Goodbye Milky Way Lyrics
Shall I go?
Shall I stay?
107 light years away, many times, so many doubts…
But no reason to talk about…
I’ll miss you children of the sun
But it’s time to go away, Goodbye, Goodbye Milky way!”
Only visions and the mind will guide you to the light.
I’ll miss you children of the sun
Now it’s time to go and say, Goodbye, Goodbye Milky way!”
I’ll miss you children of the sun
I’ll get born this one day,
I say Goodbye, Goodbye Milky way!”
Andromeda galaxy will collide with our Milky way,
A new gigantic cosmic world will be born…

It reflects on the end of a journey and the sense of leaving behind something that has been significant. The lyrics express a sense of uncertainty about whether to stay or to leave and the doubts that come with the decision.
"107 light years away" suggests that the journey or mission in question is one of great distance.
"Mission is over, mission is done" The journey has come to an end, and the singer is saying goodbye to those they have met along the way.
"I will miss you children of the sun" the singer says. They have formed a connection with the people they have met and are sad to be leaving them.
The lyrics also reference the idea of fate and following one's heart, and the line "In 5 billion years the Andromeda galaxy will collide with our Milky Way, A new, gigantic, cosmic world, will be born" suggests that even though this journey is ending, there is always something new and exciting to look forward to in the future.

a farewell song.. the horn instrument in the background gives a sense of sad departure...

Human departing from Earth, from the Milky Way.

This is a.... simple song.
It is imagery, words from a visitor from far off. It's his time to go, but he is reluctant. Reluctant to leave the children of the sun(Mankind). But before he leaves, he's giving one small piece of advice.

"I’ll get born this one day"
This line is actually "I go home, until someday," according to the lyrics in the booklet from A Posteriori.
Beautiful song.

My understanding of this song goes into a really esoteric concept. Going by the subject matter and some of their other songs, I think that Michael Cretu privately identifies as a Star-seed. This is a concept that seems totally schizophrenic at first glance but pay attention to what the people claiming that about themselves are actually saying and how they conduct themselves. The belief may seem improbable but it actually isn't co-morbid with mental illness, in summation, a Star-seed is a person who finds reason to believe that they incarnated here on Earth from an extraterrestrial source.
This opens the door onto a deeper interpretation of this song because Star-seeds report that the reason why they incarnated here on Earth is because they took on a mission in order to help uplift existence on this planet.
Many of them describe feeling like this could be akin to a Hard-ship mission because they are leaving a peaceful and more advanced society for the turmoil and entrenched psychosis of Earth.
Michael captured the feeling of this so perfectly that I can't imagine how he hasn't had the same kinds of feelings. The song represents the choice that all Star-seeds will face once this mission is accomplished:
Shall I go, shall I stay
Yet It's obvious that the narrator chooses to say goodbye. No reason is given why and the narrator even indicates that this is for personal reasons:
Many times, so many doubts But no reason to talk about
Many times they've wanted to leave and felt doubt but no reason to talk about it now.
I will miss you children of the Sun
There are those that will be missed that our Star-seed bonded with who will be remembered fondly. Humanity is encouraged to keep the higher insights and capabilities to heart and with that, their mind is made up, It's time to go back to the stars. It's a sorrowful goodbye but goodbye it is.

I have made arrangements for this song and others like it to be played at my funeral visitations and wake. I won't be happy to leave this world, . . . leaving my family its going to be hard, but, as consolation I think I am going to enjoy the trip outside this galaxy.