I'll address each question individually, starting with the hardest first.
1) Can she sing? Well, that's a matter of opinion. Unfortunately for Jessica, the majority of the opinion says "no." Those offering a different view tend to be adolescent boys, unmarried men and feis dads. This being said, I can not offer any substantial proof that she can actually sing. I have seen her perform and she looks good doing it, but I haven't a clue as to whether the words escaping her mouth isn't anything more than an awful screeching.
2) Was Jessica once a brilliant physics student? Yes. When I met her in college, she was on top of her class. She was acing all her tests and all her professors loved her (she was a favorite among the TA's). Here's one of the many examples of how she could easily solve a physics problem.

Jessica nails the test: A+
3) Did Jessica lose her brilliance? Most definitely. Once she began "singing" and dating Nick, her brain power dropped faster than the stock market did two years ago. Here are some of her test results (which are now infamous on the internet) showing just how low she had become.





As you can see, Jessica no longer had the brain power to solve complex mathematical problems, or talk without sounding like a complete idiot. For some reason, she also kept signing her name as "Peter" which no one could ever figure out why.
What does all of this mean? I haven't a clue. I can't seem to put two comprehensive sentences together at a time (though I blame my loss of cognition on over exposure to accordion music and curly wigs).
-- feis dad