字幕表 動画を再生する 英語字幕をプリント SpaceX recently launched its first batch of 60 satellites into low-Earth orbit, getting us one step closer to global internet coverage. Dubbed Starlink, this program will eventually form a mega constellation of nearly 12,000 satellites hovering about 550km above Earth. But as the twinkling post-launch satellite train moved its way across the sky, astronomers across the globe watched and wondered—are these things always going to be so...bright? Many astronomers fear that Starlink will interfere with scientific observations. Starlink's solar-powered, roughly 225kg satellites communicate with one another through optical and radio links, and connect with ground terminals that can operate from pretty much anywhere. These satellites are expected to dramatically improve data transfer speeds and connectivity compared with existing technologies, like Iridium satellites, of which there are currently 66 in active orbit. Starlink is also poised to drastically improve bandwidth—potentially surpassing fiber optics—and reduce latency, or lag, which will be great for industries that rely on getting information fast. And the biggest selling point here? Internet for all. That's great news! But what about the risks of Starlink cluttering our night sky? Roughly 5,000 satellites currently crowd Earth's immediate environment, and Starlink is set to nearly triple that number. So astronomers aren't exactly starstruck with this idea. In recent statements, astronomical groups strongly recommended that a regulatory framework be developed to address a number of new challenges posed by the potential increase in satellite bodies. As the plan currently stands, some of the satellites will utilize frequencies neighboring those that radio astronomers use to study the sky. This interference could make it tricky for ground-based instruments, like the Event Horizon Telescope, to clearly view distant objects in space. I mean if it hadn't been for a sky free of radio interference, researchers may never have captured our first image of a black hole. And then there's the problem of all the light that Starlink generates. Like Iridium satellites, they can “flare” by throwing bursts of reflected sunlight back from their solar arrays down toward Earth. Flares aside, it's suggested that the satellites will also be consistently bright. Initial estimates of the satellites' visibility suggested they'd sit at an apparent magnitude just slightly dimmer than the North star. While updated reports indicate that they'll now sit within a lower magnitude range of about 5 to 7, and this suggests that Starlink will remain visible to the naked eye. And all that satellite contamination really adds up. These reflective objects could confuse sensitive optical telescopes designed to survey the entire sky, like the Large Synoptic Survey Telescope in Chile. Once all 12,000 satellites are in orbit, estimates say up to four Starlink satellites will likely appear in every single one of the telescope's images in the hours approaching twilight. Musk has said that they'll need at least “six more launches of 60 satellites” for minor coverage. Each satellite is designed to only last for a few years, dropping from the wider Starlink array and burning up upon entry into Earth's atmosphere. And that's just it. With Starlink's satellites in space, traffic increases—and the risk of satellite collisions goes up, too. Collisions pose a national security threat, and current guidelines to safely manage orbiting objects are pretty flimsy. If a collision does occur, it would add to the already half a million pieces of space junk present in Earth's orbit. And in response to all this, Elon Musk has focused on the need for internet access for all, and that “we need to move telescopes to orbit anyway.” But where does that leave astronomers who don't have the ability to travel into space on a whim? Or even those of us who just love to stargaze? Space is basically a regulatory wild west, which presents a whole lot of unknowns for us here on Earth. To address astronomers' worries that communication satellites could ruin their careers, SpaceX has been working with the National Science Foundation and the National Radio Astronomy Observatory to try and keep observations clear of any disturbance. It's also announced plans to redesign the next Starlink batch to appear less bright. But SpaceX isn't the only company casting an Internet into the galactic sea. OneWeb launched a fleet of comms satellites earlier this year, and is also working on ways to reduce radio frequency interference and low-Earth orbit clutter. Canadian company Telestat promises to operate its satellites at higher orbits so they'll appear fainter. Amazon, too, is quietly developing tech for its own Project Kuiper. As the market for space real estate heats up, projects like Starlink are destined to become more common. Close collaboration between astronomers and these companies will be essential to keep internet connections strong and our observations of the sky clear. Because after all, astronomers are kind of like our very own guardians of the galaxy. So what do you think, is it time to move astronomy into space, or figure out a way to move satellites away from Earth? Let us know in the comments below, and don't forget to subscribe for more Seeker. I'll see you next time, thanks for watching.
B2 中上級 SpaceXのユニバーサル・インターネット計画は天文学を台無しにする? (Could SpaceX’s Plans for Universal Internet Ruin Astronomy?) 10 1 林宜悉 に公開 2021 年 01 月 14 日 シェア シェア 保存 報告 動画の中の単語