Elon Musk, on the social media platform X, explains the technical challenges of developing fully reusable rockets and why they haven't been successful in the past. He argues that Earth's strong gravity makes it difficult to achieve positive payload margins, but he believes that SpaceX's new approach, which involves using a ground tower to assist with landing, could solve this problem. Meanwhile, in the science fiction short story, "Mountain," the protagonist, Feng Fan, chooses to live on an oceanographic research vessel to avoid mountains after a traumatic experience. When an alien ship appears in Earth's orbit, it starts to draw water from the ocean, creating a massive mountain of water. Feng Fan, driven by his desire to climb mountains, decides to swim to the summit of this massive watery mountain. The aliens, who are mechanical life forms from a hollow planet, have been exploring the universe through tunnels and have learned about the nature of gravity and the existence of other worlds through their explorations. They contact Feng Fan, who is on the summit of the water mountain, and reveal that the universe is a bubble world within a larger solid super-universe, and they are on a journey to its edge.
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