Editing 54: Science
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The solid line represents the theoretical {{w|blackbody radiation|radiation for a blackbody}} at 2.73 K according to {{w|Planck's Law}} (derived as early as 1900 by {{w|Max Planck}}). The formula, almost as written in the graph, can be found {{w|Black-body radiation#Planck's law of black-body radiation|here}}. The only changes are that on Wikipedia, the frequency ''f'' is represented by the Greek letter ''Ξ½'' (nu) and the temperature ''T'' is included as an independent variable, so ''I''(''f'') becomes ''I''(''v'',''T''). However, ''I''(''v'',''T'') still represents the {{w|Radiance#Spectral radiance|spectral radiance}} (similar to energy density). In this formula, ''h'' is the Planck constant, ''c'' is the speed of light in a vacuum, and ''k'' is the Boltzmann constant. The frequency (''f'' or ''v'') along the ''x''-axis is measured in {{w|gigahertz}}. The curve peaks at 160.4 GHz. There is no scale or unit on the {{w|energy density}} on the ''y''-axis. | The solid line represents the theoretical {{w|blackbody radiation|radiation for a blackbody}} at 2.73 K according to {{w|Planck's Law}} (derived as early as 1900 by {{w|Max Planck}}). The formula, almost as written in the graph, can be found {{w|Black-body radiation#Planck's law of black-body radiation|here}}. The only changes are that on Wikipedia, the frequency ''f'' is represented by the Greek letter ''Ξ½'' (nu) and the temperature ''T'' is included as an independent variable, so ''I''(''f'') becomes ''I''(''v'',''T''). However, ''I''(''v'',''T'') still represents the {{w|Radiance#Spectral radiance|spectral radiance}} (similar to energy density). In this formula, ''h'' is the Planck constant, ''c'' is the speed of light in a vacuum, and ''k'' is the Boltzmann constant. The frequency (''f'' or ''v'') along the ''x''-axis is measured in {{w|gigahertz}}. The curve peaks at 160.4 GHz. There is no scale or unit on the {{w|energy density}} on the ''y''-axis. | ||
| β | The theory is that the blackbody in question was the universe at the point when it had cooled down enough {{w|Decoupling (cosmology)|to allow photons to escape}}, {{w|Chronology of the universe|0.38 million years}} into | + | The theory is that the blackbody in question was in fact the universe at the point when it had cooled down enough {{w|Decoupling (cosmology)|to allow photons to escape}}, {{w|Chronology of the universe|0.38 million years}} into the universe's {{w|Big Bang|13.8 billion years}} history. The photons that reach us today are the ones that have been travelling to us at lightspeed since then. As the light from astronomical objects suffers from {{w|redshift}} due to the expansion of the universe, and this shift becomes more pronounced with distance from the observer, this light displays in the infrared range. |
The title text praises viewers who can identify where this equation and corresponding graph come from (without consulting this wiki, of course). | The title text praises viewers who can identify where this equation and corresponding graph come from (without consulting this wiki, of course). | ||
