NASA的阿波罗任务为科学家带回了月球岩石样本进行研究。在随后的几十年中，我们获得了大量了解，但一个持久的谜团仍然存在。这些月球样本中有许多显示出与地球相当的强磁场的迹象，而今天的月球却没有这样的磁场。那么，这些月球岩石是如何获得其磁性的呢？

On April 14, Harvard University rejected the Trump administration's demands to make sweeping changes to its governance, hiring and admissions practices. Just a few hours later, the Trump ...

SACRAMENTO, the United States, May 23 (Xinhua) -- A U.S. federal judge has issued an injunction blocking the Trump administration from revoking the legal status of foreign students studying and ...