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The Hubble length or Hubble distance is a unit of distance in cosmology, defined as cH −1 — the speed of light multiplied by the Hubble time. It is equivalent to 4,420 million parsecs or 14.4 billion light years. (The numerical value of the Hubble length in light years is, by definition, equal to that of the Hubble time in years.)
The Hubble length / is 14.4 billion light years in the standard cosmological model, equivalent to times Hubble time. The Hubble time is the reciprocal of the Hubble constant, [5] and is slightly larger than the age of the universe (13.8 billion years) as it is the age the universe would have had if expansion was linear.
Hubble radius, Hubble sphere (not to be confused with a Hubble bubble), Hubble volume, or Hubble horizon is a conceptual horizon defining the boundary between particles that are moving slower and faster than the speed of light relative to an observer at one given time. Note that this does not mean the particle is unobservable; the light from ...
Rather, the conformal time is the amount of time it would take a photon to travel from where we are located to the furthest observable distance, provided the universe ceased expanding. As such, η 0 {\displaystyle \eta _{0}} is not a physically meaningful time (this much time has not yet actually passed); though, as we will see, the particle ...
The observable universe is a spherical region of the universe consisting of all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion.
The aim is to find so-called M Dwarfs, stars 20 times dimmer than our sun, and see if they emit too much radiation to support life on other worlds. Mini-Hubble will scan dim stars to see if they ...
In order to get an accurate measurement, it is necessary to make two observations separated by time Δt. Subsequently, we can use Subsequently, we can use d = V e j ω , {\displaystyle \ d={\frac {V_{ej}}{\omega }}\,,} where d is the distance to the supernova, V ej is the supernova's ejecta's radial velocity (it can be assumed that V ej equals ...
Hubble can also observe at ultraviolet wavelengths which do not penetrate the atmosphere. Each observatory was designed to push the state of technology in its region of the electromagnetic spectrum. Compton was much larger than any gamma-ray instruments flown on the previous HEAO missions, opening entirely new areas of observation.