I got some questions that needed answer
1. What is the meaning of the "planet in outer space" sequence ?
2. I don't understand Sean Penn's character
3. Why did the boy (I think he's Jack) throw away his mother's dress ?
1. You mean the 20 minute-ish birth of the earth scene? Well, it echoes a lot to the quote from Job (right in the beginning of the movie), since the mother asks "Why? Who are we to you?" and such, much like Job questioned God and God answered Job with: "Where were you when I laid the foundations of the Earth? ...When the morning stars sang together and all the sons of God shouted for joy?", so as an answer for the mother's questions, we get the sequence. It also shows some central themes to the movie, like mercy with dinosaurs and such.
2. The whole movie is pretty much Old Jack (Sean Penn) reminiscing his childhood on the anniversary of his brother's death. Also, Sean Penn said Terrence Malick cut most of his scenes from the final movie.
3. It was actually the neighbour lady's dress Jack threw away. The scene was pretty much about his sexual awakening and the shame of his deed, and if Terrence Malick himself did that when he was young (the movie is very autobiographical), it's incredibly naked fact about his past, considering how private person he is.