• Question: How is the sodium tail of a comet made?

    Asked by to Alan on 18 Mar 2014. This question was also asked by .
    • Photo: Alan Fitzsimmons

      Alan Fitzsimmons answered on 18 Mar 2014:

      When the comet is near the sun, it releases sodium atoms. Only orange light in sunlight is reflected by the sodium – all the other sunlight passes straight through the sodium. But so much orange light bounces off the sodium atoms, it pushes the sodium away from the direction of the Sun. So as the sodium moves away from the comet it forms a tail of sodium atoms, and we discovered it by taking a picture of a comet in orange light.

Comments