The Gravitational Waves – Q&A

The spectacular discovery of gravitational waves has stimulated the curious minds to pose thought provoking queries regarding the detection and other related phenomenon. I have answered a few interesting queries, here are the details as follows, barring the first few, rest of the questions are randomly arranged. 

What are gravitational waves?
Gravitational Waves are the ripples produced in the curvature of spacetime. It was predicted by Albert Einstein with the help of his theory of general relativity in 1916.
When two massive black holes collided and merged in one, the ripples produced in spacetime, propagated as waves, reached earth and detected by LIGO (Laser Interferometer Gravitational-Wave Observatory) on September 14th, after a careful study of the data collected, the detection of the g-waves announced on 12th Feb.

When were the first signs of gravitational waves seen?
Albert Einstein first predicted the existence of gravitational waves in 1916 through his general theory of relativity, which states that, a number of incredibly powerful cosmic collisions across the universe will generate measurable ripples in the curvature of space-time known as gravitational waves.

For the detection of the Gravitational waves the construction of LIGO started in the mid-nineties. LIGO started searching the skies for gravitational waves in 2002, and from 2002 to 2010, nothing could be materialized. The engineers upgraded the LIGO to make it ten times more sensitive to gravitational waves. As a result, the g-waves detected on 14th September 2015 and after checking and rechecking the collected data the colossal announcement of the gravitational waves detection was made on 12th Feb 2016.

Earlier, attempts were made to confirm Einstein’s predictions. The most noticeable attempt was that of Hulse-Taylor. In 1974 Russell Hulse and Joseph Taylor discovered the signal of a pulsar using the Arecibo radio telescope which believed to be a solid evidence of a binary system actually emitting gravitational waves.

Would we see gravitational waves if the source was as close as our sun?
If you mean gravitational waves of that sort, it is not possible. Finding black holes of that size and witnessing there collision in our galaxy is impossible. You know the combined size of two black holes collided was more than the mass of 65 suns, having such giant black holes in our solar system is not possible hence the possibility of seeing g-waves is ruled out.

Why are gravitational waves hard to detect?
Since the gravitational waves are the resultant of two massive black holes collision and merger, and the phenomenon doesn’t happen in a nearby space that’s why it is hard to detect. Since the sensitivity of LIGO is going to be increased by almost 1000 times in the years to come, we can expect comparatively an easy detection of the waves in near future.

Can deja vu be explained using the multiverse theory?
Multiverse (meta universe / more than one universe) is a hypothetical set of finite and infinite universes including our own. The multiverse theory explains many propositions for the existence of Meta universes. Till now no definite reasons have been explained as to how a mechanism could be involved to strengthen the fact of existing parallel universes. So it is difficult to say anything with definiteness about the explanation of deju vu (feelings of already seen) with the help of this theory.

You may argue on the bases of some hypothetical queries, it would be interesting but when we talk of the celestial bodies containing universe, mere hypothesis doesn’t work. Moreover the assumption itself appears to be quite far from being realistic that the universes will intersect.

What would be the minimum energy needed to produce a gravitational wave from 4 light years away and destabilize the Earth’s orbit?
It’s a thought based query doesn’t help answer in a way that may convince you. So with this in view please understand in our Milky Way galaxy and in and around earth’s orbit having giant black holes equal to masses of hundreds of suns is impossible. So there is no point in the discussion of minimum or max energy levels.
Try to understand the phenomenon involved in the detection of gravitational waves, it will help you understand that the solar system doesn’t have even a feeble chance of getting disturbed as a result of collision and merger of black holes.

What could be the largest strange things that can be brought by a gravitational wave?
I am not sure of what the gravitational waves can bring from the space, but one thing is sure, if they are huge enough, which is impossible though, then the humans surroundings the area would be strange species to look at. 😊

Does anything with gravity produce gravitational waves?
The recent detection of the gravitational waves made it clear that it was a resultant effect of a collision and merger of two galactic black holes as deep as 1.3 billion light years away from us.

Again, the discovery makes it clear that the sound of the waves was very feeble and heard for a tiniest part of a second. So if the collision and merger of two supermassive black holes takes place then obviously the detection will be noticeably bigger than the present one.

Does wave escape from black hole?
Black holes are the darkest spot in the universe. Because of there enormous power and space-bending gravity, anything that falls into them instantly ripped apart and dissolved. Black holes are invisible because nothing can escape them. However for a particle to escape a black hole, a quantum fluctuation must occur near a black hole’s edge, when this happens one or the other particle may tunnel out before the elimination takes place.

For this dramatic separation to happen the particle produced in the quantum fluctuations must have larger wavelengths. Quantum mechanically speaking it’s a very feeble possibility though.

Since gravitational waves have now been discovered can we manipulate gravity?
The collision and merger of two galactic back holes resulting in detection of gravitational waves was a remarkable discovery of this century. Since the cataclysmic event took place very far, 1.3 billion light years, so even slightest of chances of manipulating the gravity is ruled out.

Since for the collision of giant black holes we need an outer space, not possible within the precincts of our Milky Way galaxy, so chances of manipulating the gravity even in future too appear quite remote.

Conversation based on the queries posed:

Until recently gravity has been described as a kind of illusion due to the interaction between space/time and matter. Correct? The recent discussions about gravity waves now suggest such waves are like the electromagnetic spectrum because they transmit something (gravity itself). Correct? So in other words gravity is not just the mix of space/time and matter but something like radio waves that transmit gravity. Does this mean we could have a gravity device that could fire gravity waves?  

You have raised some important points here, would like to deal with some specifications.

Gravity an illusion?
The gravity is neither illusion nor materialistic, it is just a force that exists between any two objects. If you want to disprove gravity is an illusion? Pick up a small boulder, keep it above your foot and let it go. If it floats in the middle, gravity does not exist. If it falls down you have a proof that gravity exists. If you are not sure repeat the experiment. 😊

In reality, we understand gravity on big scale. What we don’t understand is how gravity functions on very small scale. That’s why Quantum Theory struggles with gravity. For more details please refer:
**  Newton’s theory of “Universal Gravitation”
** General relativity.

G-Waves & Electromagnetic Spectrum:
Gravitational waves are to mass what electromagnetic waves are to electric charge. At fundamental level once it was emphasized that both are quite similar. But on a practical level gravitational and electromagnetic waves are quite different. You need to understand the differences between the two. We see and use electromagnetic waves every day, while we have just detected the gravitational waves.
There are two principle differences between gravity and electromagnetism, each with its own set of consequences for the nature and content of its radiation. Gravity is a weak force, but has only one sign of charge. Whereas
Electromagnetism is much stronger, but comes in two opposing signs of charge. Gravitational charge is equivalent to inertia, while the Electromagnetic charge is unrelated to inertia.

As a source of emission, the ‘gravity waves’, which can be viewed as consisting of coherent states of many gravitons, are not similar to electromagnetic waves, which can be viewed consisting of coherent states of many photons, because photons and gravitons are fundamentally different.

Gravity Device, Gravity Waves & Radio Waves:
Any accelerating mass will emit gravitational waves in the same way as an accelerating charged particle emits electromagnetic radiation. These gravitational waves are similar to light and radio waves in many respects and carry energy from their sources.
Radio waves are easy to detect and observe and our radio and TV antennas perform the same all the time. The reason being, radio waves interact very strongly with charged particles, namely free electrons in the antenna. Unlike radio waves, gravitational waves interact with all forms of matter, both charged and neutral, but their interaction is far weaker than radio waves.

It’s not my idea that gravity is a “kind of” illusion as I’m only repeating what some prominent scientists have said, it is interesting what you say: that gravitons are similar too but different from say photons or other electromagnetic radiations. What does it mean their “charge is inertia”? For reasons of clarification: can a machine be built to emanate gravitons and/or gravity waves?                                        

Yeah I know, gravity is an illusion, is not your idea, I just explained in a lighter note. Please excuse, now look at the explanation:

Gravitational charge is inertia:
Albert Einstein’s theory of general relativity is based on the principle of the equivalence of gravitation and inertia. This means that it is impossible to differentiate through any local measurement whether one is in a gravitational field or being accelerated. Therefore it is mentioned like that.

Gravitons, photons & EM Radiations:
Photon is the name given to a quantum of light or other electromagnetic radiation. The photon is the exchange particle responsible for the electromagnetic force.
The graviton is the exchange particle for the gravity force. Although it has not been directly observed, a number of its properties can be implied from the nature of the force. Since gravity is an inverse square force of an infinite range, it can be implied that the rest mass of the graviton is zero. The current experiments LIGO and VIRGO seek to detect gravitational waves, would be regarded as coherent collections of gravitons. This provides an answer to your query about building up of a machine for gravitons also.

How can inertia be a “charge”? Normally we associate a charge with electricity or power flow. Also the other part: so it’s theoretically possible to build a machine that emits “charged” graviton particles, just yes or no please.                                         

That’s true; generally the inertia can’t be a charge. It is referred to that particular theory which is based on the equivalence of gravitation and inertia. As far the machine, till now barring the LIGO experiment we don’t have sufficient stuff to claim, so as off now its No, we need to wait for some more time.


© Muhammad Abdullah Javed – March 2016


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