Two stars collided with each other. Scientists were able to see that! These colliding stars were neutron stars. Neutron stars are formed when a large star burns all its fuel (hydrogen and helium) and loses its shell. The remaining core forms a dense neutron star. By dense, I mean real dense. Think of the Sun compressed and packed into Jamia Nagar!
These neutron starts were dancing around each other, 130 Million Light Years away, towards southern constellation of Hydra. The Earth revolves around the Sun. These two stars were revolving around each other. In the process of revolution that they came too close and finally collided with each other. This kind of collision is called Kilonova. A huge explosion takes place, emitting energy in form of light, matter and gravitational waves.
Gravitational Waves were predicted by Einstein in General Theory of Relativity. When waves are produced in water, the surface of lake or river oscillates. When sound wave is received, molecules of air begin to vibrate. When gravitation wave passes through a region, the space itself begins to contract and stretch.
Don’t worry! This collision took place 130 Million Light Years away. This means light takes 130 Million years to travel from there to earth. Moreover, this collision took place long ago! 130 Million Years to be precise. That means some light from this collision reached us on 17th August, 2017!
They first one to detect it was a LIGO antenna in USA, which detected a gravitational wave passing through and sent out an alert. Two seconds later Fermi Gamma Ray Telescope reported a Gamma Ray burst. Fermi Telescope is a satellite which is in orbit around earth. VIRGO antenna located in Italy also detected a gravitational wave and helped point the location of collision in the direction Hydra constellation.
Astronomers identified the galaxy in which the Kilonova took place within 10 minutes of initial alert. Over next days different telescopes located all over the earth observed and studied the afterglow. One of the telescopes involved in the study was Giant Metrewave Radio Telescope (GMRT) located in Pune, India.
DETECTING GRAVITATIONAL WAVE
Major reason that the collision could be observed so quickly was detection of gravitational waves by LIGO and VIRGO antenna. A gravitational wave detector consists of two really long perpendicular tubes kept at right angle to each other (4 km each for LIGO!). The length of two tubes is exactly same. When gravitational wave passes through the region, the length of tubes differs slightly. This extremely small difference can be detected!
To detect this small difference, identical LASER light is passed in two tubes. When length is exactly same, final light in two tubes is also identical (technically, in same phase). When one of the length changes, the lights also differ slightly. This small difference in distance travelled by light can be detected by a process called Interference. The real challenge is to ensure that light travels exactly same distance in two tubes when no gravitational wave is present.
In October 2017, The Physics Nobel Prize was awarded to Reiner Weiss, Barry Barish and Kip Thorne for their work in developing LIGO and VIRGO detectors.
BIG EARS
Do older persons have bigger ears? Dr. James Heathcote, a General Physician in the UK decided to investigate. Along with his colleagues, he systematically measured ear size from 206 randomly selected patients who were older than 30 years.
The Conclusion? Apparently true. Ear size keeps increasing at an average rate of 0.22 mm per year throughout lifetime. This should amount to an extra centimetre over a period of 50 years. This conclusion is backed by similar studies undertaken in Japan and Italy.
For his research, Dr. Heathcote was awarded Ig® Nobel Prize in 2017. Ig® Nobel Prize is a parody of Nobel Prize. It is awarded for strange but genuine scientific research.
ABSENT MINDED EINSTEIN
Einstein was travelling in train. Ticket Checker came and started checking tickets. Einstein put his hands into his coat pocket and a frown developed on his face. He started searching all his coat pockets and his pant pockets.
The ticket checker said, “Mr. Einstein, I recognise you. You are a world-famous scientist. Don’t worry, I am not going to fine you.”
Einstein was relieved. The ticket checker moved ahead. He turned back and noticed that Einstein was again searching for his ticket. He came back and said, “Sir, I know you are Mr. Einstein, a world-famous scientist. All of us know that you must have bought the ticket and misplaced it. There is no need to search for it.”
Einstein replied, “Even I know I am Einstein. I need the ticket to see where I am going!”
Einstein was often forgetful, especially when he was occupied by his thoughts. Many anecdotes about his absent mindedness are famous. The above incident is one of the funniest. However, it is impossible to verify if it is true.
POET, MATHEMATICIAN AND ASTRONOMER
Omar Khayyam was an eleventh century Astronomer, Mathematician and Poet from Iran. He developed a method for solving cubic equation. He also devised a new Solar Calendar (Jalali Calendar) which is still used in many places in Iran. In the western world he is more famous for his poetry. His book, Rubaiyyat of Omar Khayyam, was translated into English in 1859.
Omar Khayyam was a devout Muslim. He knew that he will have to present an account of his faith and deeds before Allah after death in this world.
If I myself upon a looser Creed
Have loosely strung the Jewel of Good deed,
Let this one thing for my Atonement plead:
That One for Two I never did misread.
[Sabat Anwar, B.Tech (Alig), is a Faculty for Physics in a Coaching Institution]