Overlapping Galaxies
This rare alignment between the two spiral galaxies “on top of each other” was captured by NASA’s Hubble Space Telescope. Look carefully at the outer rim (the left side) of the smaller foreground galaxy against the bigger background galaxy, you will notice tentacles of dust lanes extending beyond the small galaxy’s disk of starlight.
This feature – the outer dark dusty structures – is rarely so visible in a galaxy because there is usually nothing behind them to illuminate them. But in this case, we have a big, bright background galaxy to illuminate it.
Astronomers calculated that the background galaxy is 780 million light-years away. They have not as yet calculated the distance between the two galaxies, although they think the two are relatively close, but not close enough to interact. The background galaxy is about the size of the Milky Way Galaxy and is about 10 times larger than the foreground galaxy.
My Dark Sky 