COMMUNITY

A new preprint on arXiv does an excellent job of deriving strong constraints on the possible "antigravity" (gravitational repulsion) of antimatter, based on very precise experimental data and a minimum of theoretical assumptions. Karshenboim goes through several complex and detailed analyses to set tight limits on antigravity effects.The argument I like best goes as follows: if antimatter feels a gravitational repulsion relative to matter, then "pure neutral" bodies, like positronium (bound states of e+ and e-) or photons (which are their own antiparticles) should feel no gravity at all. That trivially contradicts the gravitational deflection of light, and therefore can't be true.

This book has several high voltage gadgets to build, and if you are familiar with the "evil genius" series, presents a plethora of information on each one.  There are 28 projects in all;  and the front cover also says:  * illustrated instructions & schematics * lists of materials & part suppliers * science & math behind each project The author is Bob Iannini The book cost me $24.95 (USA) new.  It will cost around $3 to ship in the USA, so if anyone feels it is worth about $15-$18 that would be grand; otherwise, make a reasonable offer. I underlined one word in the introduction, but have made no other marks in the book. My reason for selling it is that I do not see any way in the foreseeable future, of me building any of this kind of project. Contact me by way of PM  to work out the details if anyone wishes to purchase it. Thanks ahead of time.    Table of Contents: There are 28 chapters (one for each project)   Chapter One:  Anti-gravity Project   Chapter Two: Low Power Electrockenetic gun   Chapter Three: High Energy Pulser   Chapter Four: Mass Accelerator   Chapter Five: Plasma Thermal gun   Chapter Six: Wire Exploding   Chapter Seven: Magnetic Can Crushing   Chapter Eight: Hand-held Burning CO2 gas LASER   Chapter Nine: Hand-held Burning Diode LASER   Chapter Ten: Long Range Optical LASER   Chapter Eleven: Hand-held Ultrabright Green LASER   Chapter Twelve: LASER  Property protection Fence   Chapter Thirteen: LASER window Listening Device   Chapter Fourteen: 12"  Spark Tesla Coil   Chapter Fifteen: Two inch spark Tesla w/timer   Chapter Sixteen: Tesla Plasma & Ion projects     Chapter Seventeen: Sold State Tesla Coil   Chapter Eighteen: 30 "  Spark Tesla Lightning generator   Chapter Nineteen: Jacob's Ladder   Chapter Twenty: Plasma Tornado Generator   Chapter Twenty one: Plasma Light Saber   Chapter Twenty two: Ion Ray  & Charge gun   Chapter Twenty three: See in the Dark project ( IR night vision)   Chapter Twenty four: Fish stunning & Wormer (brings em to the surface of the ground) project   Chapter Twenty five: EMP Generator   Chapter Twenty six: Ultrasonic Microphone   Chapter Twenty seven: Phaser Pain field gun   Chapter Twenty eight:  Pain field Property protection guard