Space dust has been found in the white cliffs of Dover, and scientists believe it could help with space exploration in the future and explain events before Earth was created.
The iconic white cliffs are an important source of fossils for scientists, enabling them to understand the changes and upheavals the planet has gone through millions of years ago.
The fact that researchers from Imperial College London have discovered space dust alongside the ancient creatures, means that they may now be able to better understand what was happening in our solar system at the time.
- Where does cosmic dust come from?
Space dust particles are the pulverised remains of asteroid and comet collisions in our solar system.
Although around 20,000 to 30,000 tonnes of cosmic dust falls to Earth every year and is everywhere, given its size it is difficult to locate.
- What do the team's findings mean?
In another study by the same team, the scientists say they have discovered a way for working out if the cosmic dust was clay rich.
Clay can only form if water is present and if it is found to have been present in space dust, then it could suggest the presence of water-rich asteroids.
The researchers hope that in the future asteroids could provide space explorers with stop-offs during long journeys.
Dr Matt Genge, lead author from the College’s Department of Earth Science and Engineering, explained the significance of this: "Being able to source water is vital because it can be used to drink, to make oxygen and even fuel to power spacecraft.
"The relevance of our study is that cosmic dust particles that land on Earth could ultimately be used to trace where these water-rich asteroids may be, providing a valuable tool for mapping this resource.”
The team have also discovered a way in which less well preserved space dust can be examined.
- How can cosmic dust lead to water?
When cosmic dust enters Earth's atmosphere it can reach extreme heats of more than 600C (1,112F), causing the original mineral content to transform into glass and crystals.
This heat also vaporises any water.
By analysing past studies, Dr Genge and his team worked out that shattered pieces of olivine crystals contained in cosmic dust suggest that water was once present.
This is because the loss of water from the interior of the particle when it vaporises has a cooling effect, meaning that there is an extreme difference in temperature between the surface and core of the particles, causing the olivine crystals to shatter due to the stresses cause by the differences in expansion.
Dr Genge has calculated that 75% of cosmic dust which lands on Earth contains olivine crystals, suggesting the clay content, and therefore water content, of asteroids and comets are high.
- How was the space dust discovered?
The fossilised cosmic dust was spotted in chalk samples from the cliffs due to their their distinctive spherical structure and Christmas tree-like shape of their crystal content.
- What's next for the team?
Now that the team know that clay-rich asteroids may be abundant, their next step will be trying to find them.
The scientists will compare infra-red radiation from cosmic dust and asteroids to try and match the two.