Light bouncing off objects allows us to see them.

光在物體上的反彈使我們能夠看到物體。

Light is an oscillating electromagnetic wave.

光是一種振盪的電磁波。

We see different frequencies of that oscillation as different colours.

我們看到不同頻率的振盪呈現出不同的顏色。

The electric field component of a light wave can oscillate in any direction perpendicular to the direction of travel. Light from the sun oscillates in all directions, we say it is unpolarised.

光波的電場分量可以在垂直於傳播方向的任何方向上振盪。來自太陽的光可以在所有方向上振盪，我們稱之為非極化光。

If the waves have a preferred direction of oscillation, they are polarised.

如果波有偏好的振盪方向，它們就是極化的。

For example, light from your phone is vertically polarised.

例如，手機發出的光線是垂直偏振的。

Your polarised sunglasses are a polarised filter.

你的偏光太陽鏡就是一個偏光濾鏡。

Here, they let vertical polarisation through.

在這裡，它們允許垂直極化通過。

If we rotate them, almost all the polarised light gets blocked. Light produced by a torch is unpolarised.

如果我們旋轉它們，幾乎所有的偏振光都會被擋住。手電筒發出的光沒有偏振。

When we place a polarised filter in between, the light becomes polarised.

當我們在兩者之間放置一個偏振濾光片時，光線就變成了偏振光。

In space, randomly moving hot gas or plasma emits unpolarised light, like the torch.

在太空中，隨機移動的熱氣體或等離子體會發出非偏振光，就像火炬一樣。

Plasma threaded by a magnetic field is ordered and the emitted light is polarised.

被磁場穿透的等離子體是有序的，發出的光也是偏振的。

The magnetic field acts as a polarised filter.The strong gravity near a black hole bends the magnetic field and twists the polarisation direction of the light from the surrounding plasma.

黑洞附近的強大引力會使磁場彎曲，扭曲來自周圍等離子體的光的偏振方向。

The polarised light rays that manage to escape travel to a distant camera.

僥倖逃脫的偏振光射向遠處的照相機。

The intensity of the light rays and their direction are what we observe with the Event Horizon Telescope.

我們用事件視界望遠鏡觀測到的是光線的強度和方向。

Using this knowledge, we can map out the magnetic fields that surround black holes.

利用這些知識，我們可以繪製出黑洞周圍的磁場圖。