# The problem of General relativity

Did Friedmann by his equations find a problem in the theory of general relativity? Because at first Einstien built his theory on a steady state universe. But, Friedmann according to this theory estimated that universe cannot be in the steady state and should expand. If yes, what was the problem of the theory with the steady state?

• The problem is that there are no stable steady-state solutions except rather useless ones (this applies even with the cosmological constant) unless you do tricks like creating matter continually (which gives you the endlessly-expanding steady-state universe of Hoyle et al). Fortunately for GR the universe does not appear to be in a steady state. – tfb Aug 1 '17 at 22:34

However, Friedmann found that GR only works if the Universe is either constantly expanding or contracting. To force the field equations of GR to spit out a steady state universe, Einstein added the cosmological constant $\Lambda$ to the equations.