The Hoba Meteorite

The Hoba meteorite is an ataxite iron-nickel meteorite that landed in northern Namibia at some point in the last 80 000 years. Because of its shape and trajectory (it’s thought possible that it “skipped” across the atmosphere like a stone on a pond) it landed at subsonic speeds, and didn’t bury itself particularly deep, leaving no crater behind.

hoba

hoba-2

The Hoba meteorite was discovered by a farmer as he was ploughing a field, and has never been moved due to its large size; it has a mass of around 60 000 kilograms. (It was estimated to be about 66 000 kilograms when it fell, but its mass has been reduced by erosion, sampling and vandalism.) The Hoba meteorite is the world’s largest meteorite, and the most massive naturally occuring piece of iron on Earth’s surface.

Unconventional Nuclear Weapons

When people think of nuclear weapons they tend to think of bombs and missiles, but there have been (and possibly still are) some more unusual nuclear weapons.

Conventional Nuclear Weapons

Most nuclear weapons states (NWSs) use ballistic missiles as the primary tool in their nuclear arsenals. These can be battlefield (with a range less than 100 km), tactical (range up to 300 km), theatre (up to 3500 km), intermediate (up to 5500 km) or intercontinental (beyond 5500 km). These ballistic missiles can be land-based, either in underground silos or aboard mobile launchers, or submarine-launched; NWSs prefer SLBMs because they give a secure second strike capability (the UK’s only nuclear weapons are SLBMs).

trident

A Trident II SLBM (as used by the USA and the UK) ignites its first stage rocket motor.

ss-25

A Russian SS-25 Sickle ICBM aboard a transporter erector launcher vehicle.

Ballistic missile forces are frequently supplemented by cruise missiles, usually air-launched by fighter or bomber aircraft. Cruise missiles differ from ballistic missiles in that they do not follow ballistic paths but rather fly point-to-point, close to the ground (in a process known as terrain hugging). Ballistic missiles use rocket engines and can operate outside of Earth’s atmosphere, whereas cruise missiles are powered by air-breathing fanjet or ramjet engines (and are therefore unable to operate outside of the atmosphere), and generate lift and steer just as aircraft do.

mirage-asmp

A French Mirage 2000N fighter carrying an ASMP-A nuclear-capable cruise missile on its centre hardpoint.

Only the United States and China still use air-dropped nuclear bombs as part of their nuclear deterrent. The nuclear weapons programmes of Israel, India, Pakistan and North Korea are shrouded in secrecy, so it is possible – but unlikely – that they possess bombs as part of their arsenals.

b83-bomb

A B83 bomb, the most powerful weapon in the US arsenal at 1.2 megatonnes TNT equivalent.

Unconventional Nuclear Weapons

Nuclear Land Mines (AKA Atomic Demolition Munitions)

The conventional nuclear weapons listed above are all designed to be delivered to their target remotely, whereas atomic demolition munitions (ADMs) are designed to be transported and emplaced by soldiers in the field. The US and the USSR/Russia developed a number of ADMs but no current weapons are known, though it is alleged that Israel have placed ADMs in the Golan Heights to secure the area.

sadmSource: flickr/rocbolt

The most recent ADM, the US’s Special Atomic Demolition Munition (shown above) was decommissioned in 1989. It used the tiny W54 warhead, with a yield of 0.01-10 kilotons TNT equivalent, and had a mass of around seventy kilograms. It was designed to be carried in a backpack and emplaced by a team of paratrooper Special Forces.

Perhaps the strangest nuclear weapon of all falls into the ADM category. Blue Peacock was a 1950s British project to place ten kiloton nuclear landmines on the North German Plain to guard against a Soviet invasion from the east. The bomb’s designers were concerned that the cold weather would prevent the bomb’s electronics from operating correctly, and one suggestion was that live chickens be placed inside the bomb with a source of food and water and that the heat from the chicken’s bodies would be sufficient to keep the bomb operating correctly. The project was cancelled in 1958 before any bombs were placed.

So-called “suitcase nukes” also fall into the ADM category. A number of people have alleged that the US, USSR and Israel have produced suitcase nukes, but most nuclear scientists and engineers do not believe it to be possible to shrink a warhead – both in terms of size and mass – small enough to fit in a suitcase and be easily man-portable.

Nuclear Artillery

The W54 warhead used in the SADM was originally developed for the Davy Crockett recoilless rifle system. The Davy Crockett was fielded by US units between 1961-1971 and was designed to fire an M388 nuclear projectile containing a 0.01-0.02 kiloton W54 warhead up to four kilometres, and was envisaged as primarily an anti-personnel and area denial weapon due to the fallout it would produce.

davy-crockett

An M388 nuclear projectile attached to the Davy Crockett system.

The US developed a number of other shell-firing nuclear artillery pieces: the M65 atomic cannon firing fifteen kiloton W9 and twenty kiloton W19 warheads; the M110 and M115 howitzers firing W33 warheads with a selectable yield up to forty kilotons; and the M109, M114 and M198 howitzers firing 0.072 kiloton W48 warheads. The USSR also produced a number of shell-firing nuclear artillery pieces, and the US, USSR, France and others operated nuclear rocket artillery pieces.

Nuclear Depth Charges

The UK, USA and USSR have all at one time fielded nuclear depth charges for use in anti-submarine warfare. The Mark 101 Lulu was an eleven kiloton nuclear depth charge fielded from 1958-1971, and the twenty kiloton B57 nuclear bomb (1968-1993) could also be used in this role.

mark-101-lulu

A Mark 101 Lulu nuclear depth charge.

Air-to-Air and Surface-to-Air Rockets

Most nuclear rockets and missiles are air-to-surface or surface-to-surface, but some air-to-air and surface-to-air nuclear missiles have been created. Air-to-air nuclear missiles, such as the one-and-a-half kiloton AIR-2 Genie (1957-1985) and the 0.25 kiloton AIM-26 Falcon (1961-1972) were designed to guarantee a hit against incoming aircraft, and to destroy multiple aircraft with one device.

genie-firing

An F-106 Delta Dart fires an AIR-2 missile.

Surface-to-air nuclear missiles have also been used in anti-aircraft roles, but were, and are more commonly used in an anti-ballistic missile (ABM) role. The current Russian ABM system (A-135) uses ABM-3 Gazelle missiles with 10 kiloton nuclear warheads, and previously used much more powerful ABM-1 Galosh missiles with 2-3 megaton warheads. These ABM nuclear missiles are designed to destroy incoming ballistic missiles by damaging their electronic components via intense X-ray bombardment and neutron flux.

vnukovo-stitchSource: wikimapia/ogima

The image above shows the A-135 ABM complex at Vnukovo (click to enlarge). Blue control buildings are on the right, and the sliding silo covers are visible to the left. There are a total of twelve silos at this site, with a further fifty-six silos spread between four other sites surrounding Moscow.

Gini Coefficient

The Gini coefficient (named after its inventor, statistician and sociologist Corrado Gini) measures the income distribution of a country’s population. It is often used as an analogue for measuring inequality within a population in general.

gini-map

A map coloured by Gini coefficient. Darker blues represent higher Gini coefficients (greater inequality).

A Gini coefficient of zero represents perfect income equality (everybody ears exactly the same amount) and a Gini coefficient of one represents perfect inequality (one person in the population earns all the money). Denmark has the lowest Gini coefficient (0.24) and the Seychelles the highest (0.66); the UK has a Gini coefficient of 0.34 and the US 0.45.

Consider three hypothetical ten-person countries:

Country Randomland Inequaliteria Equalistan
Citizen #1 49755 500000 50000
Citizen #2 61429 10 50000
Citizen #3 80411 10 50000
Citizen #4 45021 10 50000
Citizen #5 68466 10 50000
Citizen #6 96746 10 50000
Citizen #7 18788 10 50000
Citizen #8 71039 10 50000
Citizen #9 79777 10 50000
Citizen #10 10258 10 50000
Gini Coefficient  0.250 0.900  0.00

Another way of measuring income inequality is the Robin Hood index, which indicates the portion of a country’s total income that would need to be taken from the richest half of the population and given to the poorest half of the population in order to achieve income equality. For Randomland the Robin Hood index is 18.71%, for Inequaliteria it is 90% and for Equalistan it is 0%.

Earth Sandwich

What is the significance of the areas highlighted in green on the map below?

earth-sandwich-results

Click for a much larger version.

The highlights indicate areas where there is land on both sides of the globe – that is, areas where you could create a successful Earth Sandwich.

For example, if you started in Northern Argentina and drilled through the Earth’s core you would end up in Southern China. If instead you started in southern Argentina you’d end up either in Mongolia or Russia. It’s a little bit easier to understand if you look at the overlaid maps below.

earth-sandwich-overlay

There are significant areas of overlap between South America and around the South China Sea, and between Northern Canada & Greenland and the Antarctic.

There are also some interesting smaller spots, for example where Spain/Portugal (and a tiny portion of Morocco) and New Zealand overlap, or the Islands of Hawai’i and Botswana.

spain-nz

Spain/Portugal/Morocco and New Zealand

hawaii-botswana

Hawai’i and Botswana

The EURion constellation

Take a look at the banknotes below. What do they have in common?

uk-poundeuro-euroaustralia-dollar bulgaria-lev canada-dollar chile-peso mexico-dollar romainian-leu singapore-dollar swaziland-lilangeni uae-dirham

Did you spot it? Each of the banknotes above (and many, many others) include the EURion constellation somewhere in their design.

eurion-examples

The EURion constellation is a pattern of five rings, arranged in a rough ‘X’ shape, used by banks to identify to scanners, photocopiers/printers and software that they should not reproduce the object being imaged. If you try to image a banknote that includes the EURion constellation on modern hardware or software you will generate an error, or print a blank or full-black page.

Some banknotes attempt to embed the EURion constellation into their design: for example, the Australian dollar above uses them as “leaves” on a tree to the right of Catherine Helen Spence’s head; and US dollar notes use the zeroes in the bill’s denomination (10, 20, 50, 100). The circles that make up the constellation are often printed in yellow, or another colour so that they blend in with their background.

The EURion constellation is not the only method used to protect banknotes, as Markus Kuhn, the discoverer of the EURion constellation has noted.