EdEarl

Although the internet makes educating oneself free, in many cases, the cost of refereed papers is too much for me and many other retired people. I really would like to read Eternity in six hours: Intergalactic spreading of intelligent life and sharpening the Fermi paradox, and other papers from time to time, but cannot afford them. Since university salaries and research grants are often paid by governments, it seems to me that I've already paid tax $ for many of them.

No, it doesn't. It simply refers to investing energy to obtain energy. Examples including using energy to drive oil drills to extract oil from which you extract energy, and using oil to manufacture solar panels which can be used for solar energy. That's it. This statement seems to imply that without anyone using oil, except investing to obtain energy, there would be no energy trap. If my understanding of this statement is correct, then if everyone else stopped using energy (I know it is absurd) then the energy trap would still exist. That would a significant portion of the world's energy is being used to obtain energy. Acording to Wikipedia everyone's consumption is the following: which is what everyone are producing, too. Now, 13.4×106 m3 per day is a lot of swimming pools full of oil. Why would drilling for oil or making windmills consume even 1% of that amount? There amount of oil used to make a windmill blade is a tiny fraction of 13.4×106 m3 oil, and one windmill produces enough energy to power a windmill manufacturing plant, assuming batteries to assure power when the wind doesn't blow. I haven't been able to find any facts about energy used to build wind turbines. I found this information. A wind turbine deal made with Siemens was for 1.8GW for (€2.9 = $3.828B), which is 1GW for $2.125B. The energy in 1 gallon US of diesel oil is 40,700 watt-hour, which at $0.065 per kilowatt-hour is worth $2.6455/gal diesel. Assume the cost of this wind turbine deal is typical for machinery costs estimated as: 60% material 23% labor 01% energy 16% other $2.125B*1%=$212.5M which can be converted into equivalent diesel oil gallons. $212.5M/$2.6455/gal diesel = 80.325M gallons of diesel The 84 million barrels of oil consumed per day converted into gallons is 84M barrels * 42 gal/barrel = 3528M gallons per day. A gallon of crude oil contains more energy than a gallon of diesel, but I didn't find the ratio; I shall assume 1:1. Thus, 3528M gallons of oil per day / 80.325M gallons of diesel to make 1GW of turbines, means there is enough oil produced per day to make 43.92GW of turbines, which is 43.92*365=16030.8GW of turbines per year. Now, 16030.8GW is a little less than the world uses in electricity per year (20,000G KW). Additionally, each GW of renewable energy produced, lessens the need for oil to make these turbines. If wind turbines are produces using only wind turbine power, after producing 1GW of wind turbines with oil, it would take about 6.25 years to make 16K GW of turbines. I realize that turbines will not be used to generate all the renewable energy in the world, but this calculation demonstrates we do not need another Saudi Arabia every seven years to make enough renewable energy, regardless of demand by people.

The important issue is how misconceptions of science can affect school curriculum. At least in the US, school curriculum has been under attack by people who, although meaning well, are trying to get schools to teach non-science. A number of cases have gone to the supreme court, which invariably stops the non-science. To avoid the controversy, schools avoid teaching subjects that may generate a law suit. As a result, students may not get a high quality science education. It is a tragedy to under educate children in science, when they live in a culture in which knowing science is important for getting good jobs.

I agree 10B people is too many. I'm old and will soon quit polluting, so I'll do my part. Politicians are terrified of saying anything about a stable population for fear of being tagged as supporting population control. Economists look at every person as a consumer and think about how much more money additional people will produce. We just have to trust that people will do the right thing.

I think the bait works better than spreading the powder. Ants are immune to the powder, but roaches are supposed to be killed by it.

Delbert, I'd rather Chernobyl and Fukushima had not occurred. Deformities are worse now with the highest radiation levels, but nature survives and the ill effects will probably diminish asymptotically; although, it is possible a new inherited genetic disease will occur or a new species be created. Science will benefit from things learned by the event and its aftereffects.

It is listed as 50% lethal to a 1kg rat that consumes 4.09 g of sodium bicarbonate. It is used as leavening in short breads, and people sometimes take it as medicine for an acid stomach. It is not very poisonous. A good way to control cockroaches and ants is to mix a bait of 4:1 peanut butter and boric acid powder. A dilute solution of boric acid is sometimes used as an eyewash. It is not very poisonous to people, but does a good job on insects. If your insects get tired of peanut butter, try a different vegetable (e.g., mashed beans with a little vegetable oil and the boric acid).

Why are you doing the study? Do you have a hypothesis that prompted the study?

The Chernobyl Exclusion Zone is a 2,600 km2 (1,004 sq mi) area into which few people venture; thus, it has become a refuge for wildlife, an accidental nature preserve. Slowly, nature is burying the radioactivity and recycling human artifacts. This human tragedy has been good for nature, at least in the short term. The long term effects are yet to be known. Over the years my position on the nuclear industry has varied from pro to anti. I am definitely anti bomb, but IIRC the nuclear power industry has a better safety record than the coal industry, as far as death and injury are concerned. The potential for disaster, such as Chernobyl and Fukushima, are real. However, the Chernobyl disaster has a good side, and I expect a similar result from Fukushima. That does not excuse the authorities who contributed to these disasters, and the industry must strive to do better. The world can provide power for itself with renewable resources, instead of using fossil fuel and nuclear power, and I am totally in favor of it. In the mean time, nuclear may be necessary to achieve conversion to green energy, and I will not oppose it. However, nuclear energy should only be a stop-gap measure, necessary at this time to reduce CO2 release into the atmosphere. In the long run, it should be phased out, because we do not want the entire Earth to become an Exclusion Zone.

Sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide are all white and can be powder.

Now some nit picking. The speed of light in a vacuum has been discussed thus in this thread. Light does slow down when it moves through things other than a vacuum, and different colors of light travel at different speeds in things like glass, which is why a prism and water droplets make a rainbow. Most of space is a very good vacuum, and light travels at c.

There are more than enough sharks walking on land today; one was a wall street insider, now in prison.

Moonguy, perhaps you have solved the Fermi Paradox. There is no way for people to thrive in space. To make a living in space, people need energy and resources. If there is energy, resources are available. Solar energy in the asteroid belt is iffy; the only alternative is fissionable material, unless controlled fusion is possible. Given energy water can be split into hydrogen and oxygen, and ion engines can be used to conserve fuel. Asteroids should provide metal to build and repair spaceships and space stations, and must provide expendable resources. Although, recycling everything is required, some things will unavoidably escape into space. Mostly, resources are required for population growth. Is there any need to sell things minded on asteroids to Earthbound people? Even if a population can survive without trade, they like to trade for luxuries they do not or cannot make. Is there something that limits this potential space faring population? IDK of anything.

I'd think asteroids in the main asteroid belt would have regular orbits like the planets and regular launch windows. In addition, it is always possible to launch to get to some asteroid at any time. Moreover, launching from a planet costs much more fuel than from an asteroid. AFAIK the only metal likely to be on asteroids that might be worth mining is iridium, and that is doubtful even if they found pure iridium nuggets. I believe, the other rare elements aren't expected to be on asteroids. Thus, I believe you are right Moonguy, mining asteroids to send stuff to Earth is unlikely to be economically feasible. The only possible scenario I can think of for that to change is if people decide to migrate into space stations, but that is only sci-fi ATM.

Yikes, welds are likely to be the weakest points, regardless of metal thickness. You need to determine how much fuel and air will be in the combustion chamber, and calculate the energy of that explosion. The maximum force will depend on how fast the explosion occurs and how complete the combustion. From that, you can determine what kind of metal and thickness. I recommend you start with an engine in a wind tunnel with no one nearby, everything in a hole in the ground and test your engine before you use it anywhere that might damage anyone or anything. And, run an endurance test many hours to make sure it will not fail. The welds should be tested with appropriate equipment, CT scan, x-ray or ultrasound, IDK I'm not an expert in that field. If you cannot do the calculations, I recommend you should not make the engine.

Maybe, it depends on which alkali you mean. Sodium hydroxide (lye) would kill, magnesium hydroxide (in milk of magnesia) probably would not; although, almost anything in large enough quantity can kill, including water.

No, it doesn't. It simply refers to investing energy to obtain energy. Examples including using energy to drive oil drills to extract oil from which you extract energy, and using oil to manufacture solar panels which can be used for solar energy. That's it. This statement seems to imply that without anyone using oil, except investing to obtain energy, there would be no energy trap. If my understanding of this statement is correct, then if everyone else stopped using energy (I know it is absurd) then the energy trap would still exist. That would a significant portion of the world's energy is being used to obtain energy. Acording to Wikipedia everyone's consumption is the following: which is what everyone are producing, too. Now, 13.4×106 m3 per day is a lot of swimming pools full of oil. Why would drilling for oil or making windmills consume even 1% of that amount? There amount of oil used to make a windmill blade is a tiny fraction of 13.4×106 m3 oil, and one windmill produces enough energy to power a windmill manufacturing plant, assuming batteries to assure power when the wind doesn't blow. I haven't been able to find any facts about energy used to build wind turbines.

The article said 56,000 mph. I don't know how you figure 1000 mph, but it appeared to me the meteor traveled about 1/4 the circumference of the visible Earth in a second or so. The Earth's circumference is about 24,000 miles, only 1/2 is visible in the video, so that's 12,000 miles--at the surface of the Earth. IDK how high the meteor was when it appeared on the video, but it had to travel much more than 1000 miles in a fraction of a minute, which is much faster than 1000 mph.

If it happens, I suspect it would be on the Solar City model. A company puts PV on your roof, and you are running on DC, with a DC to AC converter in your house to grid connect so you have power 24x7 and sell excess to the power company. Then, someday, the power company runs a DC line down your street and connects you to it. When everyone on the street is connected to DC, they remove the AC lines on that street. Then they work on the next street over. Rewiring a house for DC would be expensive, so you'd probably keep AC appliances. New homes might be powered by DC only. IDK if it will ever be a good economic decision to replace AC by DC, but it wouldn't have to be done everywhere at once. Edison and Tesla fought over whether AC or DC would be used to power the world, and Edison died thinking he had lost that battle. He may have been right.

Some transmission lines now use DC instead of AC. At one time AC was used because transformers could change the voltage and current when necessary. That technology is less important today, and perhaps one day most of our power distribution will be DC.

G, I'm not a biologist, so cannot answer your question. Sorry.

How can anything avoid being eaten for that long? They live in rock, which must help longevity, but they are surrounded by up to 10x viruses per bacteria. They must be immune to the viruses, or have a symbiotic relationship. Will we find similar life on asteroids?

This 6:30 video of dancing peacock spiders is brilliantly colorful and naturally choreographed.

IMO we would pose little or no threat to robots with superior intelligence, and they would have no good reason to harm us.

From: https://www.facebook.com/photo.php?fbid=628324697199206&set=a.465299380168406.106666.465298390168505&type=1&relevant_count=1&ref=nf