Algorithm notation between two functions

I have two functions,
$$ f = n ^ {1.6} $$
$$ g = n ^ {1.5} $$

I thought it was $ f = theta (g) $, since $ f $ is asymptotically linked $ g $, if $ n $ goes to infinity.
However, the answer is $ f = omega (g) $.
Can any one explain why this is $ f = omega (g) $ ?
Thanks in advance!