'One way or another, humanity’s future is in the cosmos. Perhaps spacecraft will one day manage to carry humans to the stars, or at least robots with instructions on how to create humans.
'Or, humanity may never expand beyond Earth. In two billion years, the sun’s brightness will increase by 15 percent, making our home similar to Venus today. A runaway greenhouse effect will produce surface temperatures in excess of 700 degrees Fahrenheit. Following that, in five billion years, the sun will exhaust its hydrogen fuel and its outer surface will expand as it becomes a red giant, eventually encompassing Earth within its outer layers.'