哈勃望远镜拍到木卫三

北京时间12月24日消息，据美国《连线》杂志报道，哈勃望远镜最近拍到了正要转到木星后面的卫星木卫三。木卫三是太阳系中最大的卫星，它是一个由冰冷岩石构成的卫星，甚至比水星还要大。

  这张美丽的照片还展示了木星大气的一些重要信息。木卫三正从由气体构成的木星后面经过，木星的光线从木卫三上反射回来，提供了木星云层上方薄雾构成化学物质的一些线索。从照片上还能看到的是卫星表面上亚利桑那州大小的撞击坑“特罗斯(Tros)”，它周围有着明亮的条纹状物。

  科学家认为，木卫三表层下约125英里处有一个盐水大洋，正好位于冰层中间。更深处被认为存在一个液体铁芯，为太阳系中卫星周围唯一磁场提供动力。木卫三每7天环绕木星一周，它的轨道倾斜几乎与地球正面相对。
The Hubble Space Telescope recently caught this shot of Jupiter's moon Ganymede just before it ducked behind the giant planet. The largest moon in our solar system, Ganymede is an icy rock even bigger than Mercury.

It's a gorgeous shot, but the image also reveals important information about Jupiter's atmosphere. As Ganymede passes behind the gas giant, light from the planet bounces off the moon, carrying with it clues about the chemicals that make up the haze above the Jovian clouds.

Also visible in the image is the Arizona-sized impact crater Tros on the moon's surface, with bright streaks of material blasted around it. Scientists think a saltwater ocean lies nearly 125 miles under the moon's surface, sandwiched between layers of ice. Even farther down, a liquid iron core is thought to exist, powering the only magnetic field around a moon in the solar system.

Ganymede circles around Jupiter approximately every seven days in an orbit tilted nearly head-on to Earth.

壮观啊。。。。。。。。。。。。

木卫三表层下约125英里处有一个盐水大洋，正好位于冰层中间。更深处被认为存在一个液体铁芯，为太阳系中卫星周围唯一磁场提供动力