A colourful cloud may hover over mid-Atlantic states tonight

Barium strontium cloudNASAA barium-strontium cloud creates a purple-blue blob in the upper left hand corner of this photo.

East coasters take note: A blue, green, and red cloud will likely float through the sky at some point between 7 and 9 pm Eastern tonight. And it’s probably going to be so beautiful that you won’t want to miss it.

This multi-coloured cloud won’t be due to some strange physical phenomenon. NASA will be testing a suite of new space vehicle technologies on its suborbital Black Brant IX rocket, and one of those tests involves a burst of colourful vapour tracers into the atmosphere which will create a big, vibrant cloud.

That is, if the launch goes according to plan — it’s already been postponed once and NASA has until October 12 to do it.

Once cleared, the rocket will launch from NASA’s Wallops Flight Facility in Chincoteague, Virginia. The coloured clouds should be visible to residents who live between Long Island, New York and Morehead City, North Carolina. Here’s where you’ll be able to see the launch (and the coloured clouds):

You can monitor the launch — and know when to look out for the cloud — by checking out the NASA TV stream below.

Vapour tracers have helped scientists better understand Earth’s near-space environment by visualising how particles move around in the upper atmosphere since the 1950s. The tiny amount of emitted gas can be observed from the ground.

About six minutes after the Black Brant rocket launches Wednesday night, it will release four bursts of sub-orbital payloads containing mixtures of the chemical elements barium and strontium. These are actually the same chemicals commonly used to produce brilliant reds and greens in fireworks displays.

Barium is a soft and shiny alkaline earth metal, and can be found in fluorescent lamps, paints, bricks, tiles, glass, and rubber. Strontium has similar physical and chemical properties to barium, but is much more expensive.

You can only see a vapour cloud if it is illuminated by sunlight and you’re standing in darkness. Therefore scientists normally run these tests near sunset or sunrise for optimal lighting.

This cloud is the residual water vapour from a NASA research rocket launch in New Mexico. The cloud is so high that it's being illuminated by the sunrise that is slowly creeping across the Earth's horizon.

And don’t worry, these clouds aren’t dangerous. The amount of barium and strontium they will inject into the atmosphere will be much less than that used in a typical Fourth of July fireworks display.

Are you taking photos of the vapour cloud? We’d love to share them! Please email your favourite highest-resolution images to [email protected] with a full credit, a link to your site or profile (if you’d like), and explicit permission for us to use your work.

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