In the Name of Allah the Most Gracious, the Most Merciful

Praise be to Allah, The Lord (The One and Only) of the worlds. Blessings and peace be upon our master, Prophet Muhammad, the Truthful and the Faithful. O Allah we have no knowledge except what You have taught us, You are the Omniscient and the All-Wise. Teach us what is beneficial for us, let us benefit from it and increase our knowledge. Show us the truth and help us follow it, and show us the untruth and help us avoid it. Let us be among those who listen and follow the best of what is said. Admit us by Your Mercy among Your righteous slaves.
Lead us out from the depths of darkness and illusion unto the lights of erudition and knowledge, and from the muddy shallows of lusts unto the heavens of Your Vicinity.

The sun, the moon, and every celestial body have their own orbits:

Dear brothers, there is an Ayah in Surat Ya-Sin which indicates a universal sign, Allah says:

(It is not for the sun to overtake the moon, nor does the night outstrip the day. They all float, each in an orbit)

[Ya-Sin, 40]

Apparently, this Ayah indicates that there is a specific orbit for the sun and another one for the moon, in a way that they can’t intersect with each other, nor can the sun run into the moon, rather, each one of them floats in its orbit. This fact is verified in the following Ayah:

(Verily! Allah grasps the heavens and the earth lest they move away from their places, and if they were to move away from their places, there is not one that could grasp them after Him. Truly, He is Ever Most Forbearing, Oft-Forgiving.)

[Fatir, 41]

The phrase “lest they move away from their places” means lest they depart from their orbits and the word in Arabic is “Tazool”, and “Zawal” is the Arabic word for “midday time”, which means when the sun starts to incline from the middle of the sky. Hence, the Ayah means that every planet in the universe has an orbit in which it roams. Some people said that this aya:

(By the sky (having rain clouds) which gives rain, again and again.)

[At-Tariq, 11]

Has the most subtle description of the universe, namely, every planet, star, or celestial body has an orbit in which it roams, then it gets back to its first position after a while.

Is it possible that comet Halley departs from its own orbit?

According to scientists, the Halley comet, which is spotted by people on daily basis, has roamed onto its orbit since Allah created heavens and earth, and it never departed from it, not even by one inch. Its closest point from the earth is 300 million Kilometers, its tail is more than 93 million Kilometers, and people always are frightened of the fact that it might keep moving straight forward and hit the earth.
However, the following noble Ayah indicates something else:

(Verily! Allah grasps the heavens and the earth lest they move away from their places)

[Fatir, 41]

It means, this comet has stayed its orbit for millions of years. The same is true for the earth, the sun and the moon, and this is a sign itself. Allah says:

(It is not for the sun to overtake the moon, nor does the night outstrip the day. They all float, each in an orbit)

[Ya-Sin, 40]

Do celestial bodies randomly pass by one another?

Each planet has its own orbit which never expands, decreases, accelerates, or decelerates.
Hence, It is not for the sun to overtake the moon, nor does the night outstrip the day, which means, the sun will never run into the moon, not to mention that the earth constantly revolves around itself in a way that night’s length never changes, to the extent that we are able to set up calendars accurately for a hundred years to come.
For example, we can say, on day 17 of April the sun will rise exactly at 6:02 A.M. What does this mean? It means that the night never outstrips the day.
Therefore, the earth constantly revolves around its axis and around the sun as well, and this is the meaning of “They all float each in an orbit”. Moreover, scientists have been stunned in respect of the following Ayah:

(It is not for the sun to overtake the moon, nor does the night outstrip the day. They all float, each in an orbit.)

[Ya-Sin, 40]

To what does the word “each” refer to? It refers to everything Allah the Almighty created. This pulpit I am standing on is noting but atoms, neutrons, and electrons which revolve each around its axis. Moreover, the atom resembles the pattern of the Galaxy’s system.

The same applies for any piece of metal or anything you see, as they are all constructed of molecules which are nothing but atoms, and the atom is a nuclear and electrons with orbits roaming around it in constant speeds. Hence this Ayah indicates the atom:

(It is not for the sun to overtake the moon, nor does the night outstrip the day)