قالب وردپرس درنا توس
Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ The unexpected brightness of new satellites can destroy the night sky

The unexpected brightness of new satellites can destroy the night sky



T WAS QUITE a show: a train of illuminated dots moving across the sky, many of them as bright as Polaris, the North Star. However, it was not new astronomical objects. Rather, they were the first tranche of satellites to Starlink, a project that was to provide Internet access across the globe. These were launched in circulation on May 24 by SpaceX, an American rocket company.

Seeing satellites from the ground with the naked eye is nothing new. But astronomers (professional and amateur) were surprised and unhappy about how many and how bright the Starlink satellites seemed to be. A lot of them went to Twitter to raise the alarm and send pictures and videos of the burning birds. Their concern was that these satellites and their successors could change the night sky forever. If the first 60 members of the Starlink network already caused noticeable light pollution, did they justify how little it would get when the full 1

2,000 constellation had been launched?

For those who enjoy seeing the night sky for joy, it would surely be sad, because it would more than triple the number of man-made objects in the fastening and thereby further break down the natural beauty of heaven – a beauty has already diminished in many places by light pollution from the earth. However, for those who are involved in researching the universe scientifically, it may be more than just sad. In some cases, it may be the job threatening.

For example, preliminary analysis shows that almost all images from the large synoptic survey card in Chile, currently approaching completion and intending to photograph the entire available sky every few nights, when operational, could contain a satellite track. These can be edited, but each correction destroys valuable data. It is possible that some experiments, which regularly timed observations of the variation in the behavior of astronomical objects, will no longer be possible.

Thus, optical astronomers have reason to be nervous about Starlink. For radio astronomers, its impact may be even more serious. The operating state of the satellites necessarily necessitates sending radio signals back to Earth, all of which will be stronger than any signal coming from the deep space. This can be met to some extent by knowing which frequencies the satellites transmit and adjust accordingly. But just how badly the radio observatories are affected will depend on how well the satellites manage to limit their broadcasts within those frequencies. It's still looking.

Elon Musk, SpaceX's chief, initially rejected astronomers' concerns, tweeting over the weekend there were "already 4,900 satellites in orbit that people discover ~ 0% of the time. Starlink will not be seen by anyone unless you look very carefully and will have 0% influence on the development of astronomy. "However, in later exchanges he struck a more understanding tone. Starlink wanted to avoid the frequencies associated with radio astronomy, he said, and if the satellite's orientations were to be tweaked to minimize solar reflection during critical astronomical experiments, it could easily be done. As the initial Starlink satellites moved into their operational configuration over the weekend, their brightness dropped – though they sometimes burst as they crossed the sky, probably due to reflections from their large solar panels.

Musk also appeared in his tweets to suggest that the goals of Starlink outweigh the damage. "Potentially helping billions of economically disadvantaged people is greater good. That said, we make sure Starlink has no material impact on astronomical discoveries. We love the science a lot." His claim is profitable. The problem noted by Mark McCaughrean, senior science and exploration adviser at the European Space Agency, is that there has been little public debate on the matter. From his point of view, the night sky is a public commons that risks granting in the name of private interest. Whether this appropriation serves the greater good must at least be a matter of debate.

Currently, astronomers are planning to perform additional simulations of the potential effects of Starlink and other communications satellite networks planned by companies such as OneWeb. But even when this work is finished, it is unclear what they can actually do to get SpaceX and its competitors to listen to their concerns, because there is no legislation to regulate the impact of satellites on the night sky.

The United States Federal Communications Commission draws attention to how satellites use the available radio spectrum and what happens to them after they have done their work. But it is. With the upcoming mega-constellations of communication satellites, it may be time to change it, and for governments (not just America) to engage more deeply in the use of heaven.


Source link