My family's first vacation was a trip to a beautiful lake in northern Lower Michigan. Surrounded by pine-tree bluffs, Glen Lake was a revelation to suburban kids like us.
There were no urban areas for 50 miles in any direction, so when you looked up at the night sky after dark, the Milky Way in all its magnificence was laid out like a carpet of tiny lights.
I was awestruck. Venus was so bright you felt like you could almost reach out and touch it. You could clearly see the redness of Mars, and with a pair of basic binoculars, Saturn's rings came into view.
It was like being in church. We talked very quietly, marveling at how dense the stars were, and squealed when the occasional meteor raced across the sky.
It's not as impressive today. Light pollution from the growing human footprint, boosted by an act of Congress in 1970 that established Sleeping Bear Dunes National Lakeshore, has made the night sky far less interesting.
This is a story that's been repeating itself since the 1960s. Urban sprawl has not only filled up the areas around big cities, but it has also contributed to light pollution that robs us of something special: the ability to be awed by the night sky.
“My earliest experiences noticing the night sky were on the family farm where I grew up in rural Arkansas. We lived out in the country away from city lights, and therefore, the night sky was quite dark,” says Dr. Jennifer Wiseman, senior astrophysicist at NASA’s Goddard Space Flight Center and senior project scientist on the Hubble Space Telescope in John Templeton Foundation Ideas. “I would look up in the night sky, be curious about what I was seeing, and wish I could just kind of blink my eyes and suddenly go to that star or that one and look around.”
I matured in the most exciting scientific period in human history. The advances in knowledge in the last 50 years easily outpace humanity's total accumulated knowledge up to that point. Futurist Buckminster Fuller famously proposed the "Knowledge Doubling Curve," noting that until 1900, human knowledge doubled roughly every century. By 1945, it doubled every 25 years, and by the late 20th/early 21st century, estimates put the doubling rate at every 1 to 2 years. Under an exponential model, any multi-decade doubling period means the newest window produces far more than all preceding history combined.
The price we pay for this accelerating rate of knowledge is often troubling. Resource depletion, air and water pollution, and, some might say, overpopulation, but I think that's an overhyped problem.
The lights we need to make our cities less dangerous are causing problems for astronomers. Light pollution, along with the sheer number of low Earth orbit (LEO) satellites, threatens Earth-based telescopic observations in a way that's hard to fix.
Elon Musk's Starlink Broadband fleet of satellites has reached 11,000 satellites, while the Federal Communications Commission (FCC) has authorized 12,000 with paperwork filed to expand the megaconstellation to 42,000 satellites.
That's just the start. Musk's company, SpaceX, has filed paperwork to launch a million data center satellites to fill the voracious power needs of AI agents. SpaceX has partnered with chipmaker NVIDIA to speed up application workloads.
What will that do to humanity's oldest form of entertainment (well, maybe the second oldest): stargazing?
Space is extraordinarily vast, but light pollution and the density of satellite constellations would make it nearly impossible to image the universe from the ground.
Satellites in low Earth orbit (LEO) reflect sunlight down to Earth. When passing through a telescope's field of view during long exposures, they leave bright pixel-saturating streaks across the sensors. At a scale of one million satellites, ground-based optical telescopes would rarely take a clear image without multiple satellite trails cutting across the frame.
Wide-field sky survey facilities — such as the Vera C. Rubin Observatory in Chile — are built to photograph vast regions of the deep night sky continuously. Recent astronomical studies indicate that a constellation of over a million bright satellites could corrupt a vast majority of wide-field deep-space survey images, rendering large portions of exposure data scientifically unusable.
Because of the extremely low light at night, a telescope must expose film for hours to get one photograph. While the satellites won't constantly be in the way of decent observations, passing in front of a telescope's line of sight would cause smears as if someone bumped the telescope.
Beyond individual streaks, the cumulative diffuse light reflected off hundreds of thousands of satellite bodies and massive solar arrays creates continuous atmospheric light pollution. This elevated diffuse background glow can make the night sky appear up to four times brighter, acting like artificial suburban light pollution even over remote high-altitude observatories.
Orbiting satellites are brightest during twilight hours just after sunset and before sunrise when they sit high enough to catch direct sunlight. Twilight viewing windows are critical for detecting near-Earth asteroids, tracking comets, and studying inner planets like Mercury and Venus — all of which would be heavily obscured. While we have several space-based telescopes, ground-based instruments are less expensive and can confirm space-based observations.
Worldwide satellite launches have doubled over the last three years and will double again by 2028.
These launches are necessary and beneficial but are wreaking havoc on our ability to do science using ground-based instruments. Some sort of compromise will have to be negotiated, or the night sky over much of the U.S. will inspire fewer kids to explore and discover the unknown.
