 Why does Baron think there was something wrong with Claney's filters?
F. No permanent installation with a human crew could survive at either extreme. Poor Jack met us at the rocket landing almost bawling, Sanderson had given him such a gloomy picture of what Brightside was like. But the only way to avoid it is to travel over the Pole, which would lose us days and offer us no guarantee of less activity to the west. There was an atmosphere and a constant atmospheric flow from Brightside to Darkside. Not much—the lighter gases had reached escape velocity and disappeared from Brightside millennia ago—but there was CO 2 , and nitrogen, and traces of other heavier gases. The trick was to find a passage that avoided those upheavals as far as possible.
 Claney's face is covered in cancerous tumors.
 Claney's face is extremely sunburned.  Claney's face is twisted and brown.  Claney's face is covered in scars.  Claney's face is covered in cancerous tumors.