marsokod

While on the temperature side, I would agree with you (though ideally you would want something that starts at 0 like Kelvin), this is different on the distance and weigh side.

The strength of the metric system is not on the particular dimension of their definition, but lies in the use of a decimal system. That is what makes it superior to the old imperial system and why the scientific community in the US uses it. Using a single base system for all your numbers, and the same base system as the one used in your numbering systems is the only way you can do complex computations without resorting to many magic numbers.

If you look up non-English corpus, you can see an effect. Here in Spanish, but also in French and Italian ones.

https://books.google.com/ngrams/graph?content=Dan+Simmons%2C...

The effect can obviously be very little in an English corpus. The effect of Dan Simmons' books is mostly to introduce John Keats to casual readers and is even pronounced that these readers have no reason to have been exposed to Keats at school. They (including me) are obviously a low quality public who will not be interested with Keats' work over a long period, just a mere curiosity. They won't write books and won't create a market of books about the poet so I expect ngrams to be a mediocre measurement for this effect. It would be more interesting to look at Keats book yearly sales.

Here is another one: https://www.globalpetrolprices.com/Germany/electricity_price...

This is also taken into account in software engineering. Most software have defense in depth against single point of failure, they can recover or cope with wrong input.

But you cannot compare them because the context is different: software is less regulated than aviation so while anyone can write of very bad software in 5min and sell it, this is not possible for a plane. And not everyone can pilot a plane, while there is no mandatory licencing and training to use a software.

In addition, no safety feature on a plane can prevent the pilot from crashing it willingly. Setting such an easy password and not adding additional protection (due to lack of training) is self sabotage. So far, anything related to SolarWind points towards a bad usage of the tools.

Six years is not that long. You need to have the frequency to finalize the design of your payload, if not your satellite. And for big constellations you need the frequency to talk seriously with your investors. So 6 years to design a platform, a ground segment and launch half your constellation is not an easy task.

It is available on the ITU website. You will have satellite names (which should be similar to what you'll see in space-track, most of the time). I believe you need to pay to have access to those, but when you have a direct link to a specific satellite anybody can read it.

Also note that this shows licences, not actual use. You can have a satellite licenced to a particular frequency but not using it.

They don't even have to keep the fee of the query is legitimate. They can reimburse it or keep it in the user's wallet when they consider that this was either a false positive or a honest mistake. The cost would be minimal but would deter a lot of people trying to game the system.

You can't really cross oceans with microwaves though. So a London from can gain a competitive advantage against other London firms on Wall Street exchange.

The parent poster is not talking about that, he/she is talking about the COCOM limits placed on GPS receivers sold commercially: the GPS would not provide an output when traveling faster than 1900km/h at an altitude over 18km (though some manufacturers used a logical OR instead of an AND). This limits still applies and you need to get a special license if you want to get these limits removed (or you can buy Chinese).

And Nokia bought Alcatel Lucent in 2017 so they've got a presence in France as well.

My best guess is that SpaceX did last minute changes to the rocket, either hardware or software, deviating from the documents submitted to the FAA. This could explain why the FAA only reacts now and would make sense with what Musk said about the procedures not being able to cope with the pace of development they have.

For electric thrusters on cubesats, you can basically ignore the mass variations for most high level calculations. Propellant mass is so little and the specific impulse so high that unless you are using all the propellant in one giant maneuver the difference will be minimal.

You cannot really talk about deltaV capability for a thruster. You can talk about specific impulse, power usage, power dissipation, total impulse. But deltaV implies you know the size of the satellite, which varies for all their customers.

This one flew on a 6U (~35x20x10) and that's really the minimum size for this kind of engines. And even on a 6U, the power limitations make us think twice before putting an engine, it really has to be needed.

You are right that the collisions will dissipate some of the mechanical energy will be dissipated into heat and technically collisions will reduce the duration it takes for the mass of debris that are in orbit. I am not sure if that has a significant impact on top of the atmospheric drag though.

However, the Kessler syndrome is not about the total mass of debris in orbit, but the number of individual debris. So while before the collision we had 2 nicely aggregated debris, after the collision you will have thousands of small ones.

The small ones will tend to deorbit faster on average, because of the loss of energy mentioned above and also because their aggregated surface area increases, but you still have more debris. And when we are talking about multiple decades/centuries of lifetime, these debris will collide with other satellites, creating a positive feedback loop, increasing the numbers of debris exponentially, at least initially.

Obviously this is just the beginning of the process, which will end up with a maximum number of debris and then a decrease towards zero, but that timeline is extremely long and therefore not really relevant to us.

The figures in the paper are for the carbon footprint of the bitcoin Blockchain electricity consumption at the primary energy level, while the Falcon 9 figures you give are just launch emissions from the propellant. So not exactly fully comparable. And also this omits in both case two other elements needed to do a proper comparison: whole life cycle carbon emission, including hardware manufacturing and development time, and induced footprint of the usage (what it replaces and what is also purely new usage consumption). Without these figures, it is difficult to compare them.

But just as a reminder, the figure quoted in the paper for bitcoin is 10,000 times the yearly figure we have for Falcon 9.

For the most part, and for Android users, b is achievable : https://signal.org/blog/reproducible-android/

Capella's competitor Iceye has already achieved 25cm. Physics limitations are even lower than that.

But you are right talking about computing power. SAR work in a very different way from optical imagery and data generation/processing is quite a huge difficulty.

The government of your country will need to approve, since they are covering the damage your turd could make to some other satellite.

Also, you can send the turd alone, you need to attach it to a launcher, and have a deployment mechanism. You are looking at a few thousands $ minimum regardless of the weight.

The inside of the nozzle uses copper for heat dissipation. There were previous cases of green flames with the Raptor, and Elon said it was copper. The big question is why it was low on methane - bad calculation in the planned consumption, too methane rich during the ascent?

A bit tongue-in-cheek, but Apple only just launched the public beta phase of MacOS on ARM. There is plenty of time for developers to work on this until the release of the stable product (M2 or whatever it will be named).

And the mechanical and thermal shocks it gets when it passes from the vacuum chamber to the atmosphere.

IMHO the centrifuge part is the easiest of their challenges.

Portion of cost in GDP is not equal to importance.

What is the cost of water in the GDP? Much less than the cost of the energy. What would be the GDP without water? Nil. There would be no GDP because we would all be dead.

One option is really to recycle it so that only waste are the actinides. There is plenty of uranium and plutonium that is inert/useful in the nuclear waste. It reduces the waste amount by several orders of magnitude.

https://www.heritage.org/environment/commentary/recycling-nu...

Code is not the only element in the process generating GHG. The coder's way of life, the coder's tool, the resources needed should all be taken into account. What matters in the end is the global footprint of the code.

Writing quickly a very inefficient code that will run a handful of time is much better than spending 2 months full time optimizing it. And straightforward codes are also easier to debug. It may be a concept quite linked to Python, be premature optimization is where the crux of the problem is. Except we are now talking about an optimisation in processing power with an impact that is much wider, and thus with a more complex link.

For the trigger in the last 200 years, it is just fossile fuels. Having all this energy provides us with enough food and comfort to survive, thus lot's of spare time and spare manpower dedicated to research and improving tech. It also feeds all these machines we are making.

Going back to renewable will be tough (but is mandatory). We are a species that has been high on cocaine for a couple of centuries and we just realized that it slowly killing us, and it is running out anyway. Our only option is to sober up.

Regarding the planes, the Soviets had a plane working with hydrogen (and methane I believe). It's not particularly impossible, and at least much more doable than using batteries (for commercial jets).

The flying wing is a design improving the efficiency know for a long time (Airbus guys teaching us about it during my studies 15 years ago), but creates additional difficulties, on top of which the impossibility to evacuate the plane fast enough. You would have the same benefits whether your plane is using hydrogen or kerosene.

I still do not see planes using hydrogen. Just doing the math on how much electricity would be needed makes it really unlikely.

Because your contact list is something you should backup somewhere (cardav, Google,...), and this is the expected place for all your contact information.

Signal would need to store a second contact list if it was not using the phone contacts. And suddenly you need to backup this second contact list. If every app does that you can forget about the user backing up everything, they simply won't do it and the feature becomes useless. The solution would be for Signal to store it on their server, obviously encrypted. But then you have different privacy issues to take care of: how can you retrieve a user's contact without storing its identity. How do you hide the number of contact they have...

Yeah, That's what I have been taught as well. Though the direct effect is very small and it's not part of many geoengineering plans because it is not great for us anyway. And you would also need to take into account the carbon footprint of manufacturing said aerosols.

That's completely mad! I'd love to be part of that.