Allah created Earth so it can be a temporary home for us. However he has also created other planets such as Saturn and Mars. What are the purpose of these? Why did Allah create these extra planets?
In many different verses of the Quran, we are urged to look at the world around us and to think about its creation. Basically, the existence of other planets allow us to understand certain names of God, such as the All-Powerful (القادر) and the All-Knowing (العالم). So these extra planets give us an opportunity to think and understand the names and attributes of God. For example:
اللَّـهُ الَّذِي خَلَقَ سَبْعَ سَمَاوَاتٍ وَمِنَ الْأَرْضِ مِثْلَهُنَّ يَتَنَزَّلُ الْأَمْرُ بَيْنَهُنَّ لِتَعْلَمُوا أَنَّ اللَّـهَ عَلَىٰ كُلِّ شَيْءٍ قَدِيرٌ وَأَنَّ اللَّـهَ قَدْ أَحَاطَ بِكُلِّ شَيْءٍ عِلْمًا
It is God who created the seven heavens and the same number of earths. His commandment descends among them, so that you may know that God has power over all things; and that He encompasses all things with His knowledge. [65:12]
That being said, it is also crucial to realize that humans are not the only conscious beings in this world. God also creates angels and commands them to worship Him. Some angels may see some planets which humans cannot. If you are looking for an in-depth explanation, this is discussed in the following tafseer (The Risale-i Nur collection written by the Sunni-Shaf’ii scholar Bediuzzaman Said Nursi) of the verse,
وَلَقَدْ زَيَّنَّا السَّمَاۤءَ الدُّنْياَ بِمَصَابِيحَ وَجَعَلْناَهَا رُجوُماً لِلشَّياَطِينِ
And We have adorned the lowest heaven with lamps, and We have made them missiles to drive away the evil ones. (67:5)
You may read the tafseer from here
Since not a clear explanation is given in Qur'an explaining things specifically as to why did Allah create other planets, but the reason is given as why did he create things on earth other than humans, thereby applicable and hence helpful to answer as to why there are other planets too.
And the earth, We have made it plain and cast in it mountains and We have made to grow therein of all beautiful kinds,
To give sight and as a reminder to every servant who turns frequently (to Allah). (Qur'an 50:7-8)
The reason is to remind ourselves of Allah, the Almighty, who created everything so that we may praise him and thank him by looking & understanding & admiring his creations as "How awesome they are!".
May the creator guide us all.
Maybe there is a reason to why Allah created other planets for us but scientists haven't discovered it yet. Remember how people believed that the Earth is flat?
Maybe we are going to know why he made other planets, we just need the right concept and explanation or better technology to prove the reason why we need other planets around the Earth.
Earth is created just like a baby in a mother's womb. Allah can surely make a baby outside of a womb, but rather every baby progress a certain time in the womb. These rules of developing is made by Allah. Allah wanted as this way, so did it.
In order to make a baby, womb itself doesn't enough. It needs a body, a hearth for blood, a stomach for food, a mouth for water etc. Even the body itself doesn't enough. It needs fruits, vegetables, animals, water, air etc in order to live. Just like it, Earth has been in a process, like universe. In order to make the today's universe, Allah put some physical laws and thus with these rules, Earth was able to exist. Beyond the planets in our solar system, Earth needs far away stars in order to be exist in this system. There is a good sentence explaining this: "To make a flower is to make a spring, to make a spring is to make a universe.".
Allah didn't created mankind at the beginning of the universe, rather we are created billions of years after that. Why? Same reason. Earth wasn't ready at that time. We couldn't live on a early Earth.
My point is, in this system, in order to make Earth exist, this whole universe has to be exist. Allah could have made a different system, a more quick one, but did this one.
There is an issue called Fine Tuning. Please search a little about it, and then you will understand what I mean.
I have read it somewhere, that Quran the holy book isnt a book whose purpose is to give scientific clearances bt rather its a book to guide human through righteous path. People often ask, "what does quran say abt an universal phenomenon?", but the actually the fact is Quran isnt given to us as a book of science but rather given As the words of Allah the Almighty to us. So, it will be a foolish thing to search everything of the universe in a book whose sole purpose was for the human and not for the science.
All other celestial bodies are also creations of God. There are the means through which one can understand the power of God and return to Allah. These all are the signs from God for those who think.Allah has repeatedly asked in Qur'an
"are you not thinking?".
Chapter No:88,Verse No-17-20:" Do they not look at the camels ,
how they are created?.
And at the skies ,how they are raised?.
And at the mountains ,
how they are rooted(and fixed firm)?
And at the earth,how it is outspread?" .
By exploring the truth of stars and other creations one can certainly reach to God.
The planets are like brothers to EARTH.This make system on concept based.Take an example of Jupiter which stops very big ASTEROIDS to fall on earth.I guess other planets also help to equi-balance the condition to sustain life on earth with keeping chemicals in control which can cause damage to ozone or other layers on earth.Mars help to control magnetic field of earth.Moon was SUN as per Hadith and Allaah had made night so it got dull.Prophet S.A.W.S said there was a planet in the West which is 40years of speed of SUN,the light on it is because of light on that earth itself.There exists creature which havent done sin with the blink of eyes..... they dont know human,he replied.In my guess,this planet is ROGUE planet,the astronomers just discovered and have creatures.There might possibility of other creatures also exists on planet or moon within our solar system and we are unable to see or recognize them.Be remember,God, the Almighty Allaah,hasnt created things for just.We never put BULB in jungle or not needed place, so He hasnt created stars(suns),planet,moons etc... for just.In old sky scriptures,it is written that on the time of judgement day the GOD,Allaah rabbulizzat will call all the stars with there NAME,like SUN with the name of SHAMS - The rest is ALLAAH knows all.
We simply just leave it to Allah, we have no right to question something Allah did not reveal any information for, that would be simply going against Allah if we do so, only Allah knows and He wills we do not need to know why other planets are created. Remember there was only Allah from the very beginning and Allah will be the last after everything. Just to humor you and may Allah Azza Wa Jal (SWT) forgive me if anything I say is wrong, for I do not know anything unless it is revealed to me by the Almighty Allah (SWT). Perhaps Allah has other creations in mind after ours, do not forget the creation of the jinns, and the people of Aad who have lived before us, the jinns are still living after all. Allah may use the other planet as resources after the destruction of Earth on qiyamat, but of course Allah has infinite resources. After all after our death, there are only two abodes and that is jannah and jahannam, may Allah grant us jannah, we do not have any need to know further. Allah knows best.
I have answer of the question but hope u will understand the answer nd think about it seriously with faith nd believe. ALLAH SWT created other planets bcz He knows better than humen nd better than all...if u learn QURAAN with faith nd believe thn u will see lots of verses mentioned in QURAAN for other living being like Humen for exmple...QURAAN said about Jin,farishte(angels),Shaitan(satan) etc nd the jin are also Makhlook(creature) of ALLAH SWT...so may be other planet are place for them nd they live in other planet bt we can't see them in eyes without ALLAH SWT gives us the knowledge to see them nd feel them bt we Muslim believe of all unseen creature of ALLAH SWT bcz i believe in Prophet nd no one knows better thn world otherthan prophet MOHAMMAD SAWW nd we Muslim also believe in miracle of Prophet MOHAMMAD SAWW nd others Prophet PBUH like Adam Noha Abraham David Jesus Moses PBUH...nd there r many other reason for creation of other planet like balanced the earth,moon,son for our important living life etc...nd ALLAH SWT nd his prophet MOHAMMAD PBUH nd family of Prophet MOHAMMAD PBUH knows better thn me and all of humen being...hope ths is the answer of ur question