We will find out in about two years. The number of coins generated per block falls in half every 210,000 blocks, which is about 4 years. Two years is when the next halving is due. Half the mining hardware will become uneconomic to use at that time.

The technology that underlies bitcoin, data secured by a series of chained hashes, such that the hash for one data block is part of the data for the next, enables a secure record keeping system for electronic data. Any change to past data, whether from errors or malicious tampering, is detectable because re-hashing the contents of a data block will give a different result than the one stored in the next block.

This is highly useful for a financial transaction system, the first application bitcoin represents. But secure digital record keeping applies to any kind of data whatsoever, and the applications are much wider than just digital currencies. To give one example, it can ensure the integrity of an operating system against malware. The original OS distribution and updates are encoded as a series of data blocks with chained hashes. Anything that is not supposed to be there would invalidate one or more blocks, and thus be detectable.

Corporate scrip (i.e private currencies) is a trivial application by comparison.

It could also refer to the price of the factory, which will be well over a billion dollars.

> I suspect that the name is also a bit of an homage to Back to the Future, but given that Musk is of South African origin and didn't move to North America until three years after the movie came out, I'd like to hear it from the horse's mouth to be sure.

Back to the Future 1 did 45% of it's box office gross internationally ( http://www.boxofficemojo.com/m... ). I assume South Africa had movie theaters in 1985. Most reasonably developed countries did.

Well, they can try, but it will be about as successful as controlling bitTorrent, or cannabis.

The proposed New York State regulations require the "issuer" of a virtual currency to get a license if they have users in the state. Who exactly in the bitcoin community would that be? Satoshi Nakamoto? Chinese mining farms? So I agree, good luck. At most some bitcoin-based businesses will just not deal with New York customers.

> Bitcoin is a scam magnet.

Unlike, say, the entire banking and real estate industry in the early 2000's? Or the founder and former head of the NASDAQ exchange, Bernard Madoff? LIBOR price fixing? I could go on.

Ask yourself what backs the value of UPS shipping labels, that people are willing to give substantial sums to obtain one? Intrinsically the label is just sticky paper with some printing on it. The answer is the UPS network of trucks and distribution terminals. They enable a package with a label on it to get from one place to another.

In a similar way, the Bitcoin network of p2p nodes, mining hardware, desktop apps, merchants accepting it, and user wallets enable moving money from one place to another. A bitcoin address with a non-zero balance is like a prepaid shipping label, ready to be used to transfer value to another address. But without the network, the transfers would be nearly impossible. The network makes bitcoin balances useful, and therefore have value.

In a money transfer system, the internal units don't have to have any particular value, as long as everyone agrees on their value at a given time. If I want to pay a Romanian programmer and buy X dollars worth of bitcoins, transmit them, and the programmer converts them to Leu locally, the value only needs to be stable during the time the transfer takes to be acceptable. The particular number of bitcoin units in between is immaterial, it is just an accounting unit.

People who hold bitcoin units for longer periods are speculating that demand for them will go up, or at least remain level. Since the number of units is relatively fixed (it is increasing at 11%/year currently, and will taper off to zero over time), demand will drive the exchange rate up or remain level. If you live in a country that is rapidly increasing the money supply, like Venezuela or the United States, a stable supply of an alternative good can be attractive. That store of value function is separate from the value transfer function.

Because the Senator from Alabama wants to keep the NASA center in Huntsville busy.

I beg to differ, having worked on the Space Station program for Boeing. Pound for pound the station hardware costs the same to design as passenger airplanes of the same era. That is not surprising, because they are both aluminum structures full of mechanical and electrical components, designed by the same people, using the same methods and knowledge base. The big difference is when Boeing designs a passenger airplane, they typically make 1000 copies. We only made 1 copy of the Space Station hardware. So the entire design cost falls on that one copy.

The Falcon series rockets are cheaper partly because they use lots of repetitive parts. The Falcon 9 uses ten Merlin engines, nine in the first stage, and one in the second stage. The first and second stages use common tank diameters and bulkheads. The Falcon Heavy uses three copies of the first stage. So it is bound to be cheaper because you are not designing as many kg of unique hardware.

The SLS with a once-every-two-years launch rate barely has a production line, but yet you have to have massive tooling in the factory, a trained workforce who know all the jobs, etc. That is an expensive way to fly.

Dell is using a payment processor, Coinbase, ( https://coinbase.com/ ) who accepts bitcoins on their behalf. Coinbase deposits dollars to Dell's bank account, and resells the coins to individuals, and on exchanges. So Dell never handles bitcoins themselves, just dollars like usual.

The two largest payment processors, Coinbase and BitPay, have about 65,000 merchants they accept bitcoin on behalf of and convert. The merchant gets local currency deposited to their accounts. There are an unknown number of places that take bitcoin directly, like our Seed Factory Project ( http://www.seed-factory.org/ ).

You can spend bitcoin indirectly at many major merchants through Gyft ( http://www.gyft.com/buy-gift-c... ). Note the "shop with bitcoin" item in the top menu. Gyft sells you a gift card, which you then can use at the merchant. You get a 3% discount buying the card with bitcoin, which represents part of the credit card fees, fraud, and chargebacks which Gyft and the merchant get to avoid.

Ty Warner, the inventor of beanie babies, is worth $2.6 billion. Do not scoff at collectibles.

I use a couple of inch (5 cm) high ring of aluminum foil, shiny side in, around the burner. That reflects heat from the burner and the pot itself back onto the pot, and reduces convection losses by partly blocking air coming in around the edges. Obviously if you are using gas burners, you need enough air for the flame. A strip of foil is going to be way way cheaper than an $85 pot.

When choosing pots, pick one that is black, not shiny, or make it black by burning stuff on the outside. Black surfaces absorb heat better.

You have numbers to back up this claim? Because my numbers say the opposite.

Near Earth asteroids contain up to 20% chemically bound water (in the form of hydrated minerals). They don't contain water as water, because at our distance from the Sun it is too hot for water to be retained in a vacuum. To get this water out of the minerals you heat them to typically 200-300C. So stuff the asteroid rock in a closed container, focus enough sunlight on it to reach the required temperature, then have a condenser on the shaded side to turn the vapor back into liquid.

Water has multiple uses in space as propellant, shielding, and for biology. When split to oxygen we can breathe it. Some asteroids also have a large amount of carbon, so you can reform Water + Carbon into Oxygen + Hydrocarbons, which makes an excellent high thrust fuel, but that would be a more advanced application. Simple extraction of water is about as hard as running a distillery for alcohol.