There are really only two possibilities.
1. The physical Universe always existed, and the things we see around us are just products of time, chance, matter and energy. People, aliens (if they exist) and all apparently conscious entities are just physical matter and physical energy which have occurred randomly and as a by product of the “laws of physics”. These “laws” just “are” – there is no way to explain why they are the way they are.
2. There is a spirit world, and a Great Spirit or group of spiritual entities are behind all the apparent order, design, logic of the Universe. Christians believe that there is a tri-une “Great Spirit” which we call God, although the name “God” can be different in different languages.
The best scientific research today in astonomy and general relativity indicates strongly that this physical Universe has always been expanding, and had in fact, a finite beginning. See Reasons to Believe homepage.
Simply stated, the incredible designs in nature are so complex that there simply are not enough particles in the known universe, or time available, for these things to ever have come into existence by chance. On the contrary,
The vastness of space points to the immensity and awesomeness of the Creator.
The complex relationships in the biological world point to the incredible wisdom, knowledge and intelligence of the Creator.
The pleasures we enjoy and the diversity of the beauty in this world points to a good, beautiful and loving Creator.
Humanity itself points to the fact that the Creator has a Personality.
Our consciences point to the fact that there is a Creator who has established a moral code – some things are right and others are wrong.