Seven layered Sky & Aurora , the one of the natural wonders, Engineer Mir Akter Hussain
The atmosphere has been divided into five layers according to temperature & density. The temperature & densities varies with distance from Earth. The layers of atmosphere have been described by following names having following ranges. Troposphere (0-10 km), Stratosphere (10 -30 Km), Mesosphere (30 – 50 Km ), Thermosphere (50 -400 Km), Exosphere more than 400 Km .
Functions of Troposphere
This is the lowest layer of atmosphere. Most of the clouds & weather are found here. Temperature decreases with the increase of altitude in this layer. Troposphere is thinner at pole & thicker at equator.
Functions of Stratosphere
In this layer the Ozone gas exist, which absorb most of the harmful UV light radiation from Sun. The temperature increases with the increase of height in this layer . Jet aircraft fly in this zone.
Functions of Mesosphere
Temperature decreases with the increase of altitude in this zone. Meteors are burnt out here.
Function of Thermosphere.
Astronauts orbiting Earth in space station or space shuttle spend their time in this layer . This layer is very sensitive to Sun’s activity . Thermosphere performs several important functions such as temperature regulation & filtering powerful X rays & ultra violet radiation emitted by Sun. It has unique ability to expand & absorb heat. When the temperature raises more than 1500⁰ C, it creates aurora that lights up night sky. Aurora reflected in north pole is known as Aurora Borealis & Aurora reflected in south pole is known as Aurora Australis. Aurora is generated by light wave created by collision of electrically charged particles transmitted from sun that enters into earth’s atmosphere when it strikes nitrogen & oxygen atoms. The intensity of ions & charged particles is maximum in the magnetic field of polar regions as the density of charged particles is extremely high due to very high concentration of ions & charged particles along the converging lines of magnetic field of polar regions. It creates different patterns of light wave having colours red, green, yellow, blue, violets etc. In northern hemisphere Aurora can be seen from Alaska (Fairbanks ), Canada (Yellowknife), Sweden , Finland etc, & in southern hemisphere from Queenstown ( New Zealand ) , Tasmania, Victoria of Australia.
Function of Exosphere.
It is basically a boundary between Earth & outer space . Just underneath the exosphere is the thermosphere which shrinks & expands according to how much ultra violet radiation is coming through exosphere . There is a region in exosphere called the geocorona . This is where the Sun’s radiation exerts pressure on Hydrogen atom, scatter Ultra violet radiation & glow as a result. This is a sign that the exosphere has an important role in absorbing radiation & protecting the layers underneath. If the radiation were allowed to transmit through exosphere , it may be harmful to the layers underneath .
In addition to above five layers , on the top there are two more layers known as ionosphere which is composed by ions, & on the top of ionosphere there exists another layer known as magnetosphere which is composed by charged particles transmitted by Sun. The behaviour of Ionosphere & magnetosphere is controlled by magnetic field of Earth & Sun .
Function of Ionosphere
Ultraviolet radiation from Sun collides with atoms in this region causing loss of electrons. This creates ions or atoms with missing electrons . This layer is used for radio communication.
Function of magnetosphere
Magnetosphere deflects the harmful charge particles transmitted by Sun towards the polar regions of Earth. Earth’s magnetic field created by liquid outer core and solid inner core together with Sun’s magnetic field plays very important role to control the characteristics of magnetosphere.
In 1900 A.D French scientist discovered the existence of the second layer known as stratosphere which means most probably before 19th century divisions of atmosphere by layers was not known to human being. The temperature, density etc of atmosphere can be known by sending, thermometer, hydrometer etc, in weather balloon, helicopter or airplane, satellite etc at a height of more than 10 km & these facilities were not available before 19th century.
The existence of seven layers on the top of inhabitant of earth has been mentioned in the following verse of Holy Quran in 600 -700 A.D .
Sura Naba 78 /12 We have built (Arabic-Banaina) above you (Arabic- Faokakum) seven (Arabic-Shaba) firmaments (Shidada) .
Some of religious scholars mention verse Sura Talaq 65/ 12 or similar verse like this verse where Arabic word shamawati (Heavenly bodies) has been used to describe seven layered sky which is not correct.
Sura Talaq 65/12 It is GOD Who has created Seven Heavenly bodies (Shaba shamawati) & similar like earth. This verse & other verses like this where shamawati has been used, that does not describe seven layered sky according to following verses .
Sura Rad 13/2 It is GOD Who has built Heavenly bodies (Shamawati) without pillar or any support. This means shamawati is not a gaseous layer but a solid body.
Sura Maryam 19/90 “The heavenly bodies (Shamawatiu) is ready to burst & earth break asunder” which again describe “Shamawati “ is some form of Heavenly bodies made of solid , liquid, gas etc, but is not an aerobic sky.
Sura Shura 42/29 Among His Signs is the creation of Heavenly Bodies ( Arabic-Shamawati) & the living creatures(Arabic-Dabbatins ) He has scattered through them, and He has power to gather them together when He wills.
In the above verse 42/29 it has been mentioned that the “Dabbatin “ the living creaturs exist on “Shamawati “ (Heavenly bodies ) & this “Dabbatin” or living creatures are crawling , having two legs, four legs etc, according to following verse.
Sura Nur 24/45 And ALLAH has created every “Dabbatin “ living creatures from water, some of them creeping on bellies, some of them walk on two legs , some of them walk on four legs . ALLAH creates what He wills , for verily ALLAH has power over all things .
So the verse 42/29 & verse 24/45 together clearly describes that Shamawati is not any gaseous layer or any aerobic sky but Heavenly bodies composed of solid, liquid & gas where “Dabbatin” or living creatures having two legs, four legs & crawling exist.
So sura 65/12 & some other similar verses like this clearly announce that there are in total seven inhabitable heavenly bodies / planets outside this Solar system that belongs to seven different Stars where living creatures like Human being or more developed or less developed together with other living creatures exist . The last part of sura 42/29 mentions that “ He has the power to gather them together, when he wills “ means these living creatures are separated by such a vast or enormous distance (Inter Star distance) that they cannot be united by their own desire, but can be united only when GOD allows them to unite .