HIDDEN GOLD Gold has been valued for thousands of years as money and to make precious objects especially jewelry For jewelry gold is valued for its shiny rich color and the tradition that claims gold is valuable Gold’s properties as a metal are also beneficial in jewelry making It is easily worked and can be hammered into thin sheets drawn into narrow wires or cast into a variety of shapes In addition gold does not tarnish easily so it remains shiny and bright for a long time Many other metals are harder to work tarnish quickly or are dull with plain colors Golden Mirrors Space telescopes often use microscopically thin layers of gold NASA’s James Webb Space Telescope has 18 mirror segments that each received gold coatings approximately one-millionth of an inch thick These coatings are 200 times thinner than a human hair and yet the gold remains durable and reflective 1 This provides a light-gathering ability that helps scientists study the most distant objects in the universe The James Webb Space Telescope is scheduled to launch in 2018 Gold’s physical qualities are also ideal for many electronic uses Gold is so easy to work that it can be drawn into a wire a fraction of the thickness of a human hair It can be beaten into a sheet so thin it is translucent Therefore gold can be used for very fine even microscopic electronic parts Resistance to tarnish is extremely important for any metal used in electronics Many electronic devices use very low voltages and currents The flow of electricity can be easily interrupted if there is any corrosion or tarnish in the system Electronic components made with gold are highly reliable as they rarely corrode 6
Many electronic devices from cell phones to television sets contain small amounts of gold Mobile phones contain an average of 33 gold-plated contact points a type of switch to turn the electric current on or off This averages 0 001 ounces 0 034 g of gold per phone which is worth less than two dollars 2 Computers also use gold in many electronic parts The reliability and high conductivity of gold is ideal for quickly and accurately transmitting digital data between components GOLD’S VALUE IN SPACE For these same reasons gold is used in space vehicle electronics In fact NASA uses gold throughout its spacecraft Space travel can cost billions of dollars and once a vehicle is launched it is difficult or impossible to repair Therefore the most reliable materials must be used Because gold does not corrode any electronics found in spacecraft are likely to have gold components Spacecraft also use very thin films of gold between some moving parts Two sheets of gold will slide past each other easily so the gold acts as a 7 Mixing Metals Pure gold is too soft to stand up to rough use A ring made of pure gold would quickly be damaged through normal wear Therefore gold is often alloyed or combined with other metals such as silver copper or platinum Mixing gold with another metal makes it sturdier However alloys do not resist tarnish as well as pure gold Different alloys change the color of the product Gold may have tints of white pink peach green or black because of the alloy metals The Black Hills of South Dakota is known for this type of jewelry Black Hills gold jewelry often features flower or grapevine designs The grapes are made of yellow gold while the leaves are green and pink Gold is alloyed with silver to produce the green and with copper to produce the pink
lubricant Regular lubricants would evaporate or break down in the extreme conditions of space So much gold is used in spacecraft that the Columbia space shuttle reportedly Gold in the Columbia space shuttle was used on electric contacts among other things The Best Metal for the Job All metals can conduct electricity but some do so better than others Pure silver is the best conductor but it tarnishes easily which can interfere with conductivity Copper is nearly as good and is commonly used for many electrical purposes Pure gold is the third-best conductor of electricity approximately 70 percent as good as copper 4 Gold is also more expensive than copper Yet gold is often used because it is more resistant to damage through corrosion contained approximately 90 pounds 41 kg of gold 3 Gold has a long sometimes violent history and today the gold industry faces challenges and criticisms about its treatment of people and the land Yet the world has become dependent on gold for uses no one could have imagined a century ago As gold is used in exciting new ways from industry to medicine demand for gold is likely to grow Can the gold industry meet that demand while respecting human rights and protecting the environment 8
