- TL;DR Summary
- spectra deceleration doppler shift red blue
Let's imagine we have a ship heading towards our planet. It fires forward thrusters to brake. The ship is long way away. Because the ship decelerates, (slows down towards us) would we see particles from its exhaust doppler shifted blue or red? On the one hand the gas is flying towards Earth, so that would imply a blue doppler shift. On the other hand, the ship is slowing down, but would that decleration manifest itself as a red doppler shift somehow? I feel like the fact that the exhaust gas points towards, and is liberated from the ship, the gas would be Doppler blue shifted, but I'm not sure.