"If you shine a low-pressure sodium lamp on a yellow sodium flame, the flame will be black." I shamelessly stole the above text from somewhere but it whetted my curiosity.

I am wondering if out there in the universe there is a similar condition where a star's emissions could mimic the sodium lamp and a planet could have black lightning storms?

  • $\begingroup$ If out there in the universe there is a similar condition where a star's emissions could mimic the sodium lamp and a planet could have black lightning storms you would be asking about a real-world scenario, which SE Worldbuilding prohibits. If on the other hand, you want to ignore any real rules and simply make the case, why not just do that? $\endgroup$ Jan 10, 2021 at 20:53
  • $\begingroup$ I'm confused because your question refers to both star's emissions and lightning storms. The light you see in a lightning storm doesn't come from the sun, it comes from the plasma generated by an electrical discharge. Which are you actually interested in? $\endgroup$
    – craq
    Jan 11, 2021 at 4:10
  • $\begingroup$ @craq:I need it for the backdrop ;D $\endgroup$
    – user6760
    Jan 11, 2021 at 4:59

2 Answers 2


This is what you are quoting

enter image description here

How does it work?

Flames emits light and heat, so it seems impossible to make black fire. However, you actually can make black fire by controlling the wavelengths of absorbed and emitted light.

The low-pressure sodium lamp has the same spectral signature as the sodium-tinted flame. When you add sodium (from salt) to the flame, the sodium atoms absorb the light from the lamp because it’s exactly the energy they need. What happens when you absorb all the light? You see black.

Now to your question

I am wondering if out there in the universe there is a similar condition whereby a star mimic the sodium lamp and a planet can have black lightning storm?

The problem is that no star has a narrow emission spectrum as a sodium light. As a consequence you won't see the black lightning because there would be other frequencies which would not be absorbed (same reason why a sodium flame doesn't appear black under sunlight).

For comparison, this is the emission spectrum of a low pressure sodium lamp

low pressure sodium lamp spectrum

while this is the solar spectrum (note the scale of the x axis)

solar spectrum

  • 2
    $\begingroup$ If I may ask, L. Dutch, do you just have a massive amount of knowledge stored in year head such that whenever someone asks a question you instantly know what to answer, or do you have superhuman googling skills? $\endgroup$
    – Poseidaan
    Jan 10, 2021 at 11:30
  • 9
    $\begingroup$ @MartinvanIJcken There are two secrets to success: 1. Never tell everything you know. ;) $\endgroup$
    – L.Dutch
    Jan 10, 2021 at 12:37
  • $\begingroup$ @MartinvanlJcken: 2. L.Dutch is a bot same as community but more talkative ;D $\endgroup$
    – user6760
    Jan 11, 2021 at 2:14

L Dutch's answer is correct - this wont happen under current physics. Lightning emits light, black is the absence of light. Aside from the comic book character and associated TV show, "Black Lightning" can't exit in the world as physics as we understand them.

But I'm 100% confident we don't know all the laws of physics yet; physicists are still learning things and will be for hundreds of years at least; so you need to delve into the realm of unobtainium, handwavium, magic, or "unspecified future knowledge" in order to explain your black lightning.

Some ideas:

  • Something in the atmosphere that goes opaque black briefly when a lightning bolt passes (say, due to the high voltage). The unknown substance desolidifies soon after the bolt passes, but before heating up itself to black body levels.
  • Something in the atmosphere that absorbs visible light and emits, say UV, in an exponential curve - like an automatic tinting window - normal conditions its unnoticed, maybe a slight shade in midday sun. Lightning strikes and its outline is stencilled out of the sky.
  • The eyes observing it are digital, when looking directly at lightning, they suffer integer overflow for those pixels brightness levels, wrapping the high number back around to 0, and report the lightning to the brain as black.
  • Special kind of static electricity: (Insert technobable). Therefore sparks are black. Therefore lightning is black.
  • 1
    $\begingroup$ I'd say the opaque thing in the atmosphere would be a plasma, not a solid, although that's actually a good theory (nuclear double flash phenomena are due to opaque plasma obstructing the lightfront after all) $\endgroup$
    – Shalvenay
    Jan 11, 2021 at 1:20

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .