Not nearly as hard as some of the other proposals such as shooting it down with lasers or sending up robotic ships to collect the debris.

One idea would be to spray large amounts of even smaller debris- fine dust- into these orbits. Perhaps from the moon. It would increase drag for everything, and anything that didn't have active boosting capability (ie, anything that wasn't an active satellite) would eventually fall back to earth, including all debris. The downside would be that satellites would have to carry more propellant to maintain their orbits, increasing the needed booster size and thus overall cost. Not pretty but feasible, effective and fairly benign. If enough debris accumulates up there in the next century we just may have to do this by virtue of not having any other choice.

Another option might be to require that all satellite components be made of or be alloyed with iron so that future satellites and spacecraft could generate magnetic fields to deflect the debris.

On the contrary we already know how to geoengineer our planet but we are still working on interstellar travel.

In fact, we have already geoengineered our planet several times. The most obvious one is the increase in atmospheric CO2 and thus global warming caused by burning fossil fuels. This was an accident of course. Another example is the creation and then subsequent repair of the ozone hole by first releasing CFCs then stopping. Smaller examples include programs to seed clouds to prevent/encourage rain or even cloud formation. Beyond that I think we are pretty close (~50 years) to developing global weather pattern models accurate enough to predict the effect of various variables on rainfall, currents, jetstream, etc. It won't be long before we realize, for example, putting a desert in x location will cause y results. And things like creating deserts or forests or lakes? Yea, we can definitely do that already, we've just had very few good reasons to. If the political will existed we could probably start spraying sulfer into the upper atmosphere within the next 5 years which would result in a significant and quick (and cheap) temperature drop. If we really had to we probably are resourceful enough to be able to seed a watery planet with algae and bacteria that has been toughened in a space environment and will go on to start converting the planet's atmosphere to oxygen.

On the other hand, a star ship? That's a joke. Orion (the nuclear weapon propelled ship) is fraught with problems, not least of which is that 50% of the energy of each blast must be wasted by design. What material can withstand repeated nuclear explosions at close range without vaporizing, especially in vacuum? What kind of ultra magical structural material will be able to withstand and transmit the stresses of intermittent high-g acceleration? Will nukes even be enough to move such an enormous structure through space at close to light speed? It seems far more sensible to me to take all those uranium and plutonium cores, de-enrich them, and use them to create a huge number of fission reactors which would then fuel a fusion reactor which would drive the ship via heavy-ion plasma. That kind of technology is pretty far off, as is the kind of productivity that would make such a project even remotely affordable without bankrupting our planet. We spent $200 Billion in today's dollars getting a few people to the moon in a dinky can! I'm pretty sure it's gonna be really hard to send thousands of people at light speed across the dark expanse. I'm pretty sure geo engineering is a hell of a lot easier.

Somehow I doubt aliens would endeavor for decades to build massive multi generational spaceships to travel all the way here just wipe us out. Seriously, if you can travel interstellar distances you probably don't need the resources from the only nearby planet with life on it, you can probably get them from anywhere. And wiping out the locals kind of makes going to that particular planet pointless, since there is no interest without the life. Geo-engineering a planet is far easier than traveling to another star.

Of course if the aliens are just really really xenophobic then we could be screwed, but if evolution is a universal law such a species probably wouldn't stop fighting itself long enough to be able to afford space travel.

Good point. No, it is not newsworthy. This headline is the equivalent of "CS student learns how to use buffer overflow" or "biochemistry student learns how to replicate DNA."

But it makes perfect sense when you realize who is behind what is currently the biggest Super Mileage competition in North America: Shell. And last year the Shell Eco-Marathon was not 5 miles from Cal Poly Pomona. I believe 1st place is $10,000.

As you might expect Shell makes sure that media outlets hear about this kind of stuff. They actually send the teams registering for the competition questionnaires essentially asking them to say something interesting for a potential story.

Gullibility of the media aside, it's still a great project for students and hey, at least Shell *seems* to care about fuel efficiency.

This isn't research. It's just an engineering competition for engineering students. You know, getting out of the classroom and doing hands-on work and all that good stuff.

He did become famous. Just now. When was the last time something you did personally was reported on by the world media? I'm not saying that your criticism is misplaced, just that you're using the wrong argument. More significant than becoming rich or famous is whether you have done anything worthwhile and the answer in this case is no.

We have an area several times larger than the entire country of Germany to pave, of course we can't build roads with 3 feet of cement, we'd go bankrupt and then some: we'd have to suck up the entire world output of cement for a decade or more to do it.

There are two ways in which electric heat can be said to be "inefficient." First, there are two ways to generate heat from electricity. You can use resistive dissipative heating, which you are thinking of, or you can operate a heat pump. Heat pumps are more common in cold climates and can reach something like 130% efficiency by taking heat from outside and moving it into the cold house- plus the 100% heat dissipation from electric losses in the pump itself. Compare this to a maximum efficiency of 100% for resistive heating alone. The downside of course is that a heat pump is far more expensive than a resistive heater.

However, electric heating is painfully inefficient when you look at the best solution- directly burning the energy source in the home. Think about it: to get that electricity to run your electric heater, the power company has to burn fuel in a power plant. The power plant efficiency is maybe 40%, meaning the remaining 60% of the heat released during combustion gets dumped into the environment. Then, the electricity must be transmitted over the grid which is only maybe 70% efficient. That means resistance heating, though 100% efficient starting at the wall socket, is less than 30% efficient overall when considering the original energy content of the fuel. Burning the fuel to directly obtain its heat is much better than converting it to electricity to transmit it first.

I wonder if there's a correlation between number of tabs open and messiness of desk. It's the same concept- we are reluctant to put away things we were looking at just a couple minutes ago and might need them in the future.

For the record, I usually have over 20 tabs open and a fairly messy desk to match.