Future and Related Topics

Time

4 links

Chip-scale atomic clocks, such as this one unveiled in 2004, are expected to greatly improve GPS location.

Scale of time in Jain texts shown logarithmically

Time's mortal aspect is personified in this bronze statue by Charles van der Stappen.

Two-dimensional space depicted in three-dimensional spacetime. The past and future light cones are absolute, the "present" is a relative concept different for observers in relative motion.

Relativity of simultaneity: Event B is simultaneous with A in the green reference frame, but it occurred before in the blue frame, and occurs later in the red frame.

Views of spacetime along the world line of a rapidly accelerating observer in a relativistic universe. The events ("dots") that pass the two diagonal lines in the bottom half of the image (the past light cone of the observer in the origin) are the events visible to the observer.

Philosopher and psychologist William James

Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future.

Past

3 links

Set of all events that occurred before a given point in time.

Thoughts of the Past (John Roddam Spencer Stanhope, 1859)

The past is contrasted with and defined by the present and the future.

Present

2 links

Time that is associated with the events perceived directly and in the first time, not as a recollection (perceived more than once) or a speculation (predicted, hypothesis, uncertain).

A visualisation of the present (dark blue plane) and past and future light cones in 2D space.

It is a period of time between the past and the future, and can vary in meaning from being an instant to a day or longer.

Spacetime

2 links

Mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold.

Figure 1–4. Hand-colored transparency presented by Minkowski in his 1908 Raum und Zeit lecture

Figure 2-2. Galilean diagram of two frames of reference in standard configuration

Figure 2–3. (a) Galilean diagram of two frames of reference in standard configuration, (b) spacetime diagram of two frames of reference, (c) spacetime diagram showing the path of a reflected light pulse

Figure 2–4. The light cone centered on an event divides the rest of spacetime into the future, the past, and "elsewhere"

Figure 2–5. Light cone in 2D space plus a time dimension

Figure 2–6. Animation illustrating relativity of simultaneity

Figure 2–7. (a) Families of invariant hyperbolae, (b) Hyperboloids of two sheets and one sheet

Figure 2–8. The invariant hyperbola comprises the points that can be reached from the origin in a fixed proper time by clocks traveling at different speeds

Figure 2–9. In this spacetime diagram, the 1 m length of the moving rod, as measured in the primed frame, is the foreshortened distance OC when projected onto the unprimed frame.

Figure 2-11. Spacetime explanation of the twin paradox

Figure 3–2. Relativistic composition of velocities

Figure 3-3. Spacetime diagrams illustrating time dilation and length contraction

Figure 3–5. Derivation of Lorentz Transformation

Figure 3–7. Transverse Doppler effect scenarios

Figure 3–8. Relativistic spacetime momentum vector

Figure 3–9. Energy and momentum of light in different inertial frames

Figure 3-10. Relativistic conservation of momentum

Figure 4–2. Plot of the three basic Hyperbolic functions: hyperbolic sine ([[:File:Hyperbolic Sine.svg|sinh]]), hyperbolic cosine ([[:File:Hyperbolic Cosine.svg|cosh]]) and hyperbolic tangent ([[:File:Hyperbolic Tangent.svg|tanh]]). Sinh is red, cosh is blue and tanh is green.

Figure 4-4. Dewan–Beran–Bell spaceship paradox

Figure 4–5. The curved lines represent the world lines of two observers A and B who accelerate in the same direction with the same constant magnitude acceleration. At A' and B', the observers stop accelerating. The dashed lines are lines of simultaneity for either observer before acceleration begins and after acceleration stops.

Figure 4–6. Accelerated relativistic observer with horizon. Another well-drawn illustration of the same topic may be viewed [[:File:ConstantAcceleration02.jpg|here]].

Figure 5–3. Einstein's argument suggesting gravitational redshift

Figure 5-5. Contravariant components of the stress–energy tensor

Figure 5–9. (A) Cavendish experiment, (B) Kreuzer experiment

Figure 5-11. Gravity Probe B confirmed the existence of gravitomagnetism

2-5) makes the appearance that of two right circular cones meeting with their apices at O. One cone extends into the future (t>0), the other into the past (t<0).

Illustration of the concept of eternalism, showing a man walking his dog. Time progresses through the series of snapshots from the bottom of the page to the top. In a common sense view of time, each of those fours instants would exist one after another. According to eternalism, those four instants all equally exist.

Eternalism (philosophy of time)

1 links

Approach to the ontological nature of time, which takes the view that all existence in time is equally real, as opposed to presentism or the growing block universe theory of time, in which at least the future is not the same as any other time.

The bar and ring paradox is an example of the relativity of simultaneity. Both ends of the bar pass through the ring simultaneously in the rest frame of the ring (left), but the ends of the bar pass one after the other in the rest frame of the bar (right).

Some forms of eternalism give time a similar ontology to that of space, as a dimension, with different times being as real as different places, and future events are "already there" in the same sense other places are already there, and that there is no objective flow of time.

The alien invasion featured in H. G. Wells' 1897 novel The War of the Worlds, as illustrated by Henrique Alvim Corrêa

Science fiction

2 links

Genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel universes, extraterrestrial life, sentient artificial intelligence, cybernetics, certain forms of immortality (like mind uploading), and the singularity.

Space exploration, as predicted in August 1958 by the science fiction magazine Imagination

Illustration by Aubrey Beardsley for Lucian's A True Story

Don Hastings (left) and Al Hodge in Captain Video and His Video Rangers

"Happy 1984" in Spanish or Portuguese, referencing George Orwell's Nineteen Eighty-Four, on a standing piece of the Berlin Wall (sometime after 1998)

Illustration by Theodor von Holst for 1831 edition of Mary Shelley's Frankenstein

Writer Pamela Dean reading at the Minneapolis convention known as Minicon in 2006

Plaque at Riverside, Iowa, to honor the "future birth" of Star Treks James T. Kirk

Temporal settings in the future, or in alternative histories.

Future history

1 links

A future history is a postulated history of the future and is used by authors of science fiction and other speculative fiction to construct a common background for fiction.