I think you still need to take nickel recycling into account for hybrid vehicles. I don't know the extent of it, but since nickel is $20 a pound, there should be a bunch of it. So if a pound of nickel passes through say 5 electric cars before it ends up in the dump, that vastly reduces the ecological impact of those electric cars. But in the absence of a battery recycling program, the ecological harm is much more serious.

With respect to your solar cell comments, electricity is a tricky market. Solar power doesn't need to be cheaper than grid power. It just needs to be cheaper than grid power at the time the Sun is shining. That's an easier hurdle to achieve.

In fact, one of the reasons the electricity market is messed up is because the customer is shielded from peak electricity costs (ie, there usually is no penalty to using power at peak consumption times). I bet people would be more keen on solar power if they had to deal with peak electricity costs.

Also voltage step up and step down is only part of the losses inherent in transporting power to the home or business. There is loss just in travelling down the line both from resistance and from inducing current flows in nearby wire and other conductive structures.

If I understand correctly, the idea behind the wormhole is that you open up a shorter path or bridge between Earth and Vega (the example used in the podcast). It's like adding a handle to a ball. You can now travel between two points on the surface of the ball by either travelling along the ball or pass along the handle.

The usual assumption (as I see it) is that the two ends of the wormhole are created in the same place (say by a huge particle accelerator). Then move one end to a distant location. Say we create the pair somewhere in the Solar System, then move one end to Vega (a 26+ year trip depending on how fast you do it). Then assuming that the internal distance between the two ends doesn't change and that it is much shorter than 26 light years, you then have a short cut between Earth and Vega.

Good podcast. I enjoyed listening to it.

PS, could you list the books that you cite in these podcasts?

Karl:

Glad you enjoyed the show.

The book I brought up was, of course, Ray Kurzweil's "The Singularity is Near." Look for "Kip Thorne" in the index.

For sourcing on the rest of the topics follow the links in the post above. Most of these links are to our own posts, but click on through to the original sources.

On nickel cadmium batteries, I think mandatory recycling should be enforced. Once it's too far gone to be used in recycling, we despose of it centrally. We don't want that stuff in local landfills.

Hopefully, though, we will quickly move to more environmentally friendly batteries. I suspect Lithium Ion batteries would be easier on the environment.

You said:

"Solar power doesn't need to be cheaper than grid power. It just needs to be cheaper than grid power at the time the Sun is shining."

Actually I was talking about the cost of solar over the life of the solar panel. You look at the price of that solar panel (plus installation and maintenance) and the amount of power it harvests over its lifetime to find your price/watt.

Compare that to grid power and you'll find that contemporary solar is still more expensive than grid power. That may soon change if they can get this latest MIT development ready for mass production.

But you had an important point on solar - that it only harvests power during the daytime. Improved battery tech will be a vital part of how solar becomes economically attractive.

Kip Thornes wormhole idea didn't involve sending things through the wormhole. His idea is this:

Okay, I'm in orbit with my spaceship. You're in an adjacent orbital spacestation. Before I get started on my trip we establish a wormhole between the station and my ship.

Then I take off for Vega. My trip to Vega seems like just three months to me because I'm going so close to the speed of light. Normally - from the point of view of the Earth - that trip would take 25 years.

But, Thorne argues, since we've kept a wormhole open (stretching it all the way from Earth to Vega), local Earth spacetime would be kept in sync with the spacetime of my spaceship. The trip would seem like 3 months on Earth too.

Now, I'd think that the wormhole would be useful in other ways too. You could communicate through it. Instaneous communications (instead of a 25 year delay) would be invaluable. Perhaps the wormhole could also be large enough for nanobots to move through it.

Hey! Great show as always.

I hate commenting on this, since I only have a pop-science understanding of relativity. But if you've got a wormhole kept open between the spaceship and our planet, then information is being sent through it, which is really all you need. Once you get to Vega you just expand the wormhole and bang, hello stargate.

But you're not entangling Sol and Vega in any weird sense. Let's say that when we send this spaceship out it's January 2050 here on Earth and January 2050 over in Vega. When the spaceship arrives, it's January 2075 here on Earth and January 2075 over in Vega. But the wormhole is now a link through space and time. So there's a gateway between 1 April 2050 Earth and 1 January 2075 Vega (since the wormhole only aged three months).

Of course, if you wanted, you could whip together a new wormhole in Vega and send one end back to Earth via rocket. So when it leaves, it's 1 January 2075 on Vega and 1 January 2075 on Earth. When it arrives, it's 1 January 2100 on Earth and 1 January 2100 on Vega. But since it's a spacetime tunnel, you have a link between 1 April 2075 Vega and 1 January 2100 Earth.

Of course, the other link is still active. So just wait until July 1, 2050, and you can have dinner with yourself from 50 years in the future. Or maybe just chat...I for one have no idea what to feed a posthuman foglet swarm.

It's weirder than that. Because you set up that wormhole loop (and incidentally it is possible to just skip the passage to Vega and connect your wormhole directly to Earth at a future time), 2100 Earth has a connection to both 2050 Earth and 2150 Earth.

Iterate.

Examples of weird things you could do:
* set up time paradoxes.
* Run a program far into the future and send the results to 2050 Earth.
* Perhaps you can run enormous social experiments that run out trillions of years.
* Visit the end of the universe.

Considering the security protocol required for an international flight in 2007 Earth, I doubt anyone will be crossing space-time boundaries via wormhole even by 2100.