so stars form when a bunch of matter gets together, which is why they are bigger than planets generally. but the real defining feature is the density. a white dwarf can be smaller than a planet but it's still a star because it's incredibly dense. so couldn't a planet be sun-ish sized, provided that the density was low enough? and more specifically a solid planet, not a gas giant. what's the largest solid planet?
In light of the recent eclipse, I have seen a lot of worry about the harm of even glancing at it directly, and that many people believe that glancing at it is more harmful than glancing at the sun on an ordinary day. I am trying to understand whether that is actually true, and I believe the best way is to understand the physics & biology behind this and how real the risk is.
To really get it, I think the answer comes down to the underlying mechanism: what physically damages the eye when too much light hits it? Is it the quantity of photons, the energy of photons, or something else entirely? I ask because I have also heard that even when the moon blocks much/all of the visible light (peak of total eclipse), that UV (or infrared?) light still reaches the eye, so I am curious whether the eclipse changes what kind of light reaches you, and if that affects the damage.
So, putting it together: for the same few seconds of exposure, is a solar eclipse genuinely worse for your eyes than the midday sun?
