OBJECT OF THE MONTH – COMETS

COMETS are bodies of dust, rubble and water ice that circle the Sun in regular paths that can take tens or many thousands of years to complete one full orbit.

However, their composition hasn’t been studied in detail and there is one school of thought that they might contain the building blocks of life and that comets striking the Earth billions of years ago brought water and seeded life to our planet.

When a comet approaches the Sun, the frozen ice and gases trapped beneath its surface bubble off and dislodge dust grains from the surface of the comet which can be seen from Earth as the comet’s ‘tail’.

By capturing and analysing materials in the comet’s tail, astronomers can study the composition of comets in more detail.

In 2014, after a 10-year journey, the European Space Agency’s Rosetta spacecraft finally reached its destination with Comet 67P/ Churyumov-Gerasimenko.

For the next two years, Rosetta orbited the rubber-duck-shaped comet, analysing the dust the comet was losing. Recently, an interesting study was published, reporting that about half of the 35,000 dust grains captured and analysed by the Rosetta’s probe were made of organic molecules.

Organic molecules are carbon-based molecules like proteins, carbohydrates, and nucleic acids and the finding adds weight to the suggestion that comets might indeed have distributed these on to the early Earth which might eventually have given rise to life.