Every time I am trying to solve this equation mathematica is just not doing anything. First time is showed error as quantity is not quantified or something. But since then whenever i am trying to solve this mathematica just does nothing. Even if I restart the program it works for other problems, but if I enter this equation and shift+enter it goes to the next line and does nothing and then stop working for other inputs too. Please help...I am still new in this software.

Solve[Il == 
  1/Sqrt[RTl + ((RTh - RTl) (-Tl + Ts))/(
    Th - Tl)] (\[Sqrt](-Qs + 
       17.8 D0 epsilon (-((273 + Ta)^4/100000000) + (273 + Ts)^4/
          100000000) + (-Ta + Ts) (0.02424 + 0.000037385 (Ta + Ts) - 
          1.10175*10^-9 (Ta + Ts)^2) (1.01 + 
          1462.78 ((
            D0 (1.293 - 0.0001525 He + 6.379*10^-9 He^2) (383.4 + (
               Ta + Ts)/2) Vw)/((1 + 0.001835 (Ta + Ts)) (273 + (
               Ta + Ts)/2)^1.5))^0.52) (1.194 - Cos[\[Degree] phi] + 
          0.194 Cos[2 \[Degree] phi] + 
          0.368 Sin[2 \[Degree] phi]))), Ts]