time dilation

(noun)

The slowing of the passage of time experienced by objects in motion relative to an observer; measurable only at relativistic speeds.

Related Terms

Examples of time dilation in the following topics:

  • Time Dilation

    • Time dilation is an actual difference of elapsed time between two events as measured by observers moving relative to each other.
    • Time dilation is an actual difference of elapsed time between two events as measured by observers either moving relative to each other.
    • For instance, two rocket ships (A and B) speeding past one another in space would experience time dilation.
    • The formula for determining time dilation is: $\Delta t' = \gamma \Delta t = \frac{\Delta t}{\sqrt{1 - v^{2}/c^{2}}}$
    • Thus, time dilation effects and extremely small and can be safely ignored in a daily life.

  • Doppler Effect

    • According to the time dilation, in the unprimed frame it oscillates more slowly at a time interval $\bigtriangleup t=2\pi \gamma / \omega$.
    • The time between the arrival for two crests of the wave in the unprimed frame is given by,

  • Effects of Time Dilation: The Twin Paradox and the Decay of the Muon

    • This occurs because special relativity shows that the faster one travels, the slower time moves for them.
    • This result appears puzzling because each twin sees the other twin as traveling, and so, according to a naive application of time dilation, each should paradoxically find the other to have aged more slowly.
    • In the spacetime diagram , drawn for the reference frame of the Earth-based twin, that twin's world line coincides with the vertical axis (his position is constant in space, moving only in time).
    • Time is relative, but both twins are not equivalent (the ship experiences additional acceleration to changes the direction of travel).

  • Shifting the Paradigm of Physics

    • Time could not affect space and space could not affect time.
    • This can be expressed in the time dilation equation:
    • One of the more radical results of time dilation is the so-called "twin paradox. " The twin paradox is a thought experiment in special relativity that involves identical twins.
    • The square root factor in the time dilation equation is very important and we denote it as:
    • Thus in every day life $\gamma \approx 1$ and we do not experience significant time dilation or length contraction.

  • The Speed of Light

    • The speed of light is generally a point of comparison to express that something is fast. shows a scale representation of the time it takes a beam of light to reach the moon from Earth.
    • This is known as the mass-energy equivalence, and it uses the speed of light to interrelate space and time.
    • For example, length contracts and time dilates (runs slower) for objects in motion.
    • The Lorentz factor (γ) is the factor by which length shortens and time dilates as a function of velocity (v):
    • A beam of light is depicted travelling between the Earth and the Moon in the time it takes a light pulse to move between them: 1.255 seconds at their mean orbital (surface-to-surface) distance.

  • Resolution of the Human Eye

    • The latter value decreases slowly with age; older people's eyes sometimes dilate to not more than 5-6mm.

  • Impulse

    • However, changing momentum is also related to how long a time the force acts.
    • The quantity of impulse is force × time interval, or in shorthand notation:
    • A small force applied for a long time can produce the same momentum change as a large force applied briefly because it is the product of the force and the time for which it is applied that is important.
    • Forces vary considerably even during the brief time intervals considered.
    • A graph of force versus time with time along the x-axis and force along the y-axis for an actual force and an equivalent effective force.

  • The Relativistic Universe

    • Special relativity indicates that humans live in a four-dimensional space-time where the 'distance' $s$ between points in space-time can be regarded as:
    • In this case, the set is the space-time and the elements are points in that space-time.
    • Four-dimensional Minkowski space-time is only one of many different possible space-times (geometries) which differ in their metric matrix.
    • Thus, energy and momentum curves space-time.
    • Since the Earth alters the space-time, humans are pulled toward the Earth.

  • Time

    • Time is the fundamental physical quantity of duration and is measured by the SI Unit known as the second.
    • Time is one of the seven fundamental physical quantities in the International System (SI) of Units.
    • An operational definition of time is highly useful in the conduct of both advanced experiments and everyday affairs of life.
    • Periodic events and motion have long served as standards for units of time.
    • The second is the time required for 9,192,631,770 of these vibrations to occur.

  • Four-Dimensional Space-Time

    • Observer A sets up a space-time coordinate system (t, x, y, z); similarly, A' sets up his own space-time coordinate system (t', x', y', z').
    • where, for example, $\Delta t = t - t_0$; t is the time at which the measurement took place; and t0 is the time at which the light was turned on.
    • In this situation, the space-time separation between the two events is space-like.
    • Events that are time-like or null do not share this property, and therefore there is a causal ordering between time-like events.
    • The reason is that if two space-time points are time-like or null separated, one can always send a light signal from one point to another.