There must be life other than our own in the universe.

There is no scientific evidence to suggest that there is intelligent extraterrestrial life currently existing in the universe.

Appeal To Authority

appeal to ignorance-a claim is false because it has not been proven true. we may never be able to prove the existence of aliens,yet they might exist nonetheless.

There must be life other than our own in the universe.

if what you're saying is true and there has to be life is it better to not look for it. Because if they are smart enough to communicate with us planet,they also most likely have the power to destroy us. So it's not a question of if they exist It is a question of are we willing to find out.

Irrelevant Conclusion

whether aliens are dangerous/hostile and whether we are willing to find that out has no bearing on the question of their existence