Thanks for answering. The news I found is from Inquirer.
http://business.inquirer.net/246286/bitcoin-hit-50000-end-2018/ampThe article doesn't said much. It just said about the technology changes and that might be the reason for bitcoin price to go up. Since some of here replied and answered, I know now what the factors affecting the bitcoin price to change. It's also hard to believe but we'll see what happens in the future.