아무나 하는 수학, 과학 & 라디오: 09.04 - 대식가 초거대 블랙홀(The Alternative Diets of Supermassive Black Holes)

09.04 - 대식가 초거대 블랙홀(The Alternative Diets of Supermassive Black Holes)

[커세라 강의 페이지]

Much of our discussion around the feeding of black holes has revolved around stars, the snack of choice for Stellar-mass black holes. Gourmet!

블랙홀은 주변의 별을 흡수하는 항성급 블랙홀에 대해 논의했었다. 이 항성급 블랙홀은 입맛이 까다로워 주변을 도는 동반성을 골라 먹는다. 미식가인 셈이다.

Since stellar-mass black holes make up the majority of binary pairs we associate with stellar companions, what do you think a supermassive black hole likes to snack on?

초거대 블랙홀도 항성급 블랙홀이 쌍성계를 이루는 동반성을 주로 흡입하듯이 초거대 블랙홀도 그럴까?

Well, if you were thinking surely they also eat stars, you'd be correct, but they are also voracious consumers of the gas and dust that happened to fall in too close. Some of the most spectacular phenomenon theorized to occur in the environment around a supermassive black hole are called tidal disruption events.

물론 초거대 블랙홀도 별을 잡아먹지만 근처에 떨어지는 것은 뭐든 먹는다. 초거대 블랙홀 주변에서 일어나는 굉장한 광경은 이론적인 '조석 파멸 사건'이다.

These feeding frenzies are so violent that the stars being consumed are completely torn apart. During a tidal disruption event, stars passing close to a supermassive black hole are disrupted by the strong tidal forces of the black hole's gravitational field.

(초거대 블랙홀 주변의) 조석력이 얼마나 센지 빨려들어가는 별이 온전히 제모습을 가누지 못하고 부숴진채 빨려 들어간다.

The tidal forces deform the star into a long string of hot glowing gas, just like this artist's impression of what a disrupted star might look like.

Astronomers can detect these tidal disruption events as a sudden increase in the brightness of light around the black hole.

However, direct imaging of these disruptions is not yet possible, which is why we only show an artist drawing here. The gas from a destroyed star then accretes onto the disk of the supermassive black hole feeding its insatiable appetite.

This effect was used in the Doctor Who episode, The Impossible Planet, when the Scarlet system which was home to the Baluchi was drawn out into a red cloud before being accreted onto a black hole.

---------------------------------------------------------------

Supermassive black holes can feed on stars, but the gas that the black holes devour doesn't have to come from a disrupted star. Are there other options? What about clouds of dust and gas?

초거대 블랙혼은 별을 흡입한다. 하지만 이 블랙홀이 게걸스레 흡입하는 가스는 붕괴된 별에서 나온 것들 만은 아니다. 그렇다면 빨아들이는 다른게 있을까? 먼지나 가스 구름 일까?

The centers of galaxies can be pretty messy after all. Astronomers are puzzled by the sheer size of supermassive black holes. The mass of their interiors came from somewhere, and until recently, scientists thought that supermassive black holes feed on a steady diet of hot ionized gas from the halo of the galaxy.

은하의 중심은 매우 밀집되어 있을 것이다. 천문학자들은 초거대 블랙홀의 기형적인 크기에 놀라고 있고 최근까지도 초거대 블랙홀은 은하 중심의 밀집된 물질들(halo)에서 뜨거운 이온화된 가스들을 안적적으로 흡입한다고 생각했다.

Similarly, supermassive black holes can feed on cold molecular gas clouds, sometimes the remnants of ancient supernova explosions. In this case, the food is more like a soup with lumpy noodles and vegetables in it.

이에 덧붙여 차가운 가스 구름들 때때로 고대 초신성 폭발 잔해들도 흡입한다. 이것들은 뜨거운 국물에 겯들인 국수조각이나 야채라고 보면 되겠다.

In this image, the supermassive black hole is hidden away in the center of the galaxy in the cluster ABEL 2597, which is shown as blue light in this image. The red blobs show the location of cold clouds of molecular carbon monoxide gas.

[A Galaxy-Scale Fountain of Cold Molecular Gas Pumped by a Black Hole]

When a lumpy carbon monoxide chunk is consumed by a black hole, it temporarily blocks the light emitted from the accretion disk and jets like the black blob in the inset of this image.

All of this food talk is giving me indigestion, I hope I don't, excuse me.

---------------------------------------------------------

Supermassive black holes are not the most eloquent of dinner guests either. Not only do they demand more, they don't care whether you serve them a delicious apple pie made from scratch or a pile of rocks. While they do clean up after themselves, we can all agree that they need to work on their manners. No one is going to sit at a table with a supermassive black hole.

초거대 블랙홀은 뭐든 안가리고 먹는다. 그 누구든 옆에 앉아 같이 밥먹고 싶지 않을 것이다. [초거대 블랙홀이 가진 엄청난 중력을 고려해 보라.]

We've also learned that the jets of a black hole are hot gases being accelerated into interstellar space. This is kind of like a black hole burping. While gas flows inwards towards the black hole, the material and energy can be thrown out in the form of powerful relativistic jets.

On closer inspection, astronomers have also found that supermassive black holes can also eject gas from the region even closer to the event horizon.

-------------------------------------------------------

Here, we see the Whirlpool Galaxy, a beautiful example of two colliding galaxies. The smaller galaxy visible in the inset has a bright X-ray source visible in blue, which indicates the presence of a supermassive black hole. The blue arcs and bands are hot glowing gas being ejected from the region around the black hole, this is evidence of black holes burping. Excuse me again. How rude?

멋진 월풀 은하를 보자. 두개의 은하가 충돌하는 예다. 작은 은하에서 강력한 X선이 방출되고 있다. 이는 초거대 블랙홀의 증거라고 볼 수 있다. 청색 원호모양은 블랙홀 주변에서 뜨거운 가스들이 빛을 내고 있다. 블랙홀이 트림을 하고 있다.