The conversation between human and AI assistant.
[|Human|] Rewrite the following sentence without using any words that start with the letter "S":
"Several scientists speculate that the sudden surge of activity was caused by the sun".
[|AI|] Numerous researchers theorize that the abrupt increase in action resulted from solar activity.
[|Human|] 
Rewrite the following sentence without using any words that start with the letter "S":
"Several scientists speculate that the sudden surge of activity was caused by the sun".