Hubble images, such as stars and galaxies,” says astronomer and veteran Hubble expert Roger Windhorst from Arizona State University.
“But these sky photons contain important information that can be gleaned from Hubble’s unique ability to measure faint brightness levels with high precision over its three decades of life.”
Across three separate papers, the researchers searched the Hubble archives for signs of faint galaxies we may have missed, and determined what light must be emitting from objects known to shine.
The team searching for hidden galaxies determined that not enough galaxies had been missed to account for the extra light.
The resulting excess, scientists said, is equivalent to a constant glow from 10 fireflies across the entire sky.
It may not sound like much, but it’s enough to know we’re missing something. This is important. Increasingly, scientists are finding ways to see the light between the stars. If there is a local excess, we need to know about it, because it might skew our understanding of distant ghost flares.
And of course, there could be an impact on our understanding of the solar system and how it is put together.
“When we look at the night sky, we can learn a lot about Earth’s atmosphere. Hubble is in space,” says astronomer Rosalia O’Brien of Arizona State University.
“When we look at that night sky, we can learn a lot about what’s going on inside our galaxy and solar system and on large scales like the entire universe.”
The three Skysurf papers published in The Astronomical Journal And Astrophysical Journal Lettersand can be found over hereAnd over hereAnd over here. A fourth paper was submitted to The Astronomical Journal Which has not yet been published, can be found On the arXiv prepress server.