Across the Earth, every night, thousands of automated stargazers are waiting to take pictures of shooting stars. I am one of the scientists who study these meteors.
Most movies and news alerts focus on large asteroids that could destroy the Earth. And your phones notifies you every few months that an object nine washing machines wide is going to just narrowly skim past. However, the small dust and rubble that enter our atmosphere daily tell an equally interesting story.
My planetary science colleagues and I use camera observations of the night sky to better understand dust, car-sized asteroids and debris from comets in our solar system.
In a study published in March 2026, I searched through millions of meteor observations collected by all-sky camera networks based in Canada, Japan, California and Europe and found a small, recently formed cluster. The 282 meteors associated with this cluster tell the story of an asteroid that got a little too close to the Sun.
This composite image shows the 2019 Geminid meteors and a meteorite-dropping fireball captured by a camera on La Palma island, Spain.
Global Meteor Network.
Meteor formation
When a sand-sized crumb of space rock hits our atmosphere, it heats up almost instantly, vaporizing its surface layer and turning it into an electrically charged gas. The whole fragment starts to glow — this is what we call a meteor. If the object is larger, like a boulder, and brighter, it’s called a bolide or a fireball. On average, these objects hit our atmosphere going over 15 miles per second. For small dust or sand-sized objects, the whole process lasts only a fraction of a second before they completely disappear.
Comet 67P/Churyumov–Gerasimenko releasing gas and dust as its orbit takes it close to the Sun.
ESA/Rosetta/MPS
Most of these sand-sized fragments in the solar system originate from comets – cold, icy objects from the outer reaches of the solar system. As comets pass by the Sun, their icy components turn to gas, releasing tons of dust. This is why comets are often called “dirty snowballs” and appear fuzzy in telescopic images.
Asteroids, on the other hand, are leftovers from the early solar system that formed closer to the Sun. They are dry and rocky, and do not have the same ices that give comets their characteristic tails.
What does it mean to be active?
Astronomers call an asteroid or comet “active” when it sheds dust, gas or larger fragments. This activity is caused by some external force on the object in space, like heat from the Sun, a small impact, or when asteroids spin too fast and fly apart.
Understanding and identifying activity helps scientists better understand how these objects change over time.
For comets, sublimation of ices – when solid ice turns directly into gas, skipping the liquid phase – is the primary culprit. However, for asteroids, the reason for activity can vary…
