Since the Sun settled onto the Main Sequence after its formation, it has gradually brightened. It is now 30% brighter than it was then.
The brightening is caused by accumulation of helium ash in the Sun's core. This causes the core's equilibrium state to be denser and hotter, with more energy being produced.
In another billion years or so, this will drive the Earth into a runaway greenhouse effect. The oceans will evaporate and the hydrogen will be lost to space. Not long after, the Earth will be a dead planet devoid of any life, even microorganisms. You sometimes see statements about how when the Sun expands into a red giant it will destroy life on Earth, but the Earth will have long been lifeless by that time.
In case others were curious about the term Helium ash:
Ash is the name given to the energetic alpha-particles or helium nuclei produced by fusion reactions in a deuterium-tritium plasma, even though helium bears no physical resemblance to ash from a fire.
It should be noted that deuterium-tritium fusion is not what is happening in the Sun. The primary reaction chain involves proton-proton fusion, which yields deuterium. The deuterium immediately (within seconds) reacts with another proton to make helium-3. Helium-3 eventually fuses with another He-3 to make He-4 and two protons. There are some side chains, but the ultimate overall reaction is four protons + 2 electrons --> 4He + 2 neutrinos.
The way I read it, it isn't a co2 greenhouse, in fact the death stroke is the increased co2 absorption at those temperatures due to weathering of rock. Driving co2 below what plants can survive. Building a parasol at l1 that can be modulated to vary what is passed and what is harvested will be necessary at some point. It could get a couple extra billion years potentially.
Anyone else question why astronomers are so sure about things that happened 5+ billion years ago ? I guess otherwise there’d be a probably or a maybe in every sentence ? But then how do you tell when they really are sure ?
There is always an implied "as far as we know". But astronomy has a couple reasons to be fairly certain about many things. We can see a lot of stars, and because light takes time to travel the further away they are the older the state we are observing. We only see each star as it is right now, but from looking at a lot of them you get a good idea of how they can develop. Like how you can get a good idea of how humans age by just looking at a lot of people of different ages; you don't need to follow each of them for 90 years. The other advantage is that most of it is well understood physics that can be reasoned about and simulated. And then we can compare those simulations to what we are observing across the universe to see if our simulations make sense.
Science is forming a testable hypothesis and then testing it. So you hypothesize "as stars accumulate fusion products their cores get heavier and the rate of fusion increases, making them brighter" and test this both with modeling and looking if this matches the stars we can see. How is that now science?
They build a model of the universe's laws, as simple as they can get it while matching the evidence. They then look at other evidence they hadn't looked at before. It turns out, that quite simple models can predict a lot of different phenomena, which makes us reasonably confident in our assumptions that (1) the universe is governed by simple, fundamental laws; and (2) those laws are similar to our model.
If we make the assumption that our model applies everywhere and at every time (colloquially, that the laws of physics don't change), we can ask our models what happened in the past. Under our assumption, that's probably quite close to what actually happened. This assumption is called the "principle of induction", the "uniformitarian principle", the "cosmological principle", the "Copernican principle", and many other things besides.
The models are so good that when solar neutrinos were not as predicted, it turned out to be because of new physics (neutrino oscillation) not flaws in the solar model.
Six boffins mostly hailing from Singapore-based universities have proven it's possible to interfere with autonomous vehicles by exploiting their reliance on camera-based computer vision and cause them to not recognize road signs.
How do non-camera based systems (lidar etc) get road sign information? I would expect with cameras...?
With cameras alone it seems pretty easy to trick them into dismissing road signs as nonexistent.. I think Lidar alone should be telling you there is a sign, so your camera is faulty or someone is putting up blank signs.
Lidar as I was told to use it would be in conjunction with a database of way points like signs, so the trouble would be knowing if the sign was updated.
My car doesn't seem to have any trouble reading temporary construction speed limit signs and the like. And it has lidar. This seems to be a solved problem.
These comments make it sound like Jon Stewart himself wields no power. He commands an audience he can take to any platform he wants. It just looks like he took a liking to the pot of money Apple put in front of him.You can't really make the argument that Apple is the only game in town for Jon Stewart.
Free speech laws protect against government supression of speech, not corporations.
Definitely agree here. I have been making this transition and currently work on life science lab automation robotics. It definitely takes intentionality because if you're good at software it's easy to get steered towards lucrative but higher level places in the stack.
It is common AFAIK. The most used launch sites (there's one on Hainan where rockets only go over the ocean, but it's the least used) are pretty far inland and they don't seem to mind if boosters land on the people there or if the villages get toxic fuel sprayed on them.
China has four major launch sites. Wenchang, the one on Hainan, is used for human spaceflight. Larger cargo rockets use Jiuquan in the middle of the Gobi Desert. It's the other two, Taiyuan and Xichang (this one), that are relatively close to rural villages, although both are still very remote by Chinese standards.
It's pretty much impossible to overstate how important rice is in the East Asian diet: for a comparison to the west, think something like bread, potatoes, and pasta combined.
Home chefs aren't necessarily going to want or need a top-of-the-line rice cooker, true - but considering how much rice the average Japanese home chef makes, they wouldn't necessarily not want one. $1100 at the high-end is nothing compared to the price at the high-end of virtually any other kitchen appliance; if you can afford it, why cheap out on something you're going to use almost every day, for almost every single meal?
But maybe more importantly, think about restaurants! Although the stereotypes are somewhat overstated, Japanese apartments are often too small to cook in comfortably, and people often work long hours and need quick bites at all hours of the day, so people eat out a lot. And Japanese building codes are far more liberal than western ones, so restaurants can be tiny and individual buildings in Tokyo can have twice as many restaurants as entire city blocks in the west. Net result: Tokyo has among the most restaurants per capita of any city in the world - and considering the population of Tokyo, that's a huge number of restaurants. And almost all of those restaurants are going to need at least one or two (and some a whole fleet); if you're making rice on an industrial scale, it absolutely doesn't make sense to cheap out.
Much of the above is true in many other places in East Asia too - most notably, China. That's a big market for high-end rice cookers!
I have a lower-end Zojirushi and love it. I've used it at least a couple times a week for years. I've periodically debated getting one of the stupid-expensive ones, like https://www.zojirushi.com/app/product/nwjec, but realistically the one I have is fine. If I were going to live longer, one day I'd get one!
Not big but Zojirushi is a big brand and not making a top-of-the-line rice cooker will slowly diminish its reputation from the likes of Cuckoo, Tiger, Aroma, or Midea.
I bet margins are getting razor thin and Zojirushi only has their brand name and reputation to bank on.
Fortunately for the Elephant-brand, their recipe for quality and name value is still strong.
The Walmart listing appears to be a "marketplace" listing, and is apparently shipped from Japan. Presumably these cost a bit less in Japan, since shipping isn't an issue. Perhaps one of our fellow HNers who lives there can enlighten us?
Don't live in JP but was looking to bring one back a few years ago, top of line Zojirushi _were_ ~$1000 USD, but with Yen depreciation are around $800 now. +200-300 for delivery/fees and 1100 looks around right.
That’s why there’s so much hands and fingers involved. Low volume, high price items usually involve lots of short but concentrated spurts of human labor.
I bet more mainstream rice cookers are built with more machines.
I think what the comment is saying is, if the government is spending a lot of money inefficiently (i.e. spending $100,000 on a weapon that has $10,000 in raw materials plus layers of bureaucracy that are hard to quantify as costs) and accruing a lot of debt in the process, it is hard to understand what your cost is for basic things.
While I don't disagree, this is also a city that has whole lanes on major streets reserved for cable cars. The city isn't exactly known for making decisions that drive efficiency.
Can you gather some information that backs up your claims here? How would devoting an extra lane to cars increase efficiency? I can't see a scenario where this would do anything but the opposite effect.
Simple math? Assuming a fixed number of cars on the road, more lanes will increase the flow. The cable cars are novelty transportation for tourists that residents of the city don't actually use for commuting.
In case it's not clear, I'm refering to California st starting downtown and going all the way up the hill.
No problem, so what is your argument for utilizing a whole lane for a mode of transportation that consumes a significant public resource without providing much benefit?
Car lanes in the city consume a significant public resource (space) and encourage negative externalities (noise, heat, air pollution, etc.).
They should absolutely be replaced with more space efficient options: tram tracks & bike lanes.
Not sure the point here. California St is a major artery in and out of downtown. All I'm saying is there is an opportunity for improving the quality of traffic but instead the public resource of an entire lane is wasted on a bespoke piece of transportation history that runs at a loss in excess of $40m/year
