Night Boat To Cairo
Tuesday, Sept. 29, 2015: NASA astronaut Scott Kelly photographed the Nile River from the International Space Station on Sept. 22, 2015. On Twitter he wrote: "Day 179. The #Nile at night is a beautiful sight for these sore eyes. Good night from @space_station! #YearInSpace."
— Tom Chao
Halos
Wednesday, Sept. 30, 2015: Two galaxies, NGC 4302-4298, interact as their gravitational fields pull at each other. The disturbed extended stellar halos of these two similar galaxies reveal the tidal interaction. We see one galaxy edge-on, with a dust lane showing the thin galactic disk of younger stars. The other galaxy shows the same central structure as a blue swirl. Image released September 2015.
— Tom Chao