Here are quotes from a good overview of possible scenarios at InterestingEngineering.com:
“Another anticipated pathway is the ability to manipulate matter at increasingly smaller scales. Eventually, this would allow humans to engineer materials at the atomic or even quantum level, leading to a new era in fabrication and medicine. Such technologies fall under the general heading of ‘nanotechnology’ and describe machines that measure a few nanometers [‘10 to the minus 9’ meters] in scale.”
“In the early 1990s, scientists discovered ways to synthesize buckminsterfullerenes and carbon nanotubes, nanometer-scale structures composed of carbon a single atom in thickness. By 2004, Andre Geim and Konstantin Novoselov had isolated and characterized two-dimensional sheets of carbon that are just one atom thick (known as graphene), which earned them the 2010 Nobel Prize in Physics.”
“…machines would be comparable in size to individual atoms, and capable of manipulating them…This will lead to a new age where we could synthesize precious materials out of simpler and more common elements and materials with special properties ([also known as] ‘supermaterials’) to fulfill all sorts of tasks. Examples include room-temperature superconductors and materials that are super resistant to heat and pressure in space, deep sea, and interior planet exploration.”
“In 2010, computer scientist and futurist Jaron Lanier published his futurist manifesto titled You are not a gadget. Expanding on the idea of life-extension in the physical sense, Lanier argued that immortality could be achieved through ‘Digital Ascension.’ As he described it, this would consist of ‘people dying in the flesh and being uploaded into a computer and remaining conscious’.”
“The ability to extend one’s own life indefinitely with anti-aging medicines, replacement organs, stem cell therapy, medimachines, and neural uploading will lead to the first ‘immortals.’ The ability to keep on living and reverse the scourge of time and aging will also mean that people will be able to remain active, healthy, and productive indefinitely.”
If you think some of this is completely whacko and absurd and impossible, keep in mind that scientists are actually working toward it in their labs. This isn’t just a thought-game.
Whether or not they’ll be able to achieve some of these goals, they’re busy.