Actually, your typical freight train is running regenerative braking. If you look down on a locomotive going by, you can see huge fans in the top of the cab that are used to blow air over load coils. Figure a maximum sized train weighs in at 19,000 tonnes (130 car coal train), that means that when it's operating at 60km/hr it has roughly 2.6 gigajoules of kinetic energy. To stop it, that energy has to be dumped. Some of it is done by the train's air brakes, but most of it is done through regenerative braking in each of the locomotives.

This is all irrelevant when it comes to the SSC though, since it's using air resistance to drop its speed to 260kph, then slowing down with traditional brakes. The hard part is going to be making the brakes survive spinning at 10,000rpm, not dissipating the energy from slowing down.

That assumes that the police officers in question are dedicated to traffic policing. With the possible exception of highway patrol, traffic enforcement is only a way for the officers to fill time between more important calls. If a fight breaks out at a bar, it's likely that the closest officer is the one who was looking for drunk drivers.

And some of us actually enjoy driving as an activity. Heck, I don't even really mind sitting in traffic as long as I have my CBC/NPR/Podcasts.

The policy is under the auspices of the Outer Space Treaty, which has been ratified by both China and India (along with the United States). Given that the Scientists and Engineers who tend to be involved in these projects are generally rational people (even if they're doing a politician's bidding), I'd say that the chance of things being done reasonably correctly are good.

It's actually assumed that every probe that is sent will have some form of bacteria and so forth on it; life is just so pervasive on this planet that it's impossible to perfectly sterilize everything. Instead, the goal is to strongly sterilize what's critical and exposed to the environment, and reduce the probability of accidental contamination to an acceptable level (currently defined to be in the neighbourhood of 1 in 10,000 chance).

JPL actually has a highly detailed document on "Policy for Planetary Protection" that details the standards to which a probe must be sanitized to before being sent on its mission. The level of cleanliness depends on the intended mission and target; orbiters have a lesser standard than landers, for example. The policy also takes into account different parts of the spacecraft; the inside of the box containing the CPU and so forth isn't cleaned to as high of a standard as the wheels, experiments and so forth that are directly exposed to the environment. In the case of the Galileo probe, it was deliberately crashed into Jupiter at the end of mission in order to ensure it would never impact Europa, as it had not been cleaned to that high of a standard. Cassini will face a parallel fate, of crashing into Saturn to prevent a collision with Enceladus and/or Titan.

The key part here is that when you are looking for life (or might be looking for life in the near future) you don't want to discover that the life is found is something that you brought from earth yourself, or was brought by another space probe.

Don't normally reply to myself, but that was a Cut and paste out of another article here. :)

More likely someone doesn't know that there is a difference between a Ton and a Tonne, and figures they're just the british and american ways of spelling the same thing. The dragon capsule is rated to return up to 2500kg of mass to the earth, so it stands to reason that this is just a lack of pedantry on the part of the author.

Well, the drivers get the very real benefit of fewer vehicles on the roads. Even if we ignore Stockholm's (very good) subway system, a bus carrying 40 passengers probably means 15+ cars that are not on the road.

I think that many people forget the NSA's other mission: securing US Government communications. The easiest way to figure out how secure an algorithm is, is to take a look at what level of information it's authorized for. Despite everything that all the folks here say, the NSA and other agencies aren't stupid. They know full well that if they can break the algorithm, somebody else can as well.

The saddle patch is accepted by the scientists in the field to be a unique identifier. No two whales have ever been found to have identical saddle patches, and there is enough variation to indicate they are unique. So is it possible? yes. Likely? No.

Add to this the fact that the data from these old photos lines up with her offspring history, and it's a pretty solid case. In 1971, she was photographed with a male offspring who was already fully grown, so at least 20 years old. She was not seen with any other younger offspring, indicating that he was probably her last. Orcas go through the whale equivalent of menopause at age 40, so 20+40 gives her an age of 60 at the time, and thus 1911 as a birth year.

Anyhow, combine the two pieces of data (the 1930s photo, showing her fully grown) and the offspring data, and it's pretty compelling that she was born roughly 103 years ago, give or take a few.

This case is one of the usual case studies that make up many Engineering Ethics courses (at least it was brought up in mine). The nice thing about this case is that in the end, it all worked out for the better, and is a good news story rather than a disaster.

The other typical case studies are the Therac 25, Challenger Disaster, Hyatt Walkway Collapse and in Canada the Quebec Bridge collapse (which also lead to the creation of the Iron Ring.

There is a significant portion of the Engineering education that is dedicated to reminding prospective Engineers of their responsibilities to society, and the power they can potentially wield. Ethics is also a significant portion of the licensure to get one's professional designation.

The Annals of Improbable Research is quite reasonably priced, and a good read.

After all, where else could you read about "Homosexual Necrophilia in the Mallard Duck" or "Predicting when cows will lie down"?

I work with a number of locations that lack any form of high speed internet. They have enough internet to facebook, order the DVDs, etc... but nowhere near enough bandwidth to actually stream the movies. The DVD-by-mail option is their only option, if netflix et al were to shut down this service, they would be very unhappy.

"Stationary" satellites aren't really. They drift around within an approximately 30km x 30km x 30km box, and these movements are very well known. This isn't much, but is enough that you can locate an earth station to within a few miles if you have enough time. IN this case, they only have a few pieces of data, hence the larger solution.