In the book of Psalms we read that the heavens declare the glory and righteousness of God. (See Psalm 8:1–4, Psalm 19:1–4; Psalm 50:6, Psalm 89:5, and Psalm 97:6, for example.) These declarations presume that people can see the stars, planets, and other bodies that make up “the heavens.” However, the advance of technology, ironically, is decreasing the visibility of the heavens and, in some cases, making it impossible. Perhaps one reason for diminishing belief in God is that people can’t see much, if anything, of the starry realm.
Visibility of the Heavens in Ancient Times Artificial nighttime lighting (ANL) likely dates back to Adam and Eve. The archaeological record testifies that Homo sapiens sapiens (modern humans) always had control over fire. Therefore, nighttime camp and hearth fires would have been common. The earliest written records mention the widespread use of candles and oil lamps.
These early forms of ANL were intermittent, rarely intended to provide illumination for more than a few hours, and illumination levels were low, typically below that of a 40-watt incandescent bulb. The illuminated areas were small, too, usually only about 10 square meters. For people of the Roman Empire and earlier, a short walk or a few hours wait would be sufficient to escape any ANL interference with views of the nighttime sky.
When God told Abraham to “look up at the sky and count the stars—if indeed you can count them,”1 the night sky on a moonless night was so dark that any human adult with good eyes could see ~15,000 stars. Abraham saw the Milky Way and dozens of nebulae, an awe-inspiring sight. His contemporaries’ ability to determine the great distances to the Moon and the Sun and their inability to measure distances to the stars spoke to them of the vastness of the starry realm.
With the invention of the telescope in 1608, humans could see, for the first time, hundreds of thousands of stars. By the late 1600s, millions of stars had become visible.
Decreasing Visibility of the Heavens The industrial revolution of the 1800s and especially the technological revolution that followed the end of World War II had a blinding effect. With gas lighting replacing oil lamps in the 1800s, city streets remained illuminated all night long. By the end of the 1800s, incandescent electric bulbs replaced gas lighting. In the 1900s, incandescent bulbs gave way to mercury vapor lamps, which subsequently gave way to low-pressure sodium lamps. Now, LED lighting is replacing mercury and sodium lamps.
Each technological advance in ANL has made nighttime lighting much brighter, more pervasive, and much less expensive. Thus, since 1900, ANL has been increasing exponentially, and the rise in ANL has been especially steep since 2000.
Sadly, the twenty-first-century rise of ANL has brought with it serious health challenges and ecological consequences.2 At the same time, it has drastically reduced the visibility of the heavens for the majority of the world’s population.
For the first time in human history, most people live in large metropolitan areas. In such places, ANL is so intense that when they look up at the night sky people see fewer than 50 stars! I’ve been in some Asian cities where, on a “clear” night, not even the brighter planets were visible, let alone any stars. In some of these same cities, the combination of light and air pollution makes seeing the Moon impossible, unless it is at least 15 degrees above the horizon. So, for hundreds of millions of people, the heavens declare nothing about the glory and righteousness of God. For them, the magnificent heavenly objects remain totally invisible.
Decreasing Effectiveness of Telescopes Abraham’s generation did not need telescopes. Our generation does. The availability of telescopes helps compensate for what we cannot see with our unaided eyes. With a good pair of binoculars, we can travel to the countryside to see all that Abraham could see. We can visit the NASA and ESO websites and marvel at images taken by the Hubble Space Telescope (HST), the Very Large Telescope array, and now the James Webb Space Telescope (JWST).
However, civilization and technology are now threatening the capability of telescopes to see the heavens clearly. How? Satellites now number in the tens of thousands. Within a decade, proposed satellite constellations could raise the number of satellites orbiting Earth as high as a hundred thousand, even a quarter of a million or more.
Satellites orbiting Earth reflect sunlight. They create streaks of light across images of the night sky (see figure 1). Especially in the case of long-exposure telescopic images, dozens of satellite streaks brighter than the natural objects astronomers are attempting to observe and measure severely degrade the quality of the research results (see figure 2).
Not only ground-based telescope images are being marred by satellite streaks. Satellites leave bright streaks across images taken by the HST, as well. In 2021, 5.9% of HST images exposed for just 11 minutes were streaked by satellites.3 Deep HST images take hours. The percentage of images marred by satellite streaks rises proportionally with exposure time. You can imagine researchers’ frustration.
Figure 1: Light Streak from an Artificial Satellite above the Very Large Telescope Credit: ESO
Figure 2: Astronomical Image Marred by Satellite Trails Credit: Victoria Girgis/Lowell Observatory
As seriously as optical wavelength telescopes are impacted by ANL and Earth-orbiting satellites, radio telescopes are impacted to a far greater degree. Radio interference from ground-based and satellite transmissions is both strong and pervasive, and it’s only growing stronger and more pervasive. I’ve written recently4 about how radio interference seriously limits long-wavelength radio astronomy, and I must add that it also seriously limits short-wavelength radio astronomy.
The research on which I based my doctoral thesis is no longer feasible. For the detection sensitivity required, I used broadband receivers at five different centimeter wavelengths. Today, these bandwidths are saturated by radio interference. Radio astronomy at these wavelengths is now confined to a few narrow “protected” bandwidths.
ANL Increase by Satellites In 2020, a team of astronomers calculated the degree of illumination from Earth-orbiting satellites at the zenith (directly above any point on Earth’s surface) at midnight. The skyglow amounted to 20 microcandelas per square meter.5 (1 candela expresses the light emitted by a candle of specific size and composition.) This level of illumination already degrades astronomers’ observations.
The megaconstellation satellite systems proposed for launch during the next 15 years will increase midnight zenith illumination by more than ten times. It may even become noticeable to people living in rural areas.
Dark Sky Refuges The International Astronomical Union has appealed to the United Nations Committee on the Peaceful Uses of Outer Space to protect the night sky’s darkness for the sake of future advances in astronomy. While astronomers cannot stop the launch of satellite constellations, the best they can hope for is that corporations manufacturing satellites will make them less reflective.
Radio astronomers feel especially hopeless. The proposed satellite arrays will be transmitting powerful signals across most of the radio spectrum.
The one remaining “radio quiet” location in the solar system is the far side of the Moon during the lunar night. However, even this site is under threat. In the next decade or so, the Moon will become the target of hundreds of orbiters and landers. These orbiters and landers could spoil radio astronomy’s last remaining refuge.6
At a conference called Astronomy from the Moon: The Next Decades, held at the Royal Society of London, astronomers raised the alarm. They called on governments to establish international treaties that would protect the Moon’s far side. In particular, they called for the shelving of plans to install a lunar satellite navigation system. They asked that strict rules be applied to any satellite or lander operating on the Moon’s far side.
More than 250 lunar missions are scheduled for launch during the next decade. The time window to draft appropriate treaties and acquire necessary signatures is small and rapidly shrinking.
Meanwhile, optical and infrared astronomy research is also being squeezed out. The remaining refuge for these types of observations is the Lagrange 2 point (L2) along Earth’s orbit. This point is about a million miles away from Earth, where the JWST has been operating for the past year. The European Space Agency’s Euclid Space Telescope is on its way to join the JWST in L2.
To place telescopes at the L2 site is not inexpensive. The JWST, for example, cost $10 billion. Furthermore, the L2 site is subject to meteorite and micrometeorite impacts, and L2 is too far away for repair or upgrade missions.
What’s at Stake? Increasing ANL threatens more serious consequences than interference with the astronomy research I’m passionate about. It will bring more serious health and ecological consequences than those we’re already experiencing. For one example, the Bible speaks of a time when people’s love will “grow cold.”7 It’s easy to see how ANL may be partly to blame.
ANL reduces both the duration and quality of sleep.8 A recent study shows that sleep loss exacerbates depression and reduces expression of altruism.9 Altruism would likely be further reduced and depression further increased as people lose the ability to see the beauty and wonder of God as expressed in the heavens. Much more than astronomical research is at stake.
What Can Be Done? Technological advances have made ANL, the Internet, and global positioning systems remarkably accessible. The low cost of these amenities tempts humans everywhere to expand their usage. However, the time has come to address significant questions:
Can we limit ANL to places where it’s essential for safety?
Can we move ANL wavelengths toward the red end of the spectrum, where its effects are less harmful?
Can we develop new technology so that we can get by with many fewer satellites?
Can we make satellites less reflective, less “noisy,” and place them in lower orbits?
Can we design satellites to de-orbit once they cease useful operation?
Can we develop and implement a system for the retrieval and safe disposal of obsolete satellites and space litter?
I believe we can do all these things and more, as well, to help restore access to the revelation of God’s glory and righteousness in the heavens. Personally, I love to show people the gorgeous images being released by space telescopes and explain what they tell us about our Creator.
Although I may seem to be bashing technology, I greatly value one particular smartphone app. When the phone is aimed up at the night sky, it identifies astronomical objects that can be detected there. A good pair of binoculars (e.g., 7 x 50 or 10 x 50) can be linked to the smartphone for enhanced viewing of the planets, moons, stars, and nebulae.
The sense of wonder that comes from observing and pondering the heavens nearly always leads to in-depth conversation about the One who brought them—and us—into existence.
Sandor Kruk et al., “The Impact of Satellite Trails on Hubble Space Telescope Observations,” Nature Astronomy 7 (March 2, 2023): 262–268, doi:10.1038/s41550-023-01903-3.
M. Kocifaj et al., “The Proliferation of Space Objects Is a Rapidly Increasing Source of Artificial Night Sky Brightness,” Monthly Notices of the Royal Astronomical Society: Letters 504, no. 1 (June 2021): L40–L44, doi:10.1093/mnras/slab030.
Davide Castelvecchi, “Are Telescopes on the Moon Doomed before They’ve Even Been Built?” Nature 615 (March 16, 2023): 383–384, doi:10.1038/d41586-023-00635-8.
Matthew 24:12.
Maja Grubisic et al., “Light Pollution, Circadian Photoreception, and Melatonin in Vertebrates,” Sustainability 11, no. 22 (September 14, 2019): id. 6400, doi:10.3390/su11226400.
Eti Ben Simon et al., “Sleep Loss Leads to the Withdrawal of Human Helping Across Individuals, Groups, and Large-Scale Societies,” PLOS Biology 20, no. 8 (August 23, 2022): id. e3001733, doi:10.1371/journal.pbio.3001733.
