The discovery of giant X-ray bubbles above and below the centre of the Milky Way confirms that the central supermassive black hole was once more than 100 million times brighter than its current state.

中文翻译：

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活动冒泡

在银河系中心上方和下方发现巨大的X射线气泡，证实了中央超大质量黑洞的亮度比其当前状态高出1亿倍。