Researchers have found that water-rich cosmic dust is twice as more likely to survive atmospheric entry than dry cosmic dust. Cosmic dust is formed when collision between asteroids or entry of comets in the inner solar system results in crumbling of particles into dust. Some of this dust rapidly descends into the Earth’s atmosphere.
Water-rich particles contain water trapped in clay minerals or mud. The dust turns into little droplets of magma, with water boiling inside, during its rapid descent into the Earth's atmosphere. Such changes transform the dust into a magma foam bubble, which expands, becomes lighter and gets cooler, like a parachute. This helps the dust survive the descent.
Cosmic dust hits the atmosphere at nearly 40,000 kilometres per hour. It is heated extremely by collisions with air molecules. Most of these particles turn into gas and dissipate into the atmosphere. However, the study shows that water-rich particles are more likely to survive entry compared to dry ones.
A lot of the cosmic dust in our solar system is generated in the asteroid belt located between Jupiter and Mars. Cosmic dust provides evidence of events that might have happened billions of years ago in our solar system.