EdEarl

I have not worked with a 3D printer, but I understand that FreeCAD and OpenSCAD can be used to design things for MakerBot and RepRap. FreeCAD is either a bit buggy or very difficult to learn. OpenSCAD works well, but you have to program it and the language has IMO unusual limitations. For example, AFAIK you cannot draw a line in OpenSCAD (only 2D and 3D closed geometric shapes) and its limitations on variables are severe. IMO OpenSCAD is better than FreeCAD. Of course, if you can afford it, AutoCAD is probably the best, but I have not used it. Apparently Google Sketchup can output to a 3D printer. http://nsf.gov/news/mmg/mmg_disp.jsp?med_id=74748&from= I tried to download it, and got a lot of free junk dowloads, but did not get sketchup.

Unusual weather caused flooding in Australia in 2010 and 2011, and the water was soaked up by the dry soil. As a result, the sea level dropped a bit, but since then it has continued to rise by 10 mm (0.4 inches) a year, which is an increase from rising 0.13 inches per year previously.

The home market is limited to printers that build up plastic parts and use lasers to cut wooden parts. See: http://forums.reprap.org/index.php, http://www.thingiverse.com/, http://www.makerbot.com, and http://www.carvewright.com. There are others, too. AFAIK, there are no 3D printers for home use that make things of silicon or glass.

There is a big difference between the furthest Type 1a supernovas and the furthest GRB.

Do we actually know that any base pairs except those will make a viable DNA? Even if a form of DNA can be made with different base pairs, it may be weak and unable to survive in the Earth's biosphere. Although, some viruses are able to survive, they are unable to survive without cells, AFAIK. Although, I have seen speculation that some viruses may be able to reproduce without cells. Basically, the biology we have has had 4 Gy to evolve to be strong. Other forms of life that may have once existed have been overwhelmed by superior evolution. A stronger form of DNA seems unlikely, but it is conceivable.

We do not know that abiogenesis only occurred once. It could occur from time to time, but with all the biology that exists on Earth, a neophyte life form is unlikely to survive long because something is likely to either eat it or infect and kill it. We know so little about how life formed and began evolution that our assumptions are likely to be incorrect. Recently we have learned that DNA is traded among species. Perhaps, abiogenesis occurred several times and began trading features of life before DNA existed, and that process of trading eventually resulted in DNA. Until we know a process for abiogenesis, we cannot afford to exclude speculations without careful examination. One day such a mind experiment may result in an insight that helps us truly understand abiogenesis.

A GreenTechSolar report says 2/3 of solar PV has been installed in the past 2.5 years.

It always happens; they talk their audience to death.

I think the 3D and 4D printing are already changing the world in small ways, and will probably have greater effect as the technology matures. See 4D printing video and others on YouTube. Individual 3D printers are available, for example RepRap, but most are limited to printing plastic parts, which is a big market but not the only market. There are many types of 3D printers that work with various materials, which makes predicting the long term effects of 3D/4D printing complex. At the moment, the idea of one printer being able to make anything a person wants and needs is pie in the sky. Moreover, the idea of each home owner having enough printers to make parts of several metals, several plastics, wood, and other materials necessary to make and maintain a house, vehicles, and other things is also not credible. A more realistic scenario is that various people/businesses will have different 3D and 4D printers and that some manufacturing will become community-centric. A person will order a part on-line, for example a plumbing fixture, and their local manufacturer-retailer will make it and have it ready for delivery quickly, for example next day. This kind of business will reduce shipping costs and make exact replacement parts available. Today we may need to upgrade to a newer model or downgrade to a different one. This image of 3D/4D commerce is one that may occur in the relatively near future. In the long run, perhaps scientists will develop a nanotechnology printer that can move individual atoms of any type, and make anything from raw materials. For now, that idea is science fiction.

TY John

Do you have a reference to this concept? If the concept is electronegativity, why are these atoms positively charged? That is a contradiction and doesn't make sense. If the center of the galaxy were either positively or negatively charged, everything would repel, not be attracted. In other words, additional dark matter would be needed to hold the galaxy together. in other words, your ideas are contradictory and do not make sense. Moreover, gravitational attraction is more pronounced at large distances than the electrostatic force. It is possible for an electrostatic force to overcome gravity at small distances, for example a small piece of paper may adhere to you when you are charged with static electricity (as when rubbing your feet on the carpet). However, you cannot pick up a piece of paper laying on the floor because of the static charge, the paper must be touching you. If the charge of oxygen in the Earths atmosphere were greater than gravity, the oxygen would fly off into space and not be held to the earth by gravity, because positive charges repel other positive charges and negative charges repel other negative charges. This idea is consistent with like charged particles repelling other like charged particles, but it contradicts your previous idea that galaxies are held together by charged particles. However, the distances are so vast, it does not seem electrostatic charge would have such an effect. Your ideas are not consistent; thus, please give a reference to Pauling's paper on electronegativity, because you have not explained the expected results well enough to understand.

Thanks to Science is Awesome on facebook.

It is possible to make a single atom transistor; however, it may not be reliable and requires leads to other transistors to make circuits. Let's assume one needs 1000 atoms per transistor for a reliable circuit with interconnections. The atomic weight of silicon is about 28. Avogadro's constant is 6.02214129(27)×1023 mol−1. Thus 6.02214129(27)×1023 atoms of silicon weighs 28 grams. 1kg / 28 g = 1000/28 Thus; 1kg of silicon is 1000/28 × 6.02214129(27)×1023 atoms ~= 215×1023 atoms = 2.15 × 1025 atoms. At 1000 atoms per transistor in an integrated circuit, means there could be 2.15 × 1022 transistors. It is been a long time since I did a mole weight calculation; perhaps I made a mistake. If my calculations are correct, 10^31 bits is high for 1 kg silicon or any other atom. Current processing speed is about 5 GHz. (5× 109) Thus, 5*10^50 logical operations per second logical operations per second is very high for a single core computer today, but parallel processing allows scaling to any composite speed. Even with speed improvements promised by quantum computing, 5*10^50 logical operations per second seems very high to me for 1kg silicon or any other atom. Gamma rays are 1018 and higher frequency, which may mean switching times can be much faster than 109, but we do not know where the limit is. Even if switching speeds can be 1025, it is a long way to 5*1050. But, like absolute zero, theoretical maximums are beyond reality.

My favorite numbers are 0 and 1, because they are binary digits on which all computers are based and the source of my work for many years. All numbers can be represented in binary, and the largest number divisible by a bit is 1, the analog to 252010. The largest address space, 264 is the integer analog to infinity for a computer, because it is the largest possible address on a 64 bit machine. Although, the largest floating point numbers are 128 bits, which can represent both plus and minus infinity, Of course, binary is not restricted to computers.

When there is a huge solar spill, it's just called a nice day.

Multiple signals can be sent using several methods. First, it is possible to modulate AM, and FM on the same carrier, thus sending two different signals. In addition, one can send several carrier waves, each with its own AM and FM modulation. And, third, each frequency has two sidebands that can be modulated differently; thus, one carrier with two sidebands. both modulated AM, and FM to carry four signals.

Analog signals are usually carried on sine waves which may be modulated via amplitude (AM), frequency (FM) or phase (PM). Digital data (e.g., Morse code and binary) is carried in the modulations. Whether WiFi, satellite, DSL, cellular, NASA interplanetary, amateur radio, military, or commercial EMR (radio, light, infrared, etc.) digital communications are being done, these modulation techniques are used. However, modulating a signal to carry digital signals is simple compared to the simultaneous amplitude and frequency modulations of sound used for music and voice. There are a more modulating techniques (e.g., combinations of AM, FM and PM), which can be found in the Passband Modulation box on This page, This page is about spread spectrum communications, which are techniques that use modulation to improve communications security and reliability. However, the techniquest mentioned in the Passband Modulation box are not necessarily for security and reliability.

It might be done with chemical rockets and fission power, according to The Millennial Project: Colonizing the Galaxy in Eight Easy Steps by Marshal Savage. However, it will take millennium. Basically, people live in space, inside giant domes built of materials mined from asteroids and comets. People gradually migrate outward toward the stars using the asteroid belt and smaller moons within the Sol system, then using materials from the Kuiper belt, the Oort cloud, and other small interstellar bodies. Since water can be split into H2 and O2 and appears to be plentiful in space, fuel for chemical rockets is available as long as fissionable material is abundant.

Great news if this vaccine is shown safe and effective in larger trials.

Here is an interesting case of "Craniopagus twins are conjoined twins who are fused at the cranium." They cannot be separated. See also: Tatiana and Krista The report indicates the twins can see through each others eyes and "hear" each others thoughts. There is a 3 part National Geographic Documentary on YouTube. Part 1 Part 2 Part 3

Zorro, You should get more recent reports than the Limits To Growth; it's data is old and does not include data for global warming. I don't know what books are latest. There is data to suggest population growth is under control from a Ted Talk by Hans Rosling: Religions and Babies. Another interesting Ted Talk is by Allan Savory: How to green the world's deserts and reverse climate change. Two Elon Musk companies are working to help climate change, Solar City and TeslaX. Windmills are popping up all over the place. The number of solar farms is increasing. Many companies are saving money by reducing their energy bills. The Elio three wheeler will be sold soon; it gets 80+ mpg, can go 100 mph, has air condition, power windows, and appears that it will be a good commuter car scooter. The down side is glaciers and northern permafrost are melting at astonishing rates, among other things. Whether the advancements will overcome the detriments soon enough to prevent catastrophe is unknown. I hope they will. If the US had spent money on renewable energy sources that it spent on the wars in Iraq and Afghanistan, it would have a green economy and taxpayers would already be getting billions of dollars from green jobs and not spending as much money to buy foreign oil. Oops. It would be nice if we always knew how to do the right thing. It would be nice if congress could do something right.

IIRC a video on youtube (name ?) shows a man viewing an image flashed for 50 ms with 60% recognition. It was a test of a man vs a computer vision system. However, they did not give any more details. Sorry I cannot remember more, and I am unsure of the details I have given.

It was done in the 1960s using a computer simulation with the results published in a book called the Limits to Growth. The effort did not end there; since then relate work has continued and has been published. You can find this information by starting with the following links. Knowledge about the environment has increased since the 1960s, which has changed the equations used in simulations. However, the date predicted for overwhelming the Earth's resources has remained about the same (2040-2050). But, time flies and many things need to be done if we are to avoid disaster. See: Limits To Growth, Related books, Already Beyond? – 40 Years Limits to Growth, and Books and Literature.

Zorro, I think you are too optimistic.