Name: ジュノー計画による木星の新発見! (New Jupiter Discoveries from the Juno Mission!)
Uploaded: 2021-01-14T10:31:31.000Z
Duration: 6 min 11 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

Back in July 2016, NASA's Juno spacecraft entered orbit around Jupiter.

Juno had a different orbit than previous missions to Jupiter.

The spacecraft is looping around the planet's poles,

getting as close as 3500 kilometers above the cloud tops

which is really close when you consider how big Jupiter is.

The mission will keep going for at least another few months,

but scientists are already picking apart the data from those super close flybys.

They're studying places we haven't had access to to until now,

And a group of papers published this week in the journal Nature

As a gas giant, Jupiter is mostly made out of fluids.

It also rotates pretty quickly, experiencing only 10-hour days.

astronomers expected Jupiter's mass to be distributed pretty uniformly.

These recent findings from Juno showed us

that its mass distribution actually varies depending on the latitude.

both in Jupiter's atmosphere and in its interior,

up to 3000 kilometers below the cloud level.

We also learned that, below that depth, fluid just doesn't flow the same way.

Instead, a mix of hydrogen and helium rotates together,

we can't actually look into Jupiter's interior.

Instead, scientists used Juno to measure how Jupiter's gravitational pull

changes as the spacecraft performs its flyby.

As Juno moves around Jupiter, it gets closer to different parts of the planet.

Those different parts have different amounts of mass,

which means gravity there will be a little stronger or weaker.

That will either cause Juno to speed up or slow down.

Then, scientists can then measure those changes in speed

to tell how Jupiter's mass is distributed.

This new Juno data is two orders of magnitude more accurate

than previous scans, and it'll help us better model what's happening

One additional paper reported on the discovery of multiple cyclones

in both the north and south polar regions.

Using the infrared JIRAM and optical JunoCam,

Juno snapped photos of 15 separate storms,

There were eight storms rotating around one storm in the north,

and five rotating around a storm in the south.

They all range between 4000 and 7000 kilometers in diameter,

and both sets of storms are arranged like polygons, which is cool.

Of course, it's still a mystery how they originally formed

and how they didn't manage to merge together

It just means that there are still a lot more questions

And thankfully, Juno is sure to provide many more answers.

astronomers published a paper in The Astronomical Journal

has way more water in its atmosphere than we thought.

To figure it out, they had to create the most complete atmospheric profile

The planet is WASP-39b, which was discovered back in 2011.

It's about 700 light-years from Earth and orbits a star

with a mass similar to the Sun's, although it's older and a bit cooler.

but that's about the only thing they have in common.

The most obvious difference is this planet doesn't have any rings.

It's actually one of the least dense planets ever discovered.

It's so puffy because it orbits really closely to its star

In fact, it only takes 4 days to complete one orbit!

All that intense heat fluffs up a bunch of the planet's matter.

which means only one side of the planet ever faces its star.

But powerful winds help move the heat around, so it's fairly evenly distributed.

The planet has a toasty equilibrium temperature of over 1100 Kelvin.

Because 39b doesn't really have any obscuring clouds in its upper atmosphere,

the Hubble Space Telescope could capture a good breakdown

Specifically, it looked at light from its host star

that traveled through the planet's atmosphere on its way to Earth.

Different molecules absorb different wavelengths of light,

so by looking at the wavelengths of starlight that are missing in the data,

astronomers can tell what kind of gases this atmosphere has,

What Hubble found was a lot of water vapor.

Like, three times more than we find in Saturn's atmosphere,

They figured they'd find some water, but nowhere near as much as they did.

This suggests 39b was pummeled by a lot of icy material when it was forming.

Still, based on what we know about planet formation,

if the planet formed much farther from its star than it is now.

And, like with any good paper, that only brings up more questions.

This study adds to the complex list of ways planets can develop,

and it suggests there are a lot of star systems with different stories than ours.

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ジュノー計画による木星の新発見! (New Jupiter Discoveries from the Juno Mission!)

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