This article was originally published on conversation. (opens in new tab) The publication contributed articles to Space.com’s Expert Voices: Op-Ed & Insights,
Michael G. Brown (opens in new tab)Associate Professor in Astronomy, Monash University
The night sky is a shared forest. On a dark night, away from the city lights, you can gaze at the stars just as your ancestors did centuries ago. You can see the Milky Way and the constellations associated with mythical hunters, sisters, and travel stories.
But like any forest, the night sky can also be polluted. Since Sputnik 1 in 1957, thousands of satellites and pieces of space junk have been launched into orbit.
For now, satellites traversing the night sky are largely a curiosity. But with the advent of satellite constellations – those with hundreds or even thousands of satellites – this could change.
Connected: 10 weird things about SpaceX’s Starlink internet satellites
Recent Launch of BlueWalker 3 (opens in new tab), a prototype for a satellite constellation, raises the prospect of bright satellites contaminating our night sky. At 64 square meters it is the largest commercial communication satellite (opens in new tab) In low Earth orbit – and very bright.
night sky pollution
While observing satellites in the night sky has been a curiosity, the increasing number of satellites in orbit means that night sky pollution can become a serious problem.
On a clear night, especially near twilight, you can see satellites traveling across the night sky. These satellites are in low Earth orbit, a few hundred kilometers above Earth and traveling at about 8 kilometers per second.
apps (opens in new tab) more websites (opens in new tab) Allows you to identify or predict the arrival of particular satellites overhead. And it’s really fun to watch the International Space Station travel by, realizing that there’s a crew of astronauts on that speck of light.
But in the last few years the pace of satellite launch has increased. SpaceX has made satellite launches cheaper, and it is launching thousands of Starlink satellites that provide internet services.
Roughly 50 Starlink satellites are launched into orbit by each Falcon 9 rocket, and initially produce a dazzling train of satellites. They initially prepared UFO reports (opens in new tab)But are now common enough not to be particularly newsworthy.
Once the Starlink satellites disintegrate and move into their operational orbits, they are close to the limit of what can be seen with the unaided eye.
However, such satellites are bright enough to cause streaks in images taken with telescopes. These trails overwrite the stars and galaxies below them, which can only be corrected by taking additional images. short transient events, such as a brief flash from a gamma-ray burst (opens in new tab)could potentially be lost.
blue walker 3
While Starlink is the largest satellite constellation in service, with thousands of satellites in orbit, others are planned.
Amazon’s Blue Origin plans to launch over 3,200 Project Kuipers (opens in new tab) satellite, and the AST spacemobile (opens in new tab) plans to launch 100 bluebirds (opens in new tab) satellites (and probably more).
The recently launched Bluebird prototype, BlueWalker 3, has caused genuine alarm among astronomers.
While the BlueWalker 3 was initially quite faint, it unleashed a 64-square-meter communications array—roughly the size of a squash court. This massive surface is very good at reflecting sunlight, and BlueWalker 3 is now as bright as some of the brightest stars in the night sky.
It is possible to operational Bluebird satellites could be bigger (opens in new tab) and brighter.
With a large number of satellites this bright can be bad – very bad. If there were thousands of satellites so bright, sometimes you couldn’t look at the night sky without seeing the bright satellites.
With almost constant reminders of technology in our skies, we’d lose that sense of wilderness.
Could have a big impact on professional astronomy. Brighter satellites cause more damage to astronomical images than fainter satellites.
In addition, many of these satellites broadcast on radio frequencies that can interfere with radio astronomy by transmitting radio waves. (opens in new tab) over remote sites where radio observatories observe the sky (opens in new tab),
What happens next is uncertain. The International Astronomical Union has communicated its alarm regarding the satellite constellations, and Bluewalker 3 in particular.
However, approval of satellite constellations by the US Federal Communications Commission (opens in new tab) Relatively little consideration has been given to environmental impacts.
This has recently been identified as a major problem by the US Government Accountability Office. (opens in new tab)But whether this leads to concrete change is unclear.
We may be on the edge of a precipice. Will the night sky be filled with bright artificial satellites for the sake of the Internet or 5G? Or shall we pull back and preserve the night sky as a globally shared forest?
This article is republished from conversation (opens in new tab) Under Creative Commons Licence. read the original article (opens in new tab),
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