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  • Scientists can image all kinds of things in the universe, from galaxies and stars to the

  • radiation coming out of black holes.

  • But it's really difficult to take a picture of a newborn planet.

  • They tend to be hard to find, out-shined by the light from their star, and obscured by

  • the dust clouds they form from.

  • But we've just done it.

  • No big deal.

  • On Monday, astronomers published the first confirmed image of a baby planet, and it already

  • has a lot to teach us.

  • The planet is called PDS 70b.

  • Which, like, I wouldn't name my newborn that, but to each their own.

  • It's probably less than 5.4 million years oldmore than 1000 times younger than

  • the Earthand it orbits a star around 370 light-years away called PDS 70.

  • We've known about the star for a few years now and have even taken images of it that

  • suggest a planet might be forming there.

  • But these new pictures are way clearer.

  • The image was taken using the SPHERE instrument on the European Southern Observatory's Very

  • Large Telescope, which was built to take pictures of exoplanets in visible and near-infrared

  • light.

  • And this thing is really good at its job.

  • One of SPHERE's biggest features is that it's great at filtering out light from stars.

  • Unsurprisingly, stars are super bright, and they tend to outshine most things near them

  • including baby planets.

  • SPHERE gets around this by taking multiple pictures of a star system over several hours,

  • which gives things like planets time to move around a bit.

  • Then, using a series of algorithms, the telescope's computers filter out anything in the image

  • series that hasn't movedstuff like the star.

  • And that's how it ended up with an image like this, where you can see that new planet

  • super clearly.

  • But SPHERE's photo-taking skills aren't just for pretty pictures.

  • The instrument captures star systems in multiple wavelengths of lightlike near-infrared,

  • which can tell us how much heat an object is emitting.

  • So its observations can also tell us a bit about what this new planet is like.

  • From what we can tell so far, 70b is a gas giant about 3 billion kilometers from its

  • stararound the same distance as Uranus is from the Sun.

  • It's several times the mass of Jupiter, and it's hot, with a surface temperature

  • somewhere around 1000°C.

  • Observations do suggest it has a cloudy atmosphere, although we aren't totally positive what

  • it's made of.

  • So, maybe it only feels like 999°C.

  • Imaging and studying brand-new planets is important for astronomers because, right now,

  • there's still a lot we don't know about how they form.

  • So the earlier we can sneak in there and start collecting data, the better off we are.

  • The next step is to take a closer look at 70b with another telescopelike ALMA in

  • Chilethat will be able to capture things like its composition and temperature in even

  • more detail.

  • But considering SPHERE just took one of our best baby photos ever, I'd say scientists

  • are off to a pretty good start.

  • Much closer to home, another team of astronomers has been busy tracking down the origin of

  • our solar system's asteroids.

  • Our neighborhood is filled with millions of them, and it's easy to think of them as

  • random space rocks fromwherever.

  • But like everything else, those rocks have origins.

  • And according to a new paper, published Monday in Nature Astronomy, most of them have the

  • same origins.

  • The authors estimate that 85% of the asteroids in the part of the asteroid belt closest to

  • Mars came from just five parent bodies.

  • Which means the early solar system might've been a lot less populated than we thought.

  • Scientists can sort asteroids into all kinds of groups based on things like size and composition.

  • But when it comes to grouping them based on origins, there are two main categories: family

  • and non-family.

  • Family asteroids are those that came from the breakup of known objects, while non-family

  • asteroids have mysterious origins.

  • They were probably part of larger bodies, too, but we haven't been able to figure

  • out what.

  • In their new paper, these authors argue that the answer is pretty simple: Most of those

  • orphan asteroids actually belong to some of the biggest families out there.

  • Specifically, ones called Flora, Vesta, Nysa, Polana, and Eulalia.

  • The remaining 15% probably come from so-called ghost families: Groups that have drifted apart

  • so much it's difficult to tell where they started.

  • The team got their results by plotting data from more than 70,000 inner main belt asteroids

  • those that are just past Mars, or around 310 to 370 million kilometers from the Sun

  • and then comparing features of their orbits.

  • They looked at things like how circular and tilted their orbits are, as well as how the

  • asteroids are distributed by size.

  • The asteroids that started off as one body should have many of those features in common,

  • so if any non-family asteroids matched those patterns, maybe they belong in known families,

  • too.

  • And a lot of them did!

  • More than 40% of them, according to their results, which brings the total amount of

  • family asteroids in that area to 85%.

  • This suggests that we shouldn't be thinking about these objects as lost asteroids, but

  • as part of large, established groupssomething that will make studying them a lot easier.

  • So far, scientists have only looked at the inner main belt asteroids, since we have the

  • most observations about them.

  • But the authors believe their findings should apply to the rest of the main belt, too.

  • A helpful next step would be to confirm these results using other measurementsthings

  • like size, reflectivity, and composition.

  • But this seems promising so far!

  • Knowing where asteroids came from is helpful not only for understanding the early solar

  • system, but for protecting the Earth, too.

  • After all, there is a chance — a small one, but still a chancethat one of those larger

  • asteroids could end up hurtling toward the Earth someday.

  • And if it does, knowing what it's made of could help us deflect it or break it up.

  • I wouldn't lose sleep over it or anything, but it's always good to be prepared.

  • Thanks for watching this episode of SciShow Space News!

  • Did you know that SciShow has merch?

  • Earlier this week, we launched our new merch line on DFTBA.com.

  • Head over to dftba.com/scishow to see new shirts, stickers, and mugs.

  • And thanks as always for watching and supporting SciShow!

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我們剛剛拍到了第一張嬰兒星球的圖片! (We Just Took the First Image of a Baby Planet!)

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    林宜悉 發佈於 2021 年 01 月 14 日
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