Name: 惑星9は存在するのか？ (Does Planet 9 Exist?)
Uploaded: 2021-01-14T10:26:07.000Z
Duration: 16 min 20 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：

So you think I like this with 99.8% probability?

I mean, if you're that sure, find it in the farthest reaches of our solar system way past Neptune and Pluto's and Ninth Planet may be lurking.

It's predicted to have amassed five times that of earth into orbit once every 10,000 years on a highly elliptical inclined orbit.

So why do some scientists suspect that such a strange object exists?

That's what I've come to Caltech to find out.

Wherever I have a couple of minutes of free time.

I just So this is where a lot of it against my name is Constantine Tegan.

I am a professor of planetary science at Caltech, and I do all kinds of astrophysics seen planetary studies, including stuff about planet night.

I'll tell you where the planet nine boundary lives.

It's like that everything to the left of that is all night.

So I'm here to find out about hidden planets and how to find hidden planets with math.

I mean, do you want to start at the beginning of this sort of endeavor or or do you want to jump into Planet nine?

Well, that's actually let's start at the beginning, because the beginning is ah, a long and beautiful history to it in its origins.

81 I believe when Uranus was first discovered by Herschel and when Herschel discovered Uranus, he immediately realized that the star that was slowly moving across the sky had actually been imaged many, many times before.

There was a matter of going back to old observations of kind of retracing the orbit that Uranus was following us on the sky.

And astronomers and mathematicians of the time immediately noticed that there was a problem with the orbit of this newly discovered planet.

It was deviating from where it was supposed to be, but a a French mathematician, by the name of or bombed a very A Eventually did this beautiful and very complicated set of calculations that said Okay, if there is a planet, is there right in that part of the sky.

Then we can explain the anomalous motion of Uranus.

And when once there was a mathematical prediction of where to look, astronomers were then able to discover Neptune with basically pinpoint accuracy.

They found Neptune in one night because they knew exactly where to look.

There's there's a lot of space for 1/9 planet in the outer solar system, but there's no good evidence for 1/9 planet at the present time.

Particularly scary thing about the ninth Planet is that a lot of people want to believe that there's a nice planet.

And we all know this is huge psychological bias to the effect that if you want to believe something is true, you will find evidence, real or not, that it's true.

Everyone and their brother in the last 170 years have predicted planets beyond Neptune.

Today I think that we meeting myself and my collaborator slash partner in crime, Mike Brown, are right.

Our understanding of the solar system has evolved dramatically in the last 20 years, we've discovered that there exists this one additional belt of icy debris called the Keiper Belt.

Renzi's a kind of big I see asteroids that are maybe the size of L A floating around beyond that tune.

Who's responsible for finding the caper belt I found the capable with with Ted Lieu way.

We're looking for anything actually beyond the orbit of Saturn.

The puzzle waas Why is it that the inner part of the solar system is full of asteroids and comets and also kinds of things planets, all this stuff?

But then, when you go beyond Saturn, there's Uranus, Neptune on this plateau, and then that's it.

Why would the outer solar system be so empty?

It's a very simple question of the kind that I could understand.

Theo Answer was, Well, let's have a look.

Maybe it ISS, in which case that would be interesting, but maybe it's not.

So we started a survey to find stuff beyond Saturn, and we did the survey for a long time, five years or something.

Six years on, found actually nothing for that whole time, including nothing just beyond.

Saturn will be expected to find stuff until finally, in 1992.

We've got this thing way out and we could tell immediately its way out.

45 58 years from the slow motion across this guy.

Copperbelt object is actually the second because Pluta was misidentified back in 1930 for all sorts of reasons connected with sociology and propaganda and things like that.

And so no matter what, proof must be a planet.

We have more than 2000 of these objects now.

So in 25 years, 2000 of these things have been found.

There's a 1,000,000,000 things bigger than a kilometre across.

Maybe more, maybe a couple of 1,000,000,000.

It's some of the more distant objects that appear to some people to show this orbital alignment.

They have in particular very large perihelion distance.

If you look at the most distant objects in this belt of debris called the Kuiper Belt.

All of their orbits kind of point into the same direction.

Is it possible that there are some going in the other direction?

Generically, when you search for objects in the night sky, they're always would have called observational biases.

You're always limited to finding objects on Lee where you look.

So this is a key question that you have to ask, right?

Is it that we only found objects that are all pointing that way?

They're orb is pointing that way because we only look there.

The answer is that there is a chance that this is this is all a false alarm, okay.

There are bodies that occasionally will swing out into other directions.

It's more that overall, if you look at it, there is an overall tendency.

So here what we see is a pretty typical kind of simulation of the type.

That way do we start the solar system in an initial come totally random state where all the objects are pointing everywhere for scale these pink circles here are Uranus and Neptune and this long ellipse, this long pink ellipses planet nine, these blue guys, these blue orbits are long period Keiper belt objects, the ones that in the real solar system we see the clustering among.

And these gold or greenish ellipses are the more short period, more proximate members of the Kuiper Belt, which are not clustered at all.

But about two billion years into the evolution of the solar system, you begin to see the fact that objects that Air Colin ear with Planet nine have all been scattered away, removed from the solar system dynamically and the old kind of remaining members of the distant solar system on the objects that point the opposite way again, it's a remarkable gravitational signature.

One way sign, if you will, That something is confining these orbits, keeping them clustered and pulling them all into the same plane.

You know the experts, I think Scott Shepard on chatter.

They call it a 2.6 sigma result, which means that you know, it doesn't really meet the threshold for acceptance.

The scientific would you be looking at five Sigma?

Is that I mean, the standard thing is three signal right, but half of all three signal results are wrong.

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惑星9は存在するのか？ (Does Planet 9 Exist?)

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