Data is re-analyzed in the context of new data and improved hypotheses. Data is not "disproven" as you claimed. There may be several ways to explain an observation, and some of the explanations can be shown to be wrong, but the observation itself never can.

After the discovery of standard candles, when the map of the universe was completely reconceptualized, nothing ever changed about astronomical data: observations of stellar position and brightness. What had changed was the explanation for those brightnesses and the meanings attributed to them. The data stays the same, the explanation changes, and if an explanation doesn't match the data, like the milky-way-is-the-universe hypothesis, then it's a bad explanation.