Explanation: How does a comet tail change? It depends on the comet. The ion tail of Comet C/2025 A6 (Lemmon) has been changing markedly, as detailed in the featured image sequenced over six days between September 25 and October 4 (left to right) from Texas , USA . On some days, the comet's ion tail was relatively more complex than other days. Reasons for tail changes include the rate of ejection of material from the comet's nucleus , the strength and complexity of the passing solar wind , and the rotation rate of the comet . Sometimes, over the course of a week, apparent differences even result from a change of perspective from the Earth. In general, a comet's ion tail will point away from the Sun , as gas expelled is pushed out by the Sun's wind . Comet Lemmon is still inbound and brightening , passing nearest the Earth on October 21 and nearest the Su n on November 8.