Passage Summary: Scientists have spent a lot of money and time looking for aliens but haven't found anything yet. Because of this lack of success, the author believes we will never actually find life on other planets.

Conclusion: The search for extraterrestrial life is destined to remain an unfulfilled dream.

Reasoning: Despite years of searching with increasingly expensive and advanced technology, no evidence of alien life has been found, and there is no reason to expect future success.

Analysis: To identify the main point, focus strictly on the structure of the argument to find the author's ultimate claim. The final sentence serves as the conclusion, which is signaled by the phrase 'as science's experience... should indicate'—a classic indicator that the preceding clause is the result of the evidence provided. The earlier statements regarding the cost of equipment and the historical lack of evidence function as premises to support this pessimistic outlook. When looking for the correct answer, prioritize the statement that expresses the author's final prediction rather than the facts used to justify it.