Invisible according to dictionary, means ‘Not visible’ or ‘something impossible to see.’ 
Fourteen centuries ago, Allah sent down the Qur'an to mankind as a book of guidance. He called upon people to be guided to the truth by adhering to this book. From the day of its revelation to the day of judgment, this last divine book will remain the sole guide for humanity. The matchless style of the Qur'an and the superior wisdom in it are definite evidence that it is the word of God. In addition, the Qur'an has many miraculous attributes proving that it is a revelation from God. One of these attributes is the fact that a number of scientific truths that we have only been able to uncover by the technology of the 20th century were stated in the Qur'an 1,400 years ago.
Of course the Qur'an is not a book of science. However, many scientific facts that are expressed in an extremely concise and profound manner in its aayath have only been discovered with the technology of the 20th century. These facts could not have been known at the time of the Qur'an's revelation, and this is still more proof that the Qur'an is the word of God. 
Are there really things around us that we cannot see?
There is a difference between visible light and light in general.
Here are the different types of famous rays and their existence on the wave length scale, arranged in an ascending order as per the length of waves and in a descending order as per the power range:
Its length is less than 0.1 of the nanometer, and is considered of the highest power.
Its wave length reaches up to 1 nanometer and is high in power and can penetrate lots of substances. It is commonly used in the medical field.
Its wave length reaches up to 100 nanometers and is originated from stars explosion, and the sun as well bursts huge amounts of such a ray.
The length of different waves ranges between 400 – 800 nanometers.
It length is 0.1 of the nanometer and is usually originated from hot substances and every living being. This ray is used by armies to locate targets of machineries and soldiers that emit heat. Lots of snakes use it to determine their quarries precisely.
These are used in telecommunications (specially in mobile phones), and commonly used heaters. They are used as well in guiding planes, and in determining the speed of traffic on roads.
They range between one meter to 1 km in length and are originated from stars as other rays, as well as the lightening processes in clouds, and can be received by radio sets. They are used in wireless telecommunications in general.
The Quranic miracle is thus crystallized, as Allah verily says: “I swear by that you see and by that you do not see.” Quran surah Haqqah 69:38-39
(فلا أقسم بما تبصرون ومالاتبصرون ) الحاقة (38-39).
All that we have seen so far shows us one clear fact: the Qur'an is such a book that all the news related in it has proved to be true. Facts about scientific subjects and the news given about the future, facts that no one could have known at the time, were announced in its verses. It is impossible for this information to have been known with the level of knowledge and technology of the day. It is clear that this provides clear evidence that the Qur'an is not the word of man. The Qur'an is the word of the Almighty God, the Originator of everything and the One Who encompasses everything with His knowledge. In one verse, God says on the Qur'an "If it had been from other than God, they would have found many inconsistencies in it." (Qur'an Surah 4:82) Not only are there no inconsistency in the Qur'an, but every piece of information it contains reveals the miracle of this divine book more and more each day.
What falls to man is to hold fast to this divine book revealed by God, and receive it as his one and only guide. In one of the verses, God calls out to us:
"And this is a Book We have sent down and blessed, so follow it and have fear of God so that hopefully you will gain mercy." (Qur'an Surah 6:155)
In other aayaath, Allah remarks: "Say: 'It is the truth from your Lord. Let anyone who wishes to, believe, and let anyone who wishes to, disbelieve.'" (Qur'an Surah, 18:29)