Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Submission + - The Oceanic Pole Of Inaccessibility - The Place Spacecraft Go To Die (bbc.com)

dryriver writes: Whether you launch a satellite into space or an entire space station like the Russian Mir, the Chinese Tiangong-1 or the International Space Station, what goes up must eventually come down — re-enter earth's atmosphere. The greater the mass of what is in space — Mir weighed 120 tons, the ISS weighs 450 tons and will be decommissioned in a decade — the greater the likelihood that larger parts will not burn up completely during re-entry and crash to earth at high velocity. So there is a need for a place on earth where things falling back from space are least likely to cause damage or human casualties. The Oceanic Pole Of Inaccessibility is one of 2 such places. The place furthest away from land — it lies in the South Pacific some 2,700km (1,680 miles) south of the Pitcairn Islands — somewhere in the no-man's land, or rather no-man's-sea, between Australia, New Zealand and South America, it has become a favorite crash site for returning space equipment. Scattered over an area of approximately 1,500 sq km (580 sq miles) on the ocean floor of this region is a graveyard of satellites. At last count there were more than 260 of them, mostly Russian. The wreckage of the Space Station Mir also lies there. Many times a year the supply module that goes to the International Space Station burns up in this region incinerating the station's waste. The International Space Station will also be carefully brought down in this region when its mission ends. No one is in any danger because of this controlled re-entry into our atmosphere. The region is not fished because oceanic currents avoid the area and do not bring nutrients to it, making marine life scarce.

Submission + - Does the US Need A Infrastructure Czar? (citylab.com)

mikeebbbd writes: Writing in CityLab, Kriston Capps argues that we need a better way to pick infrastructure projects for public funding. While it's unlikely that the real bill (over $1 trillion) will be covered, ever, he argues that even if it were to be covered we need a different way to pick WHAT gets funded and when. For instance, Flint needs clean water right now; Kansas City probably can wait a bit for an improved streetcar.

This ignores, of course, the fact that the feds don't fund all public infrastructure. When some place uses its own or its state's money rather than federal, they can be excused for placing their own interest first. And there's always Trump's desire to privatize it all. Still, the author has some good points, and it's clear that federal infrastructure funding is kind of fractured by type (with transportation getting a very large cut). Would a cabinet-level post or other "czar" to coordinate it all be worthwhile, as suggested in the story?

Comment Re:Boring (Score 1) 135

The original Hyperloop Alpha plan budgeted standard rates for tunneling for the sections that required it. Musk however began looking into tunneling after Hyperloop came out and found (the same thing I found when I looked into it) that today's tunneling market and contract structures disincentivise radical innovations to reduce costs, and that there's many things that people in the industry already suspect could radically increase tunneling speeds (and thus reduce costs) but have not yet been attempted. Hence he decided to try it himself (and also came up with the concept of the "intermediary" system of car sleds but ambient pressure). The big thing about tunnels is that they give you much better possibilities of getting into town (rather than the periphery like airports, as Hyperloop Alpha did) and maintain straightness in rough terrain. In the northeast corridor that they're working on now, an elevated Hyperloop would be passing through far too much built up land to maintain straightness, speed, and low right-of-way costs.

Comment Re:Boring (Score 5, Informative) 135

So many people making the same joke.

Okay, let's try to add something to the conversation. Here's what we know about the ideas behind Boring Company so far. First, the tangential aspect: the non-Hyperloop car sleds. Tunnel costs are almost linearly proportional to cross section. By having cars on sleds you don't need any lane margin around the vehicles and can use a much smaller (and thus cheaper) tunnel. Also by moving them at very high speeds you have a much higher throughput, and by computer control, you can space them closely (getting even higher throughput).

However, as for the boring itself: the rate at which a TBM bores is proportional to how fast the head is rotated. In hard rock boring they generally also spend a large portion of the time stopped; a new casing segment is set up to both support the walls and for the TBM to push off of. During downtime, maintenance tasks such as replacing cutting disks are conducted.

When you read through literature on the topic, you find that the answer to "how fast can you X?" or "Is it possible to Y" are frequently "We don't know - contractors are payed to complete a given task and generally have little incentive to experiment with new approaches." Boring company seeks to focus on all of them at once. First off, the cutting disks: if the TBM rotates too quickly, the disks heat too much and their (already short) lifetime is greatly reduced. Boring Company is looking to do three things: one, use more advanced alloys (cost more to replace, but nothing compared to the cost savings of faster boring); two, use active cooling on the cutting disks; and three, have them hot swappable so the TBM doesn't have to be stopped. All of these things together in theory should allow the TBM to be run many times faster (so long as everything else associated with the excavation is also correspondingly sped up). It's also being modified to not need to stop for casing; downtimes are only to be for when something is physically broken or there are issues with the geology that need to be dealt with.

Many of the complicating issues with boring, such as unpredictable geology, unmapped buried hardware in urban areas, etc, Boring Company's approach will not eliminate. But the goal (whether they can reach it or not) is to ensure that when they are boring, they're doing so very quickly.

Comment Re:Tunnel (Score 2) 135

Anyone who thinks you'd be hit by a crushing "wall of air" needs to read up on shock tube experiments, and in particular how propagating shocks respond to high aspect ratios (length relative to aperture size)

When the shock hits you, is it moving fast? Yes. Several times the speed of sound.
When the shock hits you, does it have meaningful density? No, unless you're talking a huge rupture and you just happen to be right next to it at the time.

Comment Re:"violence to advance their cause" (Score 5, Informative) 277

Almost everything you think you know about Antifa is due to trolling. There are extensive troll campaigns out there involving fake Antifa accounts. Each tries to outdo each other with the most outrageous thing they can say to make gullible right wingers take them seriously.

"Antifa" has no ideology except hatred of Nazis and those espousing similar ideologies (general white supremecists). It is not a "group". It has no "leaders". No little black book. Nothing except "hates and will actively oppose Nazis and other white supremecists", and random people who are of that view describe themselves with the term Antifa. Not all people who identify as "Antifa" support violence as a means to counter Nazi activity (there's been a widespread "Is it okay to punch a Nazi?" debate since Richard Spencer was punched on camera). Of those who would answer that with "Yes", there's a further subset known as "Black Bloc"; which again is not an ideology but more of a style (dressing in black and actively physically engaging when Nazis and aligned groups come to town). The "Don't punch a Nazi" crowd thinks of them as counterproductive. Black Bloc style protesting existed before "Antifa"; before the most recent flareup, it was most commonly associated in the US with WTO protests.

To reiterate: Black Bloc does engage in violence - although you might have been misled about "innocent victims". To pick an example: the most famous viral video of Black Bloc actions was this attack. Who is that poor innocent victim? Why, that's Keith Campbell, known on Twitter as "PatriotWarriorMedia". He's involved in R.A.M. ("Rise Above Movement"), a group built specifically around active training to engage in street brawls with perceived leftists. Rather than all black, their hide-their-face approach is black skeleton masks.

What did Campbell have to say about that protest where he got beaten up beforehand? Why let's look!: "Fuck Antifa! Let them come to Berkeley on August 27th so we can kick their asses AGAIN! @1776RealNews @ProudBoysCA @BasedCops"

How did that work out for you, Keith?

Anyway, this is all secondary to my main point, which was to make you aware of the fact that the vast majority of "Antifa" accounts are just trolling to try to dupe gullible right wingers. My personal take on the whole thing? Black Bloc protesters and R.A.M. deserve each other, and both can go F* themselves as far as I'm concerned.

Comment Re:Surprised? (Score 4, Interesting) 135

You'd be how easy it can be to get a teacher's password.

Back when I lived in the US and was in high school, the school offered an introductory course to programming in Basic. I already knew how to program, so I spent the course primarily either writing games or espionage tools ;) One of my favourite was a program that mimicked the DOS prompt (including most common commands), waited for them to run what they thought was the logon program, wrote out the username and password to a file, reported that the password was wrong, logged out of my account and put them back in the real DOS shell - wherein they'd log in normally and everything was fine. I'd usually leave it running on a couple random classroom computers whenever I left. By the end of the year, not only did I have most student passwords, but the password of my teacher and a different one.

Did I use it to change assignments? Alter grades? Vandalize the network? No no no, of course not. Rather, my final project was an overly elaborate demo, which had many different scenes (things like me walking around shooting lightning bolts and other similar nonsense). One scene was a stereogram generator. The hidden image in the stereogram? The teacher's username and password ;)

Thankfully she found it amusing rather than disciplining me ;) I got a perfect score. Looking back at it, I could imagine a teacher with a lesser sense of humor having me suspended or even calling the police.

Comment Are we in a stock market bubble? Another crash? (Score 3, Informative) 96

Title of the parent comment: "The heady days of the dot com bust..."

Recently I asked someone who works for an investment company if the U.S. stock market is in a bubble again. The answer was, "Yes, that's why we are buying stocks of foreign companies."

If, as in the years before 2008, stock brokers can convince a huge number of people that the stock market will continue to rise rapidly, the brokers can sell what they have for a huge profit, and there will be another crash, as in 2008.

Slashdot Top Deals

"It may be that our role on this planet is not to worship God but to create him." -Arthur C. Clarke