Move the "suspect" light source rapidly. If you see a series of images instead of a continuous line, it's flickering. Our eyes are inert enough to be unable to consciously register flicker of an unmoving light source, but the same inertia allows us to notice separate discrete flashes of quickly moving light source.
Could you pick a piece of Amethyst, look at it in this light and tell me what you see?
Amethyst is the uncanny probe of all these light sources. In daylight, it's a rich, deep violet. In most if LED, fluorescent and the likes, it looks like a piece of quite transparent, slightly greenish ordinary glass. The difference is obvious to any, even completely untrained eye.
I've seen some "warm light" LEDs recently. Their light was pretty sweet, with a nice warm golden-orange tone (like sunset or IR bulb) and more than acceptable.
Unfortunately, they still cost arm and leg comparing to normal "ultra-bright white light" and "daylight" LEDs.
From my experience, the lifetime of the energy-saving bulbs in -15C frost doesn't exceed 2 weeks. They are okay indoors, but I still use a standard bulb for the garage light. After replacing three supposedly "survives 20 bulbs" energy-saving ones in matter of two months.
1. don't install software that's infected 2. use secure browser 3. use secure email client 4. use dedicated hardware firewall......Next I could mention some 3 more vectors of attack (...pendrives?...WiFi password?...other vulnerable software?) and you could counter me with 3 other simple security countermeasures. Which would bring your list to 7 points.
Which goes way beyond your original point of "if you don't install software that's infected, you won't get infected" and nears a point where a Joe Average loses track of these necessities, forgets or neglects one of the points - and gets infected.
-now- - power of habit. -then- - it was the best (shortly). -until recently- - it can find and restore archives embedded in an arbitrary binary stream. That was used frequently for sharing files over imageboards by appending RAR to the end of a JPEG image. That way the JPEG (with data considered junk) was posted to the board, and downloading it, changing extension to.rar and opening in winrar extracted its contents. Some quite popular sites used it on regular basis - Bookchan being one of them, thousands of ebooks shared that way.
Currently 7zip can do it too with its native.7z, but I don't think it's more than half a year since it learned that trick.
even if you depend on compression wave speed, you can still propel solids faster than that using the sail effect - just like a windsurfer can go faster than the wind by going diagonally to it.
Not necessarily - only while exhaust gas speed doesn't exceed the rocket speed. A rocket engine will -still- be propelled when the exhaust gas travels in the same direction as the engine, only slower than the engine. (engine travels at 3 Mach, exhaust speed is 2 Mach, per every kg of fuel ejected the engine gets 2 Mach*kg thrust, despite the ejected gas still traveling at 1 Mach in the same direction as the engine.)
Of course the question remains whether the "break even" point (where exhaust speed equals rocket speed so exhaust gas remains static relative to surrounding air) can happen in the atmosphere, with air friction, but that's a technological barrier, not a physical one.
Imagine: a cart with two catapults on it, (total wt. 1kg). First catapult is then loaded with 2kg ball and propels its load to 4m/s. The second one is loaded with 1kg ball and can propel its load by 2m/s.
Spring the first catapult. The 2kg ball is launched at 2m/s while the cart with its 1kg ball payload starts traveling at 2m/s in the opposite direction.
Now spring the second catapult: the 1kg ball gets launched at 1m/s backwards relative to the cart speed while the cart accelerates by another 1m/s.
Now note the second ball travels at 1m/s forward in absolute terms...
If the exhaust gas is faster than movement of the engine, it creates pressure pillow and pushes it extra. For pure rocket action, the exhaust gas must escape the engine as fast or slower than the engine moves, which, considering it's air-breathing engine, means the intake air must be actually propelled forward.
Considering it has to propel all the oxidizer as it takes it in (plus inert nitrogen mixed in), it would have to waste enormous amounts of fuel just to propel the inert air.
An engine traveling at 3 Mach, ejecting exhaust gases at 2 Mach relatively to self (thus propelling them 1Mach forward) would have to eject 2 kg of fuel mass for every 1 kg of intake air it takes in just to break even.
Consider 1m^2 engine air intake surface, 1Mach = 340.3 m/s; 1m^3 of air = 1.2kg;
At 3 Mach it would take (3*340.3)m/s * 1m^2 = 1020m^3/s that is 1225kg of air/s on the intake. That is two and a half ton of fuel ejected per second just to break even with the air intake.
The air it ejects backwards moves way faster than Mach 1 relatively to the engine. The momentum of ejected material must be higher than momentum of intake material. With rockets, there's no intake material, and it depends strictly on ejecting most of its mass backwards. Speed is a boon but even ejecting the mass slower than the speed of surrounding air (or near-void) gives it thrust.
With jet, the momentum of air at the intake (which is zero, immobile air) must be lower than exhaust mix ejected backwards, and considering the mass of the jet fuel used is quite low comparing to mass of air used, the mass of the exhaust gas is not significantly higher than mass of intake air, so it must use higher speed to achieve higher momentum and thus thrust - so no matter how fast the plane moves, exhaust gas always moves backwards relative to static air - thus pushes against static air and as result creates a pressure pillow.
What REALLY annoys me is if they get more voice actors than lines. When you hear the same exact sentence repeated by three different people.
"You seem to be wounded. You should see a healer" delivered by a female orc husky voice, a stern guard, and a singing elf female, this is really horrible. Why can't they come up with some variations that would mean the same, or even ask the voice actors to improvise a little? How hard would it be to write variations of these lines, one per voice? I thought writing random dialogues for the characters is the cheapest part, and since each voice actor needs to read his/her sheet separately, why can't they be provided with different sheets?
Yep, that would be okay if you took a ready-made car. But compiling is more like car assembly process. Compiling a program is like you tell what parts should go where, you add your engine and get it running smoothly.
In this case, you tell the engineers you want a mock-up frame of bare essentials to have this bare engine you provided started. You expect them to attach the starter motor, the power from the battery, ignition switch, some frame to attach it to, and a pipe to a bottle of fuel.
Instead, what you get is a car with a complete gearbox, electric installation, steering and brake system and pretty much all the basic essentials needed to drive (no extras like AC, airbags or ABS). You didn't ask for anything of that and you wanted to use the engine to power a stationary water pump and the whole "car stuff" really gets into the way.
...besides, high-level programmers often underestimate just how big a sector embedded programming is. The $IDIOTS_PET_LANGUAGE is for a PC. Now get me more RAM and better CPU for all the devices running embedded software, that are in my sight range as I look around:
- my cell phone. - 6 different monitors (OSD doesn't happen magically. Something remembers the settings...) - a videoserver - 2 cheap switches - a regulated power supply - a heat-controlled soldering iron - a regular phone - 3 PC keyboards (hey, neither PS2 nor USB protocols happen by themselves) - 3 computer mice (optical, meaning pretty advanced image analysis) - my hand watch - a battery charger - a USB hub - a security motion sensor - an MP3 player - a webcam - a multimeter - a car alarm remote - a pendrive.
These all were programmed either in VHDL, Asembler, or C. The phone has some J2ME code too. Think of upgrading each of these devices so much that its firmware could be rewritten in, say, Perl. Or C#.
Also, think about how much embedded programming is in every PC. Each device controller has its own firmware... my bet is any average house contains more embedded programs (in embedded devices) than PC applications on the "family PC" and stored on media.
High-level programming languages are nice and have their place, but considering embedded "a niche not worthy of attention" is a bad mistake. The proportions between amounts of server:desktop:embedded software are much closer to 1:1:1 than most "high-level" programmers are willing to admit.
The iWorld in question, being a more lean and user-friendly variant of the World, created in only 4 days (compared to the original 6+1 of testing). Unfortunately, iWorld can have only one of gravity, electromagnetic, strong or weak force working at the same time. People living there say it doesn't bother them though.
...except if you enter sites with drive-by exploits, get spam email with virus that requires you to hover your mouse over the message title in Outlook to install, or some protocol you weren't even aware your computer used has a security hole and an IP scanner finds that port open on your box...
Sure most viruses use some blatant and crude social engineering to install, but there are these that don't even need user interaction to infect you.
The problem is, a couple of years ago, RAR released a new version (which gave it a lead in the industry in compression ratio for a brief time), incompatible with the older versions (old decompressors couldn't decompress stuff compressed with the new RAR). It took all the others between a few months and a few years to include support for it. 7zip being notoriously behind. So while it nominally supported ".rar", it lacked support for the "new RAR" for a couple of years.
Slashdot Mirror
I could argue other characters, but you'd be hard pressed to find any flaws in voicing of the protagonist of the Half-Life series...
...to prevent uncontrolled tissue growth, AKA cancer?
Sure, and the Moon is made of green cheese because if it was made of rock, the astronauts would crash into it during landing.
Go away, troll.
Get a plasma TV and set it to display white screen. It will emit full, smooth spectrum as only Plasma TVs can ;)
Move the "suspect" light source rapidly. If you see a series of images instead of a continuous line, it's flickering. Our eyes are inert enough to be unable to consciously register flicker of an unmoving light source, but the same inertia allows us to notice separate discrete flashes of quickly moving light source.
Officially outlawed 100W bulbs in Poland vanished from official shops but can still be found at flea markets in abundance.
Another interesting market catch was a "99W bulb" :) Unfortunately it appeared to be a hoax.
Could you pick a piece of Amethyst, look at it in this light and tell me what you see?
Amethyst is the uncanny probe of all these light sources. In daylight, it's a rich, deep violet. In most if LED, fluorescent and the likes, it looks like a piece of quite transparent, slightly greenish ordinary glass. The difference is obvious to any, even completely untrained eye.
I've seen some "warm light" LEDs recently. Their light was pretty sweet, with a nice warm golden-orange tone (like sunset or IR bulb) and more than acceptable.
Unfortunately, they still cost arm and leg comparing to normal "ultra-bright white light" and "daylight" LEDs.
From my experience, the lifetime of the energy-saving bulbs in -15C frost doesn't exceed 2 weeks. They are okay indoors, but I still use a standard bulb for the garage light. After replacing three supposedly "survives 20 bulbs" energy-saving ones in matter of two months.
Oh, so:
1. don't install software that's infected ...Next I could mention some 3 more vectors of attack (...pendrives? ...WiFi password? ...other vulnerable software?) and you could counter me with 3 other simple security countermeasures. Which would bring your list to 7 points.
2. use secure browser
3. use secure email client
4. use dedicated hardware firewall...
Which goes way beyond your original point of "if you don't install software that's infected, you won't get infected" and nears a point where a Joe Average loses track of these necessities, forgets or neglects one of the points - and gets infected.
-now- - power of habit. .rar and opening in winrar extracted its contents. Some quite popular sites used it on regular basis - Bookchan being one of them, thousands of ebooks shared that way.
-then- - it was the best (shortly).
-until recently- - it can find and restore archives embedded in an arbitrary binary stream. That was used frequently for sharing files over imageboards by appending RAR to the end of a JPEG image. That way the JPEG (with data considered junk) was posted to the board, and downloading it, changing extension to
Currently 7zip can do it too with its native .7z, but I don't think it's more than half a year since it learned that trick.
even if you depend on compression wave speed, you can still propel solids faster than that using the sail effect - just like a windsurfer can go faster than the wind by going diagonally to it.
Not necessarily - only while exhaust gas speed doesn't exceed the rocket speed. A rocket engine will -still- be propelled when the exhaust gas travels in the same direction as the engine, only slower than the engine. (engine travels at 3 Mach, exhaust speed is 2 Mach, per every kg of fuel ejected the engine gets 2 Mach*kg thrust, despite the ejected gas still traveling at 1 Mach in the same direction as the engine.)
Of course the question remains whether the "break even" point (where exhaust speed equals rocket speed so exhaust gas remains static relative to surrounding air) can happen in the atmosphere, with air friction, but that's a technological barrier, not a physical one.
Imagine: a cart with two catapults on it, (total wt. 1kg). First catapult is then loaded with 2kg ball and propels its load to 4m/s. The second one is loaded with 1kg ball and can propel its load by 2m/s.
Spring the first catapult. The 2kg ball is launched at 2m/s while the cart with its 1kg ball payload starts traveling at 2m/s in the opposite direction.
Now spring the second catapult: the 1kg ball gets launched at 1m/s backwards relative to the cart speed while the cart accelerates by another 1m/s.
Now note the second ball travels at 1m/s forward in absolute terms...
If the exhaust gas is faster than movement of the engine, it creates pressure pillow and pushes it extra. For pure rocket action, the exhaust gas must escape the engine as fast or slower than the engine moves, which, considering it's air-breathing engine, means the intake air must be actually propelled forward.
Considering it has to propel all the oxidizer as it takes it in (plus inert nitrogen mixed in), it would have to waste enormous amounts of fuel just to propel the inert air.
An engine traveling at 3 Mach, ejecting exhaust gases at 2 Mach relatively to self (thus propelling them 1Mach forward) would have to eject 2 kg of fuel mass for every 1 kg of intake air it takes in just to break even.
Consider 1m^2 engine air intake surface, 1Mach = 340.3 m/s; 1m^3 of air = 1.2kg;
At 3 Mach it would take (3*340.3)m/s * 1m^2 = 1020m^3/s that is 1225kg of air/s on the intake. That is two and a half ton of fuel ejected per second just to break even with the air intake.
The air it ejects backwards moves way faster than Mach 1 relatively to the engine. The momentum of ejected material must be higher than momentum of intake material. With rockets, there's no intake material, and it depends strictly on ejecting most of its mass backwards. Speed is a boon but even ejecting the mass slower than the speed of surrounding air (or near-void) gives it thrust.
With jet, the momentum of air at the intake (which is zero, immobile air) must be lower than exhaust mix ejected backwards, and considering the mass of the jet fuel used is quite low comparing to mass of air used, the mass of the exhaust gas is not significantly higher than mass of intake air, so it must use higher speed to achieve higher momentum and thus thrust - so no matter how fast the plane moves, exhaust gas always moves backwards relative to static air - thus pushes against static air and as result creates a pressure pillow.
What REALLY annoys me is if they get more voice actors than lines. When you hear the same exact sentence repeated by three different people.
"You seem to be wounded. You should see a healer" delivered by a female orc husky voice, a stern guard, and a singing elf female, this is really horrible. Why can't they come up with some variations that would mean the same, or even ask the voice actors to improvise a little? How hard would it be to write variations of these lines, one per voice? I thought writing random dialogues for the characters is the cheapest part, and since each voice actor needs to read his/her sheet separately, why can't they be provided with different sheets?
A rocket engine works like you explained. A jet engine still uses air pressure as a "pillow to push against".
Yep, that would be okay if you took a ready-made car. But compiling is more like car assembly process. Compiling a program is like you tell what parts should go where, you add your engine and get it running smoothly.
In this case, you tell the engineers you want a mock-up frame of bare essentials to have this bare engine you provided started. You expect them to attach the starter motor, the power from the battery, ignition switch, some frame to attach it to, and a pipe to a bottle of fuel.
Instead, what you get is a car with a complete gearbox, electric installation, steering and brake system and pretty much all the basic essentials needed to drive (no extras like AC, airbags or ABS). You didn't ask for anything of that and you wanted to use the engine to power a stationary water pump and the whole "car stuff" really gets into the way.
...besides, high-level programmers often underestimate just how big a sector embedded programming is. The $IDIOTS_PET_LANGUAGE is for a PC. Now get me more RAM and better CPU for all the devices running embedded software, that are in my sight range as I look around:
- my cell phone.
- 6 different monitors (OSD doesn't happen magically. Something remembers the settings...)
- a videoserver
- 2 cheap switches
- a regulated power supply
- a heat-controlled soldering iron
- a regular phone
- 3 PC keyboards (hey, neither PS2 nor USB protocols happen by themselves)
- 3 computer mice (optical, meaning pretty advanced image analysis)
- my hand watch
- a battery charger
- a USB hub
- a security motion sensor
- an MP3 player
- a webcam
- a multimeter
- a car alarm remote
- a pendrive.
These all were programmed either in VHDL, Asembler, or C. The phone has some J2ME code too. Think of upgrading each of these devices so much that its firmware could be rewritten in, say, Perl. Or C#.
Also, think about how much embedded programming is in every PC. Each device controller has its own firmware... my bet is any average house contains more embedded programs (in embedded devices) than PC applications on the "family PC" and stored on media.
High-level programming languages are nice and have their place, but considering embedded "a niche not worthy of attention" is a bad mistake. The proportions between amounts of server:desktop:embedded software are much closer to 1:1:1 than most "high-level" programmers are willing to admit.
The iWorld in question, being a more lean and user-friendly variant of the World, created in only 4 days (compared to the original 6+1 of testing). Unfortunately, iWorld can have only one of gravity, electromagnetic, strong or weak force working at the same time. People living there say it doesn't bother them though.
It will, you just need to start off high enough. And it will fly downwards.
1.31 Mach.
Since it's a jet engine (pushing against the air), it would be the old "Plane on a treadmill" problem. Meaning it would drive off the treadmill.
...except if you enter sites with drive-by exploits, get spam email with virus that requires you to hover your mouse over the message title in Outlook to install, or some protocol you weren't even aware your computer used has a security hole and an IP scanner finds that port open on your box...
Sure most viruses use some blatant and crude social engineering to install, but there are these that don't even need user interaction to infect you.
The problem is, a couple of years ago, RAR released a new version (which gave it a lead in the industry in compression ratio for a brief time), incompatible with the older versions (old decompressors couldn't decompress stuff compressed with the new RAR). It took all the others between a few months and a few years to include support for it. 7zip being notoriously behind. So while it nominally supported ".rar", it lacked support for the "new RAR" for a couple of years.