Nobel 2020

Introduction:                                                                                                                                                                                                                                                                                                                    

Nobel Prizes are awarded in the fields of Physics, Chemistry, Physiology or Medicine, Literature, and Peace. Nobel Prizes are widely regarded as the most prestigious awards available in their respective fields.

Alfred Nobel was a Swedish Chemist, Engineer and Industrialist most famously known for the invention of dynamite. He died in 1896. In his will, he bequeathed all of his "remaining realisable assets" to be used to establish five prizes which became known as "Nobel Prizes". Nobel Prizes were first awarded in 1901.

The prize ceremonies take place annually. Each recipient  receives a gold medal, a diploma, and a monetary award. In 2020, the Nobel Prize monetary award is 10,000,000. A prize may not be shared among more than three individuals.

Three Laureates share this year’s Nobel Prize in Physics for their discoveries about one of the most exotic phenomena in the universe, the black hole. Roger Penrose showed that the general theory of relativity leads to the formation of black holes. Reinhard Genzel and Andrea Ghez discovered that an invisible and extremely heavy object governs the orbits of stars at the centre of our galaxy. A supermassive black hole is the only currently known explanation.

Roger Penrose used ingenious mathematical methods in his proof that black holes are a direct consequence of Albert Einstein’s general theory of relativity. Einstein did not himself believe that black holes really exist, these super-heavyweight monsters that capture everything that enters them. Nothing can escape, not even light.

In January 1965, ten years after Einstein’s death, Roger Penrose proved that black holes really can form and described them in detail; at their heart, black holes hide a singularity in which all the known laws of nature cease. His groundbreaking article is still regarded as the most important contribution to the general theory of relativity since Einstein.

Sir Roger Penrose

Sir Roger Penrose is a British Mathematical Physicist, Mathematician, Philosopher of Science and Nobel Laureate in Physics. He is Emeritus Rouse Ball Professor of Mathematics at the University of Oxford, an emeritus fellow of Wadham College, Oxford and an honorary fellow of St John's College, Cambridge and University College London.

Penrose has made contributions to the Mathematical Physics of general relativity and cosmology. He has received several prizes and awards, including the 1988 Wolf Prize in Physics, which he shared with Stephen Hawking for the Penrose–Hawking singularity theorems, and one half of the 2020 Nobel Prize in Physics "for the discovery that black hole formation is a robust prediction of the general theory of relativity".

Reinhard Genzel and Andrea Ghez each lead a group of astronomers that, since the early 1990s, has focused on a region called Sagittarius A* at the centre of our galaxy. The orbits of the brightest stars closest to the middle of the Milky Way have been mapped with increasing precision. The measurements of these two groups agree, with both finding an extremely heavy, invisible object that pulls on the jumble of stars, causing them to rush around at dizzying speeds. Around four million solar masses are packed together in a region no larger than our solar system.

Using the world’s largest telescopes, Genzel and Ghez developed methods to see through the huge clouds of interstellar gas and dust to the centre of the Milky Way. Stretching the limits of technology, they refined new techniques to compensate for distortions caused by the Earth’s atmosphere, building unique instruments and committing themselves to long-term research. Their pioneering work has given us the most convincing evidence yet of a supermassive black hole at the centre of the Milky Way.

Andrea Mia Ghez

Andrea Mia Ghez is an American Astronomer and Professor in the Department of Physics and Astronomy at the University of California, Los Angeles. Her research focuses on the center of the Milky Way galaxy. In 2020, she became the fourth woman to be awarded the Nobel Prize in Physics, sharing one half of the prize with Reinhard Genzel the other half of the prize being awarded to Roger Penrose. The Nobel Prize was awarded to Ghez and Genzel for their discovery of a supermassive compact object, now generally recognized to be a black hole, in the Milky Way's galactic center.

Reinhard Genzel 

Reinhard Genzel  is a German Astrophysicist, Co-director of the Max Planck Institute for Extraterrestrial Physics, a Professor at LMU and an Emeritus Professor at the University of California, Berkeley. He was awarded the 2020 Nobel Prize in Physics "for the discovery of a supermassive compact object at the centre of our galaxy", which he shared with Andrea Ghez and Roger Penrose. Reinhard Genzel studies infrared- and submillimeter astronomy. He and his group are active in developing ground- and space-based instruments for astronomy. They used these to track the motions of stars at the centre of the Milky Way, around Sagittarius A*, and show that they were orbiting a very massive object, now known to be a black hole. Genzel is also active in studies of the formation and evolution of galaxies.

Black Hole

Black hole is a region of spacetime where gravity is so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole.

The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, according to general relativity it has no locally detectable features. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe directly.

Albert Einstein

Albert Einstein was a German-born Theoretical Physicist, widely acknowledged to be one of the greatest Physicists of all time. Einstein is known widely for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechanics. Relativity and quantum mechanics are together the two pillars of modern physics. His mass–energy equivalence formula, 

which arises from relativity theory, has been dubbed "the world's most famous equation". His work is also known for its influence on the Philosophy of Science. He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect" a pivotal step in the development of quantum theory. His intellectual achievements and originality resulted in "Einstein" becoming synonymous with "genius".

Amal Kumar Raychaudhuri

Amal Kumar Raychaudhuri was an Indian Physicist, known for his research in general relativity and cosmology. His most significant contribution is the eponymous Raychaudhuri equation, which demonstrates that singularities arise inevitably in general relativity and is a key ingredient in the proofs of the Penrose–Hawking singularity theorems.

Raychaudhuri was also revered as a teacher during his tenure at Presidency College, Kolkata. Many of his students have gone on to become established Scientists.

 Stephen William Hawking

Stephen William Hawking was an English Theoretical Physicist, Cosmologist, and author who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge at the time of his death. He was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009.

Hawking's scientific works included a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Initially, Hawking radiation was controversial.

 General Relativity:

General relativity, also known as the general theory of relativity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of partial differential equations.

Some predictions of general relativity differ significantly from those of classical physics, especially concerning the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light. Examples of such differences include gravitational time dilation, gravitational lensing, the gravitational redshift of light, the gravitational time delay and singularities/black holes.

Einstein's theory has important astrophysical implications. For example, it implies the existence of black holes—regions of space in which space and time are distorted in such a way that nothing, not even light, can escape—as an end-state for massive stars. There is ample evidence that the intense radiation emitted by certain kinds of astronomical objects is due to black holes. For example, micro quasars and active galactic nuclei result from the presence of stellar black holes and supermassive black holes, respectively.

Reference:

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INDIA'S PRIDE ADITYA L-1

Aim and Objectives:

Aditya L -1 was meant to observe only the solar corona. The outer layer of the Sun, extending to thousands of km above the disc (photosphere) is termed as corona. It has a temperature of more than a million degree Kelvin which is much higher than the solar disc temperature of around 6000K. How the corona gets heated to such a high temperature is still an unanswered question in solar physics.

It is actually observed  in Solar Eclipse but from Aditya L-1 we can collect data in real time. The data collected from this instrument would also be used as inputs to climate  modes that is used to predict Earth's atmosphere more accurately than now.

Aditya L-1 with additional experiments can now provide observations of Sun's Corona (Soft and hard X ray, Emission lines in the visible and NIR) Chromophore (UV) and photosphere (broad brand filters). In addition, particle payloads will study the particle flux emanating from the Sun and reaching L-1 orbit and the magnetometer payload will measure the variation in magnetic field strength at the halo orbit around L-1. These payloads have to be placed outside the interference from the Earth's magnetic field and could not have been useful in the low Earth orbit.

 Payloads:

Visible Emission line coronagraph: Corona/ Imaging spectroscopy and spectrometer (1.05- 30 solar radii).

Solar Ultraviolet Imaging Telescope (SUIT): Photosphere and Chromosphere imaging (200- 400nm).

Aditya Solar Wind Particle Experiment (ASPEX): Solar wind/ Particle analyzer Spectrometer (H, Alpha, ions 0.1KeV to 5MeV).

Plasma Analyser Package For Aditya(PAPA): Solar wind/ Insitu measurement (ions 0.01- 25KeV; Electrons 0.01- 3Kev).

Solar Law Energy X-Ray Spectrometer(SoLES): Soft Xray/ spectrometer( 1-30KeV)

High Energy L-1 Orbiting X Ray Spectrometer(HEL10S): High X ray/spectrometer(10- 150KeV).

Advanced Triaxial High Ronation Digital Magnetometer: Measure magnetic field(Range  -256nT to +256nT; Accurate 0.5nT)

Orbit of Satellite:

A satellite placed in the halo orbit around the Lagrangian point 1(L1) of the Sun Earth System has the major advantage of continuously viewing the sun without any occultation or eclipses. Therefore, the Aditya- 1 mission has now revised to Aditya- L1 mission and will be inserted in the halo orbit around the L1 which is 1.5 million km from the Earth.

There are five special points where a small mass can orbit in a constant pattern with two larger masses. Of the five Lagrange points three are unstable and two are stable. These are positions in space where the gravitational force of a body like Sun and Earth produce enhanced regions of attraction and repulsion.

These can be used to reduce fuel consumption needed to remain in position. At the L1 point, the orbital period of the object is exactly equal to Earth's Orbital period.

INDIAN LAUNCHING VEHICLES:

Launchers or launch Vehicles are used to carry space craft to space. India has two operational Launchers, Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV).

GSLV with indigenous Cryogenic Upper Stage has enabled the launching up to two tonne class of communication satellites. The next variant of GSLV is GSLV MK 111, with indigenous high thrust cryogenic engine and stage, having the capability of launching four tonne class of communication satellites.

In order to achieve high accuracy in placing satellites into their orbits, a combination of accuracy, efficiency power and immaculate planning are required. ISRO's Launch Vehicle Programme spans numerous centers and employ over 5000 people.

Liquid propulsion system Centre and ISRO Propulsion Complex, located at Valiamala and Mahendragiri respectively, develop the liquid and cryogenic stages for these launch vehicles. Satish Dhawan Space Centre, SHAR is the space port of India and is responsible for integration of launchers. It houses two operational launch pads from where all GSLV and PSLV flights take place.

PSLV:

 Height- 44cm

 Diameter- 2.8m

 Number of stages- 4

 Left Off Mass- 320 tonnes(XL)

 Varients- 3( PSLV- G, PSLV- CA, PSLV- XL)

 First Flight- Sept 20, 1993.

Challenges:

What makes an Aditya L1 mission challenging is the distance of the Sun from Earth (about 149 million km on average compared to the only 3.84 lakh km to the moon)

The super hot temperatures and radiations in the solar atmosphere make it difficult to study.

NASA's Parker Solar Probe’s January 29 flyby was the closest the spacecraft has gone to the Sun in its planned seven-year journey so far. Computer modelling estimates show that the temperature on the Sun-facing side of the probe’s heat shield, the Thermal Protection System, reached 612 degrees Celsius, even as the spacecraft and instruments behind the shield remained at about 30°C, NASA said. During the spacecraft’s three closest perihelia in 2024-25, the TPS will see temperatures around 1370°C.

Aditya L1 will stay much away and the heat is not expected to be a major concern for the instruments on board. But there are other challenges.

Many of the instruments and their compounds for this mission are being manufactured for the first time in the country, presenting as much of a challenges as an opportunity for India's scientific engineering and space communities. One of the such components is the highly polished mirror which would be mounted on space- based telescope.

Due to the risks involved, payloads in earlier ISRO missions have largely remained stationary in space; however, Aditya L1 will have some moving components, scientists said. For example, the spacecraft’s design allows for multiple operations of the front window of the telescope — which means the window can be opened or shut as required.

Chairman of ISRO:

Full name: Kailasavadivoo Sivan

Born on  14th April, 1957

Previous work: Served as the Director of the Vikram Sarabhai Space Center and the Liquid Propulsion Center.

Born place: Mela Sarakkalvilai, near Nagercoil, Kanyakumari District, Tamil Nadu

Education:      Madras University

                       Madras Institute of Technology( B.Tech.)

                       IISc Bangalore( M.E.)

                       IIT Bombay(Ph.D.)

He is the son of mango farmer and studied in Tamil medium at Government School in Mela Sarakkalvillai. He is the first graduate from his family. He completed his masters in Aerospace Engineering from IISc Bangalore. In 1982, he started working in ISRO for PSLV project. He completed his PhD in Aerospace Engineering from IIT Bombay. He is a Fellow of Indian National Academy of Engineering and Aeronautical society of India. In 2014, he was appointed as director of ISRO's Liquid Propulsion Center and in 2015 as a director of Vikram Sarabhai Space Center. Sivan was appointed the chief of ISRO in January 2018 and he assumed office on 15 January. Under his chairmanship, ISRO launched Chandrayaan 2, the second mission to the moon on July 22, 2019. On 2020, December 30, his chairmanship was extend by a year to 2022 January, his early tenure was up to January 2021.

Reference:

i.       https://www.isro.gov.in/aditya-l1-first-indian-mission_to_study_sun

ii.     https://www.researchgate.net/publication/327675634_Space_System_Architecture_of_India's_Aditya-L1_Mission_to_study_the_Sun

iii.   https://earth.esa.int/web/eoportal/satellite-missions/a/aditya-1

iv.    Wikipedia about Prof Kilasavadivo Sivan.

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