Some scientists believe that intelligent life forms may be exist on other planets and some want to send messages to contact them. Others think it is a bad idea because these life forms may be too dangerous.
If we want to know it is safe to contact extraterrestrial lives, we need to know what might be the result. On the positive side, alien civilization might be much more sophisticated than ours; they can solve problems that we cannot solve. For example, we are influenced by pollution and other behavior that will destroy the environment and our health. And, we do not have an efficient solution to deal with these. But, aliens might be able to help us. They have already acknowledged information about sustainable development, which means that they will not damage the environment. They can help us so that we will grow faster.
There are also things unknown that might happen. Since aliens and us come from totally different cultural backgrounds, and we are ill-informed about their culture, there will be differences between encoding and decoding messages. When we say hi to aliens, they might think we say we want to kill you. In this way, a space war will happen. We do not know if we can win the game. If we cannot, humans might die out. There might be unpredictable catastrophes.
The worst thing for us if we do not connect with aliens is that we will spend more time on improvement. Well, the worst thing that can happen if we connect with them is death. It seems that it is inadvisable to contact extraterrestrial lives because we cannot bear the cost.
Photo by brewbooks 
This was a very interesting post, Li. You were able to provide valid arguments for both sides of the issue which was very impressive. Looking at environmental issues and the potential to solve those issues was a smart perspective to take because it made it relevant to your audience. I especially enjoyed your conclusion, that “it seems that it is inadvisable to contact extraterrestrial lives because we cannot bear the cost.” You were able to make a very compelling, logical argument about how the cons of contacting extraterrestrial life significantly outweigh the pros. I am interested in what you think about the likelihood of being able to understand any communication from extraterrestrial life. Do you think we would be able to translate their form of communication into something comprehensible? You might find this Astronomy article interesting because it tackles a few of those possibilities: http://astronomy.com/bonus/alien-contact