太阳系最大的石块

2023年1月1日

The Largest Rock in our Solar System
Image Credit: NASA, Voyager 1 spacecraft

Explanation: There, that dot on the right, that’s the largest rock known in our Solar System. It is larger than every known asteroid, moon, and comet nucleus. It is larger than any other local rocky planet. This rock is so large its gravity makes it into a large ball that holds heavy gases near its surface. (It used to be the largest known rock of any type until the recent discoveries of large dense planets orbiting other stars.) The Voyager 1 spacecraft took the featured picture — famously called Pale Blue Dot — of this giant space rock in 1990 from the outer Solar System. Today, this rock starts another orbit around its parent star, for roughly the 5 billionth time, spinning over 350 times during each trip. Happy Gregorian Calendar New Year to all inhabitants of this rock we call Earth.

Tomorrow’s picture: planets align

太阳系最大的石块
图像提供: NASA, Voyager 1 spacecraft

说明: 图像右侧的亮点，就是太阳系现知最大的石块。它大于所有已知的小行星、卫星和彗星核；也大于太阳系其他的石质行星。这颗岩石是如此之大，以至于本身的重力让它聚成球形，并把较重的气体束缚在表面附近。（它曾是已知各种形态的石块中最大者，然而在不久前发现绕行其他恒星的大型致密系外行星之后，它就此跌落王座。）这幅主题图像，是由1990年飞到太阳系外围的旅行者1号飞船所拍摄，并以现在众所皆知的“淡蓝小点”来称呼这颗太空巨石。如今这颗石头，即将再次展开它绕行母星的旅程；在过去，它大约已经绕行了50亿次，而每次也自转超过350圈。于此祝这颗我们称为地球的巨石上之所有住民，格里历新年快乐。

明日的图片: planets align