And all the people saw the thunderings, and the lightnings, and the noise of the trumpet, and the mountain smoking: and when the people saw it, they removed, and stood afar off.
The Hebrew word in this passage is reyim: "they saw". They saw the thunder... and the noise of the trumpet. The Hebrew word for "hear" is azan. This passage never says they heard these things it says they saw these things.
The people of God have known this type of thing is possible for the past 3,500 years. Science is catching up with Scripture.