Depending what kind of reading material you're looking for (e.g. high level details or mathematically/jargon dense papers) look for things discussing "Rosseland optical depth" and "grey atmosphere approximation".
At a high level, the common convention is to define the radius by finding where the optical depth is 2/3 when using Rosselands clever way of calculating a weighted mean of the opacity from that layer in the star to space across different wavelengths of light. 2/3 being a clever derivation from Eddington where, in an idealized model of a star, that's when the actual temperature of the star should equal its blackbody equivalent temperature.
Pedantically, this distance to the point of equality is an ever so slightly different value than the "distance from the center where there is a 50% chance a photon traveling directly outward will escape the star without another interaction" rule of thumb (in the same idealized grey model). Practically, that the difference is so small is why it's a fantastic rule of thumb explanation.
Jesus Christ on a pogo stick, execution for stealing 12 pence worth of stuff? That's crazy! Adjusting for inflation[1][2], that would be the same as nowadays being executed for stealing £5!
There's aesthetic reasons (I'm proud of my car, I like it to look nice), and practical reasons (Leaving mud, grit, salt etc, will wear and corrode my car faster).
Where I live, summer rain doesn't really clean the car (if that's what you care about), and in the winter you are shortening your cars life by years if you don't try and get the salt off regularly.
When I bought my 8 year old car, it was from the Midwest and the mechanic I asked to check it out said "Don't buy - it's got a good amount of rust because of the salt they use". I asked whether it means the car is less safe. He said "No, just more repairs and potentially costlier repairs. I said "Over the remaining life of the car, how much extra would it cost?" In today's dollars, the answer was $2000.
I bought the car. It easily lasted another 7 years before it died in a collision.
My car prior was a purely Midwest car, and I rarely washed it. It happily lasted 16 years. I passed it on to someone else, and he used it for a few more years.
I'm 62, and grew up near Detroit. I remember cars developing major rust holes after just a few years. The rusting also affected the inside of the engine compartment, and it did make repairs more difficult. There was an industry of aftermarket rustproofing shops, that were a scam. Every teenager with a car (which was still rare) learned how to patch rust holes with Bondo.
My first car, the frame rusted out and had to be welded back together.
Toyota and Honda put a stop to that. They did a number of things: Better steel alloys, better coatings, painting the bodywork before it could start rusting, eliminating places in the body where water could accumulate, etc.
Today, you rarely see totally rusted out cars on the road.
The old days the cars would rust and take the frame with it (I've literally had them get so bad they basically folded up) - modern vehicles will stay pretty darn decent until the first time the paint gets broken, then it'll begin - but the unibody usually lasts quite a long time.
The bodies are better, but I can assure you, the frames and suspension parts are not. They still rust out here in the salt belt after 10-15 years, depending on the brand and how often you drive them. If Michigan instituted mandatory annual car inspections, it would take about half the (still working, not unsafe) cars off the road.
Yeah my wife and I inherited her parents' Highlander from Boston when they moved back to their home country. The drive shaft literally fell out on the road because the brackets holding it on rusted out. Was lucky I had enough momentum to pull over.
I live in New York, which is heavy handed with salt. Paints and alloys are better, but there’s basically a 250k and about 10 year lifespan for a car that lives upstate.
The frame, exhaust and suspension generally get corroded and start to fail. You see a lot of 200k Civics and Accords, but few 250k.
You really notice it when traveling to California. Last time I was in SFO with my son, he counted 78 Porsche 911s and about 100 “old” (80s or older) cars on the roads.
No, I watch video of cars coming into the shop and the models from the Midwest are usually in pretty rough shape due to all the corrosion from the salt on the roads. And brand doesn't seem to matter.
I've always lived in the midwest. Every car I've ever owned has been a car from the midwest, and has been driven in the midwest.
The salt from the road is driven by car tires into a briny mist that coats everything. It blocks vision through windows. It accumulates in chunks that can be kicked (like mud also can, except corrosive). It wicks its way into tiny crevices and betwixt layers and infects every part of the car that can be infected, and once there it rots everything that it can rot.
And I don't mean just the bodywork; that part has been getting better with improved processes and paint.
But stamped control arms often rust away while the ball joints and bushings are still in good form. Electrical connections rot. Frames and frame-like components often have scaly holes in them. Every exposed engine part corrodes; uncoated steel turns black, red, or brown; galvanized and aluminum parts turn white and kind of fuzzy (and stuck). Our junkyards are full of rusted-out hulks of cars with drivetrains that still work properly, even if they're ugly.
Fixing things when they break is tedious and time-consuming, and the most-sane approach to any repair on a car that's more than a few years old is to go into it with an expectation everything that doesn't crumble from rust is instead frozen with rust.
The work itself unilaterally causes a person a learn new facets of their verbal and mechanical vocabulary that they never even knew possible, and is arduous in ways that would test the emotional stamina of a Buddhist monk.
With enough cleaning and care (and just rinsing things off by driving in the rain), a car that is from the midwest can be largely saved. Getting rid of all of the salt slows the process down very dramatically.
But a car that is regularly driven in the midwestern winter is in the midst of a fairly quick process of being returned to the earth.
It's just a fact that is plain and that we live with every day. We do work to prevent it; on a warm-ish day in January, cars will line up around the block to get into a car wash and have a chance to dry out before ice freezes every orifice closed.
But it's not fear, I don't think. Just as we accept the sun coming up every day and disappearing over the opposite horizon every night, we accept the rot as something that will inevitably consume the most expensive machine that we own and that this will happen on a schedule that we play very little part in controlling.
Coincidently I was thinking about car wash just few days back, One was bought in 2014, never car washed seems fine so far. Another was bought in 2022 again no wash so far and no plan to.
I used to think everyone does it, I will do at some point but that point never came. Inside we vacuum and wipe every few months. Washed mats once in an year or so but car body wash rain takes care of it.
Watch the channel Auto Parts City on YouTube, I assure you it is not overblown. It's a junkyard owner. A ton of cars come through there that run fine and could otherwise be very serviceable, but the frame/body are crumbling from rust, so they have to be crushed. We're talking cars that are 10 years old. And yes, it even includes Toyotas and Hondas. (In fact they're more likely to end up crushed for that reason than another car is, since a Nissan or Hyundai's transmission and engine won't last long enough for rust to really end its life.)
From a certain perspective, maybe some people don't care if they would be getting rid of the car in like 5 years, but if you do want to keep a car 15 years and you live in "salt country" I would strongly suggest doing something about the salt regularly.
Selection bias. Cars that were not treated for salt, and didn't die, didn't end up in the junkyard for stories to be told.
My first car spent its first 15 years in the Midwest. No garage. Very irregular car washes (perhaps once a year when I owned it). It lasted about 20 years total. When I lived there, I didn't know anyone who had to give up a car due to rust. There definitely was rust, but not something that caused the car to break down.
I saw rusted out cars and trucks all over the place when I visited northern Minnesota and the UP of Michigan last year. Even late-model cars that couldn't have been more than 5-10 years old had rusted out rocker panels.
Yeah, those are good points I hadn't really thought of much. Thanks! I guess it's less of a priority for me because I bought my car for $1000 and it came with Michigan rust already. Lol.
Or a garden hose, bucket of soapy water, and a sponge. At least if you have a house with a garden hose. Many apartment complexes offer the amenity of an area for washing cars though.
Not sure if it's the same in Canada, but where I am from the problem is the oil (lubricant and fuel) from the car and at car washes the runoff gets treated by letting it go through an oil trap.
The trapped oil gets disposed of separately, the treated oil-free water goes to the sewer.
AFAIK the regulations were put into place to prevent untreated water from going into storm drains and into the water system, so presumably the cities are fine if you pour it down into the bathtub drain and let it go to the waste water treatment plants.
I appreciate the sentiment, but is the gunk on the car not the gunk that would have washed down the drains in the first place? Clearly there are plenty of nasty cleaning agents, but one supposes that safe ones might be used (I actually spent a while considering exactly this, and it's possible but not super easy getting an environmentally friendly car cleaner). I guess the issue is it's hard to tell from mere drive-by observation what cleaner is being used.
Yeah that could be a concern depending where you live. Where I live, water is cheap and abundant. And I've never measured, but I would guess I use maybe 10 gallons to wash a car. 2 gallons in the bucket, and just a light wetting followed by soapy sponge and then a rinse, using a nozzle to create a high velocity spray. The water doesn't run at all unless I'm spraying it on the car.
Water is cheap and abundant where I live, too. If we have a problem with water in any normal year, it is usually that we have to deal with a surplus of it. (We put drainage tiles under our farm fields to get rid of excess water and generally don't even bother with irrigation systems at all.)
But car washes are interesting systems and one of the things that makes them interesting is that the water they use is (often) recycled. The same water gets reclaimed and re-used to wash cars over and over again.
I didn't look very deep at all, but one car wash chain suggests[1] a reclamation rate of 70%. Not perfect, but way better than 0.
You can probably match that efficiency at home by using an electric pressure washer. Mine does 1.2 GPM, which means an entire car wash is only a few gallons.
That's surprising. I once tried an automated car wash just to see what all the hullabaloo was about and I think the rain actually does a better job. Worst $5 I've ever spent...
Yes. In the same way that dishwashers are an order of magnitude more water-efficient than washing by hand. (But consume a kilowatt of electricity heating the water and running the pump, which is the part that everyone always leaves out.)
You heat the water when you wash dishes by hand too, don't you? It's not very hygenic to do dishes with just cold water.
Given that by hand you use much more hot water than the dishwasher would, you're using more electricity (or gas). Since a little pump doesn't use much at all, it's mainly just the drying heat that matters. Though nobody is forced to use the drying cycle - if one enjoys drying dishes by hand, they can still use the dishwasher to do the washing.
You're assuming an absence of solar hot water heaters - the world isn't homogenous.
eg. Our household conserves water (we track every litre we bring up to the tanks and filter) and we don't have a dishwasher - hot water is heated by the sun and run-off goes to the grey water tank for the garden.
No I'm not. I don't care how you heat your water. I'm saying you (should) heat it either way, and you use more of it when hand-washing so if you do pay to heat it, you pay more by handwashing.
And in your case, you use more water because you hand-wash, than you would if you used a dishwasher. You use slightly less energy because of the pump but also a lot more of your time, so... obviously how you relatively value those different things is up to you.
Our concern here, and that of many people in the area, is total water usage per household - and to a large degree water usage for washing, showers, and toilets is a small fraction of the total usage - and one that can be ignored as most people have grey water capture (as do well planned and infrastructured cities).
Water used inside the house runs out to water food, shade, animals, etc. and that use can be deducted from the water that is required for those uses.
Energy is no great cost, it comes from the sun - both as electricity via panels and directly as heat via solar hot water systems.
In my house you don't heat the water but it's been sitting in a metal water tank at equitorial latitude for hours so is generally quite warm for evening dishes.
Is it safe? Not for a restaurant where the temps need to get to parasite killing temps to pass muster.. but if I had to guess, the odds of getting killed by a bad-tempered cow outweigh it by 10x.
When my water heating was electric, switching to a dishwasher consistently led to lower electric bills compared to a year prior (confirmed for 12 whole months).
I live next to a college. The Sororities will hold car washes. Of course, they ask us to get out of the car first, so that Cheerleading movie w/ Kristen Dundst lied. :-)
There's the punctuation and word choice tells. And the overall voice. But let's set that aside because some human writing shows similar traits, or perhaps a human used an LLM to "fix the grammar". So I'll point out another tell that this article is pure slop:
This article is overflowing with links, numbers, and graphs. When a human writes that densely, it takes effort to incorporate all those details. So the human only does that if each detail contributes to their argument. In this article it's mostly irrelevant. It's LLM filler to pad out an article that really has nothing to say beyond its (also LLM-scented) title.
I live in the west. I also have an excellent driving record and drive a small econobox.
Here's an interesting story that gave me greater understanding of how insurance is priced. Years ago, I worked at a place where I lived 5 miles away as the crow flies. However, due to geography, the only way to get between my work and my home was by car, using one of the most dangerous freeways in my state.
I got tired of the commute and moved closer to work, close enough that I didn't have to use the freeway (or even drive unless I was lazy) anymore. I reported the change of my residence to my car insurance company, and they cut my premium by a third.
They didn't say why, but I'm certain the reason was that I didn't take that freeway 10 times per week anymore.
I was genuinely shocked and it made me happier with my car insurance company. The behavior I expected is that they'd keep my premium the same and just pocket the extra profit. Of course, them doing this may earn enough loyalty and goodwill that they benefit more from being honest than from being overly greedy.
I do wonder if the same thing would have happened if I carried comprehensive rather than liability. I suspect not. They may see liability-only policies as an indicator that the customer is of limited means.
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