--%>
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 Copernican principle Copernican

    Copernican principle (N. Copernicus): The idea, recommended by Copernicus, that the Sun, not the Earth, is at the center of the earth. We now know that neither idea is accurate (that is, the Sun is not even situated at the center of o

    		•
  • Q : Define Rayleigh criterion or resolving

    Rayleigh criterion: resolving power: The criterion for determining how delicately a set of optics might be able to differentiate. This  starts with the supposition that central ring of one image must fall on the first dark ring of the other; for

    		•
  • Q : Define Trojan points Trojan points : L4

    Trojan points: L4 and L5 are the two dynamically stable Lagrange points (that is, beneath certain conditions).

    		•
  • Q : Define Centrifugal pseudo force

    Centrifugal pseudo force: A pseudo force which takes place whenever one is moving in uniform circular motion. One feels a "force" directed outward from the center of the motion.

    		•
  • Q : Define Einstein-Podolsky-Rosen effect

    Einstein-Podolsky-Rosen effect: EPR effect: Consider the subsequent quantum mechanical thought-experiment: Take a particle that is at rest and has spun zero (0). This spontaneously decays into two fermions (spin 1/2 particles), that stream away in the

    		•
  • Q : Explain Fizeau method Fizeau method (A.

    Fizeau method (A. Fizeau, 1851): One of the primary truthfully relativistic experiments intended to compute the speed of light. Light is passed via a spinning cog-wheel driven by running water, is reflected off a far-away mirror, and

    		•
  • Q : Explain Malus law Malus' law (E.L.

    Malus' law (E.L. Malus): The light intensity I of a ray with primary intensity I0 travelling via a polarizer at an angle theta among the polarization of the light ray and the polarization axis of the polarizer is specified by:

    Q : Explain Rayleigh-Jeans law

    Rayleigh-Jeans law: For a blackbody at the thermodynamic temperature T, the radiance R over a range of frequencies between the nu and nu + dnu is specified by: R = 2 pi nu2 k T/c2.<

    		•
  • Q : Define Gauss law Gauss' law (K.F.

    Gauss' law (K.F. Gauss): The electric flux via a closed surface is proportional to the arithmetical sum of electric charges contained in that closed surface; in its differential form, div E = rho,

    		•
  • Q : Define Volt or SI unit of electric

    Volt: V (after A. Volta, 1745-1827): The derived SI unit of electric potential, stated as the difference of potential among the two points on a conductor fetching  a constant current of 1 A whenever the power dissipated between the points is 1 W;

    		•