favorite story of the day. good. oh, sll got it. i m going to need to try it one more time. ready? yeah, beautiful. much better. when it comes to basic astrology of our planet, it s simple. there s one earth, a sun, and a moon last time i checked. we all knew that. that last part might not actually be true new research suggests there was a second moon. as abc s linsey davis reports, a classic storybook may need a rewrite. reporter: goodnight moon has lulled generations of kids to sleep. but the real story behind the moon we see at night is being rewritten as we speak. many moons ago, more than 4 billion years, the heavens weren t so lonely. and nightfalalnot so dark. that s if you lieve the earth didn t tave just one moon but two. the tale goes that for tens millions of years, before anyone was here to see it, a baby moon orbited the earth.