The yellow star answered with flame of its own, and Jan was forced to get into the act, and turn on his radiation shields at full capacity. A half-hour later, both coronas subsided to normal, and he cut down his shield capacity once more.
"It's damnably disturbing," said Jan. "If only natural forces are involved, why should one star reply to the other in such deliberate fashion?"
"Perhaps the green star set the other one off, like a neutron from an exploding atom setting off the next atom," Karin suggested.
"Or perhaps there are living creatures on them," Jan muttered.
Karin said, "It's beginning to seem possible. And I'm afraid that if we stay here long enough, we'll find out."
"I'm afraid so too," Jan conceded. "We both wanted living companions—but not unknown shapes of fire."
Seventeen hours after the end of the corona explosions, they noticed activity on the yellow star. What took place resembled the formation of sunspots, but the eruptions were like none they had ever seen. As they grew, they darkened, and began to rotate with increasing speed, so that soon the surface of the yellow star was covered with black, whirling specks. The specks drew together, and then shot out abruptly toward the green star.
Once more Jan acted. As the black objects raced toward him, he sent the ship full speed ahead to get out of their way, and as he did so the now elongated spheres of spinning blackness sailed straight past the ports. They were in the vacuum of space, but even so Jan noted that the ship rocked as if battered by the waves of an ocean.
From the green star came answering black objects, which grew like sinister soap bubbles. The bubbles caught the attacking spheres, and wherever defenders and attackers made contact, a blinding flash of light was followed by a quick burst of high-energy radiation.
"Rule out natural forces," said Jan decisively.