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  • SciShow Space is supported by Brilliant.org

  • [INTRO ♪]

  • If you ever find yourself traveling through the eastern United States, you might discover a spot that seems like it's stuck in the past.

  • In a lot of ways, it looks just like all the land around it, with farms and green, rolling hills.

  • But something is very different.

  • In parts of this region, which stretches for more than 33,000 square kilometers, you're not allowed to use cell phones or Wi-Fi.

  • And in some places, you can't even drive a gasoline-powered car.

  • It's called the National Radio Quiet Zone, or NRQZ, and it's more than just a peaceful getaway.

  • By sacrificing some of the comforts of modern living, the people living there contribute to some of the most important work in astronomy.

  • The NRQZ was established in 1958 to protect both the National Radio Astronomy Observatory and the U.S. Navy's Sugar Grove radio facilities.

  • It's hugelarger than the whole state of Marylandand straddles the Virginia and West Virginia borders, catching an itty bitty part of western Maryland along the way.

  • It's surrounded by the Allegheny mountains, which form a natural shield against outside radio wave interference.

  • And from the city of Green Bank, which is basically in the middle of the NRQZ, you can also get a great view of the Milky Way.

  • That makes it an awesome place for radio astronomyfor studying the stars, galaxies, and other objects that emit radio waves.

  • That isunless there are a bunch of other radio sources near your ultra-sensitive telescopes.

  • There's where the NRQZ's technology restrictions come in, especially in the region closest to Green Bank.

  • We're talking no cell phones in this area, no Wi-Fi

  • Even things you wouldn't think could be sources for interference can be a problem, like electric blankets with damaged cords.

  • Which did happen once, by the way.

  • If you're actually at the observatory, you can't even use gasoline-powered vehicles.

  • Spark plugs could also cause interference, so it's diesel engines only.

  • Of course, people living in the NRQZ still have things like cable, landlines, and broadband Internet.

  • Radio Quietdoesn't meanno technology”.

  • But it's probably still a simpler lifestyle than you or I are used to, and these days it mainly exists to protect the Green Bank Observatory.

  • The observatory has had a lot of telescopes over the years, from the world's first fully automated one to a 20-meter telescope currently run by the University of North Carolina.

  • For decades, it also had three telescopes operating in tandem as the Green Bank Interferometer.

  • Its success led to the creation of the Very Large Array in New Mexico, star of the 1997 film Contact.

  • Fine, co-star.

  • Right now, though, the most important telescope there was constructed at the turn of the century:

  • The Robert C. Byrd Green Bank Telescope, or GBT.

  • It replaced the observatory's former telescope, called the 300-Foot Telescope, which collapsed due to a structural failure in 1988.

  • The GBT is the world's largest fully steerable radio telescope, measuring almost 150 meters tall, with a dish 100 meters wide that's capable of observing 85% of its celestial hemisphere.

  • It's so big that the dish had to be made out of over 2000 aluminum panels;

  • they're individually operated to compensate for the dish sagging under its own weight.

  • The telescope also has receivers cooled to nearly -270°C to minimize interference from thermal radiation.

  • All that gives the GBT a sensitivity equivalent to a billionth of a billionth of a millionth of a Watt.

  • It can detect energies less than that of a single snowflake falling on Earth!

  • Over the years, GBT and Green Bank's other telescopes have contributed a lot to the field of astronomy.

  • Like, back in 1968, the 300-Foot Telescope discovered that pulsarsthose fast-spinning, seemingly flashing points of lightare actually the remnants of supernovas!

  • And less than a decade later, the Green Bank Interferometer detected the super powerful, point-like radio source at the center of our galaxy known as Sagittarius A*.

  • Yeah. The supermassive black hole. That Sagittarius A*.

  • In 1969, Green Bank's 43-meter telescope even discovered the first complex molecule found in space: formaldehyde.

  • Later, it also found a bunch of others, including cyanoacetylene—a possible precursor to nucleic acids, the stuff in DNA.

  • I mean, we definitely didn't discover DNA in the center of the galaxy or anything, but finding molecules like these reveals the kinds of conditions these complex molecules need to form.

  • We used to think they were pickierthat chemistry like this couldn't take place in outer space, but we were wrong.

  • There's also another thing we were wrong about: the amount of stuff out there.

  • Specifically, while tracking blobs of hydrogen found in spiral galaxies, the 300-Foot Telescope found that a galaxy's outer regions spin just about as fast as their middle regions.

  • That doesn't sound like a big deal, but under our current understanding of physics, that doesn't happen.

  • Just like the more distant planets in our solar system take more time to go around the Sun, the outer blobs should be going a lot slower than observations revealed.

  • There had to be extra, invisibleor darkmatter out there!

  • This wasn't the first evidence of dark matter, but it was important follow-up.

  • And these are just some of the discoveries made thanks to the NRQZ and the telescopes that live there.

  • We've talked about the major ones, but there are still tons more.

  • There are links in the description if you're interested.

  • One thing is for sure, though:

  • Even though these super detailed observations have required some sacrifice, they've been totally worth it for our understanding of the universe.

  • And most people seem to like living there, too.

  • We have a co-worker at SciShow who gets a little weepy at parades because they love to see people working together, and that's how I feel thinking about the citizens of Green Bank.

  • It takes an incredible amount of thought and commitment to plan something like the NRQZ.

  • I am not a civil engineer but I love thinking about how all the things we take for granted in a city come together.

  • Brilliant.org has a course on physics of the everyday, with a section on Infrastructure that I wanted to check out.

  • I took the quiz on Traffic, which I was excited about because of the SciShow episode on traffic jams.

  • I knew the answer to the first question because I helped film that video, but then the quiz continues to dig deeper into the math of traffic flow and the quiz got harder ...

  • but also more fun because I was applying what I was learning as I went.

  • The Brilliant Infrastructure course has quizzes on everything from fluoridated water to skyscrapers, so I learned a lot just playing around on the site.

  • To learn more about this or any of the other courses Brilliant offers, go to Brilliant.org/SciShowSpace to sign up for free.

  • And right now, Brilliant is offering the first 200 people to use that link 20% off the annual premium subscription.

  • So, as long as you're not sitting in traffic right now or using Wi-Fi in the National Radio Quiet Zone, check it out!

  • [OUTRO ♪]

SciShow Space is supported by Brilliant.org

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B1 中級

為了研究宇宙,這個小鎮依然禁止使用手機。 (To Study the Universe, This Town Still Bans Cell Phones)

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    林宜悉 發佈於 2021 年 01 月 14 日
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