Eli5 Why aren’t stars blurry

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That’s kind of the wrong question. I’m not exactly sure how to ask because I don’t know where I’m confused.

This morning, sitting under the stars for 2 hours before sunrise, I pondered the old light of stars.I had never thought about the journey light had to travel and retain its form. I don’t understand how we see the source as a pin prick of light from that distance… and someone standing right next to you (or half way across the earth) would see the same pin prick but it would be different photons hitting their retinas.

How does the light spread like that but retain any form? If photons move perceptibly (to our measuring equipment) in close distances in the double slit experiment, how do they stay in a tight enough formation over those vast distances to still look like a pin prick when they reach us. I’m not sure I’m asking the right question but I found my mind a little boggled by what is probably a simple to explain phenomenon that shouldn’t even be confusing. Probably a couple questions in there.

Thanks!

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6 Answers

Anonymous 0 Comments

That distant sun spreads photons out in a sphere. BUT those photons are soooo tightly packed, a single stream of an extremely small portion of those photons will travel thousands of light years until it hits your eye.

A different portion hits your other eye or your neighbor.

For this sphere of photons to travel in parallel beams (rays, stream, spike, other words) and continually hit your eye or a telescope means those electrons must be very very close together. Otherwise the beam would have spread out to invisible or flickering because your eye would be ‘between’ those photon beams from so far away.

Stars flicker on earth due to atmosphere shifting, in space it is a constant pin prick.

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