I would say between 100 and 300.. It's impossible to predict technology inventions since technology is constantly changing and most inventions actually appear by accident. I think that with the world being how it is today, we can't even predict how it will be in 5 years.. I don't know if in 5 to 10 years I will be driving a green car or a jetpack to work..
answered Feb 18 '11 at 12:07
The technology to blow up trains exist now.
The technology to transfer information from one brain to another will never exist.
answered Feb 18 '11 at 12:20