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How Do You See Distant Galaxies If Nearby Galaxies Are In The Way?

-- tom behan | December 5, 2020

Hubble Space Telescope image of galaxy and gravitationally-lensed images.

Question:

Hello. How do you ‘see’ things on the other side of some distant galaxy if there are, say, 5 other larger galaxies ‘in the way’: in a direct line between earth and that most distant galaxy?

Thanks for what you can suggest. I appreciate your time.

-- tom behan

Answer:

It is rare for two galaxies to lie exactly along the same line-of-sight, so that the one closer to us completely obscures the more distant galaxy. When two galaxies lie nearly along the same line-of-sight, we can sometimes measure an effect called gravitational lensing, where the gravity of the closer galaxy bends the light passing near it from the more distant galaxy, which produces a magnified view of the more distant galaxy.

-- Jeff Mangum

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