question:  What is the Brightside?
context: Brightside Crossing by Alan E. Nourse JAMES BARON was not pleased to hear that he had had a visitor when he reached the Red Lion that evening. Across to the right was a group that Baron knew vaguely—Andean climbers, or at least two of them were. No human beings will ever cross the Brightside alive, not if they try for centuries.” After that, I followed Sanderson’s work in the Twilight Lab up there and began to get Brightside into my blood, sure as death. I first met him on Venus; we spent five years together up there doing some of the nastiest exploring since the Matto Grasso. Then he made the attempt on Vulcan Crater that paved the way for Balmer a few years later. I want the Brightside without any nonsense about it.” “I want to make a Crossing at perihelion and I want to cross on the surface. Mercury turns on its axis in the same time that it wheels around the Sun, which means that the Brightside is always facing in. That makes the Brightside of Mercury at perihelion the hottest place in the Solar System, with one single exception: the surface of the Sun itself. The Twilight Lab, near the northern pole of Mercury, was the obvious jumping-off place. Twilight Lab wasn’t particularly interested in the Brightside, of course—the Sun was Sanderson’s baby and he’d picked Mercury as the closest chunk of rock to the Sun that could hold his observatory. On Mercury, the Brightside temperature hits 770° F. at perihelion and the Darkside runs pretty constant at -410° But with Mercury’s wobble, the twilight zone between Brightside and Darkside offers something closer to survival temperatures. The Solar ’scope could take that much change and they’d get good clear observation of the Sun for about seventy out of the eighty-eight days it takes the planet to wheel around. The Major was counting on Sanderson knowing something about Mercury as well as the Sun when we camped at the Lab to make final preparations.
output:  The Brightside is the side of Mercury that constantly faces the sun.
options:  The Brightside is the side of Mercury that constantly faces the sun.  The Brightside is the first passage to the core of Vulcan Crater on Venus.  The Brightside is the name of the passage on the Andean mountains of Venus.  The Brightside is the name of the crossing the climbers are going to climb.