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  • [♪ INTRO]

  • Human space exploration is all the rage these days,

  • with NASA and other organizations racing to get astronauts on the Moon and beyond.

  • But one UK-based startup is dreaming of something a little different.

  • They want to populate the Moon with robots.

  • And instead of building a traditional, multi-wheeled rover, they're designing ones with legs.

  • The company Spacebit announced their plans in October,

  • revealing models of their crawling, jumping, kind of adorable mini-robots.

  • You heard me! Adorable, not creepy.

  • These unnamedwalking roversare based on designs of CubeSats,

  • small, boxy spacecraft we've been launching since 2003.

  • They have a mass of about one kilogram, only cost a few million dollars to produce,

  • and can be put together in less than a single year.

  • Their small size means Spacebit can send more than one in a single rocket launch,

  • and they can access parts of the Moon that larger, wheeled rovers can't.

  • That includes features like cracks, crevices, and even lava tubes:

  • hollow tunnels formed by ancient streams of lava.

  • This kind of exploration will help reveal a lot about the Moon's geology,

  • and it could also pave the way for future human missions.

  • Scientists have proposed that, if we ever want to live on the Moon,

  • living under its surface, like in a lava tube, might be a good idea.

  • That would protect us from a lot of the Sun's radiation,

  • and there wouldn't be such drastic temperature changes over the course of a lunar day.

  • But that's a plan for the distant future.

  • For this first rover mission, things will be a little simpler.

  • In 2021, a single Spacebit rover will travel to the Moon on a lunar lander

  • from the company Astrobotic, along with more than a dozen other confirmed payloads,

  • many of which are funded by NASA.

  • Then, once our little robot buddy is on the surface,

  • it will send back some high-def video and LIDAR data, basically,

  • 3-D maps made by shooting out laser beams and having the light bounce off of things.

  • The rover won't go very far or last very long, though.

  • It will only walk about ten meters from the lander, and likely will only last one lunar day,

  • because it can't survive the Moon's nighttime temperatures.

  • But if all goes well, we might be seeing a lot more of these new mini-rovers!

  • And they'll give us an opportunity to learn some cool stuff.

  • Of course, we've got plenty more technology out there right now,

  • studying farther and farther-flung reaches of the cosmos.

  • And last month in The Astrophysical Journal Letters,

  • one group of researchers reported that they'd found a massive explosion

  • that will help us better understand the universe's lighthouses, called pulsars.

  • Pulsars form when massive stars die.

  • After a star explodes as a supernova,

  • it can leave behind a collapsed core made mostly of neutrons: a neutron star.

  • When one of those objects spins fast enough and emits enough radiation,

  • we see it from Earth as a pulsating light.

  • And we officially call it a pulsar.

  • The pulsar in question, called J1808 for short, is about 11,000 light-years away.

  • We discovered it back in 1996 when a satellite saw it release a giant flare of X-ray radiation.

  • And since then, we've seen it flare every two to four years.

  • But J1808's most recent explosion, technically referred to as a Type I X-ray burst,

  • was something of a surprise.

  • It was picked up in August by NASA's NICER telescope on the International Space Station,

  • and in only 20 seconds, it released as much energy as our Sun does in about ten days.

  • But that wasn't the most interesting part:

  • It was the fact that this pulsar had a combination of traits that's never been observed in the same flare.

  • For context, X-ray bursts happen when J1808 steals hydrogen gas from its companion,

  • a gaseous body called a brown dwarf that orbits the pulsar.

  • Over time, the pulsar steals enough gas that some of it rains down onto the pulsar's surface.

  • There, it's hot enough and there's enough pressure that the bottom layer of hydrogen

  • undergoes nuclear fusion and turns into helium.

  • And when there's enough helium, it explodes, and you get an X-ray burst.

  • Typically, these bursts get brighter, hit a peak, and then fade away.

  • But this last burst from J1808 didn't do that.

  • Instead, about half a second after its flare started,

  • the amount of X-rays it released suddenly stopped increasing.

  • For about a second, the flare stalled.

  • And then it continued on and reached maximum intensity.

  • Astronomers think that this happened because of specific events on the pulsar's surface.

  • They believe that, right after the flare kicked off,

  • the blast built up enough energy to throw any remaining hydrogen back into space.

  • That created the apparent stall in the curve.

  • Then, the flare continued, and the helium layer rapidly expanded, too,

  • although it cooled and contracted again shortly afterward.

  • The whole burst was more or less over in about a minute.

  • But even though the event was short, it's significant.

  • This is the first evidence that actually shows two separate ejection events

  • during a pulsar's X-ray outburst; one for hydrogen, and the other for helium.

  • By itself, that opens up the ability for astronomers to study

  • the differences between these events and make sure they align with our models.

  • And that wasn't the only weird thing that happened here.

  • After all that, J1808 got about 20 percent brighter for a few seconds.

  • And we don't know why that happened; at least, not yet.

  • Additionally, researchers found a few other things, like evidence of X-ray flashes

  • that happened at other locations on the pulsar's surface.

  • These features have all been seen across other pulsar outbursts,

  • but J1808 put them all together.

  • And it did so just this one time;

  • none of its other captured flare-ups have produced the same results.

  • This makes the burst an important piece of evidence for understanding pulsars.

  • It shows that the rules governing these objects can be so complex

  • that the same body doesn't react the same way every single time.

  • That might seem a little annoying, for space stuff to suddenly throw something new at you,

  • but in a way, it's good news.

  • It means we have a chance to really pin down our understanding of how the universe works.

  • This edition of SciShow Space News is brought to you by

  • this episode's President of Space: SR Foxley.

  • SR Foxley is one of our patrons on Patreon, and is part of an amazing community

  • that supports SciShow and loves learning together.

  • We're really grateful for our patrons, so if you're one of them, thank you.

  • We're so glad you're here.

  • If you want to learn about becoming a patron and maybe even

  • being our next President of Space, you can go to patreon.com/scishow.

  • And as always, thanks for watching.

  • [♪ OUTRO]

[♪ INTRO]

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パルサーの爆発は見たことがない|サイゾーウーマンニュース (We've Never Seen a Pulsar Explode Like This | SciShow News)

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    林宜悉 に公開 2021 年 01 月 14 日
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