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Comment Surprise: font doesn't work well when misused (Score 2) 182

The font was designed for reflective white on green. The legibility studies are invalid for black on yellow.

I guess the font designers should have foreseen this and designed a family of two fonts called "negative" and "positive", but I cannot really fault them for failing to fully appreciate the magnitude of human incompetence.

Comment Re:Why not a vacuum? (Score 1) 175

Yes, the air cushion is an issue. I am sure it can be solved, though. Remember that the head assembly of the cheapest optical drive maintains micron accuracy for both tracking and focus distance while the disk wobbles with each rotation (it's never really centered or rotates in-plane). The head is mounted on voice coils and uses active feedback loops.

If you use vacuum and passive magnetic levitation bearings the energy to keep the disk rotating drops to virtually zero. You can have cold storage that is ready to wake up and access in a 100 milliseconds.

Comment CloudFlare have another pragmatic proposal (Score 1) 115

CloudFlare have another pragmatic proposal - require CAs to randomize the certificate serial numbers instead of using predictable sequential numbers. Note that this precaution would have made even MD5 certificates safe against current known attacks.

https://blog.cloudflare.com/why-its-harder-to-forge-a-sha-1-certificate-than-it-is-to-find-a-sha-1-collision/

Comment First of all, don't call it statistics (Score 1) 90

First of all, don't call it statistics.

Just give them some fun game where they need to decide whether green Gabroans from the planet Gabroa are more or less likely to be wearing hats than other Gabroans based on the (relatively small) sample they have seen.

Reward them accordingly.

It's all about observing thing. It's the best method we have for determining things about the world from out imperfect observations. It's exciting stuff!

Why has statistics become synonymous with "that boring course you have to take"? Or worse, that stuff you sniff about dismissively while you complain how people can "prove" anything with statistics.

Comment Depends on your unit system (Score 1) 207

If you use Planck Units then all your coefficients (G, Ke etc) are set to a value of 1. All fields and forces are now the same. The basic equations governing the behavior of energy and matter do not favor one force over another.

Matter itself is now the issue. The question changes from "Why is Gravity the Weakest Force" to "Why is matter so fluffy?" (i.e. why is the the mass of elementary particles that make up matter so small relative to their charge).

Comment Re:Where I live there are no mail trucks (Score 1) 277

>> drones fly under 400 feet and weigh less than 55 pounds

Well that's good. I'm sure 55 pound weights dropped from 400 feet are harmless.

A four ton delivery vehicle at 25 miles per hour is not exactly harmless, either. In assessing the overall impact, you take into account both the potential damage from an accident and the probability of such accidents. For example, the fact that said delivery vehicle is operated by a driver that has been on the road for many hours and makes frequent stops and that the drone is equipped with 8 redundant rotor/motors and no doubt many other redundant systems and failure management strategies from the planning of the flight path, monitoring of vehicle health and constant assessment of possible damage-minimizing crash locations at all times.

I believe the expected impact of such drones should be an overall reduction in the death, injury, property damage and environmental impact associated with delivering replacements for important items chewed by dogs.

Comment Re:The real worry should be Kessler Syndrome (Score 1) 98

Just making a single important orbit permanently uninhabitable can be pretty devastating.

Imagine a small satellite in a retrograde orbit close to the geosynchronous ring. The satellite is just a big hunting rifle cartridge full of buckshot with a tiny remote controlled gas canister that can turn it into a slowly expanding cloud of ruin. It will destroy everything in that orbit within twelve hours, hitting satellites at a relative speed of 6000 m/s.

[shudder] I didn't know I was that evil.

Comment M-DISC and a media-grade fire resistant safe (Score 1) 174

Even a single copy on M-DISC in a media-grade fire resistant safe is more likely to survive the next 35 years intact and readable than the alternatives. Cloud, hard disk arrays, tapes, whatever. The total maintenance cost over this time is dramatically lower than the alternatives, too (virtually zero).

And I would not worry about availability of readers in 35 years. I don't see passive physical media completely going away. Passive media carrier that does not include electronics. There will always be a niche for that. The drives you will buy in 30 years are likely accept the same 12cm disc form we have been using for the last 35 years and be backward compatible with CD, DVD, Blu-ray, Violet-ray, UV-ray, Gen1 holographic, Gen2 quantum, Gen4 quarkstore and Gen4 planckstore disks :-)

Comment Re:Made of Unabtanium (Score 1) 120

In an HX thruster, liquid propellant is pressure- or pump-fed to a lightweight planar heat exchanger. For orbital launch, the propellant of choice is liquid hydrogen. H2 provides a vacuum Isp of 600 seconds, sufficient for a robust single-stage-to-orbit capability, at a heat exchanger temperature of only 1000 C (less than 2000 F). The heat exchanger can therefore be made of ordinary materials, rather than exotic high-temperature alloys, which allows building cheap expendable vehicles.

Kare, Jordin T. "Modular Laser Launch Architecture: Analysis and Beam Module Design." Final Report USRA (2004).

This report is about laser heat exchanger launch system but should be valid. Dr. Kare has studied both laser and microwave launch systems. A single-stage-to-orbit vehicle does not shed tanks or stages. When it reenters the atmosphere is it a big empty tub with a very low cross-sectional mass density. The temperatures it encounters are dramatically lower than a capsule or the shuttle.

In other words, this is far from being the most difficult part of the system.

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