Topic 1 : X-ray eye in the sky
Introduction: As the world woke up to the first morning of 2024, ISRO’s launch vehicle put into orbit a new X-ray payload (XPoSat, X-ray Polarimeter Satellite) for astronomical research. If all goes well, the instrument, totally indigenous in design and fabrication, will herald yet another milestone for Indian astronomers.
What is special about POLIX?
- For the past 15 years, the main instrument aboard the payload, POLIX (Indian X-ray Polarimeter) has been built at the Raman Research Institute (RRI), Bangalore.
- Measuring roughly half a metre in all dimensions and weighing almost two hundred kilograms, it is not large, as typical astronomical detectors in space go.
- But its size belies the unique capabilities of the new apparatus, which aims to study a special property of X-rays in space.
What are the X-rays that are being studied?
- X-rays, like ordinary light, are electromagnetic waves.
- These are generated by movements of electric charges when the electric and magnetic fields in its vicinity are disturbed.
- Just as molecules bob up and down in water waves, the electric field keeps changing as X-ray moves in space.
- The “direction” of its variation depends on the motion of the electric charge responsible for the wave.
- For an up-down motion of the charge, for example, the electric field in X-ray waves also fluctuates vertically.
- It happens in the case of ordinary light as well. But the light we see from a bulb comes from the random motion of molecules.
- The “direction” of the variation is consequently mixed up in this case.
- Ditto for sunlight. But sometimes these variations acquire directionality, and we describe the light as “polarised”.
- Although stars like the Sun mostly emit unpolarised light, it is not the case with some peculiar objects in space.
How study of X-rays will help in studying Space objects?
- There exist stars with stupendous magnetic fields, sometimes a thousand billion times of what we encounter on the Earth.
- Electrons in those objects spiral around the magnetic field lines and emit X-rays.
- Their gyrating motion endows the X-rays with some directionality.
- Suppose the magnetic field lines are mostly aligned in some direction, then the electrons would twirl in the perpendicular direction.
- This would make the resulting X-rays polarised in the same direction.
- Clearly, measuring the polarisation of X-rays would then enable astronomers to gauge the directions of magnetic fields in these objects.
- Pulsars are examples of such exotic stars. Typically, the size of a city, they can pack as much mass as the Sun.
- Pulsars often shine in X-rays, and can also boast of whopping magnetic fields.
- Then there are regions around black holes, where matter spirals inward in the shape of a disc before finally falling prey to the monster.
- The immensely hot gas emits X-rays, which although unpolarised like starlight, acquires polarisation after reflection and scattering from the gas in the disc, just as sunlight becomes polarised after reflection on ground.
- If only one could examine the polarisation of celestial X-rays, the nature of these objects would be clearer to astronomers.
- This is precisely what POLIX is designed to probe.
Challenges in studying X-rays?
- It is difficult enough to collect X-rays from space, firstly because their high energy makes it impossible to focus with lenses, like ordinary light, and secondly because the Earth’s atmosphere absorbs most of it.
- Measuring the polarisation of abundant light is one thing, and the case of feeble radiation like cosmic X-rays is something else altogether.
- There have been attempts with balloon-borne and short-lived instruments in the past.
- It was only in December 2021 that the first such instrument (IXPE) was launched into space by NASA.
- The NASA instrument contains gas, whose atoms are stripped of electrons after interacting with incoming X-rays.
- Upon scrutiny, the direction of motion of these ejected electrons gives clues to the X-ray polarisation.
How POLIX works?
- POLIX is shaped like a cubical cylinder. At its core lies a disc of beryllium.
- Detectors kept along the walls collect X-rays after their scattering from the metallic disc.
- The scheme works on the principle of polarisation after scattering.
- The lighter the scatterer atoms, the better the signal.
- Lithium would have been better than beryllium but lithium is difficult to handle, so one had to settle for beryllium.
- If the electric field in the X-ray varies in the north-south direction, for example, then the detectors stowed in the east-west directions would receive a signal, just like sunlight from the horizon becomes polarised in the overhead direction after scattering in the atmosphere.
- The other instrument (XSPECT) aboard XPoSat will study timing and spectral properties of X-ray emitting objects in space.
- Incidentally, POLIX’s beryllium disc will let astronomers probe lower energy X-rays than what the NASA instrument is capable of.
Conclusion: The Indian mission will complement NASA’s device and the information gathered by these two instruments together will help astronomers to decipher the nature of pulsars and black holes. All eyes are now set towards XPoSat, waiting for it to start scanning the cosmos.
Topic 2 : An Indic Renaissance
Introduction: As we usher in 2024, India is on the cusp of a cultural renaissance. Apart from the consecration of Lord Rama’s idol at the newly constructed Ram Temple, the 350th anniversary of Chhatrapati Shivaji Maharaj’s coronation, the centenary of Mumbai’s iconic Gateway of India and the centennial celebrations of the Vaikom Satyagraha - the first ever struggle against caste discrimination - are significant events this year.
The significance of the consecration of Ram idol and Lord Rama in Indian culture
- The consecration of the Ram idol at the newly built Ram Janmabhoomi Temple at Ayodhya shouldn’t be seen as a mere religious event.
- True, Hindus worship Ram. But just as the Ramayana and the Mahabharata are India’s national epics, Ram is our national hero.
- Visit any part of the country and you will find Ram in people’s names – from Ramachandran, Ramanathan, Ramayya or Ramappa in the South to Rambhai, Ramsingh or Ramsharan in the North.
- While the debate around the historicity of the Ramayana will continue, it is a fact that Ram in particular and the Ramayana in general reflect the essentially Hindu/Indian belief that every individual has some elements of divinity within him/her — a foundational principle that Hindus often forget and so face the threat of fragmentation.
- Ram symbolises the core of the Indic value system that is founded on a humanitarian approach.
- The Ram temple in Ayodhya is a turning point in India’s cultural history.
- A society always at the receiving end of the injustice and atrocities of aggressors will liberate itself.
- This temple is a symbol of our ability to protect our self-respect.
- The resurrection of the Ram Temple in 2024 can be compared only with the resurrection of the Somnath temple in the 1950s.
- What is being constructed in Ayodhya is not just a temple of brick and mortar but a monument saluting the civilisational journey of India.
The significance of Chhatrapati Shivaji Maharaj in Indian history
- Meanwhile, in observing the 350th anniversary of the coronation of Chhatrapati Shivaji Maharaj, we will be celebrating a philosopher king.
- For, Shivaji was much more than a warrior king or a great strategist.
- His era is a watershed in Indian history — a testament to the resolve of Indians to challenge aggressors.
- Shivaji Maharaj sowed the seeds of self-confidence amongst the masses while also emboldening the rajas and maharajas of the time to summon the political will to take on invaders.
- Protecting indigenous culture from the assaults of invaders is one of the key messages of his life.
- Shivaji Maharaj’s life inspired many of our freedom-fighters, including Veer Savarkar.
What Gateway of India symbolize?
- The iconic Gateway of India in Mumbai marks the first-ever visit of a British monarch to India, then a colony of the Britishers.
- The monument today is a symbol of India’s growing global influence.
- While many in the West continue to struggle to effectively deal with multiculturalism, in India this is inbuilt in our traditions.
- The Dalai Lama had once said, “India’s great tradition of religious tolerance can be a role model for the entire world”.
- It is important to remember this at a time when mindless Westernisation/Americanisation is eroding the rich cultures of several small countries, especially in the southern hemisphere.
- Several developing countries with distinct cultures, traditions and values, different from those of the West, feel hopelessly dependent on the latter for economic development.
- In the process, they invite a cultural flattening of sorts.
- The Gateway of India’s centenary should be a reminder that India needs to give a clarion call for what External Affairs Minister S Jaishankar recently described as “cultural re-balancing”.
- Indigenous cultures must protect themselves from the threat of distortion.
Vaikom Satyagraha and its role in social equality in India
- For our cultural renaissance to attain its truest meaning we have to collectively rise above smaller identities, especially those related to caste and community.
- Therein lies the significance of the Vaikom Satyagraha whose centenary we will observe this year.
- It was remarkable because of the large-scale participation of the so-called forward castes.
- On October 1, 1924, a group of people belonging to the forward castes submitted a petition to the Regent Maharani Sethu Lakshmi Bayi of Travancore.
- The petition asking to open the doors of the temple to everyone carried about 25,000 signatures and Mahatma Gandhi had endorsed the demand of the petitioners.
- After much persuasion, the Maharani relented.
- From Vaikom to Ayodhya, the Hindu community has come a long way.
- In seeking the presence of the priests of the Valmiki and Ravi Das temple at the consecration ceremony slated for January 22 and naming the Ayodhya Dham Airport after Maharishi Valmiki, a loud and clear message of social assimilation, justice and harmony has gone out — this is what was envisioned by Babasaheb Ambedkar.
Conclusion: Bharat is a land of ekam sat vipra bahuda vadanti (God is one but wise men describe him in different ways). India, as once described by Kerala Governor Arif Mohammad Khan, is a country that is always aging but is never old. The events in 2023 and 2024 will show the world the multicultural nature of Indian society.