A Modest Proposal

European settlers found the geography of Australia unsatisfactory in many respects. Most disappointing was the general aridity of the regions away from the coast and the lack of a large river that would assist the export of agricultural goods. Several geoengineering schemes have been proposed to deal with the lack of water. The Bradfield proposal, which suggested that the upper reaches of the Tully, Herbert and Burdekin rivers be diverted into the Thomson River on the west of the Great Dividing Range, is one famous suggestion.

A less well-known plan was put forward by L.J. Hogan in 1979. Man-made mountain: your life, your land Australia, argues the benefits of constructing a large mountain range 4 km tall, 10km wide at the base, with a 2km plateau at the top and covering 2,000km in length. Placed roughly along the Western Australian, Northern Territory and South Australian borders in a north to south orientation, this construction would have significant climatic impacts. The moisture-laden winds that come from the west would strike the mountain range and rise and cool, resulting in precipitation. Western Australia would experience much higher rates of rainfall for crops, and rivers would flow to the sea along new pathways.

The impracticality of such a plan is obvious – we have no way of moving such unimaginable amounts of soil. Hogan’s plan would require a trench 100 meters deep, 200km wide and 2,000km long. These challenges of scale have not intimidated the United Arab Emirates who, with the help of the US National Centre for Atmospheric Research, have explored the idea of artificial mountains for improving rainfall in the Middle East. Yet, there is no mechanism for soil transportation and mountain assembly for such an ambitious scale.

One ingenious alternative is the use of large scale inflatable domes. Reaching four to five kilometres into the atmosphere, these would encourage precipitation in the same manner.  People could live, and crops could grow, within these domes which would require only a small overpressure to maintain their shape. However, there are again practical difficulties. The precipitation at high altitudes may well be in the form of snow which would weigh down the domes made of thin films. The films would have to include some mechanism for heating this water to prevent collapse. The area in which they would be placed would have to exclude aircraft, and bird strikes would be a constant issue. These issues are enough to disqualify this suggestion.

I would like to put forward an alternative proposal to form a mountain range that requires no excavation or inflatable devices. There are mountains presently in orbit around the sun which we call asteroids. It would be a formidable, but not impossible, task to nudge some of the smaller asteroids into low Earth orbit. It may also be possible to capture near-Earth objects for the same purpose. These could be de-orbited (though the energy costs for such a change in velocity are high), and aimed at the Western Australian border territory mentioned above.

A mountain range of the sort imagined in the Hogan plan would take between 70 to 80 small asteroids, each with a diameter of 15 kilometres or less.  These asteroids could be selected for their ore content, providing rich new sources for Western Australia’s mining industries. While it is true that dense asteroids rich in nickel or iron would have a greater impact on landing, they would have an even greater impact on the local economy.

The cinematic depictions of such impacts have been wildly exaggerated and should be dismissed from any rational argument. The recent interstellar object Oumuamua was travelling 26.33 kilometres per second and its random collision with Earth would indeed have produced significant damage. However, an asteroid ‘lowered’ to the Earth in a controlled and targeted fashion need not be travelling at any higher velocity than 11 kilometres per second, and the impact would merely cause an ephemeral earthquake of no greater than 10 or 11 on the Richter scale. The Earth Impact Effects Program, pioneered by Purdue University and Imperial College London, allows us to plot the effects of these repeated impacts with some exactitude. And iron-rich asteroid with a density of 8000kg per cubic metre, lowered to Earth at 11 km per second would cause an earthquake of 10.2 on the Richter scale – admittedly larger than any in recorded history, but with relatively localised effects. At 2000 kilometres (nearest impact point to Perth) the effects would be moderate:

• Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably. Many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop.

The impacts would not penetrate the continental crust or shatter the tectonic plate on which Australia proudly stands, nor would it change Earth’s orbit or rotation. A few stopped pendulum clocks would be a small price to pay for progress.

If aimed at an angle slightly greater or less than 90 degrees, the asteroid would likely roll out of the impact crater that would otherwise diminish its height. The ejecta of the crater (which would be around 1.5km in depth) could be used to add to the bulk of the mountains formed. The craters would be the first recipients of the resultant precipitation and would form scenic locations that would invite tourism at first, and later new settlements with suburban housing tracts, shopping malls, and sports facilities.

Those devoid of patriotic fervour and opposed to nation building will object that much of this project must take place on what they are pleased to call Aboriginal land. It is true that the Pintupi, Gurindji, Pitjantjatjara and others might feel that they have been treated with disrespect when 70 asteroids of 15 kilometres in diameter crash into their ancestral lands. Pursuing a Greater Australia requires sacrifice, and I have no doubt that many locals will welcome advancement, opportunity, and the latest blessings of Western civilization.