A snowman may have brought life to Earth
A space rock shaped like a snowman, which has lurked in the far depths of the Solar System since the formation of the planets, could have sparked life on Earth, scientists have found.
The object, named Arrokoth, lies in the Kuiper Belt beyond Neptune and was formed more than four billion years ago when the Sun was still surrounded by a gigantic disc of planet-building material.
It is the farthest, and oldest, object to be visited by a spacecraft and was analysed in January 2019 by Nasa’s New Horizons probe, which flew past it after surveying its primary target, Pluto.
Although Arrokoth exists in the icy depths of the Solar System, some nine times further from the Sun than Jupiter, it still contains organic building blocks, demonstrating that even the most distant objects can hold the seeds of life.
Dr Will Grundy, of the Lowell Observatory at the University of Arizona, who has been analysing the data sent back from the space probe, said: ‘‘That these complex organics are so ubiquitous in colder parts of the universe means they are readily available to lead to formation of life.
‘‘Objects like Arrokoth certainly could have delivered them to early Earth from the far edge of the Solar System.’’
Scientists discovered that Arrokoth is a distinctive red colour, which indicates the presence of tholins, a complex organic gunk, or tar, which forms when organic molecules are blasted by radiation, similar to how crude oil forms, through intense heat and pressure.
Tholins are of great interest to scientists because they are linked to the beginnings of life. In the atmosphere they can create a haze that blocks damaging radiation from the Sun and may have protected the first lifeforms on Earth.
In 2012, scientists proved it was possible to produce the building blocks of DNA from tholins. If those building blocks exist even in the most inhospitable areas of the universe, it shows that life could be the norm rather than the exception.
Grundy believes the uniformity of colour on Arrokoth shows that tholins were floating around at the time of planet building, and eventually came together to form the space rock. Commenting on the findings, Dr Monica Grady, Professor of Planetary and Space Science at the Open University, said: ‘‘It’s an incredible result. It took 10 years for New Horizons to get there, and 10 minutes to get all this information. I’m stupefied at the detail they’ve produced from this fast fly-past.
‘‘With this data from Arrokoth and Pluto we’ve learnt so much about the fringes of the Solar System. It’s got ice, buckets of organics, a huge amount of chemistry going on, even though it’s cold.’’
Arrokoth has also given up some new secrets about how planets themselves form. In the Kuiper belt, objects move much more slowly in relation to each other and occupy a much bigger volume of space, so collisions are rare. This enables scientists to see their original shapes.
The head and body of the snowman shape were once independent bodies that appear to have gently come together, challenging the long-held assumption that objects crashed together in the planetbuilding era.
‘‘Basically, these bodies saw action only during and shortly after their formation phase (probably the first 2-5 million years after the Sun was formed), and have otherwise lurked out there ever since,’’ said Dr Orkan Umurhan, a senior research scientist at Nasa. ‘‘They are like a time capsule of and a window to that very early formation phase of the early Solar System. For this reason alone they interest scientists who pursue the question of the origin of the Solar System and how planets form.’’ – Telegraph Group