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Is it just coincidence that from our point of view the moon looks like it's the exact same size as the sun? Or is there something else going on?
by doakes 2y ago
Is it just coincidence that from our point of view the moon looks like it's the exact same size as the sun? Or is there something else going on?
- atonse 2y agoYes it’s an absolutely crazy coincidence that the moon is the correct proportion to its distance that results in perfect total eclipses. I remember learning this fact in an astronomy class and that we’re not aware of this happening anywhere else in our solar system.
- eichin 2y agoIt's also "temporary" (moon's orbital radius increases ~4cm/year)
- doakes 2y agoInteresting! I wonder how long ago (if ever) eclipses weren't even possible
- deleted 2y ago[deleted]
- pie420 2y agoit's the opposite, a long time ago eclipses were "bigger" and happened more often, as the moon drifts farther away, it seems smaller to us and will no longer be big enough in our sky to block the sun one day.
- doakes 2y agoThanks for clarifying
- piptastic 2y agoEstimates suggest that total solar eclipses could cease to occur in about 600 million years from now, give or take, depending on the precise nature of lunar recession and changes in Earth's rotation. This timeframe is long enough that many other changes on Earth and in the solar system will also occur, making the cessation of total solar eclipses just one of many transformations.
- Lerc 2y agoThen we will have to endure a few million years of people arguing whether or not it should be called an eclipse or a transit
- mturmon 2y agoPart of that is that Earth's moon is quite large compared to other moons like Phobos. Here's a nice pic of Phobos and Deimos as seen from the mast-camera of Curiosity, compared with Luna. I remember reading an Asimov piece many years ago where he was (typically) spinning out a kind of what-if about how the large size of the moon, and the consequent majorly-obvious eclipses, influenced the importance of ancient astronomy. Not to mention other effects like tides and moonlight.
- atonse 2y agoNice, I’d love to read that.
- basementcat 2y agoIs this the link? https://www.universetoday.com/166028/perseverance-sees-phobos-deimos-and-mercury-passing-in-front-of-the-sun/ https://www.universetoday.com/166028/perseverance-sees-phobo...
- mturmon 2y agoIt's here: https://mars.nasa.gov/resources/5511/illustration-comparing-apparent-sizes-of-moons/#:~:text=Phobos%20has%20a%20diameter%2014,from%20an%20observer%20on%20Earth https://mars.nasa.gov/resources/5511/illustration-comparing-....
- phinnaeus 2y agoHe uses the "planet with a giant satellite" description of Earth as a plot point in Foundation (I think the final novel).
- deleted 2y ago[deleted]
- make_clean 2y agoI recall reading that is a remarkable and fortunate coincidence. Cannot find citation at the moment.
- netcraft 2y agocheck out this minutephysics video that explains and also talks about other eclipses in the solar system https://youtu.be/CikPFdZdY4k?si=NXpXHz06X3nZklt4 https://youtu.be/CikPFdZdY4k?si=NXpXHz06X3nZklt4
- theodorejb 2y agoFrom my perspective it's one of many evidences that our planet was intentionally created by God. I think He wanted us to experience these rare and spectacular events and use them to make astronomical discoveries.
- grecy 2y ago[flagged]
- simion314 2y ago>Once you've seen someone die painfully and slowly from cancer over years, you know there can be no god. i agree with you, but I think the conclusion from your argument is that the Good god does not exist, it is still possible that a Creator exist, but one that is not Good. kind or have human like qualities and morals.
- PaulDavisThe1st 2y agoVonnegut had The Church of God The Utterly Indifferent. Exists, but doesn't give a shit about anything that happens to creation.
- qup 2y agoObserver mode
- plastic3169 2y agoThat’s what I wonder about simulation theory. People say that it’s just nerds coming up with another god, but isn’t there the difference that if we live in a simulation it’s highly unlikely that the folks running it will come to hand pick the believers in to a heaven program after they die.
- BrandoElFollito 2y agoWell, it really depends on the features the TA required for the project.
- exitb 2y agoIt’s not the same size BTW. Depending on a particular configuration, the moon can be between 10% bigger and 10% smaller than sun.
- lambdaba 2y agoYes, this is the strangest coincidence of this entire setup to me, it doesn't seem related to enabling the development of life (besides, when life arose, the position of the moon was quite different), but it was instrumental in verifying the theory of relativity, just in time for humanity to discover it. And here's the backstory about verifying relativity: https://en.wikipedia.org/wiki/Solar_eclipse_of_May_29,_1919 https://en.wikipedia.org/wiki/Solar_eclipse_of_May_29,_1919
- nicklecompte 2y agoThe whole idea of an annular solar eclipse is that the size is not actually exact :) I think part of the perception that a total eclipse "perfectly" blocks the sun is that the corona has a fuzzy edge but the surface does not, so when the moon is actually larger than the sun in the sky you still see the same eerie coronal glow. In particular there's little perceptible difference between blocking 100% of the sun and blocking 105% of the sun, compared to 100% versus 95%.
- creer 2y agoAnd besides all the other remarks, both earth's and the moon's orbits are something like ellipses. So that the ratio of apparent size of the moon to apparent size of the sun is not fixed either. See annular eclipse.
- al_borland 2y agoFrom what I’ve heard, the moon is also moving away from earth, ever so slightly. Something like 1cm/year. Eventually, the moon will appear too small to cover the sun and the eclipse as we know it today will be no more. But that won’t be in our lifetime. Who knows if humans will even still be around..