From their vantage point on the International Space Station (ISS), NASA astronauts Matthew Dominick and Don Pettit have been treating us to a front-row seat to a celestial spectacle: comet C2023-A3, also known as Tsuchinshan-ATLAS, on its journey towards the sun. These astronauts, renowned for their space-based photographic skills, have been tracking the comet’s movement over the past week, capturing breathtaking images and sharing their insights on social media.
Dominick shared a time-lapse video showcasing the comet’s tail, which he noted is getting longer each day. He explained the fascinating phenomenon of the tail appearing bent: “The atmosphere is more dense the closer you get to earth. Changes in the density of the atmosphere change the refractive index and thus make the comet tail appear bent.” The video, a compilation of images taken with a 200mm lens every 5 minutes, offers a unique perspective of the comet’s movement against the backdrop of Earth’s atmosphere. The upward motion in the frame is due to the space station’s orbit around Earth at a speed of 17,500 mph.
Pettit, also a seasoned space photographer, expressed his awe at witnessing the comet from orbit: “It is totally awesome to see a comet from orbit. The perspective of rising through the atmosphere on edge is truly unique from our vantage point.” He emphasized that while the comet’s tail is too dim to be seen with the naked eye, it’s steadily becoming brighter as it approaches the sun. Dominick, using his knowledge of orbital geometry, cleverly figured out where to point their cameras to capture the elusive comet.
The astronauts, privileged to witness such awe-inspiring cosmic events from their orbital home, expressed their gratitude for the opportunity: “We were discussing the other day how lucky and grateful we are to have seen amazing aurora , a solar eclipse , and a comet in a single trip to the ISS.” For those on Earth, particularly in Australia and New Zealand, the comet is visible in the morning sky. If it continues to brighten as expected, the viewing possibilities will expand for people around the world, offering a chance to catch a glimpse of this cosmic visitor in the night sky.
