These X-ray pulses take 300 years to traverse the distance between the central black hole and a large cloud known as Sagittarius B2, so the cloud responds to events that occurred 300 years earlier.
这些X射线脉冲花了300年从中心黑洞到达了一片巨大的云团人马座B2，于是云团对300年前的事件作出反应。
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