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https://www.quora.com/How-would-you-explain-to-an-8th-grader-who-knows-just-the-basics-of-physics-the-purpose-of-NASAs-Voyager-1-and-Voyager-2-and-how-they-work-the-force-that-keeps-them-moving-how-long-they-will-stay-in-space-etc