Gravitational waves can be defined as the vibration of space-time. Sky is an ocean in which the waves are stationary.

When you throw a rock into the water, when a taut rope is plucked, when a spring is compressed and then released, or when our larynx vibrates, what forms is a wave. In each case, the medium where the wave forms is different: water, air, etc. Interestingly, light waves do not need a medium to travel.  A common feature of all kinds of waves is that they have wavelengths, frequencies and amplitudes. Another important feature they have is that there needs to be a source that triggers the wave. A spring, for example, needs to be compressed to produce the wave.

Gravitational waves, on the other hand, can be defined as the vibration of space-time. These waves were predicted by Einstein in 1916 in relation to the general theory of relativity. Let us consider that all interstellar and intergalactic space is filled up with a substance similar to water. Then when, say, two black holes collide, space itself ripples like water. In fact, discussions have long continued over the existence of ether, a substance that forms the texture and essence of matter. If there are waves in space, then it is highly likely that there is ether that fills up space as well.

In a very interesting narration, the Prophet Muhammad, peace be upon him, is reported to have suggested that heavens are not a vacuum: “The sky is a wave held back” (Tirmidhi, Tafsir surah, 57/1). Bediuzzaman Said Nursi, in his interpretation of this hadith, says, “[Sky] is an ocean in which the waves are stationary” (The Gleams, Twelfth Gleam); in other words, heavens are a sea whose waves have settled, calmed and become still. The Qur’anic verse 36:40 reads “It is not for the sun to overtake the moon, nor does the night outstrip the day. All (the celestial bodies and systems) float (swim) in an orbit (determined for each).” We can infer from this verse that space is likened to a sea because floating or swimming can occur in a substance but not in a vacuum.

The discovery of gravitational waves

Gravitational waves were discovered by a team of experimental physicists on February 11, 2016, that is, exactly one hundred years after they were predicted by Einstein in 1916, and the discovery earned three physicists, Rainer Weiss, Barry C. Barish, Kip S. Thorne, the Nobel Prize in 2017. The LIGO observatory (www.ligo.caltech.edu/page/what-are-gw) used an extremely sensitive interferometer to detect the gravitational waves produced by the collision of two black holes, one having 29 times the mass of the sun and the other 36, 1.3 billion years ago. The researchers used such a precise mechanism that it (the interferometer) could measure the distance to the nearest star to an accuracy smaller than the width of a human hair.

The LIGO observatory used an extremely sensitive interferometer to detect the gravitational waves produced by the collision of two black holes, one having 29 times the mass of the sun and the other 36, 1.3 billion years ago.

The working principle of an interferometer is based on the idea of splitting a laser beam from a single source into two components and then recombining them. The split beams get to the target at the same time after diverging at a right angle and being reflected back from two mirrors. Scientifically speaking, there is not any phase difference between the two. However, if the beams are subject to an effect like gravitational waves, the waves cannot get to the target at the same time, or in scientific terms, an interference pattern is formed on the screen because of the phase difference. In the same way, the waves generated by the collision of two black holes had an impact on the movements of the perpendicular laser beams as they ran past the area that housed the interferometer built by the LIGO team and caused a time difference in their arrival at the detector. In this experiment, the effect of the gravitational waves was measured by directing laser lights through L-shaped vacuum tunnels four kilometers long. The length of the tunnels was so precisely adjusted as to measure a difference, if any, as small as a proton.

The reason why the laser interferometer was so finely tuned is that the waves generated by two colliding black holes are so infinitesimally weak that only such an experimental mechanism could capture them. In other words, the experiment had to be precise beyond the atomic scale because the gravitational waves that reached the solar system could change the distance between the sun and the earth by just the size of an atom. To reiterate, the mechanism was designed so precisely that it can detect differences between laser beams as short as ten-thousandths the size of a proton. It should be remembered that a proton is a very, very small particle in the nucleus of an atom with a diameter of 10^-15 (one-million millionth) of a millimeter.

Furthermore, the gravitational waves were discovered simultaneously by two separate interferometers, which were located at a distance of 3220 km from each other. The reason for the dual measurement tools was to ensure that the waves were indeed gravitational waves.

What has excited scientists most about the discovery of gravitational waves, besides their confirmation of Einstein’s theory, is the fact that we will be able to exploit gravitational waves in addition to light and radio waves in order to explore space. It can be foreseen that telescopes working with gravitational waves can be developed or advanced laser interferometers can be built in space and discover other gravitational waves.

Gravitational waves are generated in space all the time. Large-scale phenomena such as the collision of two black holes or the explosion of supernovae cause ripples in the sea of space. It is highly likely that systems that can detect these waves will provide us with new information about the fabric of space and thus lead to new discoveries.

The fact that gravitational waves were discovered using technological tools is an excellent example of how technology can nurture science. Moreover, this study proves that some discoveries can only be made by big teams like those in the CERN experiments.

It is postulated that the universe rippled violently during the first creation as a result of the tremendous expansion, the effects of which might still exist and should warrant new studies. It is only a matter of time that a super-sensitive mechanism could confirm the Big Bang theory. It is believed that the gravitational waves generated at the very beginning of this expansion are still present and experimental designs such as that in the LIGO are likely to discover them. The Qur’anic verse 51: 47 is considered to be referring to this expansion: “And the heaven, We have constructed it mightily; and it is surely We Who have vast power, and keep expanding it.”

It is almost certain that technological progress will lead to new discoveries that will provide us with deeper insights into the incredible composition of the universe. Bediuzzaman describes the universe as “a rosebud, wrapped in thousands a variety of veils of unity” (The Rays, Second Ray, Third Station). Every new discovery is going to show us the magnificent secrets of this rosebud.

The world may not have ended on December 21, 2012, but that does not mean it won’t end at all. So what will be the force that will disperse this robust system of ours, rendering all forces including gravity obsolete, and forcing the sun and planets out of their orbits?

The universe contains billions of heavenly systems that travel interdependently in a perfect and harmonious fashion. What could be the obvious cause or force that could disrupt this great arrangement, deorbit the stars and planets, and make every other force ineffective including gravity? If we ponder upon the verses of the Holy Qur’an, “When the sun is folded up (and darkened). And when the stars fall (losing their luster)” (At-Takwir, 81:1−2), “And when the heaven is torn away (with all the truths becoming manifest)” (At-Takwir, 81:11) with our current cosmological advances, will Black holes be the cause that will likely destroy the Sun and even devour the light of stars so that they are unable to function?

Black holes are considered to have the potential to cause a universal apocalypse. It seems plausible that with such gravitational power of Black holes, mountains would be casted away, and magma displacement via volcanic eruptions could lead to major earthquakes. There are a couple of recent geologic studies pointing out the possibility that the gravity of the sun and moon play a role in development of earthquakes. The 7-8 meter rise in seas and 35-40 cm rise in land caused by lunar and solar eclipses are considered to be a possible factor among many factors that triggers an earthquake. Earthquakes of 12-15 Richter scale magnitude can occur because of the gravitational force of Black holes. The biggest earthquake ever recorded was of 9.2 magnitude; such that if it happens again, it can lead to a major catastrophe in a very short time.

Let’s not forget that we are residing on a globe filled with fire in its center. Gases that make up the atmosphere are held only with help of planetary gravity. One of the forces that will boil all the waters away and let all the gases escape the planet could be Black hole gravitation. The air in our atmosphere and resulting “air pressure” can be destroyed by Black hole gravity. Oceans would start boiling violently and then might evaporate off the planet. In this case, living things would suffer severe structural damages since all life forms are composed mostly of water (~70%). That is why astronauts wear a special space suit filled with air made up of normal atmospheric pressure when they leave the atmosphere. We should also keep in mind that trillions of heavenly bodies (asteroids, meteors, and comets) located in the two asteroid belts (Orion and Kuiper) may be freed from their gravitational control by the vacuum impact of the Black hole, causing colossal cosmic collisions.

The disruption of gravitational balance

There is a sensitive relationship between the elements of the universe, such as electromagnetic, nuclear forces and an apocalypse may result from a disruption of these.

According to the general relativity theory, the time-space plane can be rolled or wrinkled up like a paper. The gravitational force of black holes can cause the displacement of stars which are interconnected through weak web of attractions. As if a piece of net takes a specific shape when loaded with heavy objects, the web of space-time, also known as the cosmos, could be distorted and even torn apart by black holes with their infinite mass “sitting” in it. This is a characteristic of black holes. A possible explanation for this might be that via elimination of common physical laws, the black hole region could become the gateway to metaphysical dimensions. Cosmos of space and time is described as strong-built, fracture-free in the Qur’an; “You do not see any fault or incongruity in the creation of the all Merciful. Look yet again: can you see any rifts?” (Al-Mulk, 67:3). However, in verses about the apocalypse, cosmic fractures that will occur is constantly repeated; “Day will come, land to be transformed into another, skies to be converted into others” (Ibrahim, 14:48)”On the day when the earth is changed into another earth, and the heavens (also)” (Abraham, 14:48), ”And the sky split asunder, and so, on that day it will be most frail” (Al-Haqqah, 69:16), and “The sky will cleft open thereby” (Al-Muzzammil, 73:18). We can conclude from these verses that new heavens would be created from these “fractures.”

The way that doomsday will actually take place is in the knowledge and control of Our Creator who executes these acts and maintains the order of the universe. Approaches and conclusions made with current physical and cosmic sciences will enable a better understanding of the verses related to doomsday.

The Sun rising in the West and the apocalypse

Can a comet or a planet change the direction of the earth’s rotation by colliding with it? Can the earth change direction and start to rotate from East to West instead of West to East? A catastrophic event like this may cause colossal destruction and end the lives of many organisms. As a matter of fact, a comet impact in recent years was detected to slow down the rotational speed of planet Jupiter.

Venus is a mysterious planet on many levels. For example it rotates in the opposite direction compared to other planets. Sun rises in the West on Jupiter. Dense rock and dust layers of Venusian atmosphere is theorized to be formed as a result of a collision, and because of this collision, it is thought to have started spinning in the opposite direction. A day in Venus is longer than a year. In other words Venus revolves around the Sun faster than it rotates around itself.

Bediuzzaman Said Nursi explains the sun rising in the West rather metaphorically as follows:

“While God knows best, the Qur’an, which is in effect the intellect of the earth, will disappear from its head at the end of time and, as a result, the earth will go mad. With Divine leave, it will collide with another planet and its rotation will be reversed. Through Divine Will, its journey from west to east will be reversed from east to west, and the sun will start to rise in the west. Truly, if the gravity of the Qur’an, which is the firm rope of God that binds the earth to the sun and the ground to the Divine Supreme Throne, is broken, the tether holding the earth will come unfastened. The earth will consequently become dizzy and deranged: on account of the reversal of its usual motion, the sun will rise in the west. Through its collision with another planet, Doomsday will begin at the Divine command.” (The Rays, p. 365)

Whichever way the earth comes to an end, even if the universe is not destroyed by an external destructive event, an apocalypse is foretold as something that will eventually happen with some mind-blowing descriptions in the Qur’an. What science speaks of black holes and other astrophysical possibilities in the universe seems to confirm these descriptions:

When the sun is folded up, and when the stars fall, and when the mountains are set moving. (At-Takwir, 81:1-3)
When heaven is cleft open, and when the stars fall in disorder and are scattered, and when the seas burst forth. (At-Taqwir, 81:1-3)

In this issue we discuss not the theological arguments concerning the Day of Judgment, but some scientific speculations on how it might happen. Some say global warming followed by an ice age will bring life on Earth to an end and may trigger the Apocalypse. Expounding on some Qur’anic verses, Dr. Cakmak speculates on how Divine Predestination could operate on the physical world in the folding and collection of light. He suggests, “The events depicted in the verses, by the will of the Creator, may be dependent on the gravitational power of black holes.” Dr. Polatoz argues that apocalyptic events will take place within the sphere of physical laws which will destroy the world, but these laws will not apply after a certain stage following resurrection. These arguments are certainly personal deductions and only God knows what is to come. Dr. Kurtoglu reminds us about the perfect balance established in our universe with a fascinating article on phytoplankton and the critical role these microorganisms hold in the food chain. He makes us realize the horrible destruction we cause in our beautiful world. So, now the question is: Are we preparing our own end?

The Reverend Kip Gilts’ article on “Levels of Tolerance” provides inspirational guidelines for volunteers in interfaith dialogue on how to promote understanding of others who are not like “us.” We learn from his short essay that tolerance is not a compromise, but a love-filled path of sharing the same world.

The Fountain

Defining the target

Gravitational waves are generated only by the equivalent of a rotating or oscillating system — that is, two or more masses accelerating toward or away from each other and exhibiting a quadrupole moment of inertia.

Only such quadrupole and higher multipole sources can generate gravitational waves because, whereas there are negative electric charges, there are no negative masses. A negative electric charge oscillating back and forth is the equivalent of a positive charge moving in the opposite direction, and this equivalence enhances the generation of electromagnetic waves. Since there is just one gravitational polarity, however, a mass can oscillate only with respect to a counterweight. This counterweight reacts to the oscillation and generates a gravitational disturbance that almost, but not quite, cancels the disturbance of the body.

As explained by physicist Paul Davies of Australia’s University of Adelaide, the gravitational disturbances would completely cancel out but for the time required for them to travel between the masses. It is this out-of-phase imbalance in the disturbance’s cancellation that propagates a gravitational wave. For this reason, such waves are not generated by quiescent stars, those rotating on their axis symmetrically or even exploding symmetrically, because there is no quadrupole moment. However, that situation changes if they explode asymmetrically or change their shape.

On the other hand, a typical binary star system has a quadrupole moment and should produce a slow periodic gravitational wave. A near-enough binary star system would cause a measurable distortion a little in excess of one part in 1021 on Earth.

For the wave to lie in the gravitational-wave detector’s frequency range (typically 1000 +/-1 Hz.), though, the two stars of the binary must be in the final stage of coalescing, a rare situation. For comparison, a supernova is expected to produce damped exponential impulse waveforms, each of which lasts for 1 millisecond. A collision or collapse of a binary system between two neutron stars, or between a neutron star and a black hole, would produce gravitational waves with a sliding frequency in the 1 to 1000 Hz range, as one star spirals in on its partner.

Why are we searching?

A long time ago, in the Large Magellanic Cloud-one of our Milky Way’s two companion galaxies, a star exploded. In 1987, 160,000 years later, radiation from that event finally reached Earth. The first to see the brightening star were astronomers in the southern hemisphere.

Scarcely 24 hours earlier, in other parts of the world, other types of detectors had “seen” something. At the University of Rome (Italy) and the University of Maryland at College Park (the U.S.), gravitational-wave detectors registered 12 fairly large and about 100 small pulses over a period of 2 hours. Around the same time, the Mont Blanc Neutrino Observatory (France) registered five pulses of neutrinos over a 7-second interval. Similar recordings were made by neutrino detectors in Kamioka, Japan, and Frejus, France.

Astrophysicists are still debating the significance of those observations recorded on Feb. 23 and 24. But others claim the pulses registered in Rome and Maryland may have been due to actual gravitational radiation from an identifiable source — the supernova of 1987.

Physicists find this ambiguity unsatisfactory. They want to detect the gravitational waves themselves, directly and unequivocally. Indeed, the detection of waves has been called “the most important of all tests” of Einstein’s general theory of relativity by theoretician Kip S. Thorne of the California Institute of Technology (CalTech) in Pasadena. The sensing or reception of gravitational waves also may deepen astronomers’ understanding of the dynamics of such violent events as supernovas, exploding black holes, and the interactions between black holes and neutron stars. As a bonus, whatever is learned about detecting ultra-weak signals might help engineers measuring extraordinarily small displacements or strains.

The understanding, according to Einstein’s general theory of relativity, is that all objects exist in four-dimensional space-time (that is, in a continuum having three dimensions of space and one of time). The mass of every object curves space-time, a curvature that manifests itself as the gravitational field of the mass. The greater the mass, the greater the curvature of space-time, and the greater the gravitational field.

According to the same theory, massive objects that rotate or explode asymmetrically, or oscillate, give off gravitational waves or ripples that propagate through space-time, like ripples or waves on the surface of the ocean.

Gravitational waves conform to an inverse square law relationship, just like electromagnetic waves. The force of both types of energy declines in proportion to the square of their distance from their source. But gravitational waves are so much weaker than the Coulomb electric force, which renders the detection of such weak waves a monumental challenge to instrumentation.

The evidence that gravitational waves exist is compelling, albeit indirect. The firmest evidence relies on observations made over 7 years by astronomers Joseph Taylor, of Princeton University in New Jersey, and Russell Hulse, then at the University of Massachusetts at Amherst but now also at Princeton. Their measurements of radio waves from a binary pulsar designated PSR1913+16 show that the pulsar’s 8-hour orbit around the neutron star is gradually contracting; the faster the pulsar revolves around the neutron star, the smaller its orbit gets. As the rate of decrease agrees to within 0.5 percent with predictions derived from the general theory of relativity, the finding is excellent circumstantial evidence for orbital decay being a result of energy lost by gravitational radiation. Even though the gravitational radiation itself was not detected, Taylor and Hulse shared the 1993 Nobel Prize in Physics for this work.

But what would it take to observe the weak gravitational radiation directly? Gravitational waves are generally believed to travel at the speed of light and to deform or distort an object geometrically as they pass through it. For plane-polarized gravitational waves, the two directions are at 45 degrees to each other, not perpendicular as they are for light. In other words, a passing gravitational wave distorts an object first in one direction, then (in the next half-cycle) in another, rotated at a 45-degree angle to the initial direction. It takes another half gravitational wave cycle for the wave to distort at the 90-degree angle characteristic of electro-magnetic waves in the first half-cycle.

Resonant bar detector

In principle, it should be possible to sense this distortion and its after-effects with the aid of strain detectors attached to a suitable “antenna” — a space-time seismometer, if you will. But such an antenna resembles nothing familiar to electrical engineers. In its simplest manifestation, the antenna is a large solid cylindrical bar.

The pioneering resonant-bar detector was designed in the late 1950s and built in the early 1960s by Joseph Weber, professor of physics at the University of Maryland. Weber’s design called for a mechanically isolated cylinder of solid aluminum weighing several metric tons. Piezoelectric strain transducers attached at intervals around its circumference converted the vibrations induced by any passing gravitational wave into an electric signal. Weber’s bar resonated mechanically around 1 kHz, so that it would “ring” after being distorted by an incoming damped-exponential wave, the shape expected of a gravitational wave from a supernova. Subsequently, other bar detectors were built at many institutions around the world.

The main problem with resonant-bar antennas is their insensitivity. Even the latest of them yield dimensionless strain sensitivities of about one part in 1018 (that is, only 10-18 meter distortion per meter of length), too little to detect gravitational waves from any but the nearest and most violent events.

The laser alternative

The laser interferometer owes its sensitivity in detecting gravitational waves to an arrangement of mirrors suspended on vibration-isolated pendulums. Two pairs of mirrors create two light paths perpendicular to one another. A laser beam is split and the halves sent down each path, rebounding back and forth along the leg between the mirrors hundreds of times before being recombined. The multiple passes create the very long light path required to amplify the gravitational-wave input to detectable amplitude.

In brief, if a gravitational wave passes by, the pendulums holding the mirrors are expected to move a little apart in one leg and a little together in the other leg, in each case by the same tiny fraction of the laser light wavelength. Their movement would shift the relative phase of the two halves of the laser beam, momentarily upsetting the interference patterns that would otherwise be cancelled out. At that instant, the interference pattern would brighten by an amount proportional to the strength of the gravitational wave. The job of monitoring the interference pattern for brightening is handled by electro-optic detectors, which indicate when a passing gravitational wave is detected and which recover its variation over time.

Not only are laser-interferometer detectors potentially more sensitive than resonant-bar antennas, they are also better at detecting a variety of sources because they are inherently broadband. They respond to gravitational waves having a frequency from 10 Hz to 10 kHz, versus the resonant-bar antennas’ 1-Hz bandwidth at 1 kHz.

Input from space

A third and truly exotic method of detecting gravitational waves has been proposed: monitoring the Doppler shift of the carrier frequency (or rather, the retransmission of the tracking station’s frequency) from two or more interplanetary spacecraft simultaneously. This project is known as LISA (The Laser Interferometry Space Antenna).

The technique is analogous to laser interferometry. The idea is to detect the Doppler shift in a spacecraft’s microwave frequency as the craft is jostled by a passing gravitational wave — that is, as space-time is warped in its vicinity.

Inevitably, there are obstacles to overcome. Since the effects of a passing gravitational wave are so small, the reference oscillator must be extremely stable to detect any Doppler shift. Observers must also consider variations in the pressure of the solar wind (which differs from time to time and with the changing distance of the spacecraft from Earth), in forces from the attitude control thrusters (used to occasionally correct the space-craft’s orientation), and in the refraction of Earth’s atmosphere (through which the signal must travel). Subtracting all of these variations, the interplanetary detector is expected to have a theoretical sensitivity of about one part in 1016 — corresponding to a displacement of about 0.065 mm over the shortest distance from Earth to Jupiter, and one-eighth of that over the shortest distance from Earth to Mars.

The noise problem

Noise degrades the sensitivity of any gravitational-wave receiver. The interference is mostly due to seismic activity in the earth, acoustic interference (also known as microphonics) from inhabited surroundings, and heat (thermal noise). Especially troublesome are the non-Gaussian tails of noise distribution, which produce a significant number of false detections.

When a gravitational wave passes through the cylinder and distorts its shape, the moving input coil produces minute changes in the magnetic flux. That magnetic flux change then creates a relatively large variation in the voltage across the SQUID** junctions. In turn, these variations are passed along as voltage signals to succeeding stages of amplification — generally room-temperature FET amplifiers with optimal filtering for the anticipated signals. If tuned mechanical transformers or resonators are installed between the antenna and the transducer, transfer of the gravitational wave’s pulse is maximized and amplifier noise coupling is minimized.

Conclusion

Much is being done to achieve a breakthrough in the detection of gravitational waves. A recent High Frequency Gravitational Wave conference held at MITRE Corporation featured proposals and experiment descriptions that could lead to an apparatus that uses gravitational waves for communications. Several large laser interferometer gravitational wave observatories are online and taking data while making sensitivity improvements. The reader is urged to delve further (see references below) to see why there is so much excitement about this new window on the universe.

References

– Gibbs, W. W. “Ripples in Spacetime.” Scientific American, April 2002.

– Lewis, M. “Gravitational Waves versus Electromagnetic Wave Antennas.” IEEE Antennas and Propagation Magazine 37, no. 3, June 1995. Also see http://solo3.abac.com/gwinstitute/.

– Blair, D. The Detection of Gravitational Waves. Cambridge Univ.: 1991.

– Boughn, Stephen. “Detecting Gravitational Waves,” American Scientist, no. 68. March-April 1980, 174-83. (An overview of the early work in the search for gravitational waves.)

– Will, Clifford M. Was Einstein Right? New York: Basic Books, 1986. (A readable account of the binary pulsar PSR1913+16 and its role in providing evidence for gravitational waves.)

– Blair, David G., ed. The Detection of Gravitational Radiation. England and New York: Cambridge Univ. Press, 1991. (Sums up the state of the art in gravitational-wave receivers.)

– Misner, Charles, Kip S. Thorne, and John Wheeler. Gravitation. W. H. Freeman: 1973. (Still the most used book by students and practitioners in gravitational-wave research.)

– Thorne, Kip S. Black Holes and Time Warps: Einstein’s Outrageous Legacy. New York: W. W. Norton, 1994. See chapter 10: “The Ripples of Curvature,” which summarizes plans for the Laser Interferometry Gravitational-Wave Observatory (LIGO).

– E. Amaldi et al. “Coincidences among the Maryland and Rome Gravitational Wave Detector Data and the Mont Blanc and Kamioka Neutrino Detector in the Period of SN1987A.” Annals of the New York Academy of Sciences, vol. 571, 1990, 561-76. (Proceedings of the l4th Texas Symposium of Relativistic Astrophysics). (Discusses whether or not gravitational waves were detected along with the first sightings of the 1987 supernova).

– Grishchuk, Leonid. “Update on Gravitational Wave Research. Online at Los Alamos’ website on preprints gr-qc/0305051, 13 May 2003. (Provides a more technical treatment.)

** A superconducting quantum interference device (SQUID) is a mechanism used to measure extremely weak signals, such as subtle changes in the human body’s electromagnetic energy field.

During the Renaissance, science began to develop rapidly. New discoveries about how the universe functions were termed scientific laws, even though they were actually descriptions of what had been observed. Moreover, they were believed to be the main causes. Science gradually became the ultimate explanation of existence, and caused many people to reject religion as obsolete.

All of this changed with the beginning of the twentieth century. Modern physics showed that the universe functions completely differently from what we see in daily life. The basic laws of mechanical physics, once thought to be the creator of the action, turned out to be valid only under certain approximations. The concept of absolute space-time was replaced with a relative and dynamic one. We discovered our limitations in measuring certain physical quantities, and that some particles cannot be observed directly. We recognized that physical laws are not deterministic, and thus cannot predict how a system’s state will change over time. All they can do is present possible alternatives.

Such drastic changes in our understanding forced many to reconsider science’s claim to provide the final explanation of the universe. Today, new discoveries are termed scientific theories. We know that much remains to be discovered, and are expecting more surprises. It also is becoming increasingly harder to claim that one day we will produce a complete description and resolve all mysteries.

In this article, we will illustrate some of the changes in our understanding of the universe and scientific philosophy by analyzing a simple physical event: a falling rock. Since it is an ordinary event, one may think there is nothing mysterious about it. It seems to be a completely deterministic event with no exceptions. One also may think that there is a simple reason for the rock to fall down: the attractive force between objects with mass. As we will see, however, the story turns out to be completely different.

Newton’s Law of Attraction

From experience, we know that a rock left in the air falls to the ground. We also know from astrophysical observations that the Earth circles around the sun. In these examples, the main interaction between the rock and the Earth, or between the Earth and the sun, is called gravity. Through observation, we know that gravity has an attractive nature. Let’s consider the following question, which science should be able to answer if it is the ultimate explanation: Why does a rock fall down?

A nineteenth-century physicist would reply: “A very simple question! Newton’s law of attraction. Objects with mass apply an attractive force to each other, the magnitude of which is proportional to the objects’ mass and inversely proportional to the square of the distance between the objects. Since the Earth and the rock both have mass, they are subject to this law. This is why a rock falls down.”

But this only describes a falling rock. Many who believed this claimed that there could be no change in this scenario, and especially no room for a Creator Who actually let the rock fall down. But, we ask, how do masses apply their forces to each other? Why is this force proportional to mass and inversely proportional to distance?

We do not have to pursue this argument, for we know that the so-called final explanation is incorrect. If the nineteenth-century physicist could have observed more carefully, he or she would have realized that Newton’s law of attraction could not answer all questions involving gravity. For instance, why is light, a particle without mass, deflected by gravity? Such a physicist also could not calculate correctly Mercury’s perihelion around the sun.

We now know that objects with mass do not apply attractive forces to each other. In describing gravity, Newton’s law of attraction can be used as an approximation when gravity is weak. What we see or feel as gravitational attraction is explained more accurately, but completely differently, by the theory of general relativity.

The Theory of General Relativity

What does the theory of general relativity say about a falling rock? According to it, objects with mass curve space-time, a dynamic object, in a definite manner. In this curved space-time, a free particle that is affected only by gravity moves in a geodesic path. In the space-time curved by the Earth, the geodesic path for an object with mass can be calculated through the Earth’s center. As it has mass, a rock should follow this geodesic path. Thus it moves through the Earth’s center, and we see it as falling down.

This description is radically different from the one derived from Newton’s law of attraction. Space-time is considered dynamic, rather than absolute, and is affected by matter. Also, a falling rock is in free motion and is not acted upon by any of force belonging to the Earth.

The general theory of relativity can describe many physical phenomena related to black holes, gravitational collapse, gravitational radiation, and the large-scale structure of the universe that Newton’s theory cannot. It also covers Newton’s law of attraction in a weak gravity approximation, and fits with observations made so far.

However, it has some problems. Starting from its basic principles, it can be proven that the theory cannot describe some physical phenomena properly. Equations governing the dynamics of space-time and matter allow an initial, ordinary configuration of matter to end up in a state that can no longer be analyzed by general relativity. This final state is called a singularity. A black hole’s formation by gravitational collapse is an example of this.

Thus general relativity is also an approximate description that is sensible under certain conditions. Our understanding of gravity and a falling rock is much improved when compared to the past. But this is not the end of the story.

There is another important reason why general relativity is not the final theory of gravity. Other than gravity, three known interactions occur between matter: electromagnetic, strong, and weak. These interactions can be observed in the atomic world, and are described successfully by quantum theory. The basic principles of quantum theory are very different from those of general relativity.

Quantum Theory

While general relativity is deterministic, quantum theory is indeterministic. In general relativity, a system’s state can be specified in the usual physical terms, for instance, by giving positions and velocities. In quantum theory, a system’s state is described in abstract mathematical terms by a vector in a Hilbert space, which has no a priori relation with the physical world. Furthermore, positions and velocities can no longer be known together. The formalisms of two theories are very different and contradictory.

At first, this seems to be a philosophical problem. On a large scale involving planetary distances, quantum effects are negligible and gravity dominates other interactions. But on an atomic scale, gravitational interactions are generically very weak and can be neglected when compared to other interactions. Therefore, quantum theory and general relativity seem to be complementary for a large-scale general relativity. However, quantum theory provides appropriate descriptions on an atomic scale.

Based on these ideas, one may claim that the rather deep philosophical conflict between two successful theories is, for all practical purposes, harmless and unimportant. But this is incorrect, for in some cases both gravitational and quantum effects are not negligible. For instance, a black hole may have an atomic size, which can be described properly by quantum theory. On the other hand, since black holes naturally involve strong gravitational interactions, general relativity plays a crucial role in their description. This is an important feature of black holes, one that makes them interesting objects to study.

The quantum theory of gravity describes both gravitational and quantum effects properly. Apart from the fact that there are few candidates (like string theory), we still do not know this theory’s basic principles, which should cover the principles of quantum theory and general relativity. The two main obstacles to this are that sophisticated (and as yet undeveloped) mathematics are needed to attack theoretical problems, and that direct experimentation is impossible, since such experiments involve energies that cannot be produced on Earth.

This simply means that we do not have a complete description of a rock falling, one of the simplest physical events one can imagine. On the other hand, why is a rather deeper question then describing the event. It seems that such classical deterministic theories as general relativity can answer this question if some basic principles are assumed. But these basic assumptions can be questioned, and it is hard to claim that they are immutable. As discussed earlier, the basic principles of Newton’s theory turn out to be sensible in an approximation involving weak gravity. The existence of such nonphysical states as singularities imply that a similar conclusion holds for general relativity. Therefore, even in classical deterministic theories, the question of why cannot be answered honestly.

The situation in quantum theory is completely different. In classical theories, a system’s state changes over time and in a definite manner. In quantum theory, however, only probabilities of possible changes can be calculated, and the system may change according to one of these alternatives. Furthermore, among the possible alternatives, classically forbidden ones may be present. More important, according to basic quantum theory principles, the question of why a specific alternative is chosen cannot be answered in scientific terms.

It is interesting to see the implications of quantum theory’s uncommon features for our simple example, since the unknown quantum theory of gravity should have all of these indeterministic features. According to general relativity, all rocks left free in the air fall in exactly the same manner. But this description is not completely correct, for general relativity is not the final theory of gravity.

By roughly analyzing the same event from a quantum theory point of view, one can see that, due to seemingly strange quantum effects, a rock left in the air may go up as well as down, although going up is forbidden by general relativity. This seems to conflict with daily experience, and one may wonder why we always see objects left free in the air as falling down but not up. The reason is that for macroscopic objects like rocks, quantum effects are generically very small and a system’s state changes, most probably, as classically expected. Stated differently, the ratio of rocks going up to the ones going down is incredibly small. This is why we believe that every time we let go of a rock it will fall down. However, this does not rule out exceptions.

Conclusion

In this article, we analyzed a simple event to illustrate some of the changes in our understanding of how the universe functions. Many physicists used to believe that the order around us could be explained by assuming simple physical laws. However, the more we learn about the universe, the more we encounter new principles and new surprises-and the more we recognize our ignorance. Furthermore, modern physics states that the universe does not function according to strict causality and determinism.

In light of these developments, it is clear that we should renew our understanding of physical laws and the idea that they have a role in creating the action and the order around us. Being the most fundamental natural science, this conclusion of modern physics also influences other sciences. Therefore, science should be accepted as an important tool for seeking and seeing the beauty of the created order around us, and nothing more.

References

• Hawking, S. W. and G. F. R. Ellis. The Large-Scale Structure of Space-Time. USA: Cambridge University Press, 1991.
• Wald, R. M. General Relativity. Chicago; University of Chicago Press, 1984.

Sura ‘Fussilat, which may be translated as the chapter of ‘Detailed Explanations’, is the second chapter in the Qur’an beginning with the letters ‘Haa’ and ‘Mim’ and was frequently recited by our beloved Prophet.

The eleventh verse quoted above follows a verse explaining the creation or genesis of the world. As with the other verses in the Qur’an, this verse has many profound meanings but I shall try to explain it from the point of view of geophysics.

On reading the verse several times over, we must note with care the subtle meanings which lie beyond the ordinary in the declarations of God Almighty. I would like to draw the attention of the reader to these points in what follows:

a) ‘Then He turned to the heaven which was yet but smoke.’

This expression discloses a special secret. For when God Almighty wishes something, He simply says ‘Be’ and it is. Why does the verse specifically indicate that ‘He turned to the sky’? It is drawing our attention to the fact that an important scientific insight is about to be revealed.

b) He sends out a call for cooperation to the earth and the heaven. He orders them to ‘come (and cooperate with each other) whether you like it or not. Again, in the power of God Almighty and the certainty of His commands, there can be no such thing as the insubordination of the created. The command ‘come, even if unwillingly indicates that there is difficulty in the cooperation of the earth and its heaven. Further, it is indicated that the heaven which harmonizes with the earth is the one closest to the earth.

Let us now investigate the relationship between the earth and its ‘closest heaven’ in terms of the precepts of contemporary geophysics. Until quite recently, it used to be assumed that life would originate on any planet having the proper temperature. In recent years, however, space explorations have revealed that the possession of an atmosphere is one of the most difficult things for a planet to achieve. In other words, there is a baffling opposition between a planet and its atmosphere (which might be called its ‘nearest heaven’). For the atmosphere consists of gaseous atoms in the ‘near sky’. In all large planets these atoms are assimilated to the surface of the planet, while in small planets the gravitational force is insufficient to bind the atoms. These gases then escape, leaving the planet barren.

Now let us reread the sacred verse in the light of this very brief information, and in particular the second sentence:

‘Come, both of you, (come together) willingly or unwillingly.’

The molecules and atoms in the atmosphere try to escape into space, while the earth tries to attract and captivate them. In other words, their partnership is unwilling; it is forced.

The scientific magnificence of this sacred verse consists in the fact that it is telling us this secret fourteen centuries ago. Fifty years ago no one was aware of this fact.

In order to ascertain the inner meaning of the sacred verse, let us expand our knowledge of geophysics a little further. What are the conditions for the formation of an atmosphere on a planet and so, by implication, on earth?

For the formation of an atmosphere, the motions leading to the escape of molecules have to be counterbalanced by the gravitational attraction of the earth. This is an almost impossibly difficult condition to fulfil. For all planets throughout the universe, the odds may be less than a billion to one. This is the fact that the chapter ‘Detailed Explanations’ expresses.

‘And then He turned to the heaven.’

This statement contains the secret of how God Almighty renders all things possible. From the standpoint of geophysics, these extremely difficult conditions require the preservation of three important balances:

1. Atmospheric temperature,

2. Proportionate gravitational attraction on the part of the earth,

3. The non-violation of this balance by various radiant energies arriving from space.

1. Atmospheric Heat

The ability of molecules to escape is dependent on heat. Environmental heat should obey the following characteristics:

a) The distance of the earth to the sun. If the earth were closer to the sun, the heat produced in the environment of the atmosphere would cause all the molecules to ‘boil off and escape. On the other hand, if the earth were farther away from the sun, the molecular movements would slow down, the molecules would condense and be assimilated by the earth.

b) The heat the earth receives from the sun must be evenly distributed over the earth’s atmosphere. For this the earth has to rotate on its axis with a definite velocity. If it rotated too slowly, sudden cooling would be absorbed by the surface in that region. If it were to rotate too fast, the various regions would not get the chance to be heated evenly.

The earth, therefore, must rotate at its present speed. However, this balanced rotation is likewise insufficient to dispose of the question of heating. For next the equator of the earth, which receives a larger portion of the sun’s energy, begins to heat up, while the Poles cool even further leading to the condensation and absorption of the atmosphere at the Poles. So the axis of the earth must remain tilted, balancing the heated regions by continually interchanging them. This is why the axis of the earth is slanted 23.5 degrees.

The declaration ‘They both responded, we come willingly’ at the end of the sacred verse gives expression to this inner meaning, God’s order, ‘come, (cooperate, come together)’ points simultaneously to the automatic inclination of the earth and its possession of a moderate rotation. For the earth, too, takes the appropriate physical measures demanded of it by the command.

c) The earth has to retain the heat it gains, to store it for a certain period. In other words, the earth needs a ‘blanket’. This blanket is provided by the gaseous carbon dioxide in the air. But before the atmosphere had formed, where was the carbon dioxide to regulate the heating process? We know from geophysics that the initial atmosphere of the earth was composed primarily of carbon dioxide.

The sacred verse reveals this secret as well. What does ‘which was yet but smoke (dukhan) mean?’ It is known that in its initial period, the earth possessed an atmosphere consisting mostly of smoke (carbon dioxide). It was thanks to this primordial gas that the earth retained its heat and was able to form the atmosphere of today.

2. The Properly Proportioned Gravitation Of The Earth

Modern physics defines terrestrial gravitation as follows: The sum of the active gravitational forces of the atoms comprising the earth. This means that if the escape of the atmosphere is to be prevented by gravitation and its absorption avoided, the earth gas is to possess a definite volume and density. It can easily be seen that when the earth possesses a specific density and volume, the atmosphere can be constituted without difficulty. Unbelievable subtleties, however, underlie this event. We may list these as follows:

a) The earth has to contain certain materials in a definite proportion. It has to have sufficient metals in reserve to support the existence of life and civilization, and gas to comprise large amounts of non-metals. This means that the density of the earth is not a crude but rather a very difficult calculation, involving the simultaneous consideration of many essentials.

b) The gravitational balance of the earth has to be constituted in such a way that while the atmospheric molecules are being balanced physically, they must also be chemically inert. The surface of the earth’s crust, the soil, the mountains and oceans should not have a structure that would react with the atmospheric gases, which is equivalent to saying that it should not be absorptive of the atmosphere. For instance, if the earth, or more specifically the earth’s crust were made of carbon, it would both exhaust the oxygen through chemical reactions and would absorb the nitrogen, whereas in fact the earth’s crust is comprised of silicon compounds with structures that leave them inert when brought into contact with the inner shell of the atmosphere.

c) Two other significant points regarding the earth‘s gravity relate to mailers of physical structure. Firstly, within the material density of the earth, the balanced distribution of magnetic materials such as iron has to be achieved. Further, the molten core at the centre of the earth and the semimolten metals surrounding it must maintain equilibrium with the earth’s crust.

We thus see that the gravitational balance of the earth requires many calculations; calculations of such magnitude and finesse that they could only be evaluated by the vast program of a giant computer.

3. Immolability Of Atmospheric Equilibrium By Various Radiant Energies In Space

No matter how harmonized it may be, there is such a torrential rain of particles from space that can always after the atmospheric equilibrium. It imparts violent velocities to molecules, yet an equilibrium is upheld through the presence of:

a) A magnetic field (the ‘magnetosphere’) which surrounds the earth, with a diameter equal to a hundred earth diameters. This field acts as a vast screen towards all particles and energies coming from space. This insight will be explained in detail in the interpretation of a separate verse.

b) Black holes are thought to be located at various distances to the earth. All excess energies emitted from within the Milky Way galaxy are absorbed by these centres of intense gravitation.

c) Further, the atmosphere protects itself within its own structure from the upper regions towards the lower. The filtering of particles in this protective screen is performed by the ozone layer. Isotopes of nitrogen also contribute to this protection.

It will ready be conceded that there are many things about the atmosphere that we don’t yet know. What is important is that science discovers and bears witness to a fresh miracle of our great Creator each new day.

Such are the facts we find when we set out by interpretation the word ‘heaven’ in Verse 11 as the sky of the earth in Verse 12.

It is also possible to take the word ‘heaven’ in a general sense, and to approach its interpretation from a different angle. It is known that the Glorious Qur’an declares the existence of seven different heavens. We know very little about the spatial physics of these heavens; at present, we know nothing whatsoever about the dimensions and spaces involved.

As for the man characteristics of the atmosphere, the escape velocity for any object or molecule is 11.3 kilometres per second. Normal atmospheric conditions are balanced with care as outlined above, so that atmospheric molecules cannot attain this speed.

According to Prof. De Lymak Spitser, the earth absorbs part of the atmosphere it requires, especially nitrogen. The active and violent nature of the oxygen in the atmosphere is counterbalanced by nitrogen. Furthermore, the gases we call ‘noble gases’ (helium, argon, neon, krypton, xenon, radon), which prevent the combination of nitrogen and oxygen in the course of time and particularly during lightning strokes, are also present in the atmosphere in trace but optimal amounts. The atmosphere always maintains its nitrogen/oxygen balance in the proportion 5/1.

All these magnificent geophysical systems find their origin in the secrets revealed to us in this verse by God. If we now re-read the verse in the light of all these scientific facts, we are in a much better position to appreciate what a wonderful marvel of science it embodies.