 Why do Bal and Ethaniel think they have to make time to save Earth?
But this vast distance did not mean that isolation could endure forever. "I may remind you that in two months twenty-nine days we're due in Willafours," said Bal. A meteor shower could pass over and their clumsy instruments could interpret it as an all-out enemy attack." "And how long can Earth last? They went much closer to Earth, not intending to commit themselves. "What's worse is that I now find they also have missiles, range one thousand miles and upward. There's so little time," Ethaniel said. We can't help them," said Ethaniel. The southern plains were green, coursed with rivers; the oceans were blue; and much of the northern hemisphere was glistening white.
 No one else knows Earth and its big bomb problem exisits. It will be quite a long time before anyone passes out this way again. By then, it will be too late for the Earth.
 No one else knows Earth and its big bomb problem exisits. It will be quite a long time before anyone passes out this way again. By then, it will be too late for the Earth.  If Bal and Ethaniel don't make time to save the Earth from the big bomb, the shockwave may also destroy their spacecraft.  If Bal and Ethaniel don't make time to save the Earth from the big bomb, the shockwave may also destroy Willafours.  Not saving the humans would be like letting their own people die.