The Times Australia
The Times World News

.

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

  • Written by Jessica Heim, PhD researcher, University of Southern Queensland
Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view

Since time immemorial, humans around the world have gazed up in wonder at the night sky. The starry night sky has not only inspired countless works of music, art and poetry, but has also played an important role in timekeeping, navigation and agricultural practices in many traditions[1].

For many cultures, the night sky, with its stars, planets and the Milky Way, is considered just as important[2] a part of the natural environment as the forests, lakes and mountains below. Countless people around the world gaze at the night sky: not only amateur and professional astronomers, but also casual observers who enjoy looking up at the stars to contemplate our place in the cosmos.

However, the night sky is changing. Not only is ground-based light pollution increasing rapidly[3], but growing numbers of satellites[4] and space debris in orbit around Earth are also impacting the night sky.

Earlier research[5] showed that satellites and space debris may increase the overall brightness of the night sky. In a new paper[6] in Nature Astronomy, my colleagues and I applied this knowledge to predicting the performance of a major astronomical sky survey. We found this phenomenon may make the survey 7.5% less efficient and US$21.8 million more expensive.

A brighter sky

As a cultural astronomer, I am interested in the role of the night sky in cultural traditions[7] around the world. In particular, I am interested in how light pollution[8] and increasing satellite numbers affect different communities.

The number of satellites in orbit is growing rapidly. Since 2019, the number of functional satellites in orbit has more than doubled[9] to around 7,600[10]. The increase is mostly due to SpaceX and other companies launching large groups of satellites[11] to provide high-speed internet communications around the world.

Starlink satellites already leave streaks on astronomical photographs – but growth in satellites and debris will make the whole sky brighter. Rafael Schmall / NOIRLab, CC BY[12][13]

By the end of this decade, we estimate, there may be 100,000 satellites in orbit around the Earth. Collisions that generate space debris are more likely[14] as space fills with new satellites. Other sources of debris include the intentional destruction of satellites[15] in space warfare tests.

Increasing numbers of satellites and space debris reflect ever more sunlight towards the night side of Earth. This will almost certainly change the appearance of the night sky and make it harder for astronomers[16] to do research.

Read more: Thousands of satellites are polluting Australian skies, and threatening ancient Indigenous astronomy practices[17]

One way satellites impact astronomy is by appearing as moving points of light, which show up as streaks across astronomers’ images. Another is by increasing diffuse night sky brightness[18]. This means all the satellites that are too dim or small to be seen individually, as well as all the small 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 research[19], we present the first published calculations of the aggregate effects of satellites and space debris in low-Earth orbit on major ground-based astronomy research facilities.

We looked at the effect on the planned large-scale survey of the night sky[20] to be carried out at the Vera Rubin Observatory starting in 2024. We found that, by 2030, reflected light from objects in low-Earth orbit will likely increase the diffuse background brightness for this survey by at least 7.5% compared to an unpolluted sky.

This would diminish the efficiency of this survey by 7.5% as well. Over the ten-year lifetime of the survey, we estimate this would add some US$21.8 million to the total project cost.

Read more: Starlink, Amazon and others are racing to fill the sky with bigger satellites to deliver mobile coverage everywhere on Earth[21]

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

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

Some astrophysical events are rare and if researchers are unable to view them when they occur, there might not be an opportunity to easily see a given event again during a survey’s operational period. One example of faint objects is near-Earth objects – comets and asteroids in orbits close to Earth. Brighter night skies make it more likely such potentially hazardous objects may remain undetected.

A dramatic and unprecedented tranformation

Increases in diffuse night sky brightness will also change how we see the night sky with the unaided eye. As the human eye cannot resolve individual small objects as well as a telescope can, an increase in satellites and space debris will create an even greater increase in the apparent brightness of the night sky. (When using a telescope or binoculars, one would be able to make out more of the dimmer satellites individually.)

The projected increase in night sky brightness will make it increasingly difficult to see fainter stars and the Milky Way, both of which are important in various cultural traditions[22]. Unlike “ground-based” light pollution (which tends to be the worst near large cities and heavily populated areas), the changes to the sky will be visible from essentially everywhere on Earth’s surface.

There may be 100,000 satellites in orbit around Earth by 2030. M Lewinsky / NOIRLab, CC BY[23][24]

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

As we note in our paper, “we are witnessing a dramatic, fundamental, and perhaps semi-permanent transformation of the night sky without historical precedent and with limited oversight”. Such a transformation will have profound consequences for professional astronomy as well as for anyone who wishes to view an unpolluted night sky.

References

  1. ^ many traditions (doi.org)
  2. ^ just as important (doi.org)
  3. ^ increasing rapidly (theconversation.com)
  4. ^ growing numbers of satellites (astronomy.com)
  5. ^ Earlier research (academic.oup.com)
  6. ^ a new paper (www.nature.com)
  7. ^ cultural traditions (tpt.pbslearningmedia.org)
  8. ^ light pollution (spica.org.uk)
  9. ^ more than doubled (www.ucsusa.org)
  10. ^ around 7,600 (www.space-track.org)
  11. ^ launching large groups of satellites (www.science.org)
  12. ^ Rafael Schmall / NOIRLab (noirlab.edu)
  13. ^ CC BY (creativecommons.org)
  14. ^ more likely (agupubs.onlinelibrary.wiley.com)
  15. ^ intentional destruction of satellites (doi.org)
  16. ^ make it harder for astronomers (aas.org)
  17. ^ Thousands of satellites are polluting Australian skies, and threatening ancient Indigenous astronomy practices (theconversation.com)
  18. ^ diffuse night sky brightness (academic.oup.com)
  19. ^ our research (doi.org)
  20. ^ large-scale survey of the night sky (www.lsst.org)
  21. ^ Starlink, Amazon and others are racing to fill the sky with bigger satellites to deliver mobile coverage everywhere on Earth (theconversation.com)
  22. ^ various cultural traditions (doi.org)
  23. ^ M Lewinsky / NOIRLab (noirlab.edu)
  24. ^ CC BY (creativecommons.org)

Read more https://theconversation.com/satellites-and-space-junk-may-make-dark-night-skies-brighter-hindering-astronomy-and-hiding-stars-from-our-view-202047

Times Magazine

Headless CMS in Digital Twins and 3D Product Experiences

Image by freepik As the metaverse becomes more advanced and accessible, it's clear that multiple sectors will use digital twins and 3D product experiences to visualize, connect, and streamline efforts better. A digital twin is a virtual replica of ...

The Decline of Hyper-Casual: How Mid-Core Mobile Games Took Over in 2025

In recent years, the mobile gaming landscape has undergone a significant transformation, with mid-core mobile games emerging as the dominant force in app stores by 2025. This shift is underpinned by changing user habits and evolving monetization tr...

Understanding ITIL 4 and PRINCE2 Project Management Synergy

Key Highlights ITIL 4 focuses on IT service management, emphasising continual improvement and value creation through modern digital transformation approaches. PRINCE2 project management supports systematic planning and execution of projects wit...

What AI Adoption Means for the Future of Workplace Risk Management

Image by freepik As industrial operations become more complex and fast-paced, the risks faced by workers and employers alike continue to grow. Traditional safety models—reliant on manual oversight, reactive investigations, and standardised checklist...

From Beach Bops to Alpine Anthems: Your Sonos Survival Guide for a Long Weekend Escape

Alright, fellow adventurers and relaxation enthusiasts! So, you've packed your bags, charged your devices, and mentally prepared for that glorious King's Birthday long weekend. But hold on, are you really ready? Because a true long weekend warrior kn...

Effective Commercial Pest Control Solutions for a Safer Workplace

Keeping a workplace clean, safe, and free from pests is essential for maintaining productivity, protecting employee health, and upholding a company's reputation. Pests pose health risks, can cause structural damage, and can lead to serious legal an...

The Times Features

Duke of Dural to Get Rooftop Bar as New Owners Invest in Venue Upgrade

The Duke of Dural, in Sydney’s north-west, is set for a major uplift under new ownership, following its acquisition by hospitality group Good Beer Company this week. Led by resp...

Prefab’s Second Life: Why Australia’s Backyard Boom Needs a Circular Makeover

The humble granny flat is being reimagined not just as a fix for housing shortages, but as a cornerstone of circular, factory-built architecture. But are our systems ready to s...

Melbourne’s Burglary Boom: Break-Ins Surge Nearly 25%

Victorian homeowners are being warned to act now, as rising break-ins and falling arrest rates paint a worrying picture for suburban safety. Melbourne residents are facing an ...

Exploring the Curriculum at a Modern Junior School in Melbourne

Key Highlights The curriculum at junior schools emphasises whole-person development, catering to children’s physical, emotional, and intellectual needs. It ensures early year...

Distressed by all the bad news? Here’s how to stay informed but still look after yourself

If you’re feeling like the news is particularly bad at the moment, you’re not alone. But many of us can’t look away – and don’t want to. Engaging with news can help us make ...

The Role of Your GP in Creating a Chronic Disease Management Plan That Works

Living with a long-term condition, whether that is diabetes, asthma, arthritis or heart disease, means making hundreds of small decisions every day. You plan your diet against m...