ggreer

10,948 karmajoined 13 ปีที่แล้ว

My name is Geoff. I write code. I live in Vancouver, WA.

http://geoff.greer.fm/

https://github.com/ggreer/

I've actually been on HN for 1284 days more than the created counter shows. My old HN account is https://news.ycombinator.com/user?id=AngryParsley

comments

17 วันที่ผ่านมาdiscuss

I picked 30mph because that's the current threshold for what is considered a motorcycle in the state of Washington. Until recently, e-bikes were exempt from this because the old law was made back when e-bikes were rare and couldn't go much faster than regular bicycles.

I've gone >50mph on a bicycle, 40mph on level ground. Yes it's possible, but it requires significant effort and you can't accelerate as quickly as an e-bike. That's why I said, "and has a motor". Heck, a fast runner can endanger people on the sidewalk. When I'm running, I often slow down in crowded areas so that if someone does randomly veer into my path, I'll have time to avoid them.

If lots of people (who I assume are very fit) were riding bicycles dangerously, maybe the legislature would make some laws about that. But until it becomes a problem, there's really no need.

18 วันที่ผ่านมาdiscuss

The law doesn't ban them. It classifies fast e-bikes as motorcycles (which require registration, insurance, and a motorcycle endorsement).[1] This seems reasonable to me. The previous laws for e-bikes were based on outdated assumptions about battery & motor technology.

I do think it would make more sense to simplify (and future-proof) the law to just say, "If it can go >30mph on level ground and has a motor, it's a motorcycle." But similar to code, it's easier to add legislation than it is to modify existing rules.

1. https://apps.leg.wa.gov/billsummary?BillNumber=6110&Year=202... text: https://lawfilesext.leg.wa.gov/biennium/2025-26/Pdf/Bills/Se...

25 วันที่ผ่านมาdiscuss

For sprints, shoes give additional traction for faster starts, but don't increase running efficiency. For distance events, shoes were just extra weight, and barefoot runners have won Olympic competitions.[1] Recently, springy "super shoe" designs have shown up.[2] They've been banned from most competitions, but it looks like less effective versions of the design are still allowed under current rules.

I would prefer that shoes be restricted to designs that don't allow for higher efficiency than barefoot running, but sport rules tend to lag technology advances.

1. https://en.wikipedia.org/wiki/Abebe_Bikila

2. https://en.wikipedia.org/wiki/Nike_Vaporfly_and_Tokyo_2020_O...

25 วันที่ผ่านมาdiscuss

This quirk of competition is why swimmers can win a ridiculous number of medals. If swimming only had freestyle, Michael Phelps would have 7 gold medals instead of 23.

25 วันที่ผ่านมาdiscuss

Allowing a bicycle would be like if swimming competitions allowed fins. A more accurate mapping to the swimming strokes would be race walking, which is widely ridiculed.

30 วันที่ผ่านมาdiscuss

Space gets you 24/7 solar power. To run a data center for 12 hours without sunlight, you'd need massive batteries. Also oceans have weather and corrosion.

The issue with putting stuff in space isn't the kinetic energy required. In LEO that's about 30 megajoules per kilogram or $5 worth of propellant. The issue is that orbital launch vehicles are not reusable, so you must destroy an expensive rocket to get your payload to orbit. All of these space datacenter efforts are betting that Starship will be fully reusable.

เดือนที่แล้วdiscuss

Tesla's valuation is high because investors expect them to sell goods & services other than cars, such as autonomous vehicle rides and humanoid robots for domestic & industrial use.

Who knows if they'll be able to pull it off, but an analysis that treats Tesla as a car company misses why investors have priced so much growth into the company.

2 เดือนที่ผ่านมาdiscuss

Rocket engines can’t throttle down very much. Raptor can go down to 40% of its rated thrust, which for V3 would be 100 tons. The ship’s mass is maybe 150 tons with remaining propellant at the start of the landing burn, and probably around 100 tons at the end of the burn. Even at the lowest throttle, three engines would give it a thrust to weight ratio of 2, making hovering impossible and a suicide burn tricky. Two engines gives them redundancy, roll control, and a lower thrust to weight ratio to help with landing precision.

I’m surprised they went down to one engine at the end, because that means they lose most of their roll control. The only way to roll with one engine is to use the cold gas thrusters, which aren’t nearly as powerful.

2 เดือนที่ผ่านมาdiscuss

This is the third time in two days that you’ve made this exact same comment.[1][2]

1. https://news.ycombinator.com/item?id=48215414

2. https://news.ycombinator.com/item?id=48220491

2 เดือนที่ผ่านมาdiscuss

Just FYI the sizes of the planets, stars, and their orbits are not to scale at all. To get an idea of how empty space is, there are 63,360 inches in a mile, and 63,239 astronomical units in a light-year. So if you scaled everything down such that Earth was 1 inch from the Sun, Neptune would be 30 inches away and Alpha Centauri would be 4 miles away.

If you were using a 4k display and had the Sun and Alpha Centauri visible at opposite sides of the display, the orbit of Neptune would be in the same pixel as the Sun.

2 เดือนที่ผ่านมาdiscuss

Only one of them is working right now. Their original tower needs to be overhauled to support Starship V3.

2 เดือนที่ผ่านมาdiscuss

They can build new boosters pretty quickly. New launch/catch towers take a lot longer, and they don't have any redundancy yet. Also they weren't going to reuse their V2 boosters once V3 was ready, so they could learn more by testing things like intentionally disabling an engine during the landing burn or flying at a higher angle of attack.

2 เดือนที่ผ่านมาdiscuss

They won't use barges because the booster has no landing legs (to save weight), and because the booster is massive compared to Falcon 9. Also Starship is meant for rapid reusability, and it can take days to return a barge to port and unload the booster. Getting barge landings to work would be a distraction from the goal of Starship, and SpaceX already has Falcon 9 for current payloads.

And they won't attempt a catch with the first V3 booster because it's not worth the risk. They can build a new booster every couple of months. It takes much longer to build the launch/catch tower, and they don't have any spare towers yet. A catastrophe during a booster/ship catch would set them back a year, so they'll only attempt a catch if they're confident it will succeed.

2 เดือนที่ผ่านมาdiscuss

That's because they use other terms like "Falcon 9/Heavy", "Starship", "Super Heavy", "launch vehicle/system", "booster", "upper/lower stage", and "spacecraft".

2 เดือนที่ผ่านมาdiscuss

The measured levels of arsenic, strontium, and vanadium are below the limits for drinking water, even in California. And 4% of drinking water sources in California have higher hexavalent chromium content than the water in that ditch.[1] Besides sodium from salt, the only metal that was particularly high was lithium, at 0.0714mg/L or 71 micrograms per liter. A significant fraction of drinking water in the US has higher concentrations than that.[2]

The level of salt shouldn't affect much. Adding up the chloride and sodium content gets you 684mg/L, which is on the low end of brackish water (500-30,000mg/L). The limit for agricultural irrigation is 2,000mg/L, and photos of the pipe show plenty of grass growing around and in the water.

The phosphorous could come from fertilizers, as there's plenty of farm land in the area. That would also explain the higher ammonium levels, as both anhydrous ammonia and ammonium phosphate are common fertilizers.

The article is really about how sensitive our scientific instruments are, not how dangerous the water is. It reminds me of articles like Vice's American Honey Is Radioactive from Decades of Nuclear Bomb Testing[3], where the most radioactive honey they could find was 10 times less radioactive than a banana.

1. https://www.waterboards.ca.gov/drinking_water/certlic/drinki...

2. https://www.sciencedirect.com/science/article/abs/pii/S00489...

3. https://news.ycombinator.com/item?id=26906838

2 เดือนที่ผ่านมาdiscuss

Hexavalent chromium can come from many industrial sources, including welding stainless steel. If you go to Tesla's lithium refinery in google maps[1] and follow the drainage ditch along highway 77 (to the northeast) about a half mile, you'll see a company called Tex-Isle Processing. They supply steel pipes and coating services for oil drilling.[2] It could be that one of their manufacturing processes creates hexavalent chromium.

In my opinion there isn't enough information to blame anyone for the slightly-above-drinking-water levels of hexavalent chromium. The drainage ditch goes along a highway and a rail line, so pollution could come from all kinds of places.

1. https://maps.app.goo.gl/7iNTbiPcs1sZ9CqP8

2. https://www.texisle.com/

2 เดือนที่ผ่านมาdiscuss

Different states have different rules about what sort of things insurers are allowed to charge different rates for. In the states that allow it, Tesla does offer insurance discounts for FSD usage.[1] Lemonade also offers discounts for FSD usage.[2]

1. https://www.tesla.com/support/insurance/fsd-discount

2. https://www.lemonade.com/fsd

2 เดือนที่ผ่านมาdiscuss

Your first link is for the bus budget in Portland, Maine. The system cost for busses in Portland, Oregon in 2025 was $453 million.[1]

1. https://trimet.org/about/pdf/trimetridership.pdf

2 เดือนที่ผ่านมาdiscuss

The $812 million figure for 2025 did not include the cost to build the rail system. Nor did it include many other expenses. TriMet's expenditures for this year are $1.185 billion.[1]

If you divide passenger miles for TriMet busses (141,726,107) by the number of revenue miles (21,195,016), you get an average of 6.7 passengers per bus, or around 10% of available seats. For MAX (the train) you get an average of 27.4 passengers per train, or around 16% of available seats. In both cases that's seats, not total capacity including standing room. I realize it's important to provision the system for peak demand, but still this seems very wasteful.

And because road wear scales with the fourth power of axle loading, a bus will typically cause 1,000x more road damage than a car.[2] Assuming every car on the road has only one occupant, this means that, on average, a TriMet bus causes 150x more road wear per occupant. The main externality created by cars is traffic.

I agree with you that public transportation can work. It clearly does in many places. But Portland's public transportation is dysfunctional, and I don't see that changing any time soon. That's why substitutes (even partial substitutes like Waymo) are beneficial. The more options people have for getting around, the better off they'll be.

1. https://trimet.org/budget/pdf/2026-adopted-budget.pdf

2. https://www.kgw.com/article/news/verify/yes-bus-more-road-da...

2 เดือนที่ผ่านมาdiscuss

In 2025, TriMet had 262 million passenger miles at a system cost of $812 million, for a cost of $3.09 per passenger mile.[1] Fares covered 7.8% of their costs. The other 92.2% came from payroll taxes and federal grants.

For comparison, a Lyft or Uber in the same area would cost you $1-2 per mile. Obviously it's not feasible for all 200k daily riders to take Uber/Lyft, and the Uber/Lyft cost doesn't include externalities like extra traffic, but TriMet is very expensive per passenger mile.

1. https://trimet.org/about/pdf/trimetridership.pdf