The “Space Jellyfish”: Why a Rocket Launch Sometimes Looks Like a Glowing Jellyfish

What Is a Space Jellyfish?

In the first minutes of flight a rocket's exhaust behaves normally — a bright flame and a contrail. But above roughly 60 miles the atmosphere is thin enough that the exhaust stops being confined: it expands freely in every direction, ballooning into a cloud tens of miles across within seconds. If that happens in daylight you barely notice it against a blue sky. If it happens in darkness, the cloud is unlit and invisible.

The jellyfish appears in the narrow overlap between those two cases. During twilight, the ground is in Earth's shadow but the upper atmosphere is not — the Sun, just below your horizon, still shines on anything high enough. When the expanding plume climbs into that sunlight, it glows against the dark sky: a luminous bell around the rocket with tendrils of drifting exhaust below it, often shifting from white to blue to pink as the light angle changes. The effect can persist for ten minutes or more after the rocket itself is gone from view, and every time it happens over a populated area it generates a wave of 911 calls, local-news stories, and “what was that in the sky” posts.

The October 13, 2026 CRS-35 jellyfish over the Southeast

The most widely seen recent example came on Tuesday, October 13, 2026. SpaceX’s Falcon 9 lifted off with the Dragon CRS-35 cargo mission for NASA from Space Launch Complex 40 at Cape Canaveral at 10:33:44 UTC (6:33:44 a.m. EDT), roughly 45 minutes before sunrise, flying east-northeast toward the sunrise. Our model had graded it high, with the Sun 11.4° below the horizon at the pad and a lit window of T+3–5 minutes. A few minutes into flight the plume climbed into sunlight and bloomed into a glowing bell with trailing wisps, and viewer photos show it still in the sky after the rocket itself was gone.

Local news from News4JAX in Jacksonville to WCIV in Charleston, WKMG in Orlando, CBS12 in West Palm Beach and WCTV in Tallahassee ran photo galleries of a ‘jellyfish’ reported across Central and Northeast Florida, Southeast Georgia and the South Carolina Lowcountry, with reports from North Carolina and Virginia. Those are sightings as reported by local media, not our measurements. For the minute-by-minute account, viewing directions by city, why some people missed it and how to catch the next one, see our October 13 recap guide, linked above.

What people call it: jellyfish cloud, glowing cloud, UFO over Florida

Searchers rarely use the same words. The same event gets called a space jellyfish, a jellyfish cloud, a SpaceX jellyfish, a rocket jellyfish, a glowing cloud after a rocket launch, a twilight phenomenon, or simply ‘what was that in the sky this morning’. After the October 13, 2026 launch the phrase ‘UFO over Florida’ came up as well. All of these describe one thing: a high-altitude exhaust plume lit by the Sun against a dark sky.

One term is different. A ‘space spiral’ or ‘spiral in the sky’ is a separate effect: a tight, slowly rotating pinwheel of light produced when a spent upper stage — often a Falcon 9 second stage after a Vandenberg launch, or during a deorbit burn — vents leftover propellant while sunlit, spraying it into a spiral as the stage tumbles. It happens later in a mission and much higher, has been reported over Hawaii, Alaska and Europe rather than over the launch site, and is not what our jellyfish grade predicts. If you saw a rotating spiral rather than a bell with tentacles, that is the explanation to look up.

When Do Jellyfish Launches Happen? The Sun-Angle Science

The first input is the Sun’s elevation at the launch pad at liftoff, and our model sorts it into bands. Above about −4° (daylight or bright civil twilight) the sky outshines the plume: no jellyfish. Between −4° and −6° the sky is still bright enough that a plume looks washed out, so the grade tops out at medium. From −6° to −17° is the prime band: the ground is dark and the plume reaches sunlight during its big expansion phase, so these are the only launches eligible for a high grade. Between −17° and −22° the plume catches light only late and high, or only if the rocket flies toward the terminator, so the grade is again capped at medium; below −22° the plume usually never leaves Earth’s shadow and the grade is low at best.

Within a band, the grade comes from how much of the T+2.5 to T+5 minute expansion window — when the rocket is roughly 60 to 150 km up, blooming in near-vacuum, and still above the launch area’s horizon — is actually in sunlight. That sweep is computed per launch from its azimuth and ascent profile, which is why a dawn Cape Canaveral launch flying east toward the sunrise scores better than a dusk launch flying away from it, and why the usable dusk band at the Cape is tighter, roughly −4° to −9°. The October 13, 2026 CRS-35 launch, with the Sun 11.4° below the horizon and a lit window of T+3–5 min, sat squarely in the prime band.

These thresholds are model assumptions, not universal boundaries for the phenomenon. A fixed number of minutes before sunrise or after sunset does not translate across seasons or sites, and a schedule slip of an hour can move a launch into or out of the window. Recheck the launch-specific estimate after any change, and consider the viewing direction and clouds as well as the lighting.

How LookToSpace Predicts the Jellyfish Chance for Every Launch

Because the effect is pure geometry — Sun position, launch time, pad location, and ascent trajectory — it can be computed in advance. For every upcoming launch, LookToSpace calculates the Sun's exact elevation at the pad at liftoff, then sweeps the rocket's ascent minute by minute to check when the plume is both high enough to be in sunlight and still above the launch area's horizon. Each launch page shows the result as a graded call: none, low, medium, or high, with the time window when the glow should appear (for example “T+3–5 min”) and which twilight side it falls on.

The honest caveat: geometry says whether the plume will be lit, not how bright it will be. Plume size varies with the rocket, its throttle profile, and upper-atmosphere conditions, and launch times slip constantly — a one-hour delay can move a launch out of (or into) the jellyfish window. Treat a high grade as “worth setting an alarm for,” not a guarantee, and re-check the launch page after any schedule change.

Where to See One: Florida and Texas

A Florida launch can produce a sunlit plume when the flight path and lighting align. That does not mean it is visible across the whole state. Use your own location to check direction and elevation, and look for an unobstructed part of the predicted sky path.

In South Texas, Starship launches from Starbase produce the same physics on a bigger scale — 33 engines make an enormous plume — for twilight flights, visible across the Rio Grande Valley and far up the Gulf Coast. Wherever you are, the recipe is the same: check the launch's jellyfish grade, be outside a couple of minutes before liftoff, and keep watching for several minutes after the rocket disappears — the glow often peaks after the vehicle itself is too far away to see.

Sources and further reading

• News4JAX: SpaceX launch creates jellyfish-shaped cloud over Northeast Florida, Southeast Georgia
• Weather.com: the Falcon 9 ‘space jellyfish’ rocket plume over Florida
• NASA Astronomy Picture of the Day: a sunlit launch plume before sunrise
• LookToSpace: visibility model and limitations