Question

Cosmology metric explain......​

Answer 1

Answer:

A metric is a mathematical expression describing the points in space. The scale factor determines whether the universe is contracting or expanding. In a comoving coordinate system, the measuring scale expands along with the frame (expanding universe). Proper distance is the instantaneous distance of objects

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Answer 2

Answer:

Cosmological Metric & Expansion...--

As per the law of conservation of energy and the law of conservation of mass, the total amount of energy including the mass (E=mc2) remains unchanged throughout every step in any process in the universe. The expansion of the universe itself consumes energy which maybe from the stretching of wavelength of photons (Cosmological Redshift), Dark Energy Interactions, etc.

To speed up the survey of more than 26,000 galaxies, Stephen A. Shectman designed an instrument capable of measuring 112 galaxies simultaneously. In a metal plate, holes that corresponded to the positions of the galaxies in the sky were drilled. Fiber-optic cables carried the light from each galaxy down to a separate channel on a spectrograph at the 2.5-meter du Pont telescope at the Carnegie Observatories on Cerro Las Campanas in Chile.

For maximum efficiency, a specialized technique known as the Drift-Scan Photometry was used, in which the telescope was pointed at the beginning of a survey field and then automated drive was turned off. The telescope stood still as the sky drifted past. Computers read information from the CCD Detector at the same rate as the rotation of the earth, producing one long, continuous image at a constant celestial latitude. Completing the photometry took a total of 450 hours.

Different forms of noise exist and their mathematical modelling is different depending upon its properties. Various physical processes evolve the power spectrum of the universe on a large scale. The initial power spectrum imparted due to the quantum fluctuations follows a negative third power of frequency which is a form of Pink Noise Spectrum in three dimensions.

The Metric...

In cosmology, one must first have a definition of space. A metric is a mathematical expression describing points in space. The observation of the sky is done in a spherical geometry; hence a spherical coordinate system shall be used. The distance between two closely spaced points is given by −

ds2=dr2+r2θ2+r2sin2θdϕ2ds2=dr2+r2θ2+r2sin2θdϕ2

The following image shows Geometry in the 3-dimensional non-expanding Euclidean space.