This is the first ever sunset witnessed on Mars. Nasa's Curiosity Mars rover have released a series of amazing images of a Martian sunset captured on 15 April.
But instead of the fiery oranges we are normally used to seeing on Earth, dust in the Martian atmosphere allow blue rays to light up the sky.
"The effect is most pronounced near sunset, when light from the sun passes through a longer path in the atmosphere than it does at midday," a statement from Nasa said.
Nasa's Jet Propulsion Laboratory built the project's Curiosity Rover and manages the Mars Science Laboratory Project for the Science Mission Directorate in Washington.