If you read or watch Sci-Fi movies, we often see speculations about giant asteroids being blown up, or even the moon being destroyed. Of course in those scenario's humanity somehow survives .....
However the science behind this survival of humanity is not actually so well thought out ....
In fact so badly thought out, that in 1959 the US military had laid preliminary plans to nuclear bomb the moon to frighten the USSR. Well known scientists of the day, including Physicist Leonard Reiffel, and a young Carl Sagan were even involved in planning the lunar attack. The evidence for this was uncovered in declassified documents .... "A Study of Lunar Research Flights" which seriously considered the moon bombing.
The study discussed a moon bombing, which was to take place in 1959. The demonstration of US strength was to use an atom bomb, rather than a hydrogen bomb, because the hydrogen bomb would be too heavy for the rockets of the time. The hope was that the flash from the bomb would intimidate the Russians following their successful launching of the Sputnik satellite in October 1957.
Of course it would take considerably more than one atom bomb to destroy the moon, in fact the suggestion is that you'd need 9,000 bombs of the 15,000 kiloton "Castle Bravo" class to obliterate the entire surface of the moon (but not destroy it by the way, gravity effects alone would stop that).
Way beyond the resources (or abilities) of even the most "Dr Strangelove" like hawk US generals of the time, such as Brigadier General Jack D. Ripper or General Buck Turgidson.
So what would happen if we blew up the moon (or even blew great big chunks off it)?
Well, Firstly: In order to actually blow up the moon one has to overcome the forces of gravity which bind it together .... this gravitational energy is 120 million, trillion, gigajoules (aka 'a lot!!). This means that you would need an explosive force more than that amount, delivered in one go, to stop it just cracking, then reforming again. This would need to be delivered into the centre, not the surface, so the drill hole would need to be hundreds of miles / kilometres deep. It would still take over 600 billion of our biggest nuclear bombs to deliver the necessary force.
And Secondly: Even if we couldn't manage this, just supposing some alien invasion force could manage that without us noticing (and we have the technology to deliver a nuclear defence to stop the drilling if we saw them), what would be the result of the explosion? Well there would be a rain of moon debris that would hit the earth .... from very large chunks, to pebbles, they would all hit the Earth, but with only about 1 per cent of the impact energy of a similar asteroid strike.This is because the debris would have a much lower orbital speed than a similar interstellar or deep solar object .
However, that wouldn't save us, because the quantities involved would be huge ... millions of strikes, and they would simply pass on kinetic energy, converted to heat energy, and the atmosphere and seas would boil ..... killing all life on the planet.
And finally, with Earth barren of life, the planet would eventually cool down and the seas would reform as precipitation from the cooling atmosphere. Earth would now have a ring of debris circling it like a Saturn ring (some of which would occasionally strike the Earth). However the planet would lose its stable axial tilt, and over tens of thousands of years this would move ..... eventually this would go over the 45 degrees and probably lock with one side permanently facing the Sun, and the other in perpetual darkness (like the moon is in relation to the Earth now).
So perhaps its all for the good that the US military didn't flash strike the moon, as although it wouldn't have blown it up, it potentially could have released debris to hit the Earth including a young me.
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| Blowing Up The Moon ..... Not Too Clever ... Or That Easy. |
However the science behind this survival of humanity is not actually so well thought out ....
In fact so badly thought out, that in 1959 the US military had laid preliminary plans to nuclear bomb the moon to frighten the USSR. Well known scientists of the day, including Physicist Leonard Reiffel, and a young Carl Sagan were even involved in planning the lunar attack. The evidence for this was uncovered in declassified documents .... "A Study of Lunar Research Flights" which seriously considered the moon bombing.
The study discussed a moon bombing, which was to take place in 1959. The demonstration of US strength was to use an atom bomb, rather than a hydrogen bomb, because the hydrogen bomb would be too heavy for the rockets of the time. The hope was that the flash from the bomb would intimidate the Russians following their successful launching of the Sputnik satellite in October 1957.
Of course it would take considerably more than one atom bomb to destroy the moon, in fact the suggestion is that you'd need 9,000 bombs of the 15,000 kiloton "Castle Bravo" class to obliterate the entire surface of the moon (but not destroy it by the way, gravity effects alone would stop that).
 |
| General Buck Turgidson Showing How A 'Big Bird' Can Fly .... |
Way beyond the resources (or abilities) of even the most "Dr Strangelove" like hawk US generals of the time, such as Brigadier General Jack D. Ripper or General Buck Turgidson.
 |
| Shooting The Moon Not A New Idea ..... |
So what would happen if we blew up the moon (or even blew great big chunks off it)?
Well, Firstly: In order to actually blow up the moon one has to overcome the forces of gravity which bind it together .... this gravitational energy is 120 million, trillion, gigajoules (aka 'a lot!!). This means that you would need an explosive force more than that amount, delivered in one go, to stop it just cracking, then reforming again. This would need to be delivered into the centre, not the surface, so the drill hole would need to be hundreds of miles / kilometres deep. It would still take over 600 billion of our biggest nuclear bombs to deliver the necessary force.
And Secondly: Even if we couldn't manage this, just supposing some alien invasion force could manage that without us noticing (and we have the technology to deliver a nuclear defence to stop the drilling if we saw them), what would be the result of the explosion? Well there would be a rain of moon debris that would hit the earth .... from very large chunks, to pebbles, they would all hit the Earth, but with only about 1 per cent of the impact energy of a similar asteroid strike.This is because the debris would have a much lower orbital speed than a similar interstellar or deep solar object .
However, that wouldn't save us, because the quantities involved would be huge ... millions of strikes, and they would simply pass on kinetic energy, converted to heat energy, and the atmosphere and seas would boil ..... killing all life on the planet.
And finally, with Earth barren of life, the planet would eventually cool down and the seas would reform as precipitation from the cooling atmosphere. Earth would now have a ring of debris circling it like a Saturn ring (some of which would occasionally strike the Earth). However the planet would lose its stable axial tilt, and over tens of thousands of years this would move ..... eventually this would go over the 45 degrees and probably lock with one side permanently facing the Sun, and the other in perpetual darkness (like the moon is in relation to the Earth now).
So perhaps its all for the good that the US military didn't flash strike the moon, as although it wouldn't have blown it up, it potentially could have released debris to hit the Earth including a young me.
The cold war was a crazy time. It's a real wonder that we didn't blow ourselves into the next Kingdom at that time.
ReplyDeleteIt was a case of the weapons outstripping the common sense. However I have no doubt that another European war would have been unleashed if not for the mutually assured destruction that the nuclear arsenals had threatened.
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