木卫三阴影中的木星

During its 40th close pass by Jupiter, our Juno spacecraft saw Ganymede cast a large, dark spot on the planet on Feb. 25, 2022.

JunoCam captured this image from very close to Jupiter, making Ganymede’s shadow appear especially large. At the time the raw image was taken, the Juno spacecraft was about 44,000 miles (71,000 kilometers) above Jupiter’s cloud tops and 15 times closer to the planet than Ganymede.

An observer at Jupiter’s cloud tops within the oval shadow would experience a total eclipse of the Sun. Total eclipses are more common on Jupiter than Earth for several reasons: Jupiter has four major moons (Ganymede, Io, Callisto, and Europa) that often pass between Jupiter and the Sun, and since Jupiter’s moons orbit in a plane close to Jupiter’s orbital plane, the moon shadows are often cast upon the planet.

Image Credit: Data: NASA/JPL-Caltech/SwRI/MSSS; Image processing: Thomas Thomopoulos © CC BY

2022年2月25日，在第40次接近木星时，我们的朱诺号航天器拍摄到木卫三在木星上投下了一个巨大的黑点。

JunoCam在离木星非常近的地方拍摄了这张照片，使得木卫三的阴影显得特别大。在拍摄原始图像时，朱诺号航天器距离木星云顶约44,000英里（71,000公里），距离木星的距离是木卫三的15倍。

在椭圆形阴影内木星云顶的观测者将经历日全食。日全食在木星上比在地球上更常见，原因有几个：木星有四个主要的卫星（木卫三、木卫一、木卫二和木卫二），它们经常在木星和太阳之间穿行，而且由于木星的卫星在靠近木星轨道平面的平面上运行，所以卫星的阴影经常投射在这颗行星上。

图片来源：数据来源：NASA/JPL-Caltech/SwRI/MSSS；图像处理：Thomas Thomopoulos © CC BY