In Understanding Media (1964), Marshall McLuhan distinguished between 'hot' and 'cool' media: hot media, like the radio, are 'high definition' but 'low in participation'; 'cool media', like the telephone, are 'low definition' but 'high in participation'. (In the early 1960s, TV was 'cool', compared to the 'hot' movies. Obviously that was long before the arrival of hi-def.) Predictions about the way technology is heading, whether made by SF writers or tech companies, tend to assume the future will be hot. Characters in Brave New World go to the Feelies. Thirty years ago, everyone (well, maybe not everyone) imagined that by now we'd be watching holographic movies and wandering around with virtual reality helmets on. But no one foresaw the rise of text-messaging or Twitter. Michio Kaku's whiggish Physics of the Future, published last month, follows the trend, confident that the future will be lived in high definition.

The weirdest thing about Kaku's book isn't the 'startling and provocative vision of the future' promised by the publicity material, but how incredibly old-fashioned it all seems. Kaku, a professor of physics at the CUNY Graduate Center, begins the book with a confession of how much he loved watching Flash Gordon on TV as a child. It shows. Laser-propelled spaceships, robot dogs, self-driving magnetic cars, colonies on Mars, surfing the internet telepathically through our contact lenses – weren't we, according to the SF of the 1950s and 1960s, already meant to have all this stuff by now?

Kaku's final chapter, 'A Day in the Life in 2100', reads like Asimov on a very bad day:

January 1, 2100, 6:15 a.m.
After a night of heavy partying on New Year's Eve, you are sound asleep.
Suddenly, your wall screen lights up. A friendly, familiar face appears on the screen. It's Molly, the software program you bought recently. Molly announces cheerily, 'John, wake up. You are needed at the office.'

In many of the important ways, you'll notice, 2100 will be remarkably like the 1950s.

On the other hand, the entire species may be wiped out at some point in the next 89 years, and a day in the life in 2100 will begin more like this:

After a night of heavy sulphuric acid consumption, the colony of extremophile bacteria had doubled in size.

Or maybe not, since apocalypse, like techno-utopia, has a tendency to be permanently postponed.