I always found the plastic argument in teflon vs cast iron a bit weak. Its health risks are well documented at this point. But the seasoning on a cast iron? That is polymerized fats... One might even go so far as to call it plastic. I am told the seasoning is also a carcinogen and in my experience more likely to be ingested than Teflon from a pan (getting a good seasoning that lasts on a pan can be tough!).
Yes, there are several factors that make that location particularly good, not only temperature. The cold and absence of sunlight for months at a time causes a relative absence of water vapor in the atmosphere during winter, which is extremely important for CMB observations. The high elevation (~10k ft) means there is less atmosphere to look through as well. During summers the sky heats up, contains more water vapor, and reflects so much more light that our telescopes become substantially less effective. Another advantage to the South Pole is the ability to continuously observe the same part of the sky, as the telescope is located on the earths axis there is no rising and setting of sky overhead. There is also a particularly 'dark' patch of sky in the southern hemisphere called the 'southern hole'. This is located up and away from the plane of our galaxy and contains very few objects standing in the 'path' of the CMB which also helps obtain better quality observations of the CMB.
Edit - it is as good as it gets on earth and way cheaper than a satellite! Other benefits are rapid upgrades and repairs with newer technology. A satellite, by the time it is deployed, is already pretty old! But the South Pole still isn't cheap!
The noise is inherent to our sensor technology... Very sensitive telescopes are cryogenically cooled to reduce the temperature of the focal plane, reducing the noise. As in an above comment, the light from distant objects is more spread out and appears weaker - fewer photos are arriving each second and hitting the focal plane than if the telescope were closer. At a certain point, the signal gets buried in the noise.
I worked on the BICEP Array telescope at the south Pole - the light we are observing is actually extremely low energy and we can't see it unless our detectors are colder than the light source we are looking at (which is about 2.7K). We cool our detectors to 0.3K!
Quite the change in distance from the sun. Btw, kinetic energy is proportional to 1/r, and is at a peak at the perihelion. Potential energy is highest at the aphelion.
From some information in the article, it seems possible to me that the mass sacrifice might have been a cruel pacification technique by the conquering Inca? It says the Chimu empire fell around 1475 to the Inca. The rope and textiles were radiocarbon dated to 1400 to 1450 AD.
But in this case the media companies are not the ones publishing the photo, Twitter is. The embedded data was never produced or even passed through their servers. It is loaded directly from Twitter.
I can't say this is true for all Universities, but accounting for inflation, at the University of Washington the cost to educate one student is the lowest it has ever been. So at least at one school they have been working hard at keeping costs down. Unfortunately, we keep reducing state funding to public schools, and the proportion of that cost born by the student is now much higher. Gone are the days that you could work your way through a state college, and it is not because the schools are price gouging.
That graph is very misleading. I don't have access to the published paper which may be accurate, but the article doesn't mention the reduction in opioid deaths from 2008-2010, which appears to be similar to 2014-2016. Also, the title of the graph states the timeline through 2015, but the x axis suggests there is data up to 2016?
Interestingly, South Carolina produces most of its energy using nuclear already... It is too bad the broad public perceives nuclear as a 'risky' energy source. It is in fact the safest energy source we have ever developed, in terms of deaths per kilowatt hour. Its just that when something goes wrong, it goes REALLY wrong. That makes more of an emotional reaction in the general public than the scattered and sporadic deaths in other industries, in which there are sadly many, many more. So, it seems it is hard to get support to invest in newer, safer technologies in the industry. I do understand the short term economic incentives. Nuclear is expensive to build. However it is very cheap to operate, and relatively environmentally friendly. It takes long term planning on timescales of many years, and looking at safety data rather than focusing on the disasters on their own. Neither of which humans are any good at.
The one thing that turns me off nuclear power is how to store nuclear waste. The collapsed storage tunnel at the Hanford site this year is an example of how poorly this can be done. The waste will remain dangerous for thousands of years. How do you build a storage facility that keeps it contained for that long?
You can see the sisters from Mt Adams, which is ~230 km away. I'm guessing there are several more of these that the site didn't catch. You can probably easily see Mt Rainier from 300 km+ standing at the right place. How were these determined? It would cool to see a write up on how it was done.
I do like the idea of coupling self-driving car technology with taxi service and underground highways. When it comes to urban environments, automobiles and associated infrastructure takes up an enormous amount of the available space. It hurts resident's quality of life in many ways (noise, pollution, traffic, stress, less green space, etc). This is one of the reasons I am totally on board with investing heavily in mass transit underground (super excited that Seattle is finally getting their act together on this, which is my home). If the cost of developing underground transport infrastructure is driven down enough by this venture, we could improve traffic flow and reclaim some of the space on the surface as space for people, not cars. Couple that and a future with clean energy for cars and when using a self driving car service is more convenient than owning a car, we could create a transportation system that can get you anywhere, quickly, efficiently, and without transfers.
Self driving car services would allow us to reclaim huge portions of cities by reducing the need for parking spaces everywhere we go, and make driving safer. Tunnels for highways could replace interstates that cut cities in two, as well as provide more flexible routes. Electric cars could make our cities healthier. I think I see what Elon is trying to do...
I'm assuming you mean angle of attack, not flight path angle. The aircraft could certainly be capable of a 60 degree climb until it slowed down enough that it couldn't maintain a low enough angle of attack. It probably could only sustain something less than a 30 degree climbing flight path angle (while empty), as that would be pushing the limit of the thrust to weight ratio. That being said cameras can be used in ways that make things look much more dramatic than they actually were.
As a side note, at 30 degrees AoA the aircraft will not be able to continue flying anyway, the wings will have stalled well before that, and the pilot would be made painfully aware of this fact through stick shakers, aural warnings, and very rough tail buffet.
I'm a flight test engineer, so this stuff is what I get to do for work! :)
Yes! I saw it at the 36 minute mark on the video. That had me curious. I think it was a trick of perspective, it first looked like some huge chunk of debris that the first stage flew past, but after watching it again, it looks like a little chunk of ice that got blown off of by the cold gas thrusters.
A hypersonic vehicle can travel much faster than that. We're talking about the ability to strike targets anywhere on the globe in minutes. That IS destabilizing. The example of striking carrier groups in the pacific is only the tip of the iceberg.
This race amounts to a global game of chicken, and the stakes of a mistake are world war. Let's hope cooler heads prevail.
On the other hand, there are some pretty amazing applications of air breathing hypersonic technology. You could use it to launch equipment, satellites and people into space much more efficiently (air breathing means you don't need to carry an oxidizer!). Or imagine being able to fly from NY to Hong Kong in an hour! This kind of tech is not as imminant as the article is implying. We've only barely demonstrated small air breathing hypersonic vehicles as feasible (see X-51 and X-43). The X-43 was a crude initial test that demonstrated flights of only up to 12 seconds. The X-51 managed to go for 6 minutes. Scaling this up to a transportation vehicle will pose a significant engineering challenge.
There is 'elite mathematics', just as there are in every other field. Should we come to the same conclusion for every other subject, just because there are a few gifted individuals who dominate their field? Yet, most math that is used frequently is not complicated and anyone can learn it (even calculus). The barriers to obtaining a high level education in mathematics and its related fields (there are too many to count) is less related to the education system and the complexity of the subject material, but more related to public policy and poverty. And hey, would you look at that, we can use statistics and math and our understanding of economics to help solve those too! I think the writer didn't have the interest in math in high school, had a bad experience, and chose to be a historian, as pointed out by tokenadult.
One of my friends is down at Amundsen-Scott, currently for his second overwinter. He works on the BICEP2 project. When I saw this I was worried it might be him. I was able to reach him over the internet and he let me know he was doing well. They are understandably keeping quiet about what is going on, so I can't offer any details, but it sounds like the patient is doing OK for now. That's all I know.
Interesting article. It focused on economics, but didn't really factor in the environmental effects of landfilling or recycling. I wonder how that impacts the economic assessment. Still, generating less waste in the first place is always a good goal. I like the thought of shifting responsibility of recycling to the manufacturer. It would encourage less use of wasteful materials that have little recycling value.