SpaceX recently announced that it wants to launch one million more of these satellites as orbital data centres for AI computing power.

A few years ago, we wrote a paper predicting what the night sky would look like with 65,000 satellites from four planned megaconstellations: SpaceX’s Starlink, Amazon’s Kuiper (now Leo), the U.K.’s OneWeb and China’s Guowang. We calibrated our models to observations of real Starlink satellites and came up with a startling prediction: One in 15 visible points in the night sky would be a satellite, not a star.

A million satellites would be so much worse.

The human eye can see fewer than 4,500 stars in an unpolluted night sky. If we permit SpaceX to launch these satellites, we will see more satellites than stars — for large portions of the night and the year, throughout the world. This will severely damage the night sky for everyone on Earth.

SpaceX’s proposal also completely fails to account for atmospheric pollution, collision risk or how to develop the technology needed to disperse waste heat from orbital data centres.

Predicting the night sky

SpaceX has filed its million-satellite proposal to the United States Federal Communications Commission (FCC) and has only provided bare-bones information about these new satellites so far.

We do know that the proposed constellation will have satellites in much higher orbits, making them visible for longer periods of the night.

We decided to build an updated simulation, using the website of astrophysicist Jonathan McDowell. This includes a set of orbits consistent with the limited information in SpaceX’s filing.

We used the observed brightness of Starlink satellites as a reference, scaling the brightness model by considering size jumps between Starlink V1, V2 and predictions for V3, and assuming even higher complexity and power requirements.

There are many factors we don’t know anything about, so there is some uncertainty in the brightness we predict.

In the figure above, each grey circle shows a simulation of the full night sky, as seen from latitude 50 degrees north at midnight on the summer solstice.

The left circle shows the night sky with SpaceX’s orbital data centres (SXODC), and the right shows the night sky with 42,000 Starlink satellites for comparison.

The coloured points show the positions and brightness of satellites in the sky, with blue the faintest and yellow the brightest. Below each all-sky simulation, we list the number of sunlit satellites in the sky (Ntot) and the number of naked-eye visible satellites (Nvis), with tens of thousands predicted for SXODC.

Each of our simulations shows there will be more visible satellites than stars for large portions of the night and the year.

It is hard to overstate this: Should a million new satellites be launched, in the orbits and with the sizes proposed, the stars we are able to see at night would be completely overwhelmed by artificial satellites — throughout the world.

This does not even account for additional large satellite system proposals filed to the International Telecommunication Union (ITU) in recent years by numerous national governments.

A satellite crematorium

SpaceX’s proposal is that these new satellites will operate as orbital data centres.

Data centres on the ground are drawing increasing criticism for the huge amounts of water and electricity they use. In an impressive feat of greenwashing, SpaceX suggests that launching data centres into orbit is better for the environment. This is only true if you ignore all the consequences of satellite launch, orbital operations and re-entry.

We can already measure atmospheric pollution from “re-entries,” when satellites fall back to Earth. We know that multiple satellites are falling every day and that if they do not fully burn up on re-entry, debris falls on the ground with risk for injury and death.

Increasing densities of satellites also drive up collision risks in orbit. And using the atmosphere as a satellite crematorium is changing the atmosphere in ways we don’t yet understand.

Practically, it is not at all clear whether the proposed orbital data centres are feasible any time soon. To operate data centres in orbit, they would need to disperse huge amounts of waste heat. Despite the greenwashing, this is actually very hard to do in space as they would have to manage the intense radiation from the sun, while cooling the satellite by radiation.

SpaceX should know this well: one of the first brightness mitigations they tested for Starlink was “darksat,” a Starlink satellite they effectively just painted black. The satellite overheated, and the electronics fried.

A slap in the face for astronomers

SpaceX has done a lot of engineering work to make its Starlink satellites fainter. They are still too bright for research astronomy, but thanks to new coatings, their brightness has not increased dramatically even as SpaceX has launched larger and larger satellites.

SpaceX’s proposal for one million AI data centre satellites with enormous power requirements does not include any discussion of the coordination agreement for dark and quiet skies required by the FCC.

It feels like a slap in the face after many astronomers have spent years working with SpaceX on ways to mitigate their Starlink megaconstellation and save the night sky.

Orbital space is a finite resource

The SpaceX filing does not include exact orbits, the size or shape of satellites or the casualty risk from de-orbiting (other than a vague promise that it won’t exceed 0.01 per cent per satellite). It doesn’t even include any information on how the company plans to develop the technology that does not currently exist, but is needed to make this plan work.

Despite how shockingly little information SpaceX provided, the FCC accepted SpaceX’s filing and opened the comment period within four days. Astronomers and dark sky advocates worldwide scrambled to write and submit comments in the short four weeks that the comment period was open.

The scientific process is slow and careful, and it often takes months or years to publish a peer-reviewed result. Companies like SpaceX have stated repeatedly that their method is to “move fast and break things.” They are now close to breaking the atmosphere, the night sky and anything on the ground or in space that their satellites and rockets fall on or crash into.

Earth’s orbital space is a finite resource. There is an evolving set of international guidelines for operating in outer space, grounded in a set of high-level international rules. Yet, those rules and guidelines are inadequate.

One corporation based in one country should not be allowed to ruin orbit, the night sky, and the atmosphere for everyone else in the world.

• Samantha Lawler is an Associate Professor, Astronomy, University of Regina
• Aaron Boley is an Associate Professor, Physics and Astronomy, University of British Columbia
• Hanno Rein is an Associate Professor, Physical and Environmental Sciences, University of Toronto
• This article first appeared in The Conversation

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Rather than just relying on logic in the argument or trust in the speaker, politicians and actors have long recognised that there is nothing as effective as using emotion to win the hearts and, consequently, minds of an audience.

With the launch of GTP-4o last week, we may have just seen a machine ideally suited to this task. While most see this as a fantastic breakthrough, having the potential to benefit very many people, some view it with more caution.

Despite having previously declined OpenAI’s request to sample her voice, actress Scarlett Johansson said she was “shocked” and “angered” when she heard the new GTP-4o speak.

One of the five voices used by GTP-4o, called Sky, sounded uncannily like the actress in her role as the AI Samantha in the 2013 film Her – about a man who falls in love with a virtual assistant. Adding to the discussion, OpenAI founder and CEO Sam Altman appeared to play up the comparison between Sky and Samantha/Johansson, tweeting “her” on the launch day of GPT-4o.

OpenAI later posted on X that it was “working on pausing the use of Sky” and created a web page on May 19, explaining that a different actress had been used. The company also expanded on how the voices were chosen.

The fact that the film Her was almost immediately referenced when GPT-4o was launched has helped raise awareness of the technology among the general public and, perhaps, made its capabilities seem less scary.

This is fortunate because rumours about partnering with Apple have ignited privacy fears, with iOS18 coming out next month. Similarly, OpenAI has partnered with Microsoft with its new generation of AI powered Windows system called Copilot + PC.

Unlike other large language models (LLMs), GTP-4o (or omni) has been built from the ground up to understand not only text but also vision and sound in a unified way. This is true multi-modality going far beyond the capabilities of “traditional” LLMs.

It can recognise nuances in speech such as emotion, breathing, ambient noise, birdsong and it can integrate this with what it sees.

It’s a unified multi-modal model (meaning it can handle photos and text), is quick – responding at the same speed as normal human speech (at an average of 320 milliseconds) – and can be interrupted. The result is unnervingly natural, altering tone and emotional intensity appropriately. It can even sing. Some have even complained about how “flirty” GTP-4o is. No wonder some actors are worried.

It genuinely is a new way to interact with AI. It represents a subtle shift in our relationship with technology, providing a fundamentally new type of “natural” interface sometimes referred to as EAI, or empathetic AI.

The speed of this advance has unnerved many government organisations and police forces. It’s still unclear how best to deal with this technology if it is weaponised by rogue states or criminals. With audio deepfakes on the rise, it is becoming increasingly difficult to detect what is, and is not, real. Even friends of Johansson thought it was her.

Read More: OpenAI’s content deal with the FT is an attempt to avoid more legal challenges – and an AI ‘data apocalypse’

In a year when elections are due to be held involving more than 4 billion potential voters, and when fraud based around targeted deepfake audio is on the rise, the dangers of weaponised AI should not be underestimated.

As Aristotle discovered, persuasive capability often isn’t about what you say, but in the way you say it. We all suffer from unconscious bias, an interesting report from the UK about accent bias highlights this. Some accents are more believable, authoritative, or even trustworthy than others. For this precise reason, people working in call centres are now using AI to “westernise” their voices. In GTP-4o’s case how it says things may be just as important as what it says.

If the AI understands the audience’s needs and is capable of logical reasoning, then perhaps the final piece that’s needed is the manner in which the message is delivered – as Aristotle identified 2,000 years ago. Perhaps then we will have created an AI that has the potential to become a superhuman master of rhetoric and with persuasive powers beyond the ability of audiences to resist.

• David Reid is a Professor of AI and Spatial Computing, Liverpool Hope University
• This article first appeared in The Conversation

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Like many of his peers, Olbers trained himself in astronomy. He gained a solid reputation in the academic world and spent long nights observing the sky from the observatory on the second floor of his house.

On that morning, Olbers had come to a strange conclusion: based on all that was known about the Universe at that time, the night sky should not have been dark. In fact, the entire heavens should have been glowing as brightly as the Sun.

Olbers was not the first to note this paradox. But his name is the one we attach to it today. The enigma of the night sky’s darkness has echoed down the centuries from Olbers and the poet Edgar Allan Poe to 20th-century astronomers and space probes today.

Finite light in an infinite Universe

Like many of his contemporaries, Olbers followed Isaac Newton and René Descartes in believing the Universe was infinite.

If the Universe were finite and static, the force of gravity should draw all the stars together at a central point. But if the Universe stretched on forever, gravitational forces would on average be balanced in all directions.

But Olbers realised this model of the cosmos was inconsistent with observations. In a limitless Universe filled with an infinite number of stars, wherever we look at night our gaze should land on the surface of a star, in much the same way as every line of sight in a forest ends at a tree.

This is the problem Olbers raised in his paper of May 7 1823: the cosmological model of the time suggested every point in the sky should be as bright as the surface of the Sun. There should be no night.

Olbers proposed a solution: the light from more distant stars was absorbed by dust or other material floating in space. The English astronomer John Herschel later pointed out this couldn’t be right, because anything absorbing that much light would eventually heat up enough to glow.

When Olbers died on March 2 1840, at the age of 81, the riddle we know today as Olber’s paradox was unsolved.

A poet’s intuition

Eight years later, on the other side of the Atlantic Ocean, poet and writer Edgar Allan Poe thought he had found an answer. On February 3 1848, he gave a public lecture about his ideas to 60 people at the New York Society Library.

Veering between metaphysics and science, Poe argued the cosmos had emerged from a single state of matter (“Oneness”) that fragmented and dispersed under the action of a repulsive force.

This meant the Universe was a finite sphere of matter. If the finite universe is populated by a sufficiently small number of stars, then we won’t see one in every direction we look. The night can be dark again.

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

Even if we assume the Universe is infinite, if it began at some point in the past then the time taken by light to reach us would limit the size of the amount of the Universe we can see. This travel time would create a horizon beyond which distant stars would remain inaccessible.

Poe’s audience at the New York Society Library did not give him the rapturous reception he had hoped for. Later the same year, he published his theories in the prose poem Eureka, which was little circulated.

The following year, on October 7 1849, Poe died at the age of 40. It would be more than a century before scientists confirmed his intuitions about the enigma of the dark night sky.

Two and a half facts

In the first half of the 20th century many new theories of the cosmos were developed, spurred on by Einstein’s theory of general relativity, which explained gravity, space and time in new ways. In the second half of the century, these cosmological theories began to be tested with observations.

In 1963, British astronomer Peter Scheuer argued that cosmology was based on only “two and a half facts”:

• fact 1: the night sky is dark, which had been known for some time
• fact 2: galaxies are moving away from each other, as shown by Hubble’s observations published in 1929
• fact 2.5: the content of the Universe is probably evolving as cosmic time unfolds.

Strong controversies on the interpretation of facts 2 and 2.5 agitated the scientific community in the 1950s and 1960s. Was the Universe essentially stationary, or had it begun in an enormous explosion – a Big Bang? Supporters of both sides conceded, however, they needed to explain the darkness of the night sky.

The lifetime of stars

British cosmologist Edward Harrison resolved the conflict in 1964. He showed that the main factor determining the brightness of the night sky is actually the finite age of the stars.

The number of stars in the observable Universe is extremely large, but it is finite. This limited number, each burning for a limited time, spread over a gigantic volume, lets darkness manifest itself between the stars.

Harrison later realised this solution had already been proposed not only by Edgar Allan Poe, but by British physicist Lord Kelvin in 1901.

Observations in the 1980s confirmed the resolution proposed by Poe, Kelvin and Harrison. Olber’s paradox had finally been put to rest.

Fossil light

Or perhaps not quite. Viewed from a different angle, there is another resolution to the paradox: the night sky is not actually so dark after all.

After the discovery of the expansion of the Universe in the late 1920s, scientists realised the Universe could have started off extremely compact, dense and hot. This is the “hot Big Bang” model we have today.

One core prediction of this model is the existence of “fossil light” released in the cosmic dawn. This fossil light should be observable today – but not with the naked eye, as the expanding Universe would have shifted it to longer wavelengths.

This radiation – the cosmic microwave background – was detected in 1964. Now measured with exquisite accuracy, the cosmic background radiation is the most common light in the Universe.

We now know the cosmos is also illuminated by a second, much fainter background light, produced by galaxies as they form and evolve. This light is referred to as the cosmic ultraviolet, optical and infrared background.

So we can also answer Olber’s paradox by saying the sky is not dark, but faintly glimmers with the dim relic radiation of all that has been over the finite lifetime of the Universe.

New answers, new questions

In 2023, Olber’s paradox has evolved into a rich field of research. In our own work, we carry out ever-more precise measurements of the brightness of the night sky, and simulate the stars of the cosmos with supercomputers. We can now determine the number of stars in the sky with great accuracy.

Nevertheless, puzzles remain. Last year the New Horizons space probe, out beyond the orbit of Pluto and away from the dust of the inner Solar System, found the sky is twice as bright as we expected it to be.

And so the question of the darkness of the sky lives on, crossing ages and cultures.

• Jonathan Biteau  is a Lecturer in Physique of Astroparticles, University of Paris-Saclay
• Alberto Domínguez is a Researcher in Astrophysics, University of Madrid
• David Valls-Gabaud is an Astrophysician, Director of Research at CNRS, Paris Observatory
• Hervé Dole is an Astrophysician, Professor, Vice-president, art, culture, science and society, University of Paris-Saclay
• José Fonseca is an Assistant Researcher, University of Porto
• Juan Garcia-Bellido is a Professor of Theoretical Physics,University of Madrid
• Simon Driver is an ARC Laureate Fellow and Winthrop Research Professor at the International Centre for Radio Astronomy Research, UWA., The University of Western Australia
• This article first appeared in The Conversation

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