How dark is the night sky?
If you go outside on a moonless night and look up, it probably doesn’t look that dark. Streetlights and nearby porch lights fill the air with background light, especially if they’re pale LEDs. Light pollution is so bad in your neighborhood that you may only be able to see a few bright stars.
Even in a somewhat rural area, the sky is bright and the Milky Way is not very visible. Only about a quarter of children in North America and Europe have seen the Milky Way.
Escape from all light pollution requires traveling to some pretty remote parts of the world.
One of the most remote places is Chile’s Andean desert. If you get the chance to visit the main observatory there, you’ll get a glimpse of the world’s darkest sky.
On a moonless night, the Milky Way spreads overhead and you can see a vast sea of stars. shadow constellation Along the multicolored glow of the Galactic Center. The sky is so dark there that the Milky Way casts a faint shadow, visible when the eyes are fully dark adapted.
But it’s still not a really dark sky.our atmosphere Gives off a faint glow even in the darkest night. It is caused by ultraviolet sunlight and cosmic rays that ionize the Earth’s upper atmosphere.
This airglow is not noticeable when we look straight down, but it is present and limits the field of view of telescopes on Earth. Even the best observatories have to deal with light pollution.
So we launch the telescope into space. Beyond our atmosphere, the Hubble and Webb telescopes can certainly get a pure view of the sky.
Their images are nice, but they don’t really capture the dark skies. Sungrow is still a challenge. Our solar system is filled with diffuse dust, and every particle scatters light back into our world. On Earth, this dust-scattered glow is visible as zodiac light. It’s faint to our eyes, but it’s also visible in space. The night in interplanetary space is dark, but still not dark enough.
To really see the dark sky, you have to travel beyond the dust to the farthest reaches of the solar system. far beyond the orbit of Pluto. Voyagers 1 and 2 traveled that distance, as did Pioneers 10 and 11. We have long lost contact with the Pioneers, and although we are still in communication with Voyager, they are unable to send us useful images.
But there are distant spaceships that can do that.
New Horizons passed Pluto in 2015 and then the Kuiper belt object Arrokos. Now at twice her distance from the Sun, cameras can still collect data.
Recently, the New Horizons team attempted to capture the fragile darkness of space. They pointed New Horizons at a part of the sky far from the Milky Way, far from the Sun, and far from bright stars. It then measures the amount of light captured by the camera.
Comparing the amount to that captured by Hubble’s dark sky view revealed that it was as dark as expected, but still had a faint glow that astronomers couldn’t explain.
Calculating the expected background light from distant galaxies dating back to the Big Bang, New Horizons measured about twice that amount. So the researchers plan to look at 15 other dark spots over the next month, hoping to see the naked darkness of the universe or test the glow of this mysterious background.
And perhaps through the darkest skies we will see the light.
This article was originally published the universe today.read Original work.