This is the context:
We definitely know that particles pop in and out of existence. it happens everywhere all the time and this is what people think might be responsible for dark energy. Only the problem is, when you do the calculation, it comes out wrong by 10 to the 120th power.
I don't get the bold part. can anyone explain?
When people are doing calculations they often express the answer by saying 'it comes out to...'
If I multiply 5 by 3 it comes out to 15.
The number of poor people in the country comes out to something in the hundreds of thousands, but I'm not sure exactly how many.
You can also say that the answer 'comes out wrong', meaning you get the wrong answer.
When my calculator battery is low, the answers always come out wrong.
When you add 'by' to the phrase you're giving the amount of the difference between the calculated answer and the real answer.
When my calculate battery is low, the answers come out wrong by random amounts.
It's a way of saying the size of the error (is this vast number).
If, for example, I calculate that 2 x 5 = 15, my calculation comes out wrong by 50%.
The writer is saying that the calculation concerned is wrong by zillions of times; in other words, a number far beyond the conception of the human mind.
The bolded phrase is a colloquialism (not formal; something used in conversation).
If this was written in a more formal way, one could say:
... the result is off by about 10^120.
or
... the result is incorrect by a margin of about 10^120.
I hope that makes it more clear.
