Recent years have seen unprecedentedly fast-growing prosperity in the commercial space industry. Several privately funded aerospace manufacturers, such as Space Exploration Technologies Corporation (SpaceX) and Blue Origin have innovated what we used to know about this capital-intense industry and gradually reshaped the future of human civilization. As private spaceflight and multi-planetary immigration gradually become realities from science fiction (sci-fi) and theory, both opportunities and challenges are presented. In this article, a review of the progress in space exploration and the underlying space technologies is firstly provided. For the next, a revisit and a prediction are paid and made to the K-Pg extinction event, the Chelyabinsk event, extra-terrestrialization, terraforming, planetary defense, including the emerging near-Earth object (NEO) observation and NEO impact avoidance technologies and strategies. Furthermore, a framework of the Solar Communication and Defense Networks (SCADN) with advanced algorithms and high efficacy is proposed to enable an internet of distributed deep-space sensing, communications, and defense to cope with disastrous incidents such as asteroid/comet impacts. Furthermore, the perspectives on the legislation, management, and supervision of founding the proposed SCADN are also discussed in depth.