Is all knowledge dependent on culture?

That depends on what you think "culture" means. All knowledge depends on believing. People used to look at the stars and believe they rotated around the Earth. They had strong evidence to support that belief, but in fact they only had the evidence because they believed first. When rockets were invented in the USA, they were mostly used to collect weather data. That led to scientists believing that weather principles applied in space, and that is why they speak of winds and shock waves in a vacuum. A big part of science is conjecture, which means making up "What if" scenarios. Often those scenarios get discussed a lot for a long time, and people begin to believe they are true just because they keep hearing them.

Some of the words I have used are easily confused with "culture", and that illustrates why you have to be so careful to understand the words you use, and only use words with strongly defined meanings when talking to other people.