So I've been playing Xenoblade Chronicles 2 and one of the effects that is used through the game (and the series really) is that ether (the game's version of mana) can often be seen floating in the air like a kind of glowing rain / mist.

Unfortunately it's an effect that's difficult to see in screenshots and I can't find a good one of what I mean, this is the best I could find (from the original game);

Sartoral Swamp - Xenoblade Chronicles

But as for the actual question; is it possible to have a relatively scientific reason for such a phenomenon?

What I want is;

  • Some kind of glowing particles / droplets in the air. They could hang like mist or fall like rain, I'm not particularly bothered.
  • Comes and goes, so not permanent.

  • A reasonably widespread effect, comparable to weather.

  • Can happen day or night.

  • Happens in the lower atmosphere (so near the ground where people are and can interact with it, not lights in the sky like the Aurora or shooting stars)

  • Something that occurs naturally (or at least isn't specifically triggered, so no one is pressing a button to make it happen, it could be as a result of human activity)

  • It's safe. So nothing radioactive or hot that's going to kill everyone exposed to it for more than a few minutes or anything like that.

So is it possible, and how?

  • 1
    $\begingroup$ Wouldfireflies   (Lampyridae)   do? (Links to real life photos) $\endgroup$
    – AlexP
    Jan 1, 2018 at 1:15
  • $\begingroup$ @AlexP I've never actually seen them in person, but judging from those pictures I suppose they would. Do they have any particular regularity to when they show up? (Like only once a year) $\endgroup$ Jan 1, 2018 at 1:20
  • $\begingroup$ Fireflies are out from June through September. They're about 2cm long. $\endgroup$
    – pojo-guy
    Jan 1, 2018 at 1:47
  • $\begingroup$ @pojo-guy hmmm, so a reasonable stretch then, that would definitely be a contender though I would prefer a non living solution if one existed (though some form of organic bioluminescence is probably easiest) $\endgroup$ Jan 1, 2018 at 1:52
  • 2
    $\begingroup$ At night. They use their light to communicate simple things, such as "I am receptive female and I am here, come and woo me"; during the day there is this big bright shining light in the sky, and fireflies are much too smart to try to compete with it. $\endgroup$
    – AlexP
    Jan 1, 2018 at 2:06

2 Answers 2


Biolumiscent algae or bacteria in the air can respond to moisture by lighting up. While I am not aware of any real airborne organisms that meet the criterion, the biochemistry is well understood and employed by aquatic micro organisms and macro organisms from all kingdoms and environments.

  • $\begingroup$ Yeah, that's the kind of thing I was thinking might work. How would it get in the air though (or why would it be in the air?) $\endgroup$ Jan 1, 2018 at 1:59
  • 3
    $\begingroup$ Bacteria are omnipresent in the air. There's not a problem getting them there. The problem is filtering them out when you want a sterile environment $\endgroup$
    – pojo-guy
    Jan 1, 2018 at 2:24

The aurora borealis is similar to what you are talking about, in terms of visibility. The fact that it happens in the upper atmosphere on this planet is merely a minor inconvenience here.


At the bottom of the page in the See Also section, you may find links to something that happens lower in the atmosphere.

Also, since the aurora comes from solar winds, you can have a similar effect from neutrinos passing through the atmosphere (or the planet), since that happens constantly. You would just need something to occasionally react with them.


  • $\begingroup$ Interesting, I didn't know Aurora type effects could occur in the lower atmosphere. $\endgroup$ Jan 2, 2018 at 18:51
  • $\begingroup$ I'm not saying it does in our universe (or, more simply, on our planet), but it could in yours. $\endgroup$ Jan 2, 2018 at 19:00
  • $\begingroup$ Since when do neutrinos react with anything? :) $\endgroup$
    – DonielF
    Jan 2, 2018 at 20:46
  • $\begingroup$ @DonielF, I was thinking something along the lines of a cloud chamber, but from my limited Google searches just now, they don't react to neutrinos. I used neutrinos without really thinking about it, so it's more of an example, rather than a reliable story plot, I guess... $\endgroup$ Jan 2, 2018 at 20:53
  • $\begingroup$ Neutrinos interact in exactly two ways: weak force and gravity. These things are so tiny we might as well ignore gravity. So... Weak force then. Neutrinos do interact - it’s just extremely infrequently. We do have detectors for them, but there’s a reason they’re so incredibly massive. $\endgroup$
    – DonielF
    Jan 2, 2018 at 21:10

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