Earth's atmosphere is annoying, yes, but for huge swathes of observational science it's not a deal-breaker. Not having massive telescopes on the ground where you can fiddle with your instrumentation and take advantage of apertures and construction techniques simply not possible in space _is_ a deal-breaker.
The required precision for construction of telescopes is incredible, and doesn't translate to space well, especially once you start talking about apertures that even folded won't fit into even the largest Starship SpaceX is proposing.
Ground-based astronomy is here to stay and with good reason. SpaceX needs to avoid or minimise the harms to these users of the night sky.
There is another aspect of harm, too - the casual observer. The night sky is a precious resource and shared by all. Introducing huge constellations which in many parts of the world will be visible year-round (and in some quite heavily populated areas like northern Europe, even through the night at some times of year) is like building a huge mobile phone mast outside someone's window and expecting them not to complain, but on a much larger scale.
Light pollution is a huge issue, and satellites can pollute just as well (if not more effectively) than ground based sources - it needs to be an ecological consideration of any launch.
I live in a very large city in Europe. I think the number of stars you can see is less than 20. Ground based pollution is horrible, I don't know how you can compare those two.
... it's named Observatory Hill, in the middle of Cambridge Massachusetts, quite near to downtown Boston, because it has an observatory that used to work great before light pollution.
> Not having massive telescopes on the ground where you can fiddle with your instrumentation and take advantage of apertures and construction techniques simply not possible in space _is_ a deal-breaker.
Why do you think telescopes in space - where they don't need to fight gravity just to stand - can't soon, with reasonable development, surpass land-based ones in capabilities?
So, for sleeping I'd go for softer plugs like those made by Howard Leight for shooting (Laser Leights) or Moldex Spark Plugs.
Hearing protection always talks about attenuation in terms of dB(A) (A-weighting being a sensible thing to do when measuring perceived sound levels). 30dB(A) is a significant attenuation (logarithmic scale, don't forget). 35dB(A) is quite an improvement over 30dB(A).
For long-term use, ear plugs aren't great. But ear defenders can be had cheaply which will work well; I know of some people who use ear defenders atop in-ear active-noise-cancelling headphones as a double-whammy.
The correct answer is to work/sleep in quiet places, though, but I realise this is fast becoming a luxury.
I agree with all these. If you are choosing one blindly, my preferred earplug for comfort is the Howard Leight Max Lite. Ideally, though, buy a sample pack from someone (like this, https://www.earplugstore.com/unfoamtrialp1.html) and see which one fits your ears and needs best.
Note that there is a considerable amount of technique in using earplugs correctly. You don't just shove them toward your ear and hope for the best. Normally, they are rolled tightly, and then inserted fairly deeply into the ear canal, where they then expand. Have someone demonstrate, watch a video on it, or read the instructions very closely.
This is the worst thing - they have a pretty good API and sensible terms to use it for personal use at least. Garmin by comparison is an omnishambles - no API unless you're a megacorp.
You really can't do PTP over the internet, at least not meaningfully. Anyone who needs PTP is going to have their own grandmasters, reference sources, etc - and then a distribution network.
Most telecoms applications use an ePRTC source which tends to be implemented as a GPS/GLONASS/Galileo redundant frequency source, plus a local rubidium source or cesium reference. High-end telecoms applications use a hydrogen maser.
You can't stuff that over an unmanaged network and get the performance you need. Hardware needs to support it hop-to-hop.
Yeah I agree, but ptpv2 does support unicast and you can set offsets. It would be very challenging, but not impossible sans the very high res stuff where you need oscillators on the switches and routers, as you alluded to. It wouldn't get down to the sub-10 nanosecond sync you get with a proper stratum 1 timesource (such as the rubidium decay ones), but you could get faster than the guaranteed 1 second of accuracy which is what I believe ntp used to guarantee from a protocol level.
That was my point. Also if you're inside one of Cloudflare's many POPs, this could, in theory, be provided.
PTP over Internet doesn't make much sense. PTP requires hardware support in all network devices on the path between the (grand)master and slave. Without this support it will generally perform worse than NTP. Of course, it depends also on the implementation.
PTP does support unicast messaging, but it is not meant to be used as a public service. There are two major problems: It's not stateless and it has a huge traffic amplification, which could be easily exploited for DoS attacks.
Yes, but NTP as a time service (client/server mode) is safe. A request has a single response and their lengths are symmetric (that's actually a requirement for accurate synchronization). The problem with amplification is in the optional monitoring/control modes of the protocol (modes 6 and 7 as used by the ntpq and ntpdc utilities respectively), which should be disabled on public servers. Unfortunately, there are still some old misconfigured servers causing problems for a lot of people.
In PTP the problem is in the synchronization protocol itself. A master in the unicast mode is basically a programmable packet generator. It sends sync/announce messages at a rate and duration specified by its slaves, and the address can be spoofed.
There's a dedicated device, Kardia, which does this; it's fairly low-cost and claims to be able to reliably diagnose AFib. There's also another wearable heart monitor I can't remember the name of, but I had major issues with it because the electrodes weren't hypoallergenic and so caused an uncomfortable rash...
6 is useful for non-dense high-bandwidth environments where you might need to get 10G-BASET a little further than 5e will manage, but 6 doesn't address enhanced alien crosstalk. This means in dense environments it may struggle. 6A does, via shielding, and so will work better in dense environments (where you're likely to see 10G-BT anyway).
Isn't shielding separate from the category? I recall seeing stuff like Cat5 FTP and Cat6 STP or some combination like that. I'm no cable expert, but from what I understand, STP means shielded and FTP has some other kind of shielding.
I think I put Cat6 STP or FTP in my home. Whichever it was, I wanted to have the best cable I could possibly find, because I don't want to have to redo this every 10 years.
There are practical issues there. Liquid helium is relatively expensive and scarce, magnetic fields from the machine by definition need to be high to get good results, and to throw more fun into the mix you need to stop external radio interference from getting at the machine. Could you get the cost down to "specialised doctor's office" levels? Maaaaybe. Does AI have a role to play in that? Not one bit.
Liquid nitrogen is one alternative. Some further work is being done on room temperature superconductors, which obviates the need for any kind of cooling.
The frustrating thing with Neo4j is that they have two modes - a fairly neutered open source version, and a ~$35k/node enterprise version, with absolutely nothing inbetween. They're apparently doing a cloudy hosted enterprise version somewhere inbetween but that's some time out and not a self-hostable option.
I hear you. We're working on it. I will note that we have a startup program where you can get Neo4j Enterprise for free if you're below 50 employees and also have several other programs for educational institutions, journalists, etc. And obviously the long term solution here is a DBaaS with grow-as-you-grow pricing. Watch this space! :)
There are a ton of use cases in bigger enterprises (1000+ employees) for smaller applications that are not worth the costs you are offering currently, so I'm glad you're working on it. Cypher is amazing (as is most of Neo4j). I've used Neo4j for many years, going back to pre 2.0 versions. The database has evolved massively since then.
yeah, my experience was the same. It's a really nice database to play with or for a small project but if you need a multi-node HA cluster, the price quickly becomes prohibitive.
I guess if I ever need a graph database again I will probably go for dgraph (although I haven't used it in any production environment) - https://dgraph.io or any other graph database that at least has HA setup without 100k/year bill :)
All of this. It's impossible to run Neo4j out of the box in HA in a sane way. Not to mention, you can't even run a reliable backup of the datastore without shutting down the database entirely... unless you pay for their archaic pricing model for enterprise.
This topic is also the theme of a rather good collection of essays on Singapore's politics by Cherian George - there's some available online here https://www.airconditionednation.com/
The required precision for construction of telescopes is incredible, and doesn't translate to space well, especially once you start talking about apertures that even folded won't fit into even the largest Starship SpaceX is proposing.
Ground-based astronomy is here to stay and with good reason. SpaceX needs to avoid or minimise the harms to these users of the night sky.
There is another aspect of harm, too - the casual observer. The night sky is a precious resource and shared by all. Introducing huge constellations which in many parts of the world will be visible year-round (and in some quite heavily populated areas like northern Europe, even through the night at some times of year) is like building a huge mobile phone mast outside someone's window and expecting them not to complain, but on a much larger scale.
Light pollution is a huge issue, and satellites can pollute just as well (if not more effectively) than ground based sources - it needs to be an ecological consideration of any launch.