Lec ｔｕ re １ I Ｎ TRODUC ＴＩ ON TO EA ＲＴ HMajor Concept (I） Ｔ h ｅ pla ｎ et ｓ in o ｕ r solar s ｙ s ｔ em, including Earth, began to ｆorm ｏ ut ｏ f a ｒ o ｔ ating d ｉｓ k of ga ｓ and dust ａ bo ｕｔ 4、6 billion yea ｒ s ａgo、 Ｒ elate ｄ ｏｒ supporting ｃ on ｃ epts：T ｈｅ present v ｉ e ｗ ｏ f the be ｇ i ｎ n ｉ n ｇ o ｆ the ｓｏ lar system suggest ｓ tha ｔ a ｃ lou ｄ ｏｆ ｇ as an ｄ ｄ ust w ａ s ｆｌ att ｅ ne ｄ ｉ nto a d ｉ sk by rota ｔ ion、 T ｈ e dens ｉ t ｙ of t ｈｅ ｍａ tter ｉｎ th ｅ disk w ａ s g ｒ e ａｔ e ｓ t ａ t i ｔ s ce ｎｔｅ r and d ｅ creased toward the edges、 T ｈ e su ｎ f ｏ rm ｅｄ a ｔ th ｅ cente ｒ of t ｈ e disk ｗ here the t ｅｍ p ｅ ratur ｅ w ａｓ hi ｇ hest ａｎｄ the p ｌａ nets ｆ orm ｅ d ａ t gre ａｔ er d ｉ s ｔ ances away f ｒ o ｍ the c ｅ n ｔ er、 Th ｅ p ｏ siti ｏ ns of the pla ｎ e ｔ s di ｆｆ er ｂｅ cause of a nat ｕｒ a ｌ so ｒ tinｇ of ｅ lements i ｎ ｔ he cl ｏｕ d with dista ｎｃ e from the center、 The t ｅ m ｐ e ｒ a ｔｕｒｅ o ｆ th ｅ earl ｙ Ear ｔ h was ｐ r ｏ bably ｑ uit ｅ ｈ igh due to: a、 the g ｒ avit ａｔ ional c ａｐ ture ｏ f ｐ artic ｌ es t ｈ a ｔ re ｌ eased he ａt ｏ n impact， b、 t ｈ e in ｃ reas ｅ d pressure o ｎ ｔ he ｉ nt ｅ rior of the pl ａ net as ｉｔ continu ｅｄ to grow, ａ nd c、 th ｅ c ａ p ｔ ure o ｆ ｒ a ｄ i ｏ activ ｅ e ｌ e ｍ ents th ａｔ ｇａ v ｅ o ｆ f ｈea ｔ when ｔｈ e ｙ de ｃ a ｙｅ d、 During ｔ he first fe ｗ ｈｕｎ dred milli ｏｎ ye ａ r ｓ, the internal ｔ e ｍｐ e ｒ ature rose high e ｎ ou...
