* Posts by Brangdon

394 posts • joined 15 Sep 2008

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USA! USA! We're No.1! And we want to keep it that way – in spaaaace

Brangdon
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Re: Monitor and destroy

Hydrogen is usually avoided for a first stage because it has less thrust than other fuels, and because in engineering terms it is a bastard to work with. And not everyone uses it for their second stage, either. SpaceX, for example, Falcon 9 uses purified kerosene for both stages, and their planned BFR will use methane.

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Brangdon
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@PaulFrederick

It wasn't a slight against the USA. You're both saying the article was wrong: that sending robots instead of humans won't eliminate mistakes. (And if you send a human you have more chance of fixing a problem on-site.)

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Australia wants tech companies to let cops 'n' snoops see messages without backdoors

Brangdon
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Re: Benefit of the doubt?

To me it sounded like he was trying to distinguish between a back door in the sense of a weakened crypto algorithm, and key escrow. A weakened algorithm can be broken by anyone with sufficient maths ability and computational power, so is a worse option. Key escrow can only be broken by whoever has the keys. Key escrow can seem like a viable option if you trust the keyholder to keep them safe.

That said, the quote, "There's been ideas around for decades that you should create some kind of key that law enforcement can get access to … that's not what we're proposing" could be a rejection of key escrow. But without details of what he is proposing it's impossible to be sure.

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SpaceX to pick up the space pace with yet another Falcon 9 launch

Brangdon
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Re: little appetite to bother with recovery

In addition to the GTO thing, SpaceX may figure they can get more value by testing experimental landing profiles than by recovering the booster. The booster can't be reused, is too big for museums to handle, and SpaceX have probably learnt all they can from recovering and inspecting its siblings. If they try a new landing profile, they might learn more about how the booster behaves. The data could be valuable but not valuable enough to be worth risking damage to the drone ship for, so they land it without the drone ship.

I don't know if this is what's happening for this launch, but it's a consideration. It's not just not bothering.

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'Autopilot' Tesla crashed into our parked patrol car, say SoCal cops

Brangdon
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The data isn't publicly available. We know that Tesla cars as a whole got safer around the time that autopilot was introduced, but it was introduced at about the same time that automated emergency braking was added, and it may be the latter which is wholly responsible for the improvement and not autopilot. That Tesla have the data and don't release it is regarded as suspicious by some people.

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Beardy Branson: Wacky hyperloop tube maglev cheaper than railways

Brangdon
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Re: Bezos is doing both

Bezos current rocket, New Shepherd, is also sub-orbital hops only. He plans an orbital one called New Glenn, but it is years away from its maiden flight. He's not put any commercial cargo in orbit - at most he's done some brief micro-gravity experiments.

Maybe you have him confused with Musk? SpaceX often sends cargo to LEO, GTO and the ISS. He's not put any humans in space yet, but hopes to by end of year-ish.

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First SpaceX Falcon 9 Block 5 rocket lobs comms sat into orbit

Brangdon
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BFR to fly next

You are confusing the BFR with the BFS. It's the BFS which Musk hopes will fly next year. The BFS is the second stage, and by "fly" he means make small, sub-orbital test hops. It's not as ambitious as you make it out to be.

He's also talked of making 30-50 block 5 first stages, each capable of 10+ launches. Even if SpaceX manage 50 launches a year, that will still take 10 years to get through. So he's not actually counting on BFR flying that soon.

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Mobileye's autonomous cars are heading to California. But they're not going to kill anyone. At least not on purpose

Brangdon
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Re: Strawmen

Does the bouncing ball actually change your car's movement? Or does it merely cause you to be more attentive? For me when I see a hazard I may only move my foot over the brake without actually slowing down, while I watch for developments. After the bouncing ball I'd be more ready to stop, and paying more attention to where the ball came from in case a child followed, but I wouldn't actually stop or even necessarily slow down. An autonomous car is presumably always paying attention, always alert, and always ready to stop, so doesn't need to predict as much.

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Brit govt told to do its homework ahead of talks over post-Brexit spy laws and data flows

Brangdon
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Re: What is impossible?

Leaving the EU is possible. Doing it smoothly in the timeframe available with the resources available isn't. It's a complex task.

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So when can you get in the first self-driving car? GM says 2019. Mobileye says 2021. Waymo says 2018 – yes, this year

Brangdon
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Re: You won't get into the first...

Don't just the best by the performance of the worst.

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NASA boss insists US returning to the Moon after Peanuts to show for past four decades

Brangdon
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Re: Moon base Alpha

It's easier to live on Mars for many reason. It has an atmosphere, which reduces radiation and micro-meteors, and helps slow down on arrival (so it costs less delta-v than the Moon), and which is a source of CO2 for making rocket fuel for departure. Its day/night cycle is close to 24 hours rather than 28 days, which is better for plant growth, and means you don't need so many batteries to store solar power, and which reduces the temperature extremes. Mars gravity is closer to Earth's. It has plenty of water readily available (which has yet to be proven on the Moon).

The only advantage of the Moon is that it's closer. Admittedly that's a big advantage. In every other way Mars is better.

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Password re-use is dangerous, right? So what about stopping it with password-sharing?

Brangdon
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Re: one that's also hard to type

There's your mistake. Choose an easy to type password instead. Make it longer so it's just as secure. You'll find you can type "balloon sausage monty pet dribble elephant noggin pleb" pretty quickly and it has around 100 bits of entropy.

(Or would do if you picked the words at random, rather than just making them up like I just did.)

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It's World (Terrible) Password (Advice) Day!

Brangdon
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Re: use pronounceable if you want to remember the password; random otherwise

Pronounceable passwords of the CorrectHorseBatteryStable variety have the benefit of being much easier to use if you don't have copy and paste available. Especially if the keyboard you are using makes it hard to access symbols, or even numbers. I can type several correctly-spelt English words quicker than I can type a sequence of random characters, even if the words have a greater total length. I type for a living, and most people type at least quick enough to send text messages.

It's wrong to say these passwords would be undermined if other people don't use symbols. Go read the XKCD again, and pay attention to the numbers. Each word adds 11 bits of entropy. That means it uses a dictionary of 2048 words. You get that much entropy regardless of what other people do, and regardless of whether you include spaces or capitals at word boundaries, and regardless of whether the attacker knows the dictionary. (It surprises me how many people cite the comic without understanding this point.) If you need more than 44 bits, use more words and/or pick them from a larger dictionary.

Which highlights another advantage of using correctly-spelt English words: you can calculate exactly how much entropy you have, and it doesn't depend on security by obscurity. All the schemes based on songs or substitutions or whatever, you really have no idea how secure they actually are. And because you know how much entropy, if you need to add a number or something to satisfy someone else's arbitrary password rules, you can just stick a 1 on the end. You won't make it less secure by doing so.

The main catch is that you need to pick your words from a dictionary with a genuine random method. Don't use the first words you think of, or the name of the first thing you see when you look out of the window, because you don't know how much entropy that gives you. Ideally use diceware or similar.

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I've got way too much cash, thinks Jeff Bezos. Hmmm, pay more tax? Pay staff more? Nah, let's just go into space

Brangdon
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Re: Space tourism, or improving the lives of billions?

Neither Blue Origin nor SpaceX are about space tourism, so it's a false choice. Bezos wants to see a million people living and working in space. He wants to move industry up there to reduce pollution on Earth. Tourism is just a means to raise funding, and to promote interest in space.

Musk wants to save the human species from extinction, another laudable goal. Along the way he is promoting solar power and electric cars to help clean up the environment. In addition he is trying to bring the internet to third world countries, via LEO satellites. That may not sound as important as proper toilets, but with the internet comes education - you can look up how to build a proper toilet online.

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Worried we'll make ourselves extinct? Let’s be scientific about it

Brangdon
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Re: Well ...

There is now an evolutionary pressure in favour of remembering to change the batteries in your smoke detector.

The pressure is low, because not many people die in fires, but some do (and sometimes their children die too), and so the selection bias exists. Human evolution may have slowed, but it hasn't stopped.

(If you are reading this, take it as a reminder to check your own batteries. When did you last do it?)

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Virgin spaceplane makes maiden rocket-powered flight

Brangdon
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The number of people who can afford a longish trip in space will increase enormously when SpaceX BFR gets going. They'll have orbital trips of a few hours, and circumlunar trips of a week or two. This is quite likely to happen in the next 10 years, or 15 at the outside. If you can afford Virgin, you probably should hold on to your money for a few more years and then get a much better and/or cheaper experience.

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Brangdon
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Re: the principle of an air-launched second stage is one worth pursuing

I'm not convinced. It adds a lot of complexity for not a lot of gain. The height and delta-v gains are trivial. The main benefits are avoiding most of the atmosphere, being able to use a nozzle tuned for near-vacuum, and some flexibility over where you launch from. It just doesn't seem worth the effort and complexity of adding a whole other aircraft.

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Brangdon
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Re: most likely to allow me to get 'above' the atmosphere and back alive

I'd trust Blue Origin's New Shepard over this.

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Uber self-driving car death riddle: Was LIDAR blind spot to blame?

Brangdon
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Re: with no light

There was plenty of light. Uber's released footage made it look dark, but other night time videos of the same road show it was well lit, and Uber's own headlights would have illuminated more than the released footage showed.

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Fatal driverless crash: Radar-maker says Uber disabled safety systems

Brangdon
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Re: We must ban all self-driving cars on public streets now

Not all self-driving cars. Just the Uber ones. The Waymo ones are several years ahead of the Uber ones, have done many more miles, and haven't killed anyone yet. It'd be wrong to punish Waymo for Uber's mistakes.

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Internet Society: Cryptocurrency probably not an identity system

Brangdon
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Re: hmm

Bitcoin doesn't have any particular infrastructure to support this. Another blockchain such as the Ardor platform would be much more suitable. That has persistent accounts rather than ephemeral addresses, and you can tag accounts with certificates eg to show they have been validated to some level.

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You must be yolking: English pub to launch eggstravagent Yorkshire pudding

Brangdon
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Chocolate scotch eggs

I only discovered chocolate scotch eggs were a thing when my local tea shop started advertising them.

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Bitcoin's blockchain: Potentially a hazardous waste dump of child abuse, malware, etc

Brangdon
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Re: Does every , um , wallet have a complete copy ,

Full nodes need to have a complete copy. There are light wallets that don't, which work by talking to a remote full node.

Bitcoin includes a scripting language. By using a scripts to decide whether a payment is authorised it gains a great deal of flexibility, to support things like multi signature accounts, time-locked accounts etc. The scripting language can include arbitrary data because nobody bother to make the effort to exclude it. Even if they had, you can encode information into the amounts being transacted.

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Uber breaks self-driving car record: First robo-ride to kill a pedestrian

Brangdon
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Re: Could we at least give her the dignity of a name?

Early reports suppressed her name because her next of kin had not yet been informed. This is so people don't find out about the death of loved ones from a news report. They get told by a human in a more sympathetic way. Maybe it took longer to identify her next of kin because she was homeless.

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Kepler krunch koming: Super space 'scope's fuel tank almost empty

Brangdon
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Re: Next time, include a refueling port.

It's usually better to launch a new satellite than refuel an old one. Refueling is quite hard. If you need a human to do it, well, Falcon Heavy is not man-rated and never will be, and BFS will need to be refueled itself before it can reach such a high orbit. If you want to do it without humans, then you need automated docking and other infrastructure that wasn't/isn't available and which adds weight and cost.

By the time they need refueling, the satellites are so old that you'd rather replace them with newer technology anyway.

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NASA on SpaceX's 2015 big boom: Bargain bin steel liberated your pressure vessel

Brangdon
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a face-plantingly foolish test

It's not foolish to have a wet dress rehearsal in advance. It gives you a chance to identify any issues that might cause the launch window to be missed on the day. Nor is it foolish to include the payload in the dress rehearsal. It makes the rehearsal more complete, saves time taking the rocket back to where the payload can be installed after the rehearsal, and avoids introducing problems after the rehearsal by all that movement, opening up the fairing and closing it again, etc.

Note: it was not a test to see if the rocket would explode.

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Are you Falcon sure, Elon? Musk vows Big Rocket will go up 2019

Brangdon
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Re: minimum viable poulation size for the purposes of genetic diversity is 4,139 people

He's aiming for a million people on Mars. He's planning bigger, and over longer time scales, than you.

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Wearables are now a two-horse race and Google lost very badly

Brangdon
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Re: function before appearance

My VivoActive 3 looks pretty enough to me. It has a round dial as god intended, you can pick which watch face you please, and the screen is always on.

It seems wrong to praise FitBit for a 4-day battery life when my Garmin lasts 9+ days. Currently mobile payments don't work in the UK, but I'm still hopeful that will change. Many other features, including replying to text notifications.

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Ethics? Yeah, that's great, but do they scale?

Brangdon
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Re: Something like "fiduciary duty" for software engineers?

Fiduciary duty doesn't seem to cover effects on bystanders. Examples being litter dropping, Bitcoin mining, diesel fumes. Arguably the people who suffer from Facebook misinformation are not limited to Facebook users.

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Hey, you. App dev. You like secure software? Let's learn from Tinder, Facebook's blunders

Brangdon
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Re: Seems to me the initial premise was flawed

It was supposed to be not enough to have a phone number. You also had to be able to read texts sent to that number.

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Blockchain nears peak hype: UK politicos to probe crypto-coin

Brangdon
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Re: putting large sums of money into the distributed miners pockets

That's how Bitcoin works. It's not how all blockchains work. Some use proof of stake instead of proof of work, and there-by avoid the power consumption issues. They also have low or zero fees.

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SpaceX's internet satellites to beam down 'Hello world' from orbit

Brangdon
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Re: The fairing are carbon fiber

The fairings are partly carbon fibre, and partly aluminium and other things.

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Brangdon
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The initial constellation is only 4400 satellites. They have a lifetime of 5 years, so will probably deploy over the 5 years starting from a year or so's time, and then be replenished at 20%/year. Works out at about 17 a week. We don't know how many can be deployed in a single Falcon 9 launch, but it could be 20. Falcon Heavy could do more; they will be limited by volume rather than mass. I suspect the second constellation of 7,000 satellites will need the BFR to make it viable.

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NASA budget shock: Climate studies? GTFO. We're making the Moon great again, says Trump

Brangdon
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Re: Private companies aim at profit...

SpaceX is not driven by profit. It is driven to make humanity a multi-planetary species. However, they consider the Moon a distraction to this endeavour, and they need income to achieve their goal, so they would want someone else to pay them to go there.

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Nvidia reports record revenues in latest fiscal quarter

Brangdon
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Re: GPU makers have been Borg'ed by BitCoin

Bitcoin isn't spelt like that, and doesn't use GPUs.

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What did we say about Tesla's self-driving tech? SpaceX Roadster skips Mars, steers to asteroids

Brangdon
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Re: It was never going anywhere NEAR Mars

According to https://spaceflightnow.com/2018/02/08/starman-puts-earth-in-the-rearview-mirror/, it's orbit is pretty much as originally planned. It will miss Mars by about 69 million miles (which is 2/3rds of the Earth-Sun distance, so a long way). Furthest distance from Sun will be 158 million miles. That's far short of Ceres (250 million miles), but relatively close to the inner asteroid belt (180 million miles).

It's not going to hit Mars any time in the next few thousand years. By the time it does, we'll be living there and will have contaminated it thoroughly.

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MY GOD, IT'S FULL OF CARS: SpaceX parks a Tesla in orbit (just don't mention the barge)

Brangdon
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Re: took out the landing barge

Apparently it hit the water about 100m away, and explosion did some damage to the barge, but "took out" is over-stating it.

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Brangdon
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Re: seeds of some type

This car isn't going any near Mars. It will cross Mars orbit, but Mars won't be there at the time. It'll get close to the asteroid belt before it falls back.

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No parcel drones. No robo-trucks – Teamsters driver union delivers its demands to UPS

Brangdon
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Re: no amount of clever drone technology

Drones, perhaps. Self-driving trucks should cover some cases fine. I currently have my purchases delivered to an Amazon locker at a nearby supermarket, and collect them from there myself. There's no reason why lockers couldn't be built into a self-driving vehicle and work in broadly the same way. It'd be an option you could select while ordering, if you are the kind of person who is able to walk to a curb and walk back with a package. The security isn't a problem. (Self-driving vehicles, to this level, are.)

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Look on the bright side, Pebble fans. At least your gizmo will work long enough for you to get beach body ready

Brangdon
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Sounds like a Garmin to me. My Vivoactive 3 does all that. Screen is always on and readable in normal lighting. Battery is about 9 days if I don't use the GPS. It does notifications. It also does a load more so there may be cheaper Garmin options that will do your minimum.

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New Zealand joins the Space Race

Brangdon
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Re: Cool...

I think they want to scale up to multiple launches per week, rather than heavier payloads. Getting to higher orbits is something the satellite itself can manage if it needs to. It probably needs an engine for station keeping anyway.

Ride share may be cheaper, but you need to find someone going to the same orbit and willing to share. As costs come down (eg, SpaceX), the primary payload owner becomes less willing to share because the money saved becomes too small to justify the risk and complication.

BFR is supposed to cost under $10m per launch, which doesn't leave much room for anyone else to be significantly cheaper. However, even if that is achieved, the opportunity costs of using BFR for cube sats may make it uneconomical. That is, SpaceX will always be able to make more money by launching something else instead. So Rocket Lab might have a bright future just doing what they are doing.

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Hey American business, here's how to use blockch ... sorry – we've been shut down

Brangdon
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Re: Blockchain's future...

You are confusing the general notion of a blockchain, with one specific implementation. Also, Bitcoin has always had 10-minute blocks.

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Text bomb, text bomb, you're my text bomb! Naughty HTML freezes Messages, Safari, etc

Brangdon
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Re: typographical bells and whistles

It's really not as simple as each Unicode code point mapping to a single character outline. An accented character like à can be stored as two code points, one for the 'a' and one for the accent. Or an 'f' and an 'i' might need to be combined into a ligature. Some scripts take that to extremes, with what appears to the user as a single shape being made from multiple code points the combine in complex ways. Add in changes of direction for right-to-left scripts. Think Chinese or Indic languages.

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Ice cliffs found on Mars and NASA says they’re a tap for astronauts

Brangdon
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Re: assuming the astronauts will be recycling

It's not just drinking, washing, and breathing (breathing because they'll want to extract O2 from it). They will consume large amounts of water for making rocket fuel, because it's not practical to carry enough fuel for a return journey. They might also want it for shielding. Apparently it's better than regolith against radiation.

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Cryptocurrencies to end in tears, says investor wizard Warren Buffett

Brangdon
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Re: third generation

IOTA is currently centralised, and a bit flaky. The flakiness is partly due to being designed for machine-to-machine transfers, and dumb humans don't follow the rules as well as machines do. Might be fixed by better wallet software. The centralisation they say will be removed when usage increases sufficiently. An alternative is RaiBlocks, which is working now, but not supported by many exchanges.

Neither has proven itself as well as Bitcoin in terms of security, and both have the usual issues of being deflationary and volatile. They are also proof of stake, so don't use huge amounts of electricity like Bitcoin does.

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If Australian animals don't poison you or eat you, they'll BURN DOWN YOUR HOUSE

Brangdon
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Re: Do they do it accidentally or deliberately?

Because it is too easy to attribute intelligence where there is none. People have been fooled by behaviour that was highly complex but instinctive. People have even been fooled by "Eliza"-style programs, where we know exactly how unintelligent they are. People will even suppose there is intelligence and personality behind natural phenomena like lightning strikes. Scientists need to be careful to avoid such projection.

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UK drone collision study didn't show airliner window penetration

Brangdon
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Re: Semtex

This isn't about banning drones entirely, it is about requiring owners to register them and have training. So the proposed legislation will not stop a terrorist from acquiring a drone and weaponising it. They could steal it, register under a false name, remove identifying marks or just not care what happens after their atrocity has succeeded.

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Exploding alien bodies' space death-rays gave Earth its radiation cloak

Brangdon
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Re: Mars is out

That's a bit of an over-reaction. 2x risk is still fairly low, and on Mars they have plenty of mass to make shielding from.

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US authorities issue strongly worded warnings about crypto-investments

Brangdon
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Bitcoin fees

Bitcoin fees are due to too many people using it, rather than the high price of Bitcoin. The plan to fix it is by adding another layer, called the Lightning Network, to move most transactions off-chain. This should get done over the next year, so if it can survive until then it can survive indefinitely.

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