Jordan Healey, Science and Technology editor, looks into recent discoveries from the Rosetta Spacecraft Mission that develop our knowledge of how comets could have triggered the chemical reactions that led to life evolving on Earth.
The Rosetta mission, which was launched in 2004 by the European Space Agency, has been hugely successful. Landing the probe ‘Philae’ on Comet-67P in November 2014 (the first time in history we have landed a probe on a comet) was only the beginning of a small teams endeavour to contribute to finding a potential answer to one of sciences greatest unanswered questions; how did life on Earth begin? Despite the probe dying earlier this year, the rubber duck shaped comet has continued to be monitored and in the past few weeks an amazing discovery has been made. Scientists involved in this project have found certain elements and molecules that are considered to be the ‘building blocks of life’. Phosphorous, which is an essential element in DNA and cell membranes, is amongst these newly discovered elements and compounds present on the comet which helps to support the theory that certain ‘building blocks’ arrived on Earth by extra-terrestrial means. Glycine, which is another key component of proteins (it’s the simplest amino acid), was also found to exist on the comet.
Before the new find, the evidence for the presence of glycine on comets was minimal – with traces being detected only on comet samples brought back to Earth. However we now have unambiguous evidence that eliminates the possibility of human contamination since the molecules were directly detected on a comet in outer space. This also shows that glycine formation is probably universal and therefore the same chemical processes could have easily triggered life elsewhere in the cosmos.
We were already aware of the fact that the comet contained organic molecules since within only 25 minutes of landing on the comet, ‘Philae’ had conducted its first chemical analysis on the surface. During this search it had found 16 types of organic molecules falling into 6 different groups including alcohols, carbonyls, nitriles, amines, amides and isocyanates. 4 of these molecules had never before been detected on the nucleus of a comet, so the mission seemed promising from the very beginning, especially since many of these newly discovered molecules are precursors to many complex species that give rise to life such as sugars and DNA bases such as glycine.
The new discovery develops upon these earlier finds by confirming the presence of thee molecules that would be expected, according to scientific predictions. The Rosetta mission is expected to end later this year and has proven extremely valuable to our understanding of how comets form and exactly how they are composed. Only a few days ago space.com published an article about comets experiencing ‘repeating cycles of destruction and reformation’ as they spin so fast that they separate approximately every one hundred years before being bound back together over time. This theory is currently being tested on Comet-67P so we can better understand the evolution of comets and how they may be far more complex than once thought.