1. Isaac Newton conceived of time as absolute and flowing uniformly, an idea that was later disproven by Einstein's theory of relativity.
2. Einstein's special theory of relativity established that the laws of physics are the same in all inertial frames of reference and that the speed of light is constant, independent of the motion of the observer.
3. As a result of Einstein's theory, time is shown to flow at different rates for observers in different reference frames, as demonstrated by the fact that clocks moving at high speeds are measured to tick slower than identical clocks at rest.
hello, friends it time for new scientific consideration ,usually what we think how time pass away,,,,,,,,,o come on i wish to get back in past...also in future......what you say???...take a look........
Time travel is one of my favorite topics! I wrote some time travel stories in junior high school that used a machine of my own invention to travel backwards in time, and I have continued to study this fascinating concept as the years have gone by. We all travel in time. During the last year, I've moved forward one year and so have you. Another way to say that is that we travel in time at the rate of 1 hour per hour.
But the question is, can we travel in time faster or slower than "1 hour per hour"? Or can we actually travel backward in time, going back, say 2 hours per hour, or 10 or 100 years per hour?
It is mind-boggling to think about time travel. What if you went back in time and prevented your father and mother from meeting? You would prevent yourself from ever having been born! But then if you hadn't been born, you could not have gone back in time to prevent them from meeting.
The Amazing Speed of Light Across the Universe.pdfAneeb Technology
But what is the speed of light, and how does it affect our understanding of the universe?
What Is the Speed of Light?
The speed of light is a physical constant, denoted by the symbol "c", which is approximately 299,792,458 meters per second, or about 670,616,629 miles per hour. It is the speed at which electromagnetic radiation, such as light, travels through a vacuum. The speed of light is considered to be an absolute physical constant because it is the same in all inertial reference frames and is not affected by the motion
How Fast Does Light Travel?
The speed of light is a physical constant that is the same in all inertial reference frames and is not affected by the observer's motion or the light's source. It is approximately 299,792,458 meters per second or about 670,616,629 miles per hour.
To give you an idea of how fast this is, consider that it would take light about 8 minutes and 20 seconds to travel from the Sun to the Earth, It would take light about 4 years to travel from the nearest star beyond the Sun, Proxima Centauri, which is about 25 trillion miles (4.24 light-years) away.
What Are the Implications of the Speed of Light?
The speed of light has many important implications in a variety of fields, including astronomy, physics, and engineering. Some of the key implications of the speed of light are:
The speed of light sets a fundamental limit on the speed at which information and signals can be transmitted. This means that nothing with mass can travel faster than the speed of light.
The speed of light has important implications for the study of celestial objects and the structure of the universe. For example, the finite speed of light means that when we look at distant objects in the universe, we are looking back in time.
The speed of light is an important factor in the theory of relativity, which explains how the laws of physics behave in different reference frames. The theory of relativity predicts that time and space are relative and that the speed of light is the same in all inertial reference frames.
The speed of light has practical applications in a variety of fields, including telecommunications, navigation, and satellite technology. For example, the time it takes for a signal to travel from a satellite to the Earth is used to calculate the distance between the satellite and the Earth.
Expansion of the Universe
The expansion of the universe is the process by which the distance between two distant objects or regions in the universe increases over time. This expansion is driven by the expansion of the fabric of space itself, rather than the movement of objects through space.
The expansion of the universe was first observed by Edwin Hubble in the 1920s when he discovered that the light from distant galaxies was redshifted, which is an effect that is caused by the expansion of space. This observation led to the development of the Big Bang theory, which proposes that the universe began as a singularity, or a point of infinite densi
Chapters
Reminders: light
speed of light in a vacuum
A brief historical reminder of the speed of light
Invariance of the speed of light in a vacuum
Influence of the propagation medium
Speed or celerity?
Speed, distance traveled, and duration
Relations including the speed of light
Faster than light?
Speed of light: did you know?
Reminders: light
Light is an electromagnetic wave, consisting of a magnetic field and an electric field oscillating perpendicular to each other in a plane perpendicular to the direction of propagation of the light wave. In a vacuum, light travels in a straight line at the speed of light noted c.
speed of light in a vacuum
Exact value
The exact value of the speed of light was fixed in 1983 by the Bureau of Weights and Measures at c = 299 792 458 m/s or c = 2.99792458 x 10 8 m/s, using the units of the international system. It can also be expressed in kilometers per hour by multiplying the value in m/s by 3.6: c = 1,079,252,848.8 km/h or c = 1.0792528488 x 10 9 km/h. This value, which represents a fundamental constant of physics, can be used for calculations requiring great precision. It is also used to define the meter in the international system of units: one meter corresponds to the length traveled in a vacuum by light for a duration of 1/299,792,458 seconds.
A brief historical reminder of the speed of light
The first conception concerning light suppose that it can be either present in a space, or absent: the light would therefore be instantaneous. The Arab scholar Alhazen (965-1039) was interested in optics and wrote reference treatises. He is the first to have the intuition that the appearance of light is not instantaneous, that it has a speed of propagation, but he cannot prove it.
Galileo (1564-1039) tries to measure the propagation time of light between two hills using two people a few kilometers apart and equipped with clocks. He fails to measure the speed of light (which, in the context of this experiment, takes 10 -5 seconds to travel the previously defined distance, not measurable for the time) and deduces from the failure of this experiment that the speed of propagation of light is very high.
Cassini (1625-1712) speculated that the irregularity in the movement of Io, a satellite of Jupiter, could come from a delay in the arrival of light from the satellite, "such that it takes 10 or 11 minutes for it travels a distance equal to the radius of the Earth's orbit". Römer (1644-1710) explains the discrepancy between the eclipses of Io (a satellite of Jupiter) and Cassini's predictions by assuming that light has a speed of propagation. It is the first to give an order of magnitude of the speed of light.
Bradley (1693-1762) confirms Römer's hypothesis and proposes a first estimate of the speed of light at approximately 10188 times that of the rotation of the Earth around the Sun, the latter being however poorly known. His discovery is linked to the aberration of light,
Telescope history
&facts,
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
1. Sincronizziamo gli orologi: il tempo da Newton ad Einstein
Introduzione
I concetti di spazio e tempo sono mutati diverse volte nella storia dell’umanità. Tutt’oggi l’orologio
ci dice che il tempo è una successione di periodi numerabili, che si equivalgono, e la loro somma ne
descrive lo scorrimento. È così che la fisica classica idealizzava la concezione di tempo: esso, insieme
allo spazio, era qualcosa di assoluto, che scorre in modo lineare ed uniforme senza nessuna
interazione con qualunque evento esterno. Newton era un sostenitore di questa teoria, che in seguito
fu demolita dalla rivoluzionaria “fisica relativistica di Einstein”.
Isaac Newton sradicò le basi della scienza introducendovi una massiccia dose
di matematica. Il suo ingegno era straordinario: quando si accorse che la
matematica di cui aveva bisogno per le sue ricerche non esisteva ancora, la
inventò da solo. Per trovare un altro genio del suo calibro sarebbero dovuti
passare quasi tre secoli.
Egli pubblica nel 1687 “Principi Matematici della filosofia naturale” in cui
parla del tempo (così anche dello spazio) come “Sensorium Dei” (senso di Dio)
che scorre immutabile, idea già contenuta nelle trasformazioni di Galileo
Galilei.
I presupposti di Galilei per le trasformazioni delle coordinate spazio-temporali
in un sistema di riferimento inerziale considerano spazio e tempo come
grandezze fisiche invarianti. Le esperienze di natura meccanica costituiscono
un’esperienza limite che possono valere con questi presupposti. Ma in senso generale, non tutte le
leggi aderiscono a questi principi e nuove trasformazioni necessitano di essere correlate. Attraverso
un artificio matematico, Lorentz permise ad Einstein di dimostrare che le trasformazioni tra sistemi
inerziali non sono quelle di Galileo.
Einstein dal canto suo, è stato la chiave di volta della fisica moderna e ci ha
mostrato l'Universo da un nuovo punto di vista. La formulazione della teoria
della relatività «speciale» dimostra come egli applichi la sua idea di pensiero
scientifico come libera creazione: suggerita, ma non imposta dai fatti empirici.
In particolare, la teoria della relatività speciale propone di rinunciare alle
convenzionali considerazioni di spazio e tempo.
Per farlo dovette andare contro postulati ed assiomi che per secoli erano stati
onorati, di fatti già nel 1916 scriveva:
«Concetti che si sono dimostrati utili per ordinare le cose acquistano una tale
autorità su di noi che ci dimentichiamo la loro origine terrena e li accettiamo come dati inalterabili.
[…] Il cammino del progresso scientifico è spesso reso impossibile per lungo tempo proprio da questi
errori».
Si tratta di una vera e propria rivoluzione scientifica.
È oltremodo sconcertante pensare che l’unica conoscenza matematica richiesta per ottenere gli esiti
più considerevoli della teoria della relatività di Einstein è l’algebra e che essa pone le sue basi su due
semplici postulati. Enunciati nel 1905, annus mirabilis, recitano quanto segue:
❖ Le leggi della fisica hanno la stessa forma in tutti i sistemi di riferimento inerziali;
1. Philosophiae Naturalis
Principia Mathematica (in
italiano: I principi
matematici della filosofia
naturale).
2. Albert Einstein nel 1920
2. ❖ La velocità della luce nel vuoto, 𝑐 = 3,00 ⋅ 108
𝑚 ∕ 𝑠, è la stessa in tutti i sistemi di
riferimento inerziali ed è indipendente dal moto della sorgente e da quello dell’osservatore.
Dunque, la teoria della relatività di Einstein è “ristretta” nel senso che limita le considerazioni a
sistemi non accelerati.
Invero, siamo soliti pensare che il tempo scorra per tutti nella medesima maniera. Lo percepiamo
empiricamente, come auspicherebbe Galileo. Tuttavia, se gli orologi vengono trasportati con velocità
prossima a 𝑐, la loro sincronizzazione non è garantita. Affinché la lettura del tempo di orologi diversi
sia significativa, bisogna che questi siano tutti sincronizzati. Per esserlo, dovrebbero comunicare
istantaneamente mediante segnali in grado di raggiungere ogni punto dello spazio in un intervallo di
tempo nullo, raggiungendo una velocità pressocché infinita.
Sfortunatamente questo in natura non è possibile: i segnali che viaggiano più velocemente sono i
segnali elettromagnetici che, pur avendo una velocità altissima, impiegano un certo tempo per andare
da un punto ad un altro. Dunque, per sincronizzare i nostri orologi dobbiamo ricorrere ad altri metodi.
Uno di questi prevede che orologi posti in due punti diversi A e B nello spazio abbiano una sorgente
di onde elettromagnetiche, ad esempio una lampadina, posta esattamente nel mezzo.
L’accensione della lampadina propaga un'onda luminosa. Assumendo che la velocità della luce sia
invariante, gli orologi vengono sincronizzati quando questa li raggiunge. Si possono escogitare altre
procedure che sfruttano le onde elettromagnetiche. Si può inviare da terra un'onda radio ad un satellite
e, conoscendo la distanza d che separa i due dispositivi, si può facilmente calcolare 𝛥𝑡 =
𝑑
𝑐
dopo cui
l'orologio sul satellite riceverà il segnale. Infine, sarà sufficiente posizionare l'orologio al valore 𝑡.
Questa è, in effetti, la procedura che viene utilizzata per sincronizzare gli orologi sulla terra e sui
satelliti.
Immaginiamo ora di porre un orologio all’interno di una navicella che viaggia ad una velocità
prossima a 𝑐. Questo, non potrà essere sincronizzato seguendo i metodi convenzionali. Il tempo si
dilata con l’avvicinarsi a 𝑐.
Per calcolare la differenza dell’andamento tra i due orologi, uno in quiete l’altro in movimento,
supponiamo di costruire un orologio in cui il “tic” è determinato dall’emissione di un raggio di luce
tra due specchi.
3. Nell’orologio a luce in quiete, il raggio viene emesso dalla base, rimbalza nella parte superiore e
ritorna alla posizione iniziale dopo un intervallo di tempo 𝛥𝑡0 . Il pedice indica che il tempo è proprio.
Nell’orologio a luce in movimento, il raggio di luce coinvolto è quello obliquo che deve compiere
uno spostamento maggiore, impiegando di conseguenza un tempo 𝛥𝑡 maggiore.
Allo stesso modo, se confrontiamo le misurazioni di due orologi, scorgiamo un lieve di scostamento
tra le due: esso non è altro che il loro rapporto ed è quantificabile con il cosiddetto fattore
lorentziano:
𝛾 =
𝛥𝑡
𝛥𝑡0
=
1
√1 −
𝑣2
𝑐2
Esso vale 1 per 𝑣 = 0, mentre tende a infinito quando 𝑣 si avvicina a 𝑐. Per 𝑣 → 𝑐 il tempo necessario
per un “tic” dovrebbe essere infinito, l’orologio dunque rallenta fino a fermarsi. Dal momento che
non è possibile inserirci nella prospettiva dell’eternità, a differenza di come il sommo poeta si riuscì
a proiettare nei mondi ultraterreni descritti nella Divina commedia, 𝑐 rappresenta la velocità limite,
ossia la massima raggiungibile nell’universo. Gli intervalli di tempo 𝛥𝑡 e 𝛥𝑡0 sono quindi legati dalla
relazione che esprime la dilatazione degli intervalli temporali:
𝛥𝑡 = 𝛾𝛥𝑡0 𝑐𝑜𝑛 𝛾 =
1
√1 −
𝑣2
𝑐2
La relazione è valida per qualsiasi tipo di orologio, altrimenti sarebbe violato il primo postulato della
relatività.
A poco più di un secolo dalla sua nascita, la relatività ha consentito la correzione nonché la
comprensione di diversi fenomeni. Tra questi, l’effetto Doppler. Come per le onde sonore, esso si
manifesta anche nel caso di onde luminose, ma con due differenze sostanziali. La prima è che le onde
sonore, a differenza della luce, hanno bisogno di un mezzo per propagarsi. La seconda è che la
velocità del suono può variare, a seconda che osservatore e sorgente siano in movimento o meno. Per
il secondo postulato della relatività, la velocità della luce, in particolare quella delle onde
elettromagnetiche, è indipendente dal moto della sorgente e dell’osservatore. L’unica velocità
interessata è quella relativa fra l’osservatore e la sorgente. Se la sorgente (con frequenza 𝑓) si muove
ad una velocità piccola rispetto a 𝑐, la frequenza 𝑓′
percepita da un osservatore in quiete è:
4. 𝑓′
= (1 ±
𝑣
𝑐
) 𝑓
Il segno è positivo quando la sorgente si avvicina all’osservatore, negativo quando se ne allontana.
In ambito astronomico l’effetto Doppler viene sfruttato per comprendere se le galassie sono in
allontanamento o in avvicinamento. Difatti, la luce emessa da sorgenti in movimento ha lunghezze
d’onda differenti a seconda del movimento relativo fra la sorgente e l’osservatore. Quando la sorgente
si avvicina, la lunghezza d’onda 𝛾 emessa decresce, spostandola verso il margine blu dello spettro
(blueshift). Al contrario, se la sorgente si allontana 𝛾 cresce e si sposta verso il margine rosso
(redshift).
Suppose that a particular galaxy emits orange light with a frequency of 5,000 ⋅ 1014
𝐻𝑧 and is moving
away from Earth at 3325 𝑘𝑚 ∕ 𝑠 . Thanks to Einstein’s theory of relativity we can calculate the
frequency of light when it reaches our planet.
The galaxy’s speed is smaller enough than the light one and we know that the galaxy is moving away
from us, so:
𝑓′
= (1 −
3,325 ⋅ 106
𝑚 ∕ 𝑠
3,00 ⋅ 108𝑚 ∕ 𝑠
) ⋅ 5,000 ⋅ 1014
𝐻𝑧 = 4,945 ⋅ 1014
𝐻𝑧
Almost all the galaxies we have observed so far are moving away from us.
È dunque chiaro che la comprensione della teoria della relatività speciale costituisce un’esperienza
intellettuale affascinante. Benché il campo di applicazione della relatività sia limitato, l’eredità di
Einstein è ineffabile. Il sentimento del tempo cambia e la frammentazione del presente viene espressa
attraverso nuove modalità di scrittura: James Joyce sostituisce il tempo cronologico con quello della
coscienza, composto di momenti indistinguibili che trapassano uno nell’altro in un flusso che
continuamente si arricchisce. L’infinita limitatezza dell’uomo giunge ora allo scoperto: il suo punto
di vista non coincide col vero assoluto.
5. Bibliografia
- “La teoria del tutto”, Stephen W. Hawking
- “FISICA Modelli teorici e problem solving”, James S. Walker
- “La Divina commedia e le scienze”, Prof. Maurizio Marinozzi
Sitografia
- www.matematicamente.it
- www2.ing.unipi.it
- www.asimmetrie.it
Immagini
- www.articolidiastronomia.com
- www.batmath.it
- www.studenti.it
- www.fisica.uniud.it