sᴘɪɴɴɪɴɢ ᴅɪsᴋs, ᴏᴅᴅʙᴀʟʟ sᴛᴀʀs, ᴀɴᴅ sᴛʀᴀɴɢᴇ ᴘʟᴀɴᴇᴛs ʜᴇʟᴘ ᴀsᴛʀᴏɴᴏᴍᴇʀs ᴛᴇsᴛ ᴛʜᴇᴏʀɪᴇs ᴀʙᴏᴜᴛ ᴘʟᴀɴᴇᴛᴀʀʏ sʏsᴛᴇᴍ ғᴏʀᴍᴀᴛɪᴏɴ
How Are Solar Systems Born? Many of us remember those school-room models of our Solar System, with tiny wooden planets...
ᴀɴᴅ sᴛʀᴀɴɢᴇ ᴘʟᴀɴᴇᴛs ʜᴇʟᴘ ᴀsᴛʀᴏɴᴏᴍᴇʀs ᴛᴇsᴛ ᴛʜᴇᴏʀɪᴇs ᴀʙᴏᴜᴛ ᴘʟᴀɴᴇᴛᴀʀʏ sʏsᴛᴇᴍ ғᴏʀᴍᴀᴛɪᴏɴ
