Name: Planet 9 Could Be a Black Hole?! | SciShow News
Uploaded: 2019-11-03T20:05:25.000Z
Duration: 6 min 47 s
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In 2016, two Caltech astronomers proposed

that our solar system is home to nine planets.

Instead, they found evidence for a hypothetical Neptune-sized planet

at least forty billion kilometers from the Sun

far enough that it would take fifteen thousand years for it to complete one orbit.

In the last three years, this Planet 9 hypothesis has continued to gain support.

But last week, two other scientists proposed

that this object could be something a little more exotic.

Instead of a planet out there, they say it could be a black hole,

This paper hasn't gone through peer-review yet, but it's making some big claims.

And one way or another, it could teach us more

about what's lurking in our solar system.

This whole Planet 9 thing came about after researchers noticed something strange

There's a lot of small rocky and icy bodies out there,

Ones so weird that they seem to be affected by the gravitational pull of some larger,

unknown body - something between 5-15 times the mass of Earth.

If there's something out there, it's probably a planet,

but technically, any object with the right amount of mass would do.

Normally, black holes form from massive stars,

so they're millions of times heavier than the Earth.

But there's a hypothetical kind of black hole that could be much lighter

like, five to fifteen times the mass of our planet.

and they may have been created shortly after the universe began.

At that time, everything in existence was packed close together.

And as the idea goes, primordial black holes formed

when extra dense pockets of matter collapsed in on themselves.

According to this new hypothesis, an object like this could have been captured

by the Sun's gravity, and it would easily explain

all the weird orbits we've seen past Neptune.

Now, since black holes are so dense, this thing would be small

But it might still be easier to spot than a distant planet.

At least, if you don't rely on visible light.

Scientists believe that primordial black holes would be surrounded by halos of dark matter.

This is a type of matter we can't directly detect,

but that most evidence suggests is out there.

The authors of this paper argue that, occasionally, dark matter around the black hole

could interact with similar particles and turn into gamma radiation.

Lucky for us, we have telescopes that can pick that up.

So theoretically, if we started seeing gamma ray flashes out past Neptune,

it could be a sign that we have a local black hole.

This hypothesis is definitely in need of more evidence, but even if it doesn't pan out,

searching for a primordial black hole wouldn't be useless.

It would likely allow us to learn more about dark matter, primordial black holes,

and the flashes of gamma rays we've already detected.

So one way or another, it seems like a possibility worth investigating.

In other black hole news, because it's that kind of week,

a handful of telescopes has detected something super hardcore:

A black hole three hundred seventy-five million light-years away,

ripping apart a star with the power of gravity.

The results were published last week in The Astrophysical Journal.

The discovery itself happened in January,

and the first instrument to notice something going on was NASA's TESS.

TESS has been orbiting Earth for a little over a year now,

and it stares at one large section of sky for several weeks at a time.

Its main goal is to find planets beyond the solar system, but because it's just floating

around out there with its proverbial eyes open,

it's bound to observe other phenomena, too. And that's what happened last winter.

In January, the telescope picked up an increase in brightness coming from a distant star.

Then, several days later, less-sensitive instruments on the ground noticed the same thing.

after the first project to give us data about it.

Because even though TESS technically saw it first,

it only sends data to Earth every two weeks, so the other team got the naming rights.

This brightening turned out to be the early stages of a tidal disruption event, or TDE.

Which is a scientific way of saying a star is getting absolutely wrecked by a black hole.

The murderous culprit sits at the center of a galaxy called… okay, don't make me say that.

Look, you're never going to visit this thing.

The bigger point is that this black hole seems to be

about six million times more massive than the Sun.

the supermassive black hole at the center of the Milky Way.

the more of a gravitational pull it has on the stuff around it.

So when a star wandered too close to this black hole, things got messy.

The difference in gravity between one side of the star and the other became so great

that it overcame the forces holding the star together.

In other words, the black hole ripped the star apart.

Some of the star's gas and plasma likely escaped into the void of space,

but the rest tumbled down toward the black hole,

creating a swirling disk and a large flare of radiation we could see from Earth.

Tidal disruption events are super rare, and scientists have only captured

That means each new observation can teach us something.

In this case, observing the event early-on allowed researchers

to chart the extreme drop in the star's temperature that happened

It went from forty thousand degrees Celsius to only twenty thousand.

Something like this was in our prediction models, but now we have actual evidence.

Scientists will continue to study this event, both with TESS and with other instruments.