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Astronomers have discovered the darkest known planet。 The planet, known as TrES-2b, reflects less than 1 per cent of light, which makes it darker than any other planet or moon。 The planet, roughly the size of Jupiter, is around 750 light years away。 The reason it differs from other similar-sized planets is that Jupiter, for example, is surrounded by ammonia clouds that reflect more than one third of its sunlight。 TrES-2b has no ammonia clouds to reflect light because it is extremely hot。 Instead, it has an atmosphere made up of chemicals such as vaporized sodium, potassium and gaseous titanium oxide, which absorb light, but that still does not explain the planet's extreme blackness。 However, TrES-2b is not entirely black. Its extreme heat means it gives off a faint red glow。 David Kipping of the Harvard-Smithsonian Center for Astrophysics (CfA) and his team arrived at the discovery by measuring the light TrES-2b emitted as it orbited its star, much like our moon does with earth, studying both the “visible”side and its“dark” side during orbit。 The discovery was detailed in the journal Monthly Notices of the Royal Astronomical Society。 据英国《每日邮报》8月13日报道，天文学家发现已知最黑行星。 这颗行星被命名为TrES-2b，它仅反射低于1%的恒星光线，这使得它比迄今发现的任何行星或卫星都要暗。 | 
