Constants of the universe - Planck Units of Max Planck :

In 1899, German physicist Max Planck proposed a universal set of units for length, time, mass, temperature and other physical qualities. He was trying to come up with a way to define units that depended only on constants of the universe. Planck units are a set of units of measurement defined exclusively in terms of four universal physical constants, in such a manner that these physical constants take on the numerical value of 1 when expressed in terms of these units.

To determine and measure the fundamental constants. The four most important of these are:

• Speed of light c = 299792458 m s^-1
• Gravitational constant G = 6.673(10) x 10^-11 m^3 kg^-1 s^-2
• Planck’s constant (reduced) h(bar) = h/2π = 1.054571596(82) x 10^-34 kg m^2 s^-1
• Boltzmann constant k = 1.3806503(24) x 10^-23 kg m^2 s^-2K^-1

Note, that these constants in SI units: metres (m), kilograms (kg), seconds (s) and degrees Kelvin (K). The numbers in brackets represent the decimal places where the values are uncertain.

The Planck length, denoted ℓP, is a unit of length in the system of Planck units that was originally proposed by physicist Max Planck, equal to 1.616255(18)×10^−35 m. 

The Planck time tP is the time required for light to travel a distance of 1 Planck length in vacuum, which is a time interval of approximately 5.39×10^−44 s. No current physical theory can describe timescales shorter than the Planck time, such as the earliest events after the Big Bang.

However, according to Planck the velocity of electromagnetic waves, or light, is equal to one Planck length per Planck time; the limit to which photon can travel. 

Planck units are a set of units of measurement defined exclusively in terms of four universal physical constants. Originally proposed by the German physicist Max Planck in 1899, these units are a system of natural units because their definition is based on properties of nature. It may be mentioned here that Einstein first published his special theory of relativity in 1905, which describes his revolutionary ideas about light, time and energy.

Dark Energy and Andromeda-Milky Way galaxy merger:

Yes. Andromeda galaxy is moving towards us instead of moving away. This exception does not rule out that the galaxies are moving away. Because there is a reasonable scientific explanation behind this exception.

The Universe consists of less than 5% interactive baryonic matter, about 26% non-interactive but gravitationally interactive dark matter, and more than 68% dark energy - with an effective mass <0.

Galaxies or clusters of galaxies have zero-gravity spheres outside the gravitational influence, where there is a tug-of-war between gravity and anti-gravity, with dark energy causing antigravity. Dark energy, at least on the intergalactic scale, can only be effective in space unless such galaxies are gravitationally bound clusters, mega or superclusters.

A galaxy, gravitationally bound but not externally bound to a cluster of galaxies, will be affected by dark energy. That is, an independent galaxy or an independent cluster of galaxies will be affected by dark energy, whereas gravity will have no effect on dark energy-dominated space. Dark energy has no effect within the influence of gravity, and gravity will have no effect where dark energy dominates.

The effective mass of dark energy is much greater than the combined mass of ordinary matter and the effective mass of dark matter. So antigravity caused by dark energy overcomes gravity. Therefore, galaxies move away and the space between galaxies appears to expand.

The Milky Way and Andromeda belong to a small cluster of Local Group galaxies known as the Virgo Cluster. Since the Andromeda Galaxy is also gravitationally bound to the Milky Way Galaxy and bound to the Local Galactic Cluster, the distance between Andromeda and the Milky Way Galaxy does not increase, but rather decreases.

However, regardless of the merger of Andromeda and the Milky Way, the galactic clusters to which these galaxies belong will be overruled by dark energy in the distant future.

#darkenergy #gravity #antigravity #galaxymerger #effectivemass