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  • { ♪INTRO }

  • One of the hardest parts of astronomy is figuring

  • out causes and effects.

  • After all, just because it seems like two things are related

  • doesn't necessarily mean they are.

  • But last week, a team of radio astronomers presented one of those raresmoking gun

  • pictures at a meeting of the American Astronomical Society's High Energy Astrophysics Division.

  • It shows a so-called cannonball pulsar blasting away from a nearby supernova, and a trail

  • of energized gas clearly points to where it came from.

  • Pulsars are the rapidly-spinning cores of neutron stars, which are stars mostly made

  • of neutrons.

  • But this thing isn't just spinning fast: It's also traveling in a straight line at

  • more than a /million/ kilometers per hour.

  • This pulsar is named J0002+6216 — which I swear is not a random string of numbers

  • that I made up,

  • it's actually describing the coordinates, so is useful for astronomers.

  • Regardless, it was discovered as part of a really cool project called Einstein@Home.

  • Instead of using a single supercomputer to comb through telescope data, this project

  • uses computer power donated by hundreds of thousands of citizen scientists.

  • It's specifically searching for pulsars, and so far, it's been pretty successful.

  • For this new discovery, researchers used the equivalent of 10,000 years of computing time

  • to search observations made by NASA's Fermi Gamma-ray Space Telescope.

  • They discovered 23 pulsars, but J0002 really caught their eye.

  • This object is about 6500 light-years from Earth, and it spins 8.7 times every second.

  • But what was really significant was its speed.

  • This thing moves through space at around 4 million kilometers per hour, which is faster

  • than 99% of measured pulsars.

  • Follow-up observations with the ground-based Very Large Array also revealed that it has

  • a dramatic, 13 light-year-long tail,

  • caused by a shockwave that forms as the super-speed object blasts through nearby gas.

  • Yes, I said 13 light-years.

  • Scientists think this object was formed thanks to a supernova.

  • Based on the size of the bubble of material that the supernova left behind, called a supernova

  • remnant, the team estimates the explosion happened around 10,000 years ago.

  • It crushed the dying star's core into a pulsar and then gave it a kick in one direction.

  • At first, the light, outer layers of the star were likely blasted away much faster than

  • the pulsar, but as everything slammed into the gas and dust surrounding the supernova,

  • that light material also quickly lost its momentum.

  • Think about a cannon firing: The first stuff to come out is fire and smoke, but the heavy

  • cannonball eventually goes the farthest.

  • In the case of J0002, the astronomers estimate it overtook the supernova remnant after about

  • 5000 years.

  • And today, it appears about 53 light-years from the bubble's center.

  • Still, that doesn't explain how this thing ended up moving so fast.

  • And that's… well, it's still kind of a mystery.

  • After all, if a spherical star explodes, you'd think it would be relatively symmetric.

  • So it would make sense that forces pushing on the star's core should mostly cancel

  • out.

  • But clearly, that's not what happened.

  • This means J0002 is going to be a really useful objectespecially since scientists have

  • been able to figure out so much about its behavior.

  • So as we keep studying it, it could provide valuable new data to solve the riddle.

  • Also, it just looks really darn cool.

  • Changing gears to something much, much smaller, another team of researchers announced last

  • week that they've successfully tested a new tool to fight against bacteria in space.

  • The paper was published in the journal Frontiers in Microbiology, and it described a new material

  • tested onboard the International Space Station that dramatically reduced the population of

  • potentially-harmful microbes.

  • Bacteria are a big problem in space for many reasons.

  • For one, to keep the air in and space out, all spacecraft are closed systems, meaning

  • that every time an astronaut sneezes, that sneeze is justthere.

  • Our immune systems can also get weaker under the stresses of spaceflight, making it harder

  • for our bodies to fight off an infection.

  • And to top it all off, microbes can actually get stronger in microgravity and can mutate

  • even faster.

  • This is why NASA sterilizes almost everything that goes to space, from new equipment to

  • some of the food astronauts eat.

  • But since you can't exactly sterilize the astronauts themselves, there's no way to

  • keep bacteria totally out.

  • Scientists have even found so-called superbugs up there, which are microbes resistant to

  • many kinds of antibiotics.

  • And that's where this new paper comes in.

  • Researchers created a new material, called AGXX, that combines the elements silver and

  • ruthenium.

  • Then, they took their mixture, coated a few pieces of steel, and stuck the pieces on a

  • spot you might expect to be dirty: the bathroom door!

  • The test had three parts: an uncoated patch of plain steel, a region covered in a coating

  • of pure silver, and an area with AGXX.

  • After 19 months, the silver-only part showed 30% fewer bacteria than the steel region,

  • while the area covered by AGXX had a whopping 80% reduction.

  • That kind of reduction could be important for long-term spaceflight, like what it would

  • take to send a crew to Mars and keep them healthy while they're there.

  • It's not surprising that silver is a key ingredient in this stuff: We've known about

  • the metal's antibacterial properties for thousands of years, and modern medicine uses

  • it in things like bandages for burn victims.

  • Ruthenium, on the other hand, is one of our newest attempts to fight bacteria.

  • It's not used by itself, though; instead, its antimicrobial properties seem to come

  • in combination with other elements.

  • But here's the thing: Scientists don't really know why these metals work.

  • They seem to be able to bind with a bacteria's DNA and disrupt its basic functions, but why

  • that's so effective isn't really understood.

  • And, like with that mysteriously-fast pulsar, this puzzle makes any new data worth its weight

  • inruthenium, I guess.

  • Which probably is more expensive than gold?

  • I'm just guessing, cause I don't hear about it very much.

  • Thanks for watching this episode of SciShow Space News!

  • Being able to bring you news is one of the coolest things that we get to do here on SciShow,

  • and we couldn't do it without the generosity of our patrons on Patreon.

  • So if you're a patron, thanks for your support!

  • If you want to join our community of patrons and help us make episodes like this one, we

  • would love to have you.

  • You can learn more at patreon.com/scishow.

  • { ♪OUTRO }

{ ♪INTRO }

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    林宜悉 に公開 2021 年 01 月 14 日
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