Time travel is the hypothetical activity of traveling into the past or future. Time travel is a widely recognized concept in philosophy and fiction, particularly science fiction. In fiction, time travel is typically achieved through the use of a hypothetical device known as a time machine. The idea of a time machine was popularized by H. G. Wells's 1895 novel The Time Machine.
Jet lag is a temporary physiological condition that occurs when a person's circadian rhythm is out of sync with the time zone they are in, and is a typical result from travelling rapidly across multiple time zones. For example, someone travelling from New York to London, i.e. from west to east, feels as if the time were five hours earlier than local time, and someone travelling from London to New York, i.e. from east to west, feels as if the time were five hours later than local time. The phase shift when travelling from east to west is referred to as phase-delay of the circadian cycle, whereas going west to east is phase-advance of the cycle. Most travellers find that it is harder to adjust time zones when travelling east. Jet lag was previously classified as a circadian rhythm sleep disorder.
In physics, black hole thermodynamics is the area of study that seeks to reconcile the laws of thermodynamics with the existence of black hole event horizons. As the study of the statistical mechanics of black-body radiation led to the development of the theory of quantum mechanics, the effort to understand the statistical mechanics of black holes has had a deep impact upon the understanding of quantum gravity, leading to the formulation of the holographic principle.
The Cambridge Union Society, also known as the Cambridge Union, is a historic debating and free speech society in Cambridge, England, and the largest society in the University of Cambridge. The society was founded in 1815 making it the oldest continuously running debating society in the world. Additionally, the Cambridge Union has served as a model for the foundation of similar societies at several other prominent universities, including the Oxford Union and the Yale Political Union. The Union is a private society with membership open to all students of Cambridge University and Anglia Ruskin University. The Cambridge Union is a registered charity and is completely separate from the Cambridge University Students' Union.
A travel agency is a private retailer or public service that provides travel and tourism-related services to the general public on behalf of accommodation or travel suppliers to offer different kinds of travelling packages for each destination. Travel agencies can provide outdoor recreation, arranging logistics for luggage and medical items delivery for travellers upon request, public transport timetables, car rentals, and bureau de change services. Travel agencies can also serve as general sales agents for airlines that do not have offices in a specific region. A travel agency's main function is to act as an agent, selling travel products and services on behalf of a supplier. They are also called Travel Advisors. They do not keep inventory in-hand unless they have pre-booked hotel rooms or cabins on a cruise ship for a group travel event such as a wedding, honeymoon, or other group event.
The chronology protection conjecture is a hypothesis first proposed by Stephen Hawking that laws of physics beyond those of standard general relativity prevent time travel on all but microscopic scales—even when the latter theory states that it should be possible. The permissibility of time travel is represented mathematically by the existence of closed timelike curves in some solutions to the field equations of general relativity. The chronology protection conjecture should be distinguished from chronological censorship under which every closed timelike curve passes through an event horizon, which might prevent an observer from detecting the causal violation.
A temporal paradox, time paradox, or time travel paradox, is a paradox, an apparent contradiction, or logical contradiction associated with the idea of time travel or other foreknowledge of the future. While the notion of time travel to the future complies with the current understanding of physics via relativistic time dilation, temporal paradoxes arise from circumstances involving hypothetical time travel to the past – and are often used to demonstrate its impossibility.
Ronald Lawrence Mallett is an American theoretical physicist, academic and author. He has been a faculty member of the University of Connecticut since 1975 and is best known for his position on the possibility of time travel.
Time travel is a common theme in fiction, mainly since the late 19th century, and has been depicted in a variety of media, such as literature, television, film, and advertisements.
Catherine Lucy Hawking is an English journalist, novelist, educator, and philanthropist. She is the daughter of the theoretical physicist Stephen Hawking and writer Jane Wilde Hawking. She lives in London, and is a children's novelist and science educator.
Stephen Hawking (1942–2018), a theoretical physicist, has appeared in many works of popular culture.
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. Between 1979 and 2009, he was the Lucasian Professor of Mathematics at Cambridge, widely viewed as one of the most prestigious academic posts in the world.
There have been multiple accounts of people who allegedly travelled through time reported by the press or circulated on the internet. These reports have turned out either to be hoaxes or to be based on incorrect assumptions, incomplete information, or interpretation of fiction as fact, many being now recognized as urban legends.
Model-dependent realism is a view of scientific inquiry that focuses on the role of scientific models of phenomena. It claims reality should be interpreted based upon these models, and where several models overlap in describing a particular subject, multiple, equally valid, realities exist. It claims that it is meaningless to talk about the "true reality" of a model as we can never be absolutely certain of anything. The only meaningful thing is the usefulness of the model. The term "model-dependent realism" was coined by Stephen Hawking and Leonard Mlodinow in their 2010 book, The Grand Design.
Harsh Vardhan is a former Indian politician and otorhinolaryngologist. He had served as the Minister of Health and Family Welfare, Minister of Science and Technology and Minister of Earth Sciences in the BJP-led NDA government of Prime Minister Narendra Modi from 30 May 2019 to 7 July 2021. He represents Chandni Chowk in Delhi as a Member of Parliament in the 17th Lok Sabha. He was elected to the office of chairperson of the executive board of the World Health Organization from 22 May 2020. Vardhan has been prominent in the Indian government's response to the COVID-19 pandemic. He later resigned from his cabinet post ahead of the cabinet reshuffle in July 2021.
Jane Beryl Wilde Hawking Jones is an English author and teacher. She was married to Stephen Hawking for 30 years before divorcing.
Breakthrough Starshot is a research and engineering project by the Breakthrough Initiatives to develop a proof-of-concept fleet of light sail interstellar probes named Starchip, to be capable of making the journey to the Alpha Centauri star system 4.34 light-years away. It was founded in 2016 by Yuri Milner, Stephen Hawking, and Mark Zuckerberg.
Brief Answers to the Big Questions is a popular science book written by physicist Stephen Hawking, and published by Hodder & Stoughton (hardcover) and Bantam Books (paperback) on 16 October 2018. The book examines some of the universe's greatest mysteries, and promotes the view that science is very important in helping to solve problems on planet Earth. The publisher describes the book as "a selection of [Hawking's] most profound, accessible, and timely reflections from his personal archive", and is based on, according to a book reviewer, "half a million or so words" from his essays, lectures and keynote speeches.
The following is a timeline of the COVID-19 pandemic in Singapore in 2021.
Peter Dean is a British artist and designer. His artistic work often takes inspiration from examples of Victorian letterpress printing. He is most notable for his recreation of the Victorian circus poster that was owned by John Lennon and inspired the Beatles song Being for the Benefit of Mr. Kite!. as well as creating the poster at the centre of Stephen Hawking’s famous time travel experiment. His work can be found in both the permanent collections of the Victoria and Albert Museum and the Science Museum, both in London, UK and has also been seen on The Late Show with Stephen Colbert.
