14 August 2022

মুক্তির মন্দির সোপানতলে কত প্রাণ হলো বলিদান, লেখা আছে অশ্রুজলে - মোহিনী চৌধুরী।

 মুক্তির মন্দির সোপানতলে কত প্রাণ হলো বলিদান, লেখা আছে অশ্রুজলে।

কত বিপ্লবী বন্ধুর রক্তে রাঙা বন্দীশালার ওই শিকল ভাঙা, তারা কি ফিরিবে আজ সুপ্রভাতে,যত তরুণ-অরুণ গেছে অস্তাচলে?

যারা স্বর্গগত তারা এখনো জানে স্বর্গের চেয়ে প্রিয় জন্মভূমি,আজ স্বদেশব্রতে মহাদীক্ষা লভি সেই মৃত্যুঞ্জয়ীদের চরণ চুমি।

যারা জীর্ণ জাতির বুকে জাগাল আশা, মৌন মলিন মুখে জাগালো ভাষা,আজ রক্তকমলে গাঁথা মাল্যখানি বিজয়লক্ষ্মী দেবে তাদের-ই গলে।

Rough English Translation:

How many lives have been sacrificed on the steps of the temple of liberation are written in tears.

Shall the broken chains of prisons stained with the blood of many revolutionary friends return today, those young suns that have set?

Those who have gone to heaven know even today that the motherland is dearer than heaven, take the great initiation of swadesh vrata today to kiss the feet of those death winners.

Those who have instilled hope in the hearts of a worn-out nation; brought the language in silent, dull mouths, today the Vijaya Lakshmi will put garlands of blood lotuses on their necks.

04 August 2022

Time in presence of gravity:

The concept of time is relative to the events; referred as in imperceptible fourth dimension, such a concept naturally rises within the Human minds as an inevitable consequence of existential events within perceptible three spatial dimensions.

Ancient Indian and Greek philosophers were among the first to question time as a mysterious concept. Ever since Human beings existed, they have always tried to make sense of the Universe, accordingly, conceptualised time by observing the events in the nature; as such they have used archaic devices like, candle clock, sundial, water clock, sand clock etc.

Nowadays, clocks all over the world are based on seconds, minutes, and hours. The first mechanical clock said to have invented in 1275 by replacing archaic devices, and in 1656 first pendulum clock was made. The quartz clock was invented in 1927 and the atomic clock in 1948.  

Time is now defined as “the indefinite continued progress of existence and events in the past, present, and future regarded as a whole in irreversible succession, referred in fourth dimension above three spatial dimensions.[Ref1. Wikipedia – Time.]

Time standard specifies the method for measuring divisions of time i.e. a time scale, newer time standard is based on atomic time as per caesium atomic clock. The standard describes the second is equal to the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the unperturbed ground state of the caesium-133 atom.

“The second, symbol s, is the SI unit of time, defined by taking the fixed numerical value of the caesium frequency, the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9,192,631,770 when expressed in the unit Hz, which is equal to s^–1.” [Ref2. The international reference time scale (UTC) - SI base unit: second (s).]

i.            Time is called T, the period of oscillation, so that ωT = 2π, or T = 2π/ω.  The reciprocal of the period, or the frequency f, in oscillations per second, is given by f = 1/T = ω/2π.

ii.            Frequency (f) and time interval (t): The time interval for 1° of phase is inversely proportional to the frequency. If the frequency of a signal is given by f, then the time t(deg) (in seconds) corresponding to 1° of phase is t(deg)  = 1/(360f) = t/360. Therefore, a 1° phase shift on a 5 MHz signal corresponds to a time shift of 555 picoseconds (ps).

iii.            The energy equation is a direct relationship between frequency (f) and energy (E) because as frequency increases, so does energy, as described by the equation E=hf. This is possible because (h) is Planck constant.

iv.            Thus, equivalently, the relationship between the electromagnetic energy (E) and the wavelength (λ) of electromagnetic wave is an inverse relationship, as described by the equation E=hc/λ where h is Planck's constant and c is constant as the speed of light.

v.            Since wave frequency (f) is inversely proportional to the period of the wave f=1/t and also inversely proportional to its wavelength (f=c/λ); and thus, the wavelength (λ) of a wave is directly proportional to the time period (t) of the wave derives the equation λt where c is constant, we get the wave corresponds to time shift, e.g.

1° phase shift on a 5 MHz wave corresponds to a time shift of 555 picoseconds (ps). 

t=1/f; f = 5000000 Hz; 1° phase shift = t/360. 

t (deg) = (1/f)/360 = (1/5000000)/360 = (5.55x10^-10) = 555 ps.

·        phase shift for a 59.95 m wavelength (λ), f (5 MHz), time shifts (time delays Δt) aprox. 555 ps.

·        90° phase shift for a 59.95 m wavelength (λ), f (5 MHz), time shifts (time delays Δt) aprox. 50000 ps.

·        360° phase shift for a 59.95 m wavelength (λ), f (5 MHz - 1 Hz) time shifts (time delays Δt) aprox. 200000 ps.

·        A 360° phase shift means a complete cycle of the wave, so from the above calculation, we can say that a 360° phase shift or a complete cycle of a 5 MHz wave takes 200000 ps (0.0000002 s) to complete one cycle (1 Hz).

·        The caesium-133 atom used in atomic clocks vibrates at frequencies 9192631770 Hz on the ground and the GPS satellite clock advances faster than a clock on the ground by about 38 microseconds per day.

·        (i) For phase shift of a 9192631770 Hz wave time shifts (time delays Δt) aprox. 0.0000000003021743769660185 ms on the ground i.e. time shifts in a day 0.00002610786616986399 ms on the ground.

·        Time shift of the caesium-133 atomic clock above the ground:

(ii) For 360° phase shift or, 1 complete cycle (1 Hz), of a 9192631770 Hz wave; aprox. 0.00000010878277570776666 ms.

·        Time shift of the caesium-133 atomic clock in the GPS satellite in space:

(iii) For 1455.50003025° phase shift (or, 4.043055639583333 cycles) of a 9192631770 Hz wave; aprox. 0.0000004398148148148148 ms. time is taken (or, 0.038 milliseconds time is taken per day, or, 38 microseconds time is taken per day.)

vi.            Gravitational–Electromagnetic Interaction - Gravitational Redshift: The wavelength (λ) of electromagnetic radiation will lengthen as it climbs out of a gravitational well. Photons must expend energy to escape, but at the same time must always travel at the speed of light (c), so this energy must be lost through a change of frequency (f) rather than a change in speed (c). If the energy (E) of the photon decreases, the frequency (f) also decreases. This corresponds to an increase in the wavelength (λ) of the photon, or a shift to the red end of the electromagnetic spectrum, hence the name gravitational redshift.

z ~ GM/rc^2 

Where z is the gravitational redshift, G is Newton’s gravitational constant, M is the mass of the object, r is the photon’s starting distance from M, and c is the speed of light. In this case, the gravitational redshift suffered by a photon emitted from the star’s surface is a tiny 3 × 10^-4. In other words, wavelengths are shifted by less than one part in 30,000.

vii.            Gravitational field: Two masses (Earth ‘M’ and GPS Satellite ‘m’) separated by a distance (r) exert gravitational forces on one another. This is called action at-a-distance. They interact even though they are not in contact. When another body (say a ‘clock’) is brought in this field, it would experience gravitational force of attraction. Whereas, gravitational field intensity is the measure of gravitational field.

Gravitational field intensity or strength at a point is defined as the force experienced by a unit mass placed at that point. It is denoted by E. It is a vector quantity. Its unit is N kg^-1. By considering a body of mass M placed at a point Q and another body of mass m placed at P at a distance r from Q. The mass M develops a field E at P and this field exerts a force "F = mE." The gravitational force of attraction between the masses M and m is F = GMm/r^2. The gravitational field intensity at point P is E = F/m. Therefore, E = GM/r^2.

Therefore, a clock within the GPS Satellite would experience lesser Gravitational strength of E = GM/r^2 than it was experiencing it at the surface of the Earth M at a distance r0 from point Q, thus GM/r^2 < GM/r0^2.

viii.            Radiation gravitates - anything that carries energy, momentum and stresses is a source of a gravitational field. An electromagnetic field have its own gravitational field, because an electromagnetic field contains energy, momentum and so on, it is considered as a real thing capable of gravitating, as such, it will produce a gravitational field of its own. This gravitational field is in addition to that produced by the matter of the charge or magnet. Electric charges and magnets are manifestations of certain types of matter, most particularly electrons. Since matter carries energy (via E=mc^2), such objects will have a gravitational field and so they will curve the fabric of space. So, one way in which a charge or a magnet will curve the fabric of space is by virtue of its matter.

ix.            A clock and time are two different considerations. A clock does have mass but time doesn't.

x.            A clock mechanism 'always follows the order of time,' as it should never work arbitrary except the order of time, else a clock would cause wrong reading.

xi.            Gravitational effect on oscillation resulting corresponding time: Frequency and oscillation can never remain perfectly constant, as long as there is varying effects of gravity.

xii.            The events invoke time, when time is independent from eventual influences as such; free from all fundamental interactions.

xiii.            Existential events are necessary for time to exist. Time would be meaningless even for an existence but without events. There is existence of enormous mass and gravity in the core of a black hole, however, since there is no event; so time is a meaningless proposition there in the core of a black hole. Absence of event cause no time in the core of a black hole.     

xiv.            The conceptual time is irreversible in succession and uniformed in scale. In case of a clock dial; sixty uniformed divisions of seconds need to be within a circle of 360° exactly, it cannot be >360°, to accommodate time dilation), nor can be <360°, to accommodate time reduction.

xv.            The equation of time dilation " T'= T√ (1-V²/C²) " is wrong. The error in said equation is that time (T) can never be modified - through external interference or influence or interaction of real event like speed or gravity - to get Time Dilation (T’). It would be an illegal operation to try to modify cosmic time (T) progressing in its uniformed and irreversible succession. Speed or gravity can never interfere time (T) to get time dilation (T'). So called time dilation is rather wavelength (λ) dilation of the clock oscillation.  

xvi.            Time is a higher, fourth dimensional concept, imperceptible to lower, real and spatial three dimensions. A lower three-dimensional entity can never modify or interfere or influence a higher, fourth dimensional concept of time. However, a clock mechanism 'always follows the order of time.' Therefore, the concept of space-time is an absurd proposition by Albert Einstein.        

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