--%>
Assignment Help - homework help

What is Hubble constant

Hubble constant: H0 (E.P. Hubble; 1925): The constant that determines the relationship among the distance to a galaxy and its velocity of recession due to the growth of the Universe. As the Universe is self-gravitating, it is not truthfully constant. In cosmology, it is stated as

H = (da/dt)/a,

Here a is the 4-radius of the Universe. Whenever computed for the present, it is written as:

H0 == H (t = now)

The Hubble constant is not acknowledged to great accuracy (only in about a factor of 2), however is believed to lie someplace between 50 and 100 km/s/Mpc.

   Related Questions in Physics

  • Q : Define Cosmic background radiation or

    Cosmic background radiation: primal glow: The background of radiation is generally in the frequency range of 3 x 1011 to 3 x 108 Hz discovered in space in the year 1965. It is believed to be the cosmologically re

    		•
  • Q : What is Negative feedback principle

    Negative feedback principle: It is the idea that in a system where there are self-propagating situations, those new situations tend to act against formerly existing situations. Such a principle is in actuality a restatement of the conservation law.

    		•
  • Q : Define Fermi paradox Fermi paradox (E.

    Fermi paradox (E. Fermi): E. Fermi's inference, simplified with the phrase, "Where are they?" questioning that when the Galaxy is filled with intelligent and scientific civilizations, why haven't they come to us hitherto? There are nu

    		•
  • Q : Black-hole dynamic laws or laws of

    Explain  laws of black-hole dynamics or First law of black hole dynamics and Second law of black hole dynamics? 

    Q : Bragg's law Bragg's law - Whenever a

    Bragg's law - Whenever a beam of x-rays strikes a crystal surface in which the layers of ions or atoms are often separated, the maximum intensity of the reflected ray takes place when the complement of the angle of incidence, theta (θ), the wave

    		•
  • Q : Conservation laws and illustrations of

    Explain Conservation laws and illustrations of conservation laws (Conservation of mass-energy, electric charge, linear momentum and angular momentum) ? Conservation laws: The law which states that,

    		•
  • Q : Define Watt or SI unit of power Watt: W

    Watt: W (after J. Watt, 1736-1819): The derived SI unit of power, stated as a power of 1 J acting over the period of 1 s; it therefore has the units of J/s.

    		•
  • Q : Explain Ohms law Ohm's law (G. Ohm;

    Ohm's law (G. Ohm; 1827): The ratio of the potential difference among the ends of a conductor to the current flowing via it is constant; the constant of proportionality is termed as the resistance, and is distinct for different materials.

    		•
  • Q : Define Radian or SI unit of the angular

    Radian: rad: The supplementary SI unit of the angular measure stated as the central angle of a circle whose subtended arc is equivalent to the radius of the circle.

    		•
  • Q : Define Kilogram or SI unit of mass

    Kilogram: kg: The basic SI unit of mass that is the only SI unit still maintained by a physical artifact: a platinum-iridium bar reserved in the International Bureau of Weights and Measures at Sevres, France.

    		•