When you see Mars, planets, galaxy in your dream or vision, it tells about passion and ambition the future, daydreaming, fantasy and wanting to be progressive. Another explanation is that planets and the galaxy face challenges and expect too much from yourself.
Yet another explanation is that you are allowed to look further (going off the beaten track) outside yourself; different from what you have done so far. Think and live out of the box. See it through the eyes of a child, judge and judge the situation you are in and / or the situation you are dealing with from a completely different vision.
A spiritual explanation is the connection with the higher, dimensions, other life forms, god, angels and / or that with which you are connected. Another spiritual explanation is that there may be hypersensitivity to, for example, the positions of the moon, planets, stars and / or interest in it (including extraterrestrial, astronomy, astrology, etc.). Another explanation is that stars represent the connection with the deceased loved ones and / or souls who have passed on to the afterlife and / or with whom you are connected.
Each planet has a special personal message and influence on your dream or vision with which you can get started; also the constellations and so on this is very personal and often you can find the answers yourself and / or through astronomy.