Month of March

On 14^th March 2016, I delivered a talk on Gravitational waves at Christian College, Chengganur. The topic was well received by the students and their interest in knowing the present research updates in gravitational waves need special mention. Students were well disciplined and interacted with their teachers in such a way that they never seemed to be lost in outlook. I would like to congratulate the faculty members who take effort to maintain discipline as well as friendly in nature towards every endeavor in their student’s life. Attaching some interesting facts about Gravitational waves for blog readers…

Gravitation Waves-A Window to Universe

Gravitational wave is the most important prediction made by Albert Einstein during his last years of research in General Relativity. It seemed to be impossible to detect these waves and even Einstein believed that it is not conceivable. Researchers couldn’t stop themselves from pursuit of finding Gravitational waves since Einstein is considered to be the most influential person of this century. Time magazine acknowledge his contribution to science by naming Albert Einstein, the Time person of the century. Einstein showed through general relativity that Newton’s most celebrated equation for gravitational force is a mere illusion and gravity is a manifestation of spacetime curvature. People were once skeptical to accept his theory are now embracing it with full heart since it is the only possible theory which could explain the profound effects like length contraction, time dilation observed in GPS, nuclear/cosmic ray research. Einstein’s theory are physically tested and verified million times per day today.

So people fancy their dreams of testing his last predictions about Gravitational waves. According to his theory, quadrupole moment of a mass distribution caused ripples in spacetime fabric and we call it Gravitational waves. It should be also noted that spherical or cylindrical symmetry distribution of mass cannot create ripples in spacetime. These ripples propagate at speed determined by the stiffness of fabric of space time and their frequency changes from few milihertz to several hundred kilohertz at speed of light. Hence it is apt to say that speed of light is not a simple theory as it seems. It is not merely concerned with light alone but rules the highways of spacetime.

G waves have importance in real life too. Its discovery may open a new area of research in astronomy. That is the reason why it is often called as “new window to the universe”. Let me share an interesting fact about G waves. If it passes through us, we will become shorter or thinner. People may feel quite uncomfortable with such an argument. But it is a fact theoretical proved beyond doubts. And as said before any quadrupole moment of mass distribution such as spiraling neutron starts or collisions between giant black holes creates gravitational waves. So G waves are obviously present which may lengthen or contract our space. Then why doesn’t man feel its presence? This is because the contraction or extension is only a factor of 1 billionth of size of protons. It is a huge relief both in explaining the stability of earth’s orbit as well as we would feel that this change will be impossible to detect. Even Einstein felt the same way. But that is the beauty of research in Physics. Whatever seems to be impossible becomes possible in matter of time resulting in many thoughtful inspiring results. The same happened in the case of indirect detection of G waves from radio waves resulting in Nobel Prize in 1974 and 1993. But in 11 February 2016, the Advanced LIGO team under the direction eminent scientist Rainer Weiss announced that they have detected gravitational waves on 14 September 2015 from a merger of two black holes (1.3 billion light years) from Earth. The merger event is named GW150914.

R Weiss makes use of LASERs to detect these tiny fluctuations by making a giant Michelson interferometer where the mirrors in arms are kept at a distance of 4 km apart from the interference detector. These little blips creates small path difference which oscillates in characteristic way that scientist could distinguish it from extremely weak seismic activity, or from a disturbance of vibration of car engine which is a mile away from the lab or even from a bird farting in the sky. Such perfection is possible now for man who is always imperfect. Measurement is cross checked across different countries so that we are cent percent sure about what is happening. LIGO-Hanford Observatory in Washington, LIGO-Livingston observatory, Vienna, VIRGO, facility of ESA in Italy confirms the detecting simultaneously and thereby confirming G waves beyond doubt.  

The success which we are celebrating today is not fool’s luck. It is a result of years of dedication and refinement in LIGO. It should be noted that LIGO was established in 2002. Till 2010, Result was a big “0” while counting gravitational waves. But scientists were not disheartened. Astrophysics estimated that “Every year one should get gravitational waves in somewhere between 1 or 1/10,000 of event. Best case was predicted to be 8 events in 10,000 years. People may get demotivated since some may wait till the end of their life and may not even detect a single event. LIGO was even shut down due to these negative results. But let me tell you that failure is not the end. It is a start of new beginning. LIGO was modified to detect it 10 times more efficient than previous, increased its chance of detecting g waves by 10 times, reopened as Advanced LIGO with full valor  and they tasted their success in September 18, 2015. Scientists were also extremely cautious to distinguish this from false signals and 100% sure. If Einstein was there, sure that he would have been tremendously happy. 

Also I am happy to inform that National Science day was celebrated on February 29^th, 2016 by organizing a talk on Gravitational waves and EPR Paradox. Attaching some photos of the same...

Sibi