Airbrush

Yes, Metal Halides and HPS create a LOT of heat and therefore a a hazard for indoor growing. They can start a fire if you don't vent the heat properly with electric fans. Not for beginners. Flourescents remain cool to the touch even after hours of use. I purchased a 250w MH and a 250w HPS many years ago and never actually used them because I've come to prefer the simplicity of good old-fashioned sunshine in my back yard.

It sounds like somebody wants to grow something naughty indoors. Ordinary flourescents work just fine especially at early stages of growth. If you want to get fancy there are metal halides and high pressure sodium.

The word "rifle" comes from rifling which are spiral grooves in the barrel of a rifle that cause a bullet to spin, but the axis of spin is parallel to the path of the bullet. That increases accuracy by gyroscopically stabilizing the bullet, improving its aerodynamic stability. The kind of spin needed to curve the path of a bullet would be perpendicular to rifling spin. It would cause the bullet to tumble the wrong way and be totally out of control. http://en.wikipedia.org/wiki/Rifling

Maybe some of the long gamma ray bursts are from merging SBHs. Wiki says that the long GRBs (longer than a couple of seconds) are from massive stars collapsing into black holes, and the short ones come from merging neutron stars. I propose that when supermassive black holes merge they would look like binary quasars until the final moment.

Look up "El Nino" on wikipedia and it also discusses "La Nina". "La Niña is the name for the cold phase of ENSO, during which the cold pool in the eastern Pacific intensifies and the trade winds strengthen. The name La Niña originates from Spanish, meaning "the little girl", analogous to El Niño meaning "the little boy". It has also in the past been called anti-El Niño. "La Niña causes mostly the opposite effects of El Niño, for example, El Niño would cause a wet period in the Midwestern U.S., while La Niña would typically cause a dry period in this area." http://en.wikipedia.org/wiki/El_Nino#La_Ni.C3.B1a

What if there was a way to tap into the magma at Yellowstone as an unlimited source of energy for the entire North American continent? Is there a way to "disarm" Yellowstone to release the inexorable energy build-up, and use the energy at the same time? What I envision, if possible, is a way to allow Yellowstone to "let off steam" at a steady rate so it won't explode, and use the energy to generate electricity for the USA? It would require a lot of exploration and testing to find a safe way to tap into Yellowstone. A series of either small nuclear or conventional explosives could open a passageway for the magma and allow a giant magma gyser on the surface where it could be used to power steam turbines. But they better be careful or they could accidentally trigger the Big Eruption, and game over.

The merger of two SBH seems like the ultimate heavyweight fight. Some SBH have a billion solar masses or more. Consider that a quasar's tremendous energy output is probably the result of an accretion DISK. What if the two SBHs have accretion disks that are not parallel? As they approach each other each tears away the other's accretion disk resulting in matter crashing into both over much broader areas. Instead of accretion DISKS this could result in a chaotic disbursion of matter all around each in an accretion SPHERE, a shell of massive energy outbursts. This could vastly multiply the energy output of both. After each strips away the other's accretion disk then there would be little left but 2 naked black holes which would spin around each other at relativistic speed, and then merge at near light speed. Their tremendous gravity would suppress any other outburst. So I propose that the most energetic phase of the merger would be binary super-quasars leading up to the merger, as each tears appart and starts a feeding frenzy on accretion material, with huge amounts of gas and dust falling every which way into each black hole, all over the spherical event horizons, and not the moment of merger which would only end with a unpresedented spike in gravity waves.

If a quasar is a supermassive black hole (SBH) devouring matter at the rate of solar masses per month, then my guess is that when two SBH collide, after a long dance around each other, it happens very quickly and a lot of accretion disk material gets dragged around and forced fed into each as they get closer. It should look like a couple of quasars orbiting each other and in the critical moment of collision, there is a massive burst of energy greater than all the galaxies in the observable universe, but just for an instant. Then it settles down to a long meal of accretion disk material so it shines like a mega-quasar for a long time afterwards, unless the impact blasts all the accretion disk material away and out of reach. Or as Martin stated that the intense gravity would slow the energy release? I don't understand gravitational waves so maybe someone else can explain that aspect. I think the processes in quasars are more energetic than gravitational waves. The gravity waves is how we could detect these mergers. Here is an animation of 2 black holes merging and tell me what you think of the discussion that followed it. http://www.newscientist.com/blog/space/2007/05/battle-of-black-holes.html

Thanks Sisyphus, that is the kind of stuff I like to hear.

Would you care to elaborate? Does the magnetic field depend upon currents in the Earth's core? I agree that gliding thru solid rock by means of a rotating lazer cutting a pathway sounds far-fetched, but long-term human space travel to the stars seems almost as preposterous.

Sorry Mr. Alien, you are correct. On second thought, I can't imagine how heavy 13.1 grams would be for something only one cubic centimeter. What I need is a common object, one that I pick up often, and the weight of that object in units I grew up with. Sorry, but I am not a scientist. I miss a lot of good science when the standard units of measure just whizz over my head.

Did anyone see the movie "The Core"? Was it realistic? Apparently magnetic pole reversals do not cause mass extinctions. "Because the magnetic field has never been observed to reverse by humans with instrumentation, and the mechanism of field generation is not well understood, it is difficult to say what the characteristics of the magnetic field might be leading up to such a reversal. Some speculate that a greatly diminished magnetic field during a reversal period will expose the surface of the earth to a substantial and potentially damaging increase in cosmic radiation. However, Homo erectus and their ancestors certainly survived many previous reversals. There is no uncontested evidence that a magnetic field reversal has ever caused any biological extinctions. A possible explanation is that the solar wind may induce a sufficient magnetic field in the Earth's ionosphere to shield the surface from energetic particles even in the absence of the Earth's normal magnetic field. "Although the inspection of past reversals does not indicate biological extinctions, present society with its reliance on electricity and electromagnetic effects (e.g. radio, satellite communications) may be vulnerable to technological disruptions in the event of a full field reversal." http://en.wikipedia.org/wiki/Geomagnetic_reversal

Why complicate the density? It is far easier to visualize the density your link gave (for the Earth's lower core) as 13.1 gm/cm^3 than to gross it up to a cubic meter. Same goes for speeds greater than 3,600 mph, better call it one mile per second. That you can visualize. Or if your audience is not in the US, call it km/second. Scientists need to consider their audience, unless they want their only audience to be other scientists.

Another thing, missions into space are very physically demanding. Astonauts must be in tip-top physical condition, like a fighter pilot. A pregnant woman should never be subjected to such abuse as strenuous physical conditioning before launch and then withstanding several G's to fly into orbit, followed by weightlessness.

There is absolutely no reason for giving birth in zero gravity, nor for extended human space missions in zero gravity. Artificial gravity, by means of cabin rotation, is a must for long-term human space exploration. Giving birth in space is only something that would happen during long multi-generational space missions to the stars. Robotic probes are far more cost-efficent than sending people anywhere further than the Moon.

This is not about conventional mass achieving the speed of light, this is about the striking similarity of E=mc^2 and Kinetic E=0.5mv^2. Energy contained in a mass is double its' own mass moving at light speed by the equation simply by substituting v with c. OK, matter cannot reach light speed, but the light energy equivalent of a given amount of matter does travel at light speed. So what's the problem?

I am here because of the History Channel "The Universe". NowThat lead me here. Thank you NowThat. If there are inaccuracies then I wish people would discuss them in detail so THC will know what things were not accurate. The cgi was fantastic on "The Universe" and if the program could be corrected, and thus improved, then that would be stupendous. I don't remember hearing anything inaccurate, but I don't have much science background. My degrees are in art and accounting. Hahaha. I found inaccuracies on wikipedia and reported them here but I should have reported them to wiki.

Do they expect to witness a merger in the near future?

Thanks for all your comments Lakmilis. Interesting subject. That is a beautiful comparison between Einstein's equation and the equation for kinetic energy. The energy stored in a given mass is exactly double the kinetic energy of that mass moving at light speed! Awesome revelation for me.

You hear that folks? Since 70-80% of meteoroids are stony, when playing with the kinetic energy formula use the Stony-Iron density value of 4.5 to calculate energy released in the majority of impacts. The cool thing about the "Energy = 0.5 X Mass X Velocity-Squared" equation is that it looks a lot like Einstein's famous "E = mc^2". I never realized that until now. Why "times 0.5"? From wikipedia I get volume for a sphere as V = 4/3 X pi X r^3.

Great to hear that stuff Martin. So in at least 3 years they should know something about such planets. But how long will it take for them to know if this method will even work? If they find this method will work, would that appear in the news? After detecting "semi-earths" in HZ, when will they know more about the actual planets? Will that take more advanced technology? "The method is fundamentally so elegant that it is hard not to suspect that humans were evolved by nature specifically to find habitable planets. What other purpose could evolution possibly have had in mind?" My sentiments exactly!

According to wikipedia.org: "The random probability of a planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit. For an Earth-like planet at 1 AU transiting a solar-like star the probability is 0.465%, or about 1 in 215." Does that mean they will need to look at 215 stars before there is a high probability that they are looking at a proper angle to see an Earth-like planet pass in front of the star? "In addition, the 1 in 215 probability means that if 100% of stars observed had the exact same diameter as the Sun, and each had one Earth-like terrestrial planet in an orbit identical to that of the Earth, Kepler would find about 465 of them." http://en.wikipedia.org/wiki/Kepler_mission

I don't know why they would specify different energy releases. Have you ever heard of two components to an explosion? That thing hit the ground, plain and simple. It was not an air burst. It burned off about half it's mass (165,000 tons of 330,000 tons) on the way down. I wonder how that data affects the calculation?

Thanks for the help folks. I like the looks of Moth's formulas which yield a number of over 35 quadrillion joules which convert to over 8 megatons. http://www.unitconversion.org/energy/joules-to-megatons-conversion.html Those numbers come from the Barringer Crater impact of 50,000 years ago. "The object that excavated the crater was a nickel-iron meteorite about 50 meters (54 yards) across, which impacted the plain at a speed of several kilometers per second. The speed of the impact has been a subject of some debate. Modelling initially suggested that the meteorite struck at a speed of up to 20 kilometers per second (45,000 mph), but more recent research suggests the impact was substantially slower, at 12.8 kilometers per second (28,600 mph). It is believed that about half of the impactor's 300,000 tonnes (330,000 short tons) bulk was vaporized during its descent, before it hit the ground. "The meteor hit the ground at an 80 degree angle from the north or northeast and it is theorized that the bulk of the remaining unvaporized 150,000 tons of the meteorite is under the crater's south rim which shows signs of uplift. The last major mining effort to recover the meteorite in that area was abandoned in 1929. "The impact produced a massive explosion equivalent to at least 2.5 megatons of TNT – equivalent to a large thermonuclear explosion and about 150 times the yield of the atomic bombs used at Hiroshima and Nagasaki. The explosion dug out 175 million tons of rock. The shock of impact propagated as a hemispherical shock wave that blasted the rock down and outward from the point of impact, forming the crater. Much more impact energy, equivalent to an estimated 6.5 megatons, was released into the atmosphere and generated a devastating above-ground shockwave..." http://en.wikipedia.org/wiki/Barringer_Crater Maybe because of the 6.5 megatons released into the atmosphere (whatever that means), plus the 2.5 megaton explosion, add up to 9 megatons, which is close to the number Moth calculated. "The blast and thermal energy released by the impact would certainly have been lethal to living creatures within a wide area. All life within a radius of three to four kilometers (1.9-2.5 miles) would have been killed immediately. The impact produced a fireball hot enough to cause severe flash burns at a range of up to 10 km (7 miles). A shock wave moving out at 2,000 km/h (1,200 mph) leveled everything within a radius of 14-22 km (8.5-13.5 miles), dissipating to hurricane-force winds that persisted to a radius of 40 km (25 miles)."

7.5 x 3.14 x 125,000m^3 x 144km^2/sec^2 and divide it all by 6 = 7.5 x 3.14 x 125,000 x 24 (m^3Km^2/sec^2) = 70,650,000 (m^3 x km^2/sec^2) joules How do you combine the meters cubed and km squared?