Hacker News Reader

_moofon SpaceX's Starship launching to orbit for first time ever today

Altitude doesn't change (much) at the point where an orbit raising maneuver is performed. It increases the altitude of the rest of the orbit, with the greatest change ~180 degrees later.

If you'll excuse some poor ASCII art:

                                       _______
                  ______              /       \
                 /      \            /         \
    burn here -> *    O |    result: |    O    |
  in elliptical  \______/            \         /
    orbit                             \_______/

_moofon Real-time feedback: My closing move in every interview

You've got 30-45 minutes with the candidate. Is this question the best use of that time?

_moofon Anecdotally, programmers dislike "reduce"

What's hard to understand about it? It's just

  x = initial
  for y in collection:
    x = f(y, x)

_moofon Let's make quality the norm again

Walmart used to be (and maybe still is?) known for doing this. They would get companies to produce lower-quality versions of products under the same name as the standard versions available elsewhere. They could sell them for cheaper and consumers were none the wiser - or so the theory went, anyway. Obviously people caught on.

_moofon NTSB issues investigative update on B-767 runway excursion accident in Miami

I don't know the specific items that were called out here but I can tell you, as a flight instructor, that the failure to capture the glideslope was already enough to require a go-around. The late flap settings were too. So was the high airspeed. At no point did they have a stabilized approach. There were multiple unequivocal mandatory go-around conditions before they got to the runway.

_moofon NTSB issues investigative update on B-767 runway excursion accident in Miami

Turbofans being slow to spool up is jets 101.

_moofon Cheap GPS jammers are filling the world with navigation dead zones

Time was, if you didn't understand how to use VORs, you couldn't really fly. We used them as primary en route nav, as well as for approaches, for many decades. As a CFI I think most of the confusion around VORs these days comes down to poor or inadequate training.

_moofon Cheap GPS jammers are filling the world with navigation dead zones

> sustaining human life

Not really. Drone ships are very much a thing these days.

_moofon Black hole singularity is a surface not a point

It's unfortunately misleading shorthand for what actually happens: space becomes timelike. It doesn't become time. All this means is that once you cross the event horizon, you can only ever move toward the center of the black hole, in the same way that outside of a black hole, you can only ever move toward the future. You might not take a direct route to the center, but no matter which way you move, you will be following a track that ends at the center.

The reason this phenomenon has a spooky-sounding name is that it also affects whether two objects can be causally connected. If you can only ever move closer to the center of the black hole, then there are (conceivably) other objects inside the event horizon that you can never have a causal relationship with.

But it doesn't mean that space and time literally switch places.

_moofon Civilian plane crash in New Mexico tied to military GPS blocking

> If the sky was clear, as the article states, then lack of GPS is not a good enough excuse for a trained pilot to crash into a mountain, unless the cockpit has no windows.

I have thousands of hours as pilot in command and have worked as a professional pilot.

Unlit terrain is invisible at night. The moon was new. They did not see, and could not have seen, the mountains.

_moofon Civilian plane crash in New Mexico tied to military GPS blocking

The "skill issue" is that they chose to press on instead of returning to base. Yes, the jamming was a factor, but making a decision to fly a visual into field surrounded by mountains at night is a bad call.

_moofon Civilian plane crash in New Mexico tied to military GPS blocking

I'm sorry, what? Pilot error is absolutely a factor in contemporary accidents. It's the most common one, in fact, because we've rooted out almost all the other risks.

_moofon Civilian plane crash in New Mexico tied to military GPS blocking

Not true. You also need an accurate altimeter to fly the intermediate segment, as well as the missed approach segment. There are mountains under the obstacle clearance surfaces on both segments. That is why this ILS procedure is explicitly not authorized when the local altimeter setting isn't available.

_moofon Civilian plane crash in New Mexico tied to military GPS blocking

It would not be safe at this airport, and the ILS procedure there explicitly forbids it. In the remarks at the top of the approach plate you'll see "When local altimeter setting not received, procedure NA." (NA = Not Authorized.) Here's the plate: https://aeronav.faa.gov/d-tpp/2607/06922IL24.PDF

The reason you need an accurate altimeter for this ILS is that the obstacle clearance surface for the intermediate segment - the part where you're flying straight and level without a glideslope - lies atop the very mountains these pilots crashed into. Vertical guidance on the missed approach is also barometric, and there are mountains in that direction too.

_moofon Civilian plane crash in New Mexico tied to military GPS blocking

Lack of GPS was one factor here, but poor judgment was the real killer. Flying a visual approach at night into a field surrounded by unlit mountains is suicidal.

There's a saying among medevac pilots when it comes to making go/no-go decisions: don't turn one tragedy into five.

_moofon The Difference Between a Button and a Link

I do think cancel is a poor example because it's conceptually very near "go back" - but it doesn't actually mean that. It means "I've changed my mind".

Implementing cancel with a URL is an implementation detail. That's one way to do it, but it's far from the only way. Cancel could also be implemented by hiding a UI element, for example.

_moofon US citizen charged after GrapheneOS phone wipes during airport search

Turns out immigration in other countries isn't a cakewalk either.

_moofon Kill The Cookie Banner

And in a truly twisted move, ad tech companies were also using Do Not Track as part of browser fingerprinting.

This industry is a paperclip maximizer, and it needs to be dealt with accordingly.

_moofon Humans haven't stopped evolving

I can't find the source now but an idea that really stuck with me is that evolution happens on the margins. If a 0.0001% increase in the height of a giraffe makes it 0.0001% more likely that the giraffe will survive and reproduce, then in 1 million years giraffes as a species will become taller.

As for humans: I mean, duh? The selective pressures faced by humans have changed radically in the time we've been around.

_moofon Humans haven't stopped evolving

Because that isn't what evolution does. Evolution is the process whereby traits that make reproduction more likely under selective pressures become more common. There is nothing in that process that necessarily implies a lack of harm to each other or the environment.

_moofon Punch yourself in the face with reality

No, they're actually the same thing: making an honest assessment of reality. In the first case you're doing so to prevent self-delusion. In the second you're doing so to prevent others from clouding your judgment.

_moofon Men's average testosterone levels have halved in last 50 years

> testosterone is linked to social status and mental well being

As well as a zillion other things. And "linked" in which direction?

_moofon Space Shuttle Endeavour's 20-story vertical display

There's a series of platforms where you can see it from progressively higher vantage points.

_moofon Satellite reveals immense scale of GPS signal tampering

> Before this, everybody in the industry thought GPS solved the aerial navigation problem.

Many people in industry believed this but no one with a brain ever did. The vulnerability of GPS has been cause for concern for a long time, and the decimation of the VOR network has always had a lot of people up in arms.

_moofon United Airlines 767 returns to Newark after Bluetooth name sparks alert

I'm well aware of the law. I was a full-time flight instructor for years, and the relevant regulation is the first one I taught when introducing students to the regs.

But I'm not talking about whether the captain has final responsibility and authority for the operation of the aircraft.

I'm talking about whether it's sane to escalate directly from something that is very much not an explicit threat of violence, to involving people whose primary tools are suspension of physical liberty and acts of violence.

(Also, please note: that rule says two things. The captain has final authority, yes, but they are also responsible for the choices they make. It's not a free pass to do anything they want for any reason.)

_moofon United Airlines 767 returns to Newark after Bluetooth name sparks alert

> Actually, I don't think it's a good idea to bring your politics into a an enclosed pace like this where people are forced to be a captive audience, notwithstanding that I agree with theparticular sentiment expressed.

That is a very, very, very different statement than "I'm calling the FBI."

You're talking about should or shouldn't. The issue here is past that point: whether it's then right to involve people who are empowered to take away your physical liberty, and worse.

_moofon Blue Origin's New Glenn blows up during static fire test

Sorry, no, I've worked on multiple launch vehicles and "full duration" doesn't mean anything consistent to anyone actually working on rockets.

_moofon Blue Origin's New Glenn blows up during static fire test

From the industry: I would expect to hear "mission duty cycle" in that case. "Full duration" doesn't have a consistent meaning (a fact which is sometimes used to the marketing team's advantage).

_moofon Blue Origin's New Glenn blows up during static fire test

They blew up LC-36.

_moofon Blue Origin's New Glenn blows up during static fire test

> TNT equivalent is defined as 4.2 MJ/kg.

It isn't this simple for liquid oxygen and methane mixtures, and there's a great deal of disagreement between industry and regulators over what the right percentage of TNT equivalence is. Naturally, industry thinks the percentage is low, and regulators are skeptical, so there's a government-run test campaign going on as we speak to collect data for proper modeling.