Early risers along the United States east coast were treated to an extraordinary sight this week when a SpaceX rocket launch at twilight produced a glowing, spreading cloud that many witnesses compared to a giant jellyfish drifting across the sky. The luminous display, visible far from the launch site in Florida, prompted a flood of photographs and videos on social media as people from the Southeast to the Northeast tried to work out what they were seeing.
The spectacle was not a weather event, a meteor or anything mysterious. It was the exhaust plume of a Falcon 9 rocket, caught by sunlight at exactly the right moment. As reporting on the launch explained, the rocket lifted off from Cape Canaveral in Florida in the pre-dawn darkness, carrying a Dragon cargo spacecraft on a resupply mission to the International Space Station for NASA.
A Routine Cargo Flight That Became a Regional Light Show
The mission, known as CRS-35, is SpaceX’s 35th commercial resupply flight for NASA. According to NASA, the Falcon 9 lifted off from Space Launch Complex 40 at Cape Canaveral Space Force Station at 6:33 a.m. EDT on October 13, carrying scientific investigations, supplies and equipment to the orbiting laboratory. The uncrewed Dragon spacecraft was scheduled to rendezvous and dock with the station on October 15.
On paper, it was a routine cargo run of the kind SpaceX now flies regularly. What made this launch different was its timing. Liftoff came less than an hour before sunrise, when the ground below was still dark but the upper atmosphere was already beginning to catch the first light of day. That narrow window turned an ordinary ascent into one of the most widely seen launch displays of the year.
Why the Plume Glowed Like a Jellyfish
The so-called space jellyfish effect happens with launches that take place shortly before sunrise or shortly after sunset. As the rocket climbs, its exhaust plume expands in the thin upper atmosphere, where there is far less air pressure to keep it contained. The plume spreads out into a broad, translucent bulb with trailing tendrils — the shape that gives the phenomenon its nickname.
Crucially, while observers on the ground are still in darkness, the plume at high altitude is already in direct sunlight. Sunlight illuminates the water vapour and exhaust particles from below the horizon, making the cloud appear to glow against the dark sky. The same basic geometry is why satellites and the International Space Station itself can appear bright overhead in the twilight even though night has fallen, or not yet lifted, at ground level.
Meteorologists who tracked Tuesday’s display noted that clear skies across much of the coast helped the effect carry over an unusually wide area. Reports and photographs came in from Florida and Georgia, through the Carolinas and central Pennsylvania, and as far north as New Jersey and the New York area, where the glowing plume was photographed passing near the Manhattan skyline at dawn. Observers have reported seeing similar phenomena from hundreds of miles away from the launch site when conditions are right.
Not the First Time, and Not the Last
Long-time space watchers will recognise the effect. Twilight launches from Florida and California have produced jellyfish-like plumes before, and each time they generate the same mix of wonder and confusion among people who happen to look up at the right moment. Before official explanations circulate, such sightings routinely spark speculation online, which is one reason space agencies and local news outlets now move quickly to identify the cause.
For readers sharing launch photos from their phones, a quick safety habit is worthwhile before installing any new photo or tracking app to follow the next launch — our guide on what to check before installing an APK explains the basic checks that help keep a device secure.
There should be further chances to see the effect. SpaceX maintains a busy launch cadence from Cape Canaveral, and any flight scheduled in the twilight window — roughly within an hour of sunrise or sunset — has the potential to produce a similar display if skies are clear. Skywatchers hoping to catch one should check launch schedules the night before, find a spot with an unobstructed view towards the coast, and simply look up a few minutes after liftoff.
A Reminder of Why Launches Still Stop People in Their Tracks
Rocket launches have become frequent enough to feel routine, especially in Florida. Yet Tuesday’s jellyfish cloud was a reminder that the right combination of timing, altitude and light can still turn a cargo flight into a shared public moment, watched simultaneously by millions of people across several states.
For a few minutes before dawn, commuters paused, cameras came out, and a supply run to a space station became the most talked-about sight in the eastern sky. The Dragon spacecraft, meanwhile, continued quietly on its way to the station — its work just beginning as the glowing cloud that announced its departure faded into the sunrise.
