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  2. Expansion of the universe - Wikipedia

    en.wikipedia.org/wiki/Expansion_of_the_universe

    For example, galaxies that are farther than the Hubble radius, approximately 4.5 gigaparsecs or 14.7 billion light-years, away from us have a recession speed that is faster than the speed of light. Visibility of these objects depends on the exact expansion history of the universe.

  3. Supersonic speed - Wikipedia

    en.wikipedia.org/wiki/Supersonic_speed

    A United States Navy F/A-18F Super Hornet in transonic flight U.S. Navy F/A-18 approaching the speed of sound. The white cloud forms as a result of the supersonic expansion fans dropping the air temperature below the dew point. [1] [2] Supersonic speed is the speed of an object that exceeds the speed of sound (Mach 1).

  4. Accelerating expansion of the universe - Wikipedia

    en.wikipedia.org/wiki/Accelerating_expansion_of...

    For supernovae at redshift less than around 0.1, or light travel time less than 10 percent of the age of the universe, this gives a nearly linear distance–redshift relation due to Hubble's law. At larger distances, since the expansion rate of the universe has changed over time, the distance-redshift relation deviates from linearity, and this ...

  5. Time dilation - Wikipedia

    en.wikipedia.org/wiki/Time_dilation

    The faster the relative velocity, the greater the time dilation between them, with time slowing to a stop as one clock approaches the speed of light (299,792,458 m/s). In theory, time dilation would make it possible for passengers in a fast-moving vehicle to advance into the future in a short period of their own time.

  6. Cosmological horizon - Wikipedia

    en.wikipedia.org/wiki/Cosmological_horizon

    A cosmological horizon is a measure of the distance from which one could possibly retrieve information. [1] This observable constraint is due to various properties of general relativity, the expanding universe, and the physics of Big Bang cosmology. Cosmological horizons set the size and scale of the observable universe. This article explains a ...

  7. Alcubierre drive - Wikipedia

    en.wikipedia.org/wiki/Alcubierre_drive

    The Alcubierre drive ([alkuˈβjere]) is a speculative warp drive idea according to which a spacecraft could achieve apparent faster-than-light travel by contracting space in front of it and expanding space behind it, under the assumption that a configurable energy-density field lower than that of vacuum (that is, negative mass) could be created.

  8. Space travel under constant acceleration - Wikipedia

    en.wikipedia.org/wiki/Space_travel_under...

    From the planetary frame of reference, the ship's speed will appear to be limited by the speed of light — it can approach the speed of light, but never reach it. If a ship is using 1 g constant acceleration, it will appear to get near the speed of light in about a year, and have traveled about half a light year in distance. For the middle of ...

  9. Sonic boom - Wikipedia

    en.wikipedia.org/wiki/Sonic_boom

    The sound source is travelling at 1.4 times the speed of sound (Mach 1.4). Since the source is moving faster than the sound waves it creates, it leads the advancing wavefront. A sonic boom produced by an aircraft moving at M=2.92, calculated from the cone angle of 20 degrees.