One of the most popular beliefs was that Stonehenge was built by the Druids. These high priests of the Celts constructed it for sacrificial ceremonies. The rocks in Stonehenge were quarried 180 miles away.
Galileo was right and wrong. Gravity affects all objects at the same rate. but some objects have higher air resistance making them fall slower. Einstein's general relativity is right but not his cosmology constant. As for why people want to prove them wrong well everyone likes finding mistakes...
The coronavirus is highly contagious and can spread through the air and through direct contact. As for how far it will spread it depends on many factors and is hard to predict.