MigL

'Imagine there's no heaven It's easy if you try No hell below us Above us only sky Imagine all the people Living for today. Imagine there's no countries It isn't hard to do Nothing to kill or die for And no religion, too Imagine all the people Living life in peace. Imagine no possessions I wonder if you can No need for greed or hunger A brotherhood of man Imagine all the people Sharing all the world. You may say I'm a dreamer But I'm not the only one I hope someday you'll join us And the world will live as one." John Lennon 1971 Imagining is easy. Realization is the hard part.

No two trees are exactly alike, even if the same type. And as you've never pruned these trees before, there's always going to be some element of 'trial and error'. Or were you planning to start off as an expert ? Its not rocket science. Remove dead, or unwanted growth. Encourage new, and aesthetic growth.

I'm definitely not an expert, but my ( previously my dad's ) lemon tree is over 20 years old. Start by removing any dead branches; they should be easy to spot. Also remove any branches that are growing down, in other weird directions, or off the trunk. The next part depends on the kind of tree, and you should start pruning conservatively to see how it goes this year, and if you should be more aggressive next year. Branches that are still 'green' will continue to grow and keep other branches/fruit from sprouting, but if you cut them shorter, leaving a few 'buds', new growth will result from those 'buds' and allow the tree to fill out ( not just a few long branches ). Most fruit trees/grape vines like to be pruned by March. ( grape vines usually leave only 4-6 'shoots', depending on supporting wires )

Photons don't have mass, they have momentum. And are incapable of any speed other than c . A neutrino has ( very small ) mass, and is a fermion ( obeys Fermi-Dirac statistics ), while a photon is a boson ( obeys Bose-Einstein statistics ). There are, however, bosons that do have mass ( W and Z bosons involved with the weak nuclear force which governs neutrino interactions, for one ). That which gravitates is mass energy, and either will gravitationally interact. The property of energy will just as readily interact gravitationally as the property of mass, in fact J A Wheeler hypothesized non-singular collapsed EM waves ( photons ), and labelled them geons; they are perfectly compatible with GR. Why do you use a definition of matter which is dependent on the human experience ( philosophical ? ) ??? Matter is simply an aggregate of elemental building blocks called fermions, such as electrons, muons, quarks and their antiparticles. ( neutrinos are fermions, but interact so weakly, they don't 'aggregate' at all )

If you 'reverse' time and approach t=0, at the Planck era t = 10^-43 sec, Some of our physical laws, such as GR, cease making meaningful predictions; Some others don't. Quantum Mechanics, and all its effects, still work to some degree. Even the isotropic, homogenous, hot, dense state, that was present when the Big Bang began, was subject to the Heisenberg Uncertainty Principle. And anything subject to the HUP, by necessity, experiences quantum fluctuations. These quantum fluctuations would have experienced exponential inflation ( possibly ), and expansion, since that era. And they would have 'seeded' the large scale structures of the present day universe. ( which is still isotropic and homogenous on large enough scales )

Part of the problem ( or advantage ) is that J Biden is much more likeable, people are more apt to forgive his 'indiscretions', and attribute it to, J Biden being 'good old Joe', and not really being intentional. B Kavanaugh, on the other hand, exudes 'grown-up rich boy' arrogance, and a certain level of 'sliminess'. Not very likeable; at least compared to his accuser.

That's a problem with all democratic political systems. Political leaders only govern four years down the road, and can't see past the next election. But I'll take that over a dictatorship, or one-party system, any day.

Don't you Americans have any politicians with a clean conscience ? ( just kidding, neither do we Canadians ) J Biden seems like the type who would commit an infraction unwittingly, and if told the action wasn't welcome, would stop. I really can't see him doing what he's been accused of. Then again, I have been wrong about things many times, nd Joe is getting old; maybe he forgets when he's told to stop. D Trump has paid people ( S Daniels ) to keep quiet, so as not to ruin his chances for election. What would stop him from paying people to lie ( and ruin his opponent's chance for election ), to secure his own re-election ?

Really ? 1apple - 1apple =0 You had one apple, and you ate it; now you have none. What action and reaction are you ascribing to simple math operations ? ( unless you mean eating is the action, and going to the toilet is the reaction ? )

Effective mass is not the same as inertial mass. It is the mass the electron 'appears' to have when subjected to certain fields/forces. See here... https://en.wikipedia.org/wiki/Effective_mass_(solid-state_physics) The earliest ( easiest ? ) way quantum tunneling was described to me ( back in 2nd year ) is if you consider the wave nature of the electron as described by a wave packet. If that wave packet is 'wider' than the potential barrier, then some part of the wave packet will lie outside the barrier. IOW there is a finite probability of finding the electron outside the barrier. ( and as simplistic as this is, it still assumes you are familiar with some aspects of QM )

Thanks Studiot. That clears up things.

Excellent book; better than the movie. But it was Orson Scott Card.

On the other hand... Did you ever see the movie, The Abyss ? https://en.wikipedia.org/wiki/The_Abyss

Most of the Canadians of Italian descent I know, don't seem to like Brits. They consider them snobbish and self-serving; I am always having to defend them. I realize the Covid-19 pandemic has brought a lot of good will out in people. It is now not uncommon for a person to say "hello" from across the street, whereas before, they would have bumped into you, on the same sidewalk, without greeting. But this old British vet, Capt. Tom Moore, has really amazed a lot of people. He started out trying to raise 1000 pounds, for the NHS, by his 100th birthday ( 24 days ), by walking laps of his garden. He's mentioned in a single which topped the UK music charts, received a fly-past from the RAF, received over 150 000 birthday cards and letters ( including from the Queen ) and made an honorary Colonel. During the 24 day period, he received 1.5 million donations for a total of 32.8 million pounds. Not bad at all. Read about it here.. https://en.wikipedia.org/wiki/Tom_Moore_(fundraiser) You guys are amazing; there's hope for humanity yet.

Don't know if determinism will survive Quantum Gravity. But currently Quantum theory and GR are kicking and screaming trying to avoid unification. As Batman said... "My parents taught me a different lesson, dying in the gutter for no reason at all... They taught me the world only makes sense if you force it to.” What... I'm not gonna believe Batman ?

Definitely. I can certainly agree that D Trump is dancing as fast as he can to try and divert blame for the many failures, from himself, in an attempt to secure re-election. That's been his MO for the last 3 1/2 years.

You know that a helicopter, or a WW1 Sopwith Camel, can easily outmaneuver an F-18, right Alex? The F-18 has a turning radius measured in miles, dependent on speed of course. ( unloaded, it can pull +9g in a banked turn, but only for seconds as the pilot will black-out ) I would be more surprised by the displayed acceleration. An AV-8B Harrier can hover, move sideways or backwards, and possibly accelerate to high subsonic speed faster than an F-18, due to its higher power to weight ratio. But apparently we have no hard numbers as to its speed or acceleration. Only subjective eye-witness reports.

If you want to blame D Trump for the stupid advice he gives ( Hydroxychloroquine, UV light and disinfectants, etc. ), fine. If you want to blame D Trump for squabbling with medical professionals, instead of listening to their advice, fine. If you want to blame D Trump for worrying about his re-election more than mitigating the pandemic, and associated death toll, that's fine too. But in 2009, during the H1N1 epidemic, the CDC estimate for the death toll is between 9000 and 18000. "During the pandemic, CDC provided estimates of the numbers of 2009 H1N1 cases, hospitalizations and deaths on seven different occasions. Final estimates were published in 2011. These final estimates were that from April 12, 2009 to April 10, 2010 approximately 60.8 million cases (range: 43.3-89.3 million), 274,304 hospitalizations (195,086-402,719), and 12,469 deaths (8868-18,306) occurred in the United States due to pH1N1. These final estimates are available at: Estimating the burden of 2009 pandemic influenza A (H1N1) in the United States (April 2009-April 2010), " From https://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm Who do we blame for those deaths ? Seems B Obama prepared his pandemic response playbook a little late ? ( hey, it's my duty to stir up controversy ) PS: ( and generate discussion )

And your question provides the answer... That pesky quantum uncertainty at the scales of the Planck era, toss determinism out the window. ( until we can force Quantum theory and GR to 'play nice' )

You're in the wrong 'Universe', Bufofrog. You can't get Romulan, or Cardassian, ale on Tatooine.

IIRC an O'Neill cylinder actually consists of 2 counter-rotating ( once about every 2 min ) cylinders, about 5 mi in diameter, and 20 mi in length. Each cylinder is divided lengthwise into 6 alternating transparent and habitable areas,, for a total habitable area of almost 1900 mi^2. Since these cylinders rely on sunlight just as the Earth does, any travel away from the Sun would need not only propulsive power, but also a replacement for sunlight. You mentioned nuclear power ( fission ), but that would involve carrying all of the fuel for the long journey with you, as well as the shielding. Your original idea of fusion ( from a Bussard ramjet type of propulsion/power source ) seems more practical, other than the fact that it doesn't exist yet ( fusion in a hi-speed flow ), and may never exist; and you would still need an alternate means of propulsion ( chemical or fission ) to get up to sufficient speed for the 'scoops' to be efficient, and establish orbit at your destination. Then you would need landing craft, and fuel to make all the landings ( and take-offs ) to transfer the ( by then ) large colony of the two cylinders. Once you actually start considering the scale and logistics of such a project, you realize how immense an endeavor it actually is. But it does seem simple enough to say " You take an O'Neill cylinder, slap a fusion reactor on one end, and you have your slow boat."

Although I am familiar enough with 'compactification ( in the Physical sense ), where dimensions are rolled up on Calabi-Yau spaces, to discuss it, I cannot do the math. But Taeto seems to have a point, as your own link Mordred, gives various ways to 'compactify' a space ( in the Mathematical sense ), which seem different from the use of boundary conditions to 'limit' a space. At the top of your link... "For the concept of compactification in mathematics, see compactification (mathematics)." which leads you to... https://en.m.wikipedia.org/wiki/Compactification_(mathematics) As I said, the two don't seem equivalent to me, but my math skills, especially topology, are wanting.

Then why didn't it show up on aircraft radar ? Electromagnetic stealth being prototyped ? ( look up the Northrop-Grumman Tacit Blue stealth demonstrator's shape )

I would have thought you'd give him a white hood ( KKK ) mask, INow, not a 'gimp' ( Pulp Fiction ) mask.

I can see an electromagnetic disturbance, such as lightning. And while a weather radar would certainly pick it up, I'm not sure an I band pulse doppler radar would. Diagnostics only look for 'known' glitches. Say there was excessive solar flare activity, which might affect a wide band radar, would that show up on the diagnostics the next day, if the solar activity had subsided ? I don't think I'd be jumping to extra-terrestrial conclusions as my first choice; just sayin'.