Temperatura CMB em z
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Cosmic Microwave Background (CMB) temperature at a given redshift (z) is calculated using T = T₀·(1+z), where T₀ is the current CMB temperature (~2.725 K). This calculation is essential in cosmology to understand how the universe's temperature evolved in the past. Redshift (z) reflects cosmic expansion, with higher z values indicating older, hotter radiation.
The formula assumes the CMB follows Planck's law and that the universe is isotropic and homogeneous. It's applied in studies of cosmic structure formation, gravitational lensing, and distant object analysis. For z > 0, temperature increases linearly, representing a hotter past universe.
Note that this is a valid approximation for moderate redshifts (z < 1000). In more complex models, such as non-flat universes or dark energy-dominated scenarios, adjustments may be needed. Always confirm the redshift input validity, as negative or unrealistic values could produce meaningless results.
Frequently asked questions
Why does temperature increase with redshift?
Temperature increases with redshift (z) because the universe was hotter in the past. Higher z values indicate older radiation observed from earlier cosmic times.
What is the current CMB temperature?
The current Cosmic Microwave Background temperature is approximately 2.725 K, measured at the present epoch (z = 0).
Can I use negative redshift values?
No, negative redshift values (z < 0) do not represent physical scenarios, as they would imply a contracted universe in the future.
How does the formula T = T₀·(1+z) work?
The formula relates CMB temperature to redshift: T = T₀·(1+z). Redshift z measures cosmic expansion, and temperature scales with (1+z) due to space-time dilation.