Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view

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Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view

Credit: ESA

Since time immemorial, human beings all over the world have been staring in wonder at the night sky. Not only has the starry night sky inspired countless works of music, art, and poetry, but it also played an important role in timekeeping, navigation, and agricultural practices in ancient times. many traditions.

For many cultures, it is the night sky with its stars, planets and the Milky Way Just as important Part of the natural environment such as forests, lakes and mountains below. Countless people around the world look up at the night sky: not only amateur and professional astronomers, but also casual observers who enjoy looking at the stars to ponder our place in the universe.

However, the night sky is changing. Not only is terrestrial light pollution increasing rapidly, however An increasing number of satellites And space debris In orbit around the Earth they also affect the night sky.

previous search showed that satellites and space debris may increase the overall brightness of the night sky. in new leaf in natural astronomyAnd my colleagues and I have applied this knowledge to predict the performance of a large astronomical sky survey. We found that this phenomenon could make scanning 7.5% less efficient and $21.8 million more expensive.

brighter sky

As a cultural astronomer, I am interested in the role of the night sky cultural traditions around the world. In particular, I am interested in how light pollution And it increases Satellites Numbers affect different societies.

The number of satellites in orbit is growing rapidly. Since 2019, the number of operational satellites in orbit has reached more than doubled to about 7,600. The increase is mostly due to SpaceX and other companies Launching large groups of satellites To provide high speed internet connections around the world.

Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view

Starlink satellites do leave streaks on astrophotos — but the growth in satellites and debris will make the entire sky much brighter. credit: Raphael Schmoll / NOIRLabAnd CC BY

By the end of this decade, we estimate there could be 100,000 satellites in orbit around Earth. Collisions that generate space debris are more likeable It fills space with new satellites. Other sources of debris include The deliberate destruction of satellites in space warfare tests.

Increasing numbers of satellites and space debris are reflecting more sunlight towards Earth’s night side. This will almost certainly change the appearance of the night sky and make it more difficult for astronomers to perform the search.

One of the ways satellites affect astronomy is by appearing as moving points of light, which appear as streaks across astronomers’ images. another by augmentation The diffused brightness of the night sky. This means that all of the satellites that are too faint or too small to be seen individually, as well as all of the smaller bits of space debris, still reflect sunlight, and their collective effect is to make the night sky appear less dark.

Hard times for astronomers

in Our researchIn, we present the first published accounts of the aggregate effects of satellites and space debris in low-Earth orbit on major terrestrial astronomy research facilities.

We looked at the impact on the chart A large-scale survey of the night sky They will be conducted at the Vera Rubin Observatory starting in 2024. We found that by 2030, light reflected from objects in low-Earth orbit is likely to increase the diffuse background brightness for this survey by at least 7.5% compared to unpolluted skies.

This would reduce the efficiency of this scan by 7.5% as well. Over the ten year life of the survey, we estimate that this will add about US$21.8 million to the total cost of the project.

Brighter night skies mean longer exposures are needed with telescopes to see more distant objects in the universe. This means that for projects with a fixed observing time, less science will be done, and there will be increased competition for access to the telescope.

In addition, the brighter night sky will also reduce the detection limits of sky surveys, and faint objects may not be detected, resulting in missed search opportunities.

Some astrophysical events are rare, and if researchers can’t see them when they happen, there may not be a chance to easily see a particular event again during a survey run. One example of faint objects is near-Earth objects – comets and asteroids in near-Earth orbits. The bright night sky increases the likelihood that such potentially dangerous objects will remain undetected.

A dramatic and unprecedented transformation

Increases in diffuse night sky brightness will change the way we see the night sky with the naked eye. Since the human eye cannot resolve individual small objects as well as a telescope can, the increase in satellites and space debris will lead to an even greater increase in the apparent brightness of the night sky. (When using a telescope or binoculars, one can make out more faint satellites individually.)

The expected increase in the brightness of the night sky will make it more difficult to see the faint stars and the Milky Way, both of which are important to the planet different cultural traditions. In contrast to the “ground” light pollution (which tends to be worst near large cities and densely populated areas), changes in the sky will be visible from everywhere on Earth’s surface.

Our models give us a conservative lower bound for a possible increase in the brightness of the night sky. If the numbers of satellites and space debris continue to grow at the expected rate, the effects will be even more pronounced.

As we note in our paper, “We are witnessing a dramatic, fundamental, and perhaps semi-permanent shift in the night sky without historical precedent and with limited oversight.” Such a shift would have dire consequences for professional astronomers as well as for anyone willing to watch untainted night sky.

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the quote: Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view (2023, March 26) Retrieved March 26, 2023 from https://phys.org/news/2023-03-satellites- space-junk -dark-night. html

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