Where did these gigantic space bubbles come from? - Ashkbiz Danehkar

翻译人员: Yutian Gao 校对人员: Sophia Ye

In November 2010, NASA announced the discovery of a strange,

2010 年 11月，美国宇航局宣布 发现了一种奇怪的、

never-before-seen galactic object:

前所未见的银河天体：

two gigantic gaseous bubbles,

两个巨大的气体泡，

each emanating an impressive 25,000 light years

每个泡从我们家园星系——银河系中心，

from the center of our home galaxy, the Milky Way.

辐射出令人印象深刻 的 25,000 光年。

Inside the structures, named the Fermi Bubbles,

在被命名为费米泡泡的结构内，

streams of high energy particles traveling faster than the surrounding medium,

高能粒子流的速度 比周围介质更快，

collide with dust, gas, and light,

与尘埃、气体和光碰撞，

to create gamma rays, the most energetic form of light.

产生伽玛射线，这是最能量充沛的光。

Astronomers were perplexed.

天文学家们感到困惑。

While gamma rays are not uncommon in space,

尽管伽玛射线在太空中并不罕见，

radiation of this magnitude had only been observed in distant galaxies.

但这种强度的辐射 仅有在遥远的星系中观察到。

And they are typically produced by large-scale powerful events,

它们通常由大规模的强力事件

like explosions of supernova.

（例如超新星爆炸）产生。

Yet, compared to our galactic neighbors,

然而，与我们的银河系邻居相比，

the center of the Milky Way and the supermassive black hole

银河系中心

that resides within it,

以及其中的超大质量黑洞

was always thought to have been relatively calm.

一直被认为是相对平静的。

So, what was the powerful event that created these massive structures?

那么，是什么强力事件创造了 这些庞大的结构？

And is the center of our galaxy not so sleepy after all?

而且，我们的银河系中心是 否真的如此宁静？

A clue to answering these questions came in December 2020,

回答这些问题的线索 出现在 2020 年 12 月，

when astronomers announced the discovery

当天文学家宣布

of yet another set of radiating spheres.

发现了另一组辐射球。

Entitled the eROSITA bubbles, these structures are even wider,

这些被称为 “eROSITA 气泡” 的结构更加宽广，

extending nearly half the distance of the entire Milky Way in both directions,

几乎延伸到整个银河系的一半距离，

and fully encapsulating the Fermi Bubbles.

并完全包裹了费米泡泡。

They emit soft X-rays, which have frequencies lower than gamma rays,

它们发出的软X射线的频率低于伽玛射线

but are still highly energetic forms of light.

但仍然是高能的光。

Astronomers quickly surmised that the overlapping bubbles

天文学家迅速推测，这些重叠的气泡

most likely share a single origin.

很可能有一个共同的起源。

And the event that formed them must have generated a massive amount of energy—

而且，形成它们的事件一 定产生了大量的能量，

approximately 1 million times that which the Sun will produce

约为太阳在其整个寿命周期内

during its entire lifetime.

产生能量的一百万倍。

Based on the speed of the jets of energetic electrons within the bubbles,

根据气泡内高能电子射流的速度，

they calculated the event most likely took place

他们计算出这一事件很可能发生在

less than 3 million years ago.

不到 300 万年前。

This is relatively recent compared to the galaxy’s 13-billion-year lifespan,

与银河系 130 亿年的寿命相比， 这是一个相对较新的事件，

and means our early ancestors might have even witnessed the powerful event,

这意味着我们的早期祖先 甚至可能亲眼目睹了这一强大的事件，

as a gigantic ball of heated mass illuminating the night sky.

如一个巨大的受热物质球照亮夜空。

But what exactly was the powerful event?

但究竟是什么强大的事件呢？

Two theories quickly emerged about what could have created the bubbles

关于是什么原因造成了这些气泡 和内部的高能粒子射流，

and the high energy particle jets within.

很快涌现出两种理论。

And both are still debated today.

而且，这两种理论至今仍在争论中。

The first theory is that the bubbles

第一种理论认为，

stem from a recent massive burst of star formation

这些气泡源于最近在银河系中心爆发的

toward the center of our galaxy.

大规模恒星。

Newly forming stars produce a vast outflowing of hot gas,

新形成的恒星会导致大量的热气体流出，

called stellar winds.

被称为恒星风。

Meanwhile, young massive stars die quickly,

同时，年轻的巨大恒星会迅速死亡，

causing energetic supernova explosions.

引发高能超新星爆炸。

Stellar winds combined with these explosions

恒星风与这些爆炸相结合，

can lead to the formation of large-scale galactic winds.

可以形成大规模的星系风。

These galactic winds can push away the surrounding material,

这些星系风可以推开周围的物质，

creating gigantic bubbles.

从而形成巨大的气泡。

The second theory is that the structures are the result of a powerful outburst

第二种理论认为， 这些结构是我们银河系中心的

from the supermassive black hole at the center of our galaxy.

超大质量黑洞强力爆发的结果。

Named Sagittarius A*,

这个黑洞被命名为射手座 A*，

this black hole lives up to its title of supermassive,

它不负超大质量的名号，

as it’s approximately 4 million times the mass of the Sun.

因为它的质量大约 是太阳的 400 万倍。

And scientists have documented similar jets of energy

科学家还记录了来自其他遥远活跃星系中

emanating from similar black holes in other distant active galaxies.

类似黑洞的类似能量射流。

These jets are found in active galactic nuclei known as quasars,

这些射流出现在被称为类星体的活动星系核中，

and they're created as dust and gases rapidly fall into the feeding black hole.

它们随着尘埃和 气体迅速坠入喂养的黑洞。

This gathers hot ionized gas around the vicinity,

这会在附近聚集热的电离气体，

which is then ejected from the center at ultra-fast velocities.

然后以超快的速度从中心喷射出去。

This theory suggests that Sagittarius A*, which is thought to be relatively quiet,

这一理论表明，被认为相 对安静的射手座A*

may have been active relatively recently.

最近可能比较活跃。

And it begs the question: will it wake up again?

这就引出了一个问题：它会再次苏醒吗？

Scientists use supercomputers

科学家们使用超级计算机

to run what is known as hydrodynamic numerical simulations,

进行所谓的流体运力学数值模拟，

where different physical conditions that may have led to bubble formation

探索可能导致气泡形成的

are explored.

不同物理条件。

While several results suggest that extreme outbursts from Sagittarius A*

尽管有几个结果表明， 射手座A*的极端爆发

likely contributed to the creation of the bubbles,

可能是气泡形成的原因之一，

it remains to be seen whether past star formations may have also played a role.

但过去的恒星形成是否 也发挥了作用尚有待观察。

Other simulations show evidence of other contributing factors,

其他模拟显示了其他影响因素的证据，

like the influence of circumgalactic medium winds from outside our galaxy,

例如来自银河系外的 环星系中的风的影响，

which may explain some of the bubbles’ unique features.

这也许可以解释气泡的某些独特特征。

These computational simulations will only get more precise

随着我们继续向太空发射更灵敏、 更具动态性的望远镜，

as we continue to launch more sensitive and dynamic telescopes into space.

这些计算模拟将变得更加精确。

But whatever answers we unlock will undoubtedly lead to more surprises

但无论我们解开了什么答案， 无疑都将给我们这个神秘而

about our mysterious, and perhaps not so calm, galaxy.

可能并不那么平静的星系 带来更多惊奇。