But far from an wild party of death, galaxies collisions yield hotbeds for new star formation,

但這絕不是什麼瘋狂的死亡派對，星系碰撞是新恆星形成的溫床，

leading astronomers to suspect that this not-so-violent event is actually a driving factor behind galactic evolution.

導致天文學家猜想這並非如此暴力的事件，實際上是銀河系演變的驅動因素。

The big question here is how can galaxies collide and not just destroy everything?

這裡有個大問題，就是星系要如何碰撞，而不是單單毀滅一切？

It helps to think about what a galaxy really is.

它有助於思考星系究竟是什麼。

Every galaxy is made up of some 100 billion stars with planets orbiting their host stars,

每個星系大約由一千億顆恆星組成，還有行星圍繞的它們的主星，

but those stars are really far apart.

但這些恆星距離相當遠。

Take the Milky Way for example.

以銀河系為例。

We're about here on the edge of a spiral arm called Orion Spur.

我們大約在這裡，在名為獵戶座分支的螺旋臂邊緣。

It looks crowded in our little neighborhood, but our nearest neighbor Alpha Centuri A, is actually 4.3 light years away.

它在我們的小社區中看起來很擠，但我們最近的鄰居半人馬座 α 星 A，實際上距離我們 4.3 光年。

So galaxies might full of stars, but those stars are really far apart, meaning the likelihood of two hitting is pretty low.

所以星系中可能佈滿恆星，但那些恆星彼此距離太遠，代表兩個恆星撞擊的可能性相當低。

But that doesn't mean nothing happens, because there is stuff in those vast distances.

但這並不代表什麼事也不會發生，因為在那廣大的距離中存在某些東西。

The “space” between stars is actually full of gas and dust.

恆星之間的「空間」實際上充滿氣體和星塵。

Within these regions are dense pockets of interstellar material, called molecular clouds,

在這些區域內有密集的星際介質，稱為分子雲，

that collapse under their own mass and gravity, forming protostars and eventually new stars.

在自身質量和重力作用下崩塌，形成原恆星，最終形成新的恆星。

When galaxies collide, it's this material — the interstellar gas and dust — that

星系碰撞時，正是這種物質——星際氣體和星塵，

interacts gravitationally with some neat results.

與一些不錯的成果在重力下相互作用。

In a collision, one galaxy can rip material from another, disrupting star formation and

在碰撞中，一個星系可從另一個星系中撕裂物質，擾亂恆星的形成，

adding more material to its own molecular clouds.

並為自身的分子雲中加上更多物質。

A direct collision between these gases can also result in shockwaves reverberating through

這些氣體間的直接碰撞也可能導致震波在兩個星系中迴盪，

both galaxies, triggering new regions of star formation where there wasn't any before.

產生出以前從未有恆星形成的新區域。

Aside from generating new pockets of star formation, both close passes and full-on collisions

除了產生出新的恆星外，近距離的經過和全面碰撞

cause gravitational interactions begetting interesting changes, causing spiral arms, tidal tails, and even rings.

導致重力相互作用產生有趣的變化，造成螺旋臂、潮汐尾，甚至是環狀星系。

Two spiral galaxies could merge and form an elliptical galaxy with more active star formation than either had before.

兩個螺旋星系能合併形成一個橢圓星系，行星形成也比以往更活躍。

But it's not like this happens overnight… not that there's a “night” where galaxies are concerned.

但這並不是在一夜之間發生的......星系甚至沒有「一晚」這回事。

This process can take millions of years.

這個過程可能需要數百萬年。

Which is a good thing because our own Milky Way is on a crash course with the Andromeda galaxy, but we've got a good 4 billion years…

這是一件好事，因為我們的銀河系正準備撞上仙女座星系，但我們還有 40 億年可以好好過......

That should be enough time to live my best life.

這時間應該足夠來過我最棒的生活。

If you want more cosmic science in your feed be sure to subscribe to Seeker.

如果你想看更多宇宙科學的影片，那務必要訂閱 Seeker。

And if you want to know what happens when galaxies die, Trace has more on that right here.

如果你想知道星系死亡時會發生什麼，Trace 在這裡可以告訴你更多內容。

You know what'd be awesome?

有件令人驚嘆的事，你知道是什麼嗎？

If after the Andromeda collision our sky lit up with tons of newly forming stars!

如果與仙女座星系碰撞後，我們天空會照亮大量新形成的恆星！