Charalas put the flier into a steep dive and landed in the open space between the buildings. They entered the long, low building at the end opposite the most ornate building of the seven that surrounded the landing area and Charalas told the receptionist that they were expected. The long hall was excellently illuminated, and on either side of the corridor were murals; great twelve-foot panels of rare color and of photographic detail. Upon close examination they proved to be paintings. The first panel showed an impression of the formation of Ertene, along with the other eleven planets of Ertene's parent sun. It was colorful, and impressionistic in character rather than an attempt to portray the actual cataclysm that formed the planets. The next few panels were of geologic interest, giving the impressions of Ertene through the long, geologic periods. There were dinosaur-picturizations next, and the panels brought them forward in irregular steps through the carboniferous; through the glacial ages; through the dawn ages; and finally into the coming of man to power. The next fourteen panels were used in the rise of man on Ertene from the early ages to full, efficient civilization. They were similar to a possible attempt to portray a similar period on Terra, showing wars, life in the cities of power during the community-power ages, and the fall of several powerful cities. Then the rise of widespread government came with its more closely-knit society made possible by better means of communication and transportation. This went on and on until the facility of the combining factors made separate governments on Ertene untenable, and there were seven great, fiery panels of mighty, widespread wars. "Up to here, it is similar to ours," commented Guy. "And here it changes," said Charalas. "For the next panels show the impending doom of Ertene's parent sun. The problem of space had been conquered but the other planets were of little interest to Ertene. We fought about four interplanetary wars as you see here, all against alien races. Then came trouble. The odd chance of a run-away star coming near Ertene did happen, and we faced the decision of living near an unstable sun for centuries, for our astronomers calculated that the two stars would pass close enough to cause upheavals in the suns that would result in instability for thousands, perhaps millions of years." "Instability might not have been so bad," said Guy thoughtfully, "if it could be predicted. No, I'm not speaking in riddles," he laughed. "I may sound peculiar, saying that it would be possible to predict instability. But a regular variable of the cepheid type is predictable instability."