Most street lights are made from one or two elements mercury or sodium. Explain why astronomers preferred that cities you sodium streetlights instead of mercury streetlights
mercury is very harmful to the average human being. the mercury can easily be released from the lamp if the lamp is knocked over and broken. mercury is also harmful if inhaled. sodium on the other hand is not harmful in any way.
Astronomers prefer that cities use sodium street lights because the emission spectrum of sodium produces fewer lines than the emission spectrum of mercury
