Are there rainbows in deep space?
This week's question comes from Tyson Nordal from New Westminster, B.C, who asks, "If I were floating in space by Saturn's moon Enceladus and caught the sun's light through the geysers that Enceladus sprays up into space, would I be treated to a space rainbow?"
Dr. Mohamad Ali-Dib, an astrophysicist from the University of Toronto, says there's almost a constant eruption of water geysers coming from Saturn's moon Enceladus. Since Saturn is about ten times as far from the sun as Earth, it's much colder out there, so the water vapour erupting from the moon's surface would freeze very quickly into ice crystals. Ice crystals behave differently than water vapour droplets that can create a multicolour rainbow here on Earth. Water ice crystals will instead create a single colour yellowish or white rainbow, otherwise known as a sun dog. We can see such sun dogs here on Earth in very cold temperatures, but due the distance between Saturn and the sun, any sun dog coming from Enceladus would be much fainter than anything seen here. Dr. Ali-Dib says you'd have to be floating fairly close to the surface Enceladus to witness it.