Since the early 1960s astronomers have discovered cosmic objects known as quasars that exhibit larger redshifts than any of the remotest galaxies previously observed. This law of redshifts has been confirmed by subsequent research and provides the cornerstone of modern relativistic cosmological theories that postulate that the universe is expanding. That is to say, the greater the redshift manifested by light emanating from such an object, the greater the distance of the object and the larger its recessional velocity ( see also Hubble’s constant). This generalization became the basis for what is called Hubble’s law, which correlates the recessional velocity of a galaxy with its distance from Earth. The American astronomer Edwin Powell Hubble reported in 1929 that the distant galaxies were receding from the Milky Way system, in which Earth is located, and that their redshifts increase proportionally with their increasing distance. It is attributed to the Doppler effect, a change in wavelength that results when a given source of waves (e.g., light or radio waves) and an observer are in motion with respect to each other. Redshift, displacement of the spectrum of an astronomical object toward longer (red) wavelengths. For more information about signing requests, go to Signing an HTTP request. If you use the Amazon Redshift Query API, you must authenticate every HTTP or HTTPS request to the API by signing it. For more information, see Amazon Redshift clusters.Īs an application developer, you can use the Amazon Redshift API or the AWS Software Development Kit (SDK) libraries to manage clusters programmatically. If you prefer to manage your Amazon Redshift resources manually, you can create provisioned clusters for your data querying needs.
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