Given the ever-changing nature of the world, the potential accuracy of a prediction has a tendency to drop in inverse proportion to the distance between present and future. But here are a dozen possibilities about what the world may be like forty-five years from now--and what those changes may mean for you.

1. "Solar paint" with embedded semiconductor particles will draw energy from the sun to help power any device, machine, or building on which it is used.

2. Wearable electronic devices will be powered by using the wearer's skin as a conduit. Because Microsoft patented this method in 2004, the company (with a market value by then of $1.4 trillion) will derive a major income stream from licensing it.

3. People of two or more races will be so common in the U.S. that the Census Bureau will consider dropping the "race" question from the census due to overcomplexity and irrelevance. (The bureau will continue to pose the question until 2100.)

4. Printable transistors will have many applications, including clothing that can receive video signals. Average citizens will be able to sell commercial time on the backs of their jackets.

5. Tuition, room, and board for a year at Harvard will top $320,000--if anyone still wants to go. Many students will put a degree program together through distance-learning classes at a variety of institutions, which will vie for their business on cost and quality. The best teachers will become superstars with international reputations, and will copyright their lectures and class materials.

6. Due to shifting ethnic makeup, California will have a referendum on the 2048 ballot to revisit the issue of English as the sole official language of the state. The 1986 constitutional amendment will be repealed, and by 2050 all official signage in California will be in English, Spanish, and Chinese.

7. Human tissues, bones, and organs will be custom-made using devices similar to inkjet printers that can build three-dimensional structures of living cells. This technology will transform plastic and restorative surgery and the field of organ transplants.

8. Use of cash will be way down, and Congress will finally deep-six the penny, though sentiment, a love of privacy, and the needs of criminals and the Tooth Fairy will ensure a continued market for bills and coins. An international "Netcash" currency will remove exchange-rate issues from online transactions, and will beat out the dollar, the euro, the yuan, and the rupee as a de facto standard.

9. The market will be hot for landfill-mining stocks, as prospectors dig through garbage for metals, minerals, and other materials whose natural sources have been exhausted.

10. The youngest baby boomer will be 86, the oldest 104.

11. Books will be a retro luxury, as most nonfiction reading matter will have migrated to the Internet or portable storage devices. Book-binding will become a popular hobby, and many printed books will be works of art.

12. To deal with seething social unrest caused by an excess of single men, China will offer attractive financial packages to Chinese girls adopted by U.S. families to get them to resettle in China. FP

Elizabeth Gardner is a correspondent for Small Times, a magazine and Web site specializing in nanotechnology. She was the information-technology columnist at Modern Healthcare and, for several years during the dot-com boom, a contributing writer at Internet World.

Sources: 1) University of Toronto; National Renewable Energy Laboratory; 2) Philips Electronics; Arizona Biodesign Institute; The Economist; 3) U.S. Census Bureau; 4) Philips Electronics; Arizona Biodesign Institute; The Economist; 5) Thomson Peterson's Tuition Finder (assuming 5% annual increase); Pew Internet and American Life Project/Elon University; 7) University of Manchester, England; 10) U.S. Census Bureau.
Other items are our creations, based on observations of current trends.