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  • You might remember that almost exactly a year ago, there was a lot of buzz about one particular

  • star.

  • There were strange signals coming from this star, and no one was exactly sure what was

  • causing them.

  • Some people were even saying that the signals could have been caused by an alien civilization.

  • Well, last week, the story got even weirder.

  • Because not only does the star’s light flicker unpredictably, but it’s been getting dimmer

  • over time.

  • This star’s called KIC 8462852, and it’s been nicknamed Tabby’s star after Tabetha

  • Boyaijan , the scientist who described its weird propertiesand who Hank interviewed

  • on SciShow in August!

  • Tabby’s star caught the attention of astronomers after it was observed by the Kepler telescope’s

  • exoplanet-hunting mission.

  • Kepler spots exoplanets by watching for stars to dim slightly as a planet passes in front

  • of them.

  • Most planets that it spots do this regularly, once every revolution around the star.

  • But, Tabby’s star is different.

  • Its light dims unpredictably, at irregular intervals, and scientists aren’t sure why.

  • The most likely explanation is that a comet has recently broken up in front of the star,

  • and dust and chunks of debris are obscuring our view at random.

  • The far less likely, but way more awesome, explanation is that an alien civilization

  • is using some kind of huge structure to harness the star’s energy.

  • Astronomers have been scratching their heads ever since this phenomenon was announced last

  • year.

  • Then, in January of this year, another researcher announced that Tabby’s Star has gotten dimmer

  • overall since 1890, based on old photographic observations.

  • But, as you can probably imagine, data collecting methods have changed a little since the nineteenth

  • century, and comparing old photographic plates to new digital data could introduce some errors.

  • In a paper being published by The Astrophysical Journal, researchers at Carnegie and Caltech

  • checked into this claim using more recent data: the observations from Kepler over the

  • course of four years.

  • Kepler would check in on the star every now and then to look for changes in its light.

  • Plus, because of the way Kepler works, it has to make a lot of observations to calibrate

  • the camera and get a complete picture.

  • So there are lots of observations made by the same instrument.

  • The results were surprising.

  • Tabby’s star is dimming over time, the researchers say.

  • Over the first three years of Kepler observations, it got darker by one percent.

  • That might not seem like much, but stars are huge, so that amounts to a whole lot of energy.

  • Then, in the next six months, the star’s brightness plunged by two percent, before

  • leveling off for the rest of the observation period.

  • A few of the other stars in Kepler’s dataset got a little dimmer over the same period,

  • but not so much or so quickly.

  • If the star had only dimmed in the past six months, a comet or planet breaking up would

  • fit the data really well.

  • But four years of dimming is harder to explainand the dimming might go all the way back

  • to 1890!

  • Weve never seen another star act this way, and we don’t have a good explanation for

  • it.

  • And another space news closer to home, Blue Origin, the spaceflight company run by Amazon

  • CEO Jeff Bezos, has pulled off a pretty cool flight testand it went way better than

  • they expected.

  • Blue Origin’s New Shepard launch system consists of a crew capsule sitting on top

  • of a booster rocket.

  • And both the capsule and booster are built to be reusable.

  • On October 5th, New Shepard passed a crucial test.

  • The flight was abortedon purposepartway through launch.

  • That meant the crew capsule fired an engine to separate itself from the booster.

  • Blue Origin intentionally picked a time, 45 seconds into the flight, where the spacecraft

  • would be most difficult to control.

  • The capsule used parachutes to land in the Texas desert, and it was recovered safely,

  • which means the crew of a launch system like this could probably survive an accident mid-launch.

  • As an added bonus, the booster survived too, and it wasn’t really expected to.

  • Blue Origin predicted that the capsule’s escape motor would send the rocket into a

  • death spiral.

  • Which is an acceptable loss, when youre trying to save the crew.

  • But the booster was fine, and came back to land on its pad like nothing was wrong.

  • So, with five successful tests in less than a year, Blue Origin seems ready to get off

  • the ground.

  • As for New Shepard, it’s flown five successful test missions and will now be retired.

  • It’s done its job of proving that Blue Origin can build a rocket that works, is reusable,

  • and can pass safety tests.

  • But it was also only meant for short flights that don’t achieve Earth orbit.

  • The next planned spacecraft, New Glenn, will have a lot more power under the hood.

  • It’s designed to be capable of orbital flight.

  • And they plan to make even bigger rockets after that.

  • Crewed Blue Origin test flights could happen as early as next year, and the company eventually

  • plans to take private passengers, too.

  • No word yet on how much a ticket will cost, but you might want to start saving up.

  • Thanks for watching this episode of SciShow Space News, and thanks especially to our patrons

  • on Patreon who help make this show possible.

  • If you want to help us keep making episodes like this, you can go to patreon.com/scishow.

  • And don’t forget to go to youtube.com/scishowspace and subscribe!

You might remember that almost exactly a year ago, there was a lot of buzz about one particular

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タビーの奇妙な星は、単に奇妙になった (Tabby's Strange Star Just Got Stranger)

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    Caurora に公開 2021 年 01 月 14 日
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