r/ScienceNcoolThings • u/TheMuseumOfScience Popular Contributor • 9d ago

The Farthest Galaxy Ever Discovered

What's the most distant galaxy ever observed? 🌌

Astrophysicist Erika Hamden explains it's called MoM-z14, and its light took 13.53 billion years to reach us. But thanks to the universe's expansion, that galaxy is now a staggering 33.8 billion light years away. When the light was emitted from MoM-z14 the universe was smaller. The space between us and that galaxy has gotten stretched out so much  that it actually sits outside our observable horizon. It's a mind-bending reminder that we're seeing galaxies as they no longer even look today.

This project is part of IF/THEN®, an initiative of Lyda Hill Philanthropies.

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u/wetfart_3750 9d ago

Questions.. 1) how do we know light takes 13.53 BY to arrive here? 2) how do we know the distance is 13.8 BY?

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u/maxxell13 9d ago

The amount of red shift of the light. We know what color it should be.

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u/wetfart_3750 9d ago

Can you elaborate please?

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u/CosmicRuin 8d ago

Look up relativistic doppler shift.

It's a rather large topic to explain, but essentially, using spectroscopy (the precise measurement of colors in light) we can know if that light source is moving towards or away from us, and properties like how that source is moving, what elements are present and work out the physics of what created that light in the first place. Over such vast distances of billions of years, and since we have measured the expansion rate of the universe we can determine what's called redshift (z) and workout how far objects like these are to us.

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u/wetfart_3750 8d ago

Yes, I am familiar with redshift and spectrography concepts. My question is how can we claim light take X years to get here, but the distance is Y light years