To answer the first part of your question, I'd like to say that our studies were very extensive.
你问题的第一部分,我要说的就是我们的研究非常广泛。
may have left an automatic messenger behind to await the possible awakening of an advanced civilization.
很可能会在离开太阳系时留下自动化信息装置,等待先进文明的觉醒。