Steady-state model

<p>In <a href="/facts/Physical_cosmology/ww4ChbEq">cosmology</a>, the steady-state model or steady-state theory was an alternative to the <a href="/facts/Big_Bang/I5T1vTnv">Big Bang</a> theory. In the steady-state model, the density of matter in the <a href="/facts/Expanding_universe/f6Uvt79B">expanding universe</a> remains unchanged due to a continuous creation of matter,  thus adhering to the <a href="/facts/Perfect_cosmological_principle/snaj0VNu">perfect cosmological principle</a>, a principle that says that the <a href="/facts/Observable_universe/CdTGMdsp">observable universe</a> is always the same at any time and any place. A <a href="/facts/Static_universe/bbeTuj6V">static universe</a>, where space is not expanding, also obeys the perfect cosmological principle, but it cannot explain astronomical observations consistent with expansion of space.
</p><p>From the 1940s to the 1960s, the astrophysical community was divided between supporters of the Big Bang theory and supporters of the steady-state theory. The steady-state model is now rejected by most <a href="/facts/Cosmologists/ww4ChbEq">cosmologists</a>, <a href="/facts/Astrophysicists/PpzNpsWq">astrophysicists</a>, and <a href="/facts/Astronomers/ronF8j4a">astronomers</a>.
The observational evidence points to a hot Big Bang cosmology with a finite <a href="/facts/Age_of_the_universe/BaByputq">age of the universe</a>, which the steady-state model does not predict.
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Steady-state model open-in-new

Steady-state model