We think that 1 soldier a day dying in Iraq is so bad, whereas that death rate is lower than the murder rate in Washington,D.C. or close to it.
You know, back in 2001 I used to argue that this 9/11 attack wasn't a big deal. If we make a conservative estimate of one 9/11 attack per year, we're looking at numbers comparable to swimming pool deaths. So we should spend as much money on this as we spend each year to keep people from drowning in swimming pools.
I didn't get very far with that argument. The quantitative risk in deaths per year isn't always the appropriate thing to be concerned with.
One soldier dying in Iraq IS bad. It's not that I think there's a risk of myself or someone I know dying in Iraq, and I'm more likely to be killed by a giant meteorite. But keep in mind that the figures reported by the media are the combat deaths. The number of noncombat deaths in Iraq is similar (jeeps flipping over, etc.). If you've noticed, not many people are making a big deal about the noncombat deaths compared to the combat deaths even though the risk assessment for both is about the same.
We expected the noncombat deaths. We were told to expect a smooth, orderly transfer of power, cheers from liberated Iraqis, lots of cheap oil, and a flowering of democracy across the region. In a large operation like that, you'd expect some car accidents, and friendly fire incidents. What you would not expect is a steady trickle of combat deaths. Each one underscores the fact that we were lied to.
The first thing I can think of is that antimatter electricity (positricity?) will flow in the opposite direction. All things that depend upon the charge of electricity, for example, say, magnetic attraction, will be reversed. Matter north would attract antimatter north, and repel antimatter south, and vice-versa.
Also, electromagnetism would be reversed. With matter, magnetic fields generated by an electric current follow the left-hand rule. Magnetic fields generated by a positric current would follow the right-hand rule.
A magnetic field generated by an antielectron current would point the opposite way than a field generated by an ordinary electron current, that's true. But that magnetic field will have the same effects on antimatter electrons as an ordinary field does on ordinary electrons. The field direction has reversed, but so have the charges, so the motion will be the same.
Electromagnetism is charge-symmetric. You can't determine whether you and the things in your lab are made of matter or antimatter by observing the way electrons move in a field created with a current of those same kind of electrons. In fact there is no electromagnetic experiment you can do at all to determine that. Field direction (and charge sign) are just conventions- they aren't true physical phenomena except in a relative sense. The "direction" of a field is completely determined by the decision Ben Franklin made when he picked one charge (the wrong one, too) and called it "positive".
SPAM is shoulder pork meat but the parent post was correct- it was originally marketed as "Hormel Spiced Ham". (The "spice" was salt.) Hormel decided they needed a catchier name, and the brother of a Hormel executive won $100 in a contest for suggesting "SPAM", short for "spiced ham".
Things like this used to happen all the time before companies stopped allowing employee family members to participate in contests.
and as such, it will change as time goes on when scientists "understand more".
So? At least science remains open to new evidence, even if it might contradict a book of superstition.
As an example, recently, scientists learned that fire, or the effects of fire, can effect the dating done by carbon-14 dating on certain matrials such as linen (carbon is addded to it).
It has been known for a long time that carbon dating does not yield correct results when applied to nonatmospheric carbon.
In other news, the cop that pulled me over today learned that a tree can fool a radar gun into reporting the wrong speed for my car. Clearly, the fact that a radar gun can be pointed at a tree means the radar gun is no good!
I am sure the age of the Universe will change--just like there view of when planets can form changed with new evidence.
The age of the universe cannot change. The reported age may change, but there's a subtle difference there.
What is virtually certain, however, is that the reported age will remain above 6000 years.
Science hasn't gotten much better than the days when people believed the world was flat.
I challenge you to produce any evidence to back up this ridiculous assertion you just made.
They make guesses and think it's true until what is expected to happen doesn't happen--like when nobody fell off the edge of the flat planet!
Who were these "scientists" that said the earth was flat? The earth has been known to be round for many centuries.
If this is an elastic collision, and the sail gains energy, then the photon must lose some energy. Where do you propose this energy comes from?
The photon's initial energy.
Clearly, the photon's velocity can't decrease. Hence the redshift.
That's the redshift from the elastic collision, not the redshift from the mirror's motion relative to the solar system. They are two different redshifts.
Not true. I'm sure you would not say this had the argument been based on conservation of momemtum, or conservation of mass/energy.
Usually it's obvious where momentum is going (energy is trickier to track down). And the cases where it isn't obvious sometimes turn out to be interesting phenomena, like neutrinos.
Thermodynamics, in comparision, is so abstract and so prone to misinterpretation that it becomes a reasonable question to ask for a direct mechanism. Often people make implicit assumptions, incorporate subtle errors, or use imprecise definitions in forming their logic. (Like in this case, the definition of a "heat engine".) Anyone who's ever heard the one about how "the Second Law of Thermodynamics disproves evolution" knows what I mean. And it's not as if the exact mechanism wouldn't be interesting here. Exactly where and how do the thermodynamics affect the situation? How do they manifest themselves?
No. In addition to conservation in momentum, in an elastic collision we have conservation of energy. If the photons were returned with the same energy (that is color, wavelength, frequency, etc.) the kinetic energy of the mirror could not change.
Yes, but the point is that they're not the same energy, because the sail has a finite mass. They will have a slightly redder color for having scattered off it. So the kinetic energy of the mirror can change and there is no problem.
A mirror moving away from the sun increases its speed and hence its energy, while a mirror moving towards the sun is slowed down so the energy diminishes. In the first case the light is redshifted (getting lower energy), while in the second case it is blueshifted (getting higher energy).
These are not connected statements. A force on the mirror exists even in absence of the type of redshift you are describing. As seen from its own reference frame, the mirror will experience a force from radiation pressure. This will happen whether the solar system frame observes a redshift or not.
There will be a miniscule "redshift" observed in the mirror frame, from elastic recoil, and this is what powers the sail. The additional redshift you're talking about is seen when you move from the mirror frame to the solar system frame. That isn't the same redshift attributable to the force on the mirror. If it were, then the motion would be affected by your choice of coordinate system. So a mirror starting at rest with respect to the sun will still work fine.
Actually the redshift is misleading and completely irrelevant anyway. A sail will work fine with zero redshift.
The point is that the interaction between the sail and the photons is characteristic of an elastic collision, exchanging momentum, with an associated increase in entropy. It's a trivial and easily understood interaction. There's just no hole here that you can poke a thermodynamic argument into. If some guy wants to convince us that this is a "heat engine" and then derive the fact that it can't work because of general thermodynamic principles, the onus is on him to explain where the thing breaks down in a specific, non-abstract way. So far, it seems he hasn't convinced everybody that the sun+sail system even fits the definition of a heat engine in the first place.
I am not sure what you mean by "intermediate temperature".
I was referring to the equilibrium temperature of a blackbody in that position, which meets the requirement that its radiating surfaces are all at the same temperature. This is almost true for the earth because of the atmosphere, and by a solar sail because it is so thin. (It was just for sake of argument, to demonstrate that the radiated energy may in general have zero overall momentum in the mirror frame. This isn't a real requirement.)
so the mirror sees a Planck spectrum of radiation at 6000k in one side
...within the solid angle in which the sun appears in its sky on that side. That means the "intermediate temperature" would in fact be 300K as we have found out by experiment (to the approximation that the Earth is a blackbody).
It was obvious from the original story that the guy was wrong. He made fundamental errors that you could spot after a freshman level course in physics 101. The rebuttal doesn't really address the specific flaws in the original paper- it has the character of "ahh this is nonsense" which it is. But the original paper has some obvious conceptual errors:
But what will be the performance of the mirror as a heat engine? If the mirror receives heat energy from the Sun and converts some of this into free energy, namely the kinetic energy of its motion, it falls into the strict definition of a heat engine, and Carnot's rule defining the maximum efficiency for this energy conversion must apply. We can determine the incoming temperature of the radiation by measuring the temperature an absorbing (black) body would reach when exposed to the radiation being sent to the mirror, and the temperature a black body would reach exposed to the outgoing radiation from the mirror, both measurements carried out in common motion with the mirror. Carnot's rule would then give the maximum efficiency as that fraction of the heat flow trough the mirror, given by the difference of the two temperatures, divided by the input temperature. It would be that fraction of the heat flow that could maximally appear as kinetic energy gained by the mass of the mirror. If this was a perfect mirror, the two temperatures will be the same, and it follows that the mirror cannot act as a heat engine at all: no free energy can be obtained from the light. The proposed solar sail cannot be accelerated by sunlight.
The two temperatures are NOT the same. They are slightly different. The mirror is not infinitely massive, so in the mirror's own reference frame the photons reflecting from the mirror have a lower energy / longer wavelength after their elastic collision with it- the mirror receives a small bit of momentum from each photon in the collision. And in the sun's frame, the mirror is receding and the reflected photons are doppler shifted. He can't assume that the incident and reflected energy are the same and run off making derivations from that. They are extremely close, but the difference between them is not zero like he assumes.
Would it be better to place a black sheet there instead of a mirror-faced one? Unlike the mirror, this could absorb energy and the momentum associated with that. But it would do this only from the moment of its exposure until it reached thermal equilibrium with the available radiation. Then energy absorption would cease, and with that the delivery of momentum to the sheet would also cease. For any lightweight sheet, this time would be only seconds.
Does he even realize the sun is a point source? The sun shines on one side of the sail, not both sides! One side is exposed to radiation with a temperature of 300K. The other side sees only 3K radiation. The sail temperature will rise to some intermediate temperature between 3 and 300K and reach thermal equilibrium with all available radiation. So what? This means nothing for momentum transfer! Once it reaches thermal equilibrium, the sail is receiving X watts of radiation coming from one direction, and radiating X watts thermally in all directions! While the wattages are the same for both, the radiated energy has no overall momentum, while the incoming energy has a very definite momentum. The point isn't to heat the sail, it's to move it. He seems to be confusing the sail's kinetic energy of motion with its internal thermal energy.
The rebuttal is very sparing. I think it would probably have been more vicious if its author didn't "know Prof. Gold well" and didn't have any reservations about embarrassing him.
Yeah but that isn't relevant. His point went straight over your head.
Just because I am visible to you over a network doesn't mean I am obligated to do business with you. The nationality independence of the web means Turkish people can buy things off Turkish sites, Japanese people can do business on Japanese sites, etc. and it works well for everybody. It doesn't imply that everyone doing business on the Internet is responsible for servicing customers from anywhere in the rest of the world.
People might have a whole bunch of reasons for limiting service to locations closer to themselves. There could be all sorts of paperwork and infrastructure that might not be properly set up to handle the transaction, or the associated overhead may overwhelm the profits from an extended market.
I don't understand where people come up with some of these strange beliefs about the Internet that they seem to have. How is it in principle any different from the global telephone network? For some reason, nobody has any common sense regarding the web, but phones don't seem to confuse people.
If I have a pizzeria in New York City and I install a phone, and you call me from Los Angeles trying to order a pepperoni pizza, I'm going to hang up on you. Having a phone number that is accessible to you doesn't mean I owe you my business. Even though you can dial my number and easily get in touch with me, there might be other problems, like the difficulty in getting a physical object like a pizza to you. The ease of the phone call hardly enters into it. "Why aren't you calling pizzerias in Los Angeles?" I'd ask, before hanging up. And that would be a reasonable response. How is having a web site any different? It isn't.
Oy- is that what you think the good thing about JSP is? Getting rid of out.printlns?
Frankly I'd rather work with a servlet that has out.printlns. At least you can figure out a way to abstract them away with some sort of template mechanism. I work with a large servlet based application and I never even see the out.printlns. In fact, I rarely even see the servlet. All the page layout stuff is contained in special files that are edited by design people. We have a special syntax that the servlet parses and replaces with chunks of calculated data. (And that's all the servlet should do. Unless it's a really trivial application, you should immediately abstract all your hard work away from that level- a servlet or JSP should not be among the files you're editing on a daily basis as a developer. Its job should be simple- to handle the interaction with the web server, and that's it.)
You could do that with a JSP and the JSP bean syntax, I guess, but it seems nobody does. JSP makes it too easy for people to write things that are basically servlets with the out.printlns stripped and surrounded with %> and <% punctuation. There's code all over the place doing loops, SELECTs, try/catch/finally blocks etc. and once in a while you see a line like %>Welcome to XXYZY Industries!%< While this may look nicer and seem straightforward to you as a developer when you start out, often you will find that the artsy HTML people are mucking with the same files and will decide that this block of stuff on the left would look better on the right, and when the code moves with it, sometimes they will try to patch it up so it looks to them like it will still work. The result can only be described as sad.
Everyone knew from the beginning that JSP was Sun's copycat reaction to ASP, which became popular for some strange reason but is also riddled with these problems. It thoroughly mixes logic and presentation. This is OK if you're in a hurry, but if you have the time and ability to come up with something that will work better, you should just stick to servlets- which is what JSPs are pretending not to be anyway. Simplicity is a virtue.
"Anti-Patriot" has taken on a new meaning lately. It used to be an English phrase, and it meant antipathy or disobedience toward one's country. Now, "anti-patriot" and "anti-patriotic" are Newspeak phrases. They merely imply that. According to current usage, they refer to disagreement with or opposition to the Bush Administration and its political allies.
There have been a lot of scary people asserting themselves as being the only "patriots", so no, "anti-patriot" no longer scares me. Once you realize how people have been playing games with the language you were taught in grade school, you realize how much the things you learned about patriotism when you were growing up no longer apply.
"Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism." How stupid are we to swallow this shit? I'm sure they could have made an acronym to spell "QUISLING" or "TRAITOR" if they wanted, but smart traitors know to drape the flag around themselves and everything they do. When they introduce the anti-subversion bill, it's going to have an acronym like "MOM" or "APPLEPIE".
Comparing prescription drugs to a standard commodity such as gold by weight is likely to produce very skewed results, for two reasons. First, gold is a commodity. You can buy it from anybody and there is no patent-protected monopoly on it. Second, the masses of effective doses for most pharmaceuticals are extrememly variable and can vary by something like six orders of magnitude from one compound to another.
To get really ridiculous, why not talk about the cost of software per gram? It approaches either positive or negative infinity, depending on whether a blank CD gains or loses mass when they stamp it.
Agreed... I think if you showed this guy a windmill he'd argue that it couldn't exist and he'd go into explaining why it won't ever turn.
The flaws in his argument are right there on the page:
But what will be the performance of the mirror as a heat engine? If the mirror receives heat energy from the Sun and converts some of this into free energy, namely the kinetic energy of its motion, it falls into the strict definition of a heat engine, and Carnot's rule defining the maximum efficiency for this energy conversion must apply. We can determine the incoming temperature of the radiation by measuring the temperature an absorbing (black) body would reach when exposed to the radiation being sent to the mirror, and the temperature a black body would reach exposed to the outgoing radiation from the mirror, both measurements carried out in common motion with the mirror. Carnot's rule would then give the maximum efficiency as that fraction of the heat flow trough the mirror, given by the difference of the two temperatures, divided by the input temperature. It would be that fraction of the heat flow that could maximally appear as kinetic energy gained by the mass of the mirror. If this was a perfect mirror, the two temperatures will be the same, and it follows that the mirror cannot act as a heat engine at all: no free energy can be obtained from the light. The proposed solar sail cannot be accelerated by sunlight.
The bold sentence has two flaws. The first is a minor grammatical point- he mixes tenses and should be using the subjunctive ("If this were a perfect mirror..."). But that's just a smartass observation.
The reason it's wrong is that the two temperatures are NOT the same. They are different. Unless the mirror is infinitely massive, the photons will lose energy from their elastic collision with it, and recoil with a slightly longer wavelength. This is true in the mirror's own reference frame. The difference in radiation temperatures between incoming and reflected radiation is where the mirror gets its momentum. He implicitly assumes that the differences in the two temperatures are zero. No wonder he can't get his solar sail to work!
Would it be better to place a black sheet there instead of a mirror-faced one? Unlike the mirror, this could absorb energy and the momentum associated with that. But it would do this only from the moment of its exposure until it reached thermal equilibrium with the available radiation. Then energy absorption would cease, and with that the delivery of momentum to the sheet would also cease. For any lightweight sheet, this time would be only seconds.
This would be a rather elegant proof that you can't construct a sail powered by cosmic microwave background radiation. Unfortunately, he thinks he's talking about the sun, which is a point source. The Sun shines on one side of the sail, not both sides! One side is exposed to radiation with a temperature of 300K. The other side sees only 3K radiation. The sail temperature will rise to some intermediate temperature between 3 and 300K and reach thermal equilibrium with all available radiation. But this means nothing for momentum transfer! Once it reaches thermal equilibrium, the sail is receiving X watts of radiation coming from one direction, and radiating X watts thermally in all directions! While the wattages are the same for both, the radiated energy has no overall momentum, while the incoming energy has a very definite momentum. He seems to be confusing the sail's kinetic energy of motion with its internal thermal energy.
And this guy is from Cornell! I only have a B.A. from Rutgers. Man, I wish I'd gone for the PhD instead of trying to get into med school.
I see where he's coming from. Here's how you would set it up as a perpetual motion machine.
Get two solar sail ships facing away from each other with focused perfect mirrors. Set off a light bomb in between them. Watch them accelerate forever without any additional energy imparted to the system as the photons from the light bomb bounce back and forth between them without loss of energy.
First of all, as they recede, the light loses energy upon each reflection because of the doppler shift. So the wavelength gets longer and longer. Second, this is not a reversible engine. How do the mirrors come back to each other so you can do it again?
The same thing happens with the solar sail. I read Gold's paper and don't see how this guy's argument applies. A solar sail system doesn't constitute a perpetual motion machine. You could construct something with a cyclic process, maybe. The solar sail unfurls inside the orbit of Mars until the sun pushes it away with radiation. Then as it passes Mars, the sail is folded up, and you wait for the sun's gravity to pull it back in again. Then you could connect a long chain to it, and perhaps make it do work as it travels in and out.
And in theory, this will work. According to Gold's paper, this would be a perpetual motion machine. But it isn't. "Perpetual" means "forever". It doesn't mean "until after I'm dead". The sun is running down!
A real perpetual motion machine runs perpetually. This one is going to work for a few billion years and then stop. People always overlook the fact that the entropy of the sun is increasing as heavier elements build up in its core!
If you replaced the sun with a giant magic lamp that would keep burning forever, then he would have an argument. Yeah, the magic lamp + solar sail system constitutes a perpetual motion machine, and the place where it doesn't work is the magic lamp which keeps shining with no loss in entropy. Real suns don't do that. He is making the same damn mistake that the creationists make when they yap about how the Second Law of Thermodynamics forbids evolution- ignorant of the fact that a local loss of entropy on earth is more than counterbalanced by the entropy gain within the sun. The sun isn't going to shine perpetually.
Your solution does not solve the problem. Sure, YOU aren't seeing the spam physically with your eyes, but it is still coming, consuming bandwidth and ISP resources. From the ISP's point of view, once the email has been handled and forwarded to the end user, the damage is done. Client filtering makes little difference afterwards. What is the signal to noise ratio in your private mailbox? How many spams arrive per legitimate email? 1000? 10000?
it's not a big deal for ISPs to implement the same service on their mail servers.
Ha! Have you ever done tech support at an ISP? They'll have to hire 400 Bombay phone bank workers just to field the phone calls from people who can't understand why they're not getting email from their grandchildren.
Don't you think that someone who has the resources that Intel has would not need to resort to this? That is, if their sys admins are any good. Find this whole thing a bit odd.
Well, you're looking at this from a system administrator's perspective (i.e. a techie's perspective). That is, you'd want to find out how it happened, and set up some sort of filter in the firewall or SMTP server so it won't happen again. At that point you will consider the problem effectively solved.
Intel's management and legal department clearly don't think that's enough. From their viewpoint, preventing similar emails from arriving is merely a first step. Once that's been done, problems still remain that need to be rectified. After all, this !@#$ smartass has just gotten away with using our infrastructure to defame us in front of all our underlings! He must be smashed, to serve as a warning to others. You've solved the technical problems, but the social problems remain, and they can be made into legal problems for greater effect.
When this happened at the company I worked at, no technical remedies were taken (we didn't bother). The "social remedies" consisted of a few debunkments and jokes at the weekly company meeting, and that was it. No legal action was even discussed. Small companies are great to work for. I thank my lucky stars every day I don't work for a company like Intel.
A better analogy would be putting a "NO TRESSPASSING" sticker on your mailbox. Remember, the mailbox's intended use is a receptacle for incoming mail. (Note that this does not extend to flagrant abuse of the mailbox, say by stuffing it with thousands of flyers, especially if measures have been taken to prevent mass emails from clogging the mailbox. That does not fall within intended use.) The mailman arrives, and puts ten letters in the mailbox. I read nine letters which concern my usual business. The tenth distresses me emotionally- so I sue the sender, claiming that they have trespassed my mailbox! But the sender has used it as intended, the mailbox functioned properly as a receptacle for the letter, and no damage was done to it. You cannot define the intended use of your mailbox as "a receptacle only for letters that you like".
Can you imagine the legal consequences if this summary judgment were allowed to stand? Sending even a single handwritten email to anybody would open you up to a lawsuit for "mailbox trespass"- if the recipient decided he doesn't like you or your message, he could sue you for trespass and cite this case as precedent!
It's a good thing Intel was told to get bent. They may have had a case if they built their case differently (like, where did this guy get everyone's email addresses?) but the precedent they sought to create would have been a disaster. What is truly scary is the fact that someone in the lower courts actually granted Intel's motion for summary judgment.
I got one once. One of our sales guys was secretly trying to get his own competing startup company going (after the boom was over- mistake #1), but he accidentally submitted his cellphone bill to the company for reimbursement (mistake #2) and they noticed the calls. When it hit the fan, he quit and sent a "swan song" email to the company and badmouthed a whole bunch of people in it (mistake #3). Most of us didn't know a thing about it until we came in one morning, checked our mail, and found the "fond farewell" in our inboxes. It didn't advertise any open positions in his new company (I guess that would make it commercial speech). It was just an emotional rant, with some badmouthing of a few specific individuals. Clearly he wasn't exercising good judgment when he sent it. But it blew over rather quickly. Nobody wasted too much time talking about it, other than to remark "well I guess X isn't working here anymore."
I've never deleted that email. Every so often I open it again just to imagine the balls it must take to send something like that. If a court were to rule that such an email constituted "electronic trespass", I would be very upset. That having been said, I cannot stress enough that SENDING AN EMAIL LIKE THAT IS A MISTAKE. If you're ever tempted to do it, DON'T. Once you send it they'll be talking about what an idiot you are forever. If you're in a small industry, you'll forever be meeting people who have heard about it.
He got work with another company after his startup failed. Ironically, we signed a deal with that company recently, so he'll be selling our products again. When he's not stabbing you in the back, he's a pretty good sales guy.
You miss the point - why do you connect the company selling a product with the spammer advertising it?
If that connection is made, then some companies are in trouble. One is Symantec. I got plenty of spam offering Symantec products in a notorious spam campaign that happened some time ago. Recently a new campaign started where you get a too-good-to-be-true offer on Symantec products. Except the download isn't from Symantec, it comes from the spammer- meaning you could be running a trojan.
Reminds me of a nasty one I got a few weeks ago that claimed to be from "update-notification@paypal.com":
Dear PayPal Customer
This e-mail is the notification of recent innovations taken by PayPal to detect inactive customers and non-functioning mailboxes.
The inactive customers are subject to restriction and removal in the next 3 months.
Please confirm your email address and credit card information by logging in to your PayPal account using the form below:
Email address: _____________ Password: ___________ Full Name: ___________ Credit Card #: ___________ Exp. Date(mm/yyyy): __________ ATM PIN (For Bank Verification)#: ____
[Log In] This notification expires September 31, 2003 Thanks for using PayPal! This PayPal notification was sent to your mailbox. Your PayPal account is set up to receive the PayPal Periodical newsletter and product updates when you create your account. To modify your notification preferences and unsubscribe, go to https://www.paypal.com/PREFS-NOTI and log in to your account. Changes to your preferences may take several days to be reflected in our mailings. Replies to this email will not be processed.
It's obvious you don't contribute anything to the world. Your country probably doesn't either, unless you're a traitor the U.S. and are posting from within its borders. If so, why don't you move to france so you can get buggered by other smelly people that think like you?
He can move to any other country in the world, really. They feel the same everywhere now. France was just the one with the balls to speak up.
I'm going to a conference there in two months. If you give me the money, I'll buy a bottle of French wine and pour it down the gutter for you.
This is how I would do it. During the period where only subscribers can see the story, Slashdot would quickly build a cache of the site. Then, every minute, it would send a small HTTP request (like for robots.txt) and keep track of the response time. Maybe it could even generate a small postage-stamp sized log-scale graph of the response time as a PNG and insert or link to it from the front page, so you'd know how the site is holding up before clicking on the links. Once the response time has increased by a certain factor, the bot assumes the site has crashed under load. It then automagically posts a comment to the story with the subject "uhhh... it seems to be slashdotted" and then spits the site (stripped of HTML) into the comment body. This would save karma whores a lot of time.
Slashdot Mirror
We think that 1 soldier a day dying in Iraq is so bad, whereas that death rate is lower than the murder rate in Washington,D.C. or close to it.
You know, back in 2001 I used to argue that this 9/11 attack wasn't a big deal. If we make a conservative estimate of one 9/11 attack per year, we're looking at numbers comparable to swimming pool deaths. So we should spend as much money on this as we spend each year to keep people from drowning in swimming pools.
I didn't get very far with that argument. The quantitative risk in deaths per year isn't always the appropriate thing to be concerned with.
One soldier dying in Iraq IS bad. It's not that I think there's a risk of myself or someone I know dying in Iraq, and I'm more likely to be killed by a giant meteorite. But keep in mind that the figures reported by the media are the combat deaths. The number of noncombat deaths in Iraq is similar (jeeps flipping over, etc.). If you've noticed, not many people are making a big deal about the noncombat deaths compared to the combat deaths even though the risk assessment for both is about the same.
We expected the noncombat deaths. We were told to expect a smooth, orderly transfer of power, cheers from liberated Iraqis, lots of cheap oil, and a flowering of democracy across the region. In a large operation like that, you'd expect some car accidents, and friendly fire incidents. What you would not expect is a steady trickle of combat deaths. Each one underscores the fact that we were lied to.
The first thing I can think of is that antimatter electricity (positricity?) will flow in the opposite direction. All things that depend upon the charge of electricity, for example, say, magnetic attraction, will be reversed. Matter north would attract antimatter north, and repel antimatter south, and vice-versa.
Also, electromagnetism would be reversed. With matter, magnetic fields generated by an electric current follow the left-hand rule. Magnetic fields generated by a positric current would follow the right-hand rule.
A magnetic field generated by an antielectron current would point the opposite way than a field generated by an ordinary electron current, that's true. But that magnetic field will have the same effects on antimatter electrons as an ordinary field does on ordinary electrons. The field direction has reversed, but so have the charges, so the motion will be the same.
Electromagnetism is charge-symmetric. You can't determine whether you and the things in your lab are made of matter or antimatter by observing the way electrons move in a field created with a current of those same kind of electrons. In fact there is no electromagnetic experiment you can do at all to determine that. Field direction (and charge sign) are just conventions- they aren't true physical phenomena except in a relative sense. The "direction" of a field is completely determined by the decision Ben Franklin made when he picked one charge (the wrong one, too) and called it "positive".
SPAM is shoulder pork meat but the parent post was correct- it was originally marketed as "Hormel Spiced Ham". (The "spice" was salt.) Hormel decided they needed a catchier name, and the brother of a Hormel executive won $100 in a contest for suggesting "SPAM", short for "spiced ham".
Things like this used to happen all the time before companies stopped allowing employee family members to participate in contests.
OK, I'll bite, since I'm using 3.0 and don't feel like using the early access build.
What does it have in store that makes you go "Wow!"?
The age of the universe is just speculation,
Ummm... not really...
and as such, it will change as time goes on when scientists "understand more".
So? At least science remains open to new evidence, even if it might contradict a book of superstition.
As an example, recently, scientists learned that fire, or the effects of fire, can effect the dating done by carbon-14 dating on certain matrials such as linen (carbon is addded to it).
It has been known for a long time that carbon dating does not yield correct results when applied to nonatmospheric carbon.
In other news, the cop that pulled me over today learned that a tree can fool a radar gun into reporting the wrong speed for my car. Clearly, the fact that a radar gun can be pointed at a tree means the radar gun is no good!
I am sure the age of the Universe will change--just like there view of when planets can form changed with new evidence.
The age of the universe cannot change. The reported age may change, but there's a subtle difference there.
What is virtually certain, however, is that the reported age will remain above 6000 years.
Science hasn't gotten much better than the days when people believed the world was flat.
I challenge you to produce any evidence to back up this ridiculous assertion you just made.
They make guesses and think it's true until what is expected to happen doesn't happen--like when nobody fell off the edge of the flat planet!
Who were these "scientists" that said the earth was flat? The earth has been known to be round for many centuries.
If this is an elastic collision, and the sail gains energy, then the photon must lose some energy. Where do you propose this energy comes from?
The photon's initial energy.
Clearly, the photon's velocity can't decrease. Hence the redshift.
That's the redshift from the elastic collision, not the redshift from the mirror's motion relative to the solar system. They are two different redshifts.
Not true. I'm sure you would not say this had the argument been based on conservation of momemtum, or conservation of mass/energy.
Usually it's obvious where momentum is going (energy is trickier to track down). And the cases where it isn't obvious sometimes turn out to be interesting phenomena, like neutrinos.
Thermodynamics, in comparision, is so abstract and so prone to misinterpretation that it becomes a reasonable question to ask for a direct mechanism. Often people make implicit assumptions, incorporate subtle errors, or use imprecise definitions in forming their logic. (Like in this case, the definition of a "heat engine".) Anyone who's ever heard the one about how "the Second Law of Thermodynamics disproves evolution" knows what I mean. And it's not as if the exact mechanism wouldn't be interesting here. Exactly where and how do the thermodynamics affect the situation? How do they manifest themselves?
No. In addition to conservation in momentum, in an elastic collision we have conservation of energy. If the photons were returned with the same energy (that is color, wavelength, frequency, etc.) the kinetic energy of the mirror could not change.
Yes, but the point is that they're not the same energy, because the sail has a finite mass. They will have a slightly redder color for having scattered off it. So the kinetic energy of the mirror can change and there is no problem.
A mirror moving away from the sun increases its speed and hence its energy, while a mirror moving towards the sun is slowed down so the energy diminishes. In the first case the light is redshifted (getting lower energy), while in the second case it is blueshifted (getting higher energy).
These are not connected statements. A force on the mirror exists even in absence of the type of redshift you are describing. As seen from its own reference frame, the mirror will experience a force from radiation pressure. This will happen whether the solar system frame observes a redshift or not.
There will be a miniscule "redshift" observed in the mirror frame, from elastic recoil, and this is what powers the sail. The additional redshift you're talking about is seen when you move from the mirror frame to the solar system frame. That isn't the same redshift attributable to the force on the mirror. If it were, then the motion would be affected by your choice of coordinate system. So a mirror starting at rest with respect to the sun will still work fine.
Actually the redshift is misleading and completely irrelevant anyway. A sail will work fine with zero redshift.
The point is that the interaction between the sail and the photons is characteristic of an elastic collision, exchanging momentum, with an associated increase in entropy. It's a trivial and easily understood interaction. There's just no hole here that you can poke a thermodynamic argument into. If some guy wants to convince us that this is a "heat engine" and then derive the fact that it can't work because of general thermodynamic principles, the onus is on him to explain where the thing breaks down in a specific, non-abstract way. So far, it seems he hasn't convinced everybody that the sun+sail system even fits the definition of a heat engine in the first place.
I am not sure what you mean by "intermediate temperature".
I was referring to the equilibrium temperature of a blackbody in that position, which meets the requirement that its radiating surfaces are all at the same temperature. This is almost true for the earth because of the atmosphere, and by a solar sail because it is so thin. (It was just for sake of argument, to demonstrate that the radiated energy may in general have zero overall momentum in the mirror frame. This isn't a real requirement.)
so the mirror sees a Planck spectrum of radiation at 6000k in one side
...within the solid angle in which the sun appears in its sky on that side. That means the "intermediate temperature" would in fact be 300K as we have found out by experiment (to the approximation that the Earth is a blackbody).
It was obvious from the original story that the guy was wrong. He made fundamental errors that you could spot after a freshman level course in physics 101. The rebuttal doesn't really address the specific flaws in the original paper- it has the character of "ahh this is nonsense" which it is. But the original paper has some obvious conceptual errors:
But what will be the performance of the mirror as a heat engine? If the mirror receives heat energy from the Sun and converts some of this into free energy, namely the kinetic energy of its motion, it falls into the strict definition of a heat engine, and Carnot's rule defining the maximum efficiency for this energy conversion must apply. We can determine the incoming temperature of the radiation by measuring the temperature an absorbing (black) body would reach when exposed to the radiation being sent to the mirror, and the temperature a black body would reach exposed to the outgoing radiation from the mirror, both measurements carried out in common motion with the mirror. Carnot's rule would then give the maximum efficiency as that fraction of the heat flow trough the mirror, given by the difference of the two temperatures, divided by the input temperature. It would be that fraction of the heat flow that could maximally appear as kinetic energy gained by the mass of the mirror. If this was a perfect mirror, the two temperatures will be the same, and it follows that the mirror cannot act as a heat engine at all: no free energy can be obtained from the light. The proposed solar sail cannot be accelerated by sunlight.
The two temperatures are NOT the same. They are slightly different. The mirror is not infinitely massive, so in the mirror's own reference frame the photons reflecting from the mirror have a lower energy / longer wavelength after their elastic collision with it- the mirror receives a small bit of momentum from each photon in the collision. And in the sun's frame, the mirror is receding and the reflected photons are doppler shifted. He can't assume that the incident and reflected energy are the same and run off making derivations from that. They are extremely close, but the difference between them is not zero like he assumes.
Would it be better to place a black sheet there instead of a mirror-faced one? Unlike the mirror, this could absorb energy and the momentum associated with that. But it would do this only from the moment of its exposure until it reached thermal equilibrium with the available radiation. Then energy absorption would cease, and with that the delivery of momentum to the sheet would also cease. For any lightweight sheet, this time would be only seconds.
Does he even realize the sun is a point source? The sun shines on one side of the sail, not both sides! One side is exposed to radiation with a temperature of 300K. The other side sees only 3K radiation. The sail temperature will rise to some intermediate temperature between 3 and 300K and reach thermal equilibrium with all available radiation. So what? This means nothing for momentum transfer! Once it reaches thermal equilibrium, the sail is receiving X watts of radiation coming from one direction, and radiating X watts thermally in all directions! While the wattages are the same for both, the radiated energy has no overall momentum, while the incoming energy has a very definite momentum. The point isn't to heat the sail, it's to move it. He seems to be confusing the sail's kinetic energy of motion with its internal thermal energy.
The rebuttal is very sparing. I think it would probably have been more vicious if its author didn't "know Prof. Gold well" and didn't have any reservations about embarrassing him.
Yeah but that isn't relevant. His point went straight over your head.
Just because I am visible to you over a network doesn't mean I am obligated to do business with you. The nationality independence of the web means Turkish people can buy things off Turkish sites, Japanese people can do business on Japanese sites, etc. and it works well for everybody. It doesn't imply that everyone doing business on the Internet is responsible for servicing customers from anywhere in the rest of the world.
People might have a whole bunch of reasons for limiting service to locations closer to themselves. There could be all sorts of paperwork and infrastructure that might not be properly set up to handle the transaction, or the associated overhead may overwhelm the profits from an extended market.
I don't understand where people come up with some of these strange beliefs about the Internet that they seem to have. How is it in principle any different from the global telephone network? For some reason, nobody has any common sense regarding the web, but phones don't seem to confuse people.
If I have a pizzeria in New York City and I install a phone, and you call me from Los Angeles trying to order a pepperoni pizza, I'm going to hang up on you. Having a phone number that is accessible to you doesn't mean I owe you my business. Even though you can dial my number and easily get in touch with me, there might be other problems, like the difficulty in getting a physical object like a pizza to you. The ease of the phone call hardly enters into it. "Why aren't you calling pizzerias in Los Angeles?" I'd ask, before hanging up. And that would be a reasonable response. How is having a web site any different? It isn't.
Oy- is that what you think the good thing about JSP is? Getting rid of out.printlns?
Frankly I'd rather work with a servlet that has out.printlns. At least you can figure out a way to abstract them away with some sort of template mechanism. I work with a large servlet based application and I never even see the out.printlns. In fact, I rarely even see the servlet. All the page layout stuff is contained in special files that are edited by design people. We have a special syntax that the servlet parses and replaces with chunks of calculated data. (And that's all the servlet should do. Unless it's a really trivial application, you should immediately abstract all your hard work away from that level- a servlet or JSP should not be among the files you're editing on a daily basis as a developer. Its job should be simple- to handle the interaction with the web server, and that's it.)
You could do that with a JSP and the JSP bean syntax, I guess, but it seems nobody does. JSP makes it too easy for people to write things that are basically servlets with the out.printlns stripped and surrounded with %> and <% punctuation. There's code all over the place doing loops, SELECTs, try/catch/finally blocks etc. and once in a while you see a line like %>Welcome to XXYZY Industries!%< While this may look nicer and seem straightforward to you as a developer when you start out, often you will find that the artsy HTML people are mucking with the same files and will decide that this block of stuff on the left would look better on the right, and when the code moves with it, sometimes they will try to patch it up so it looks to them like it will still work. The result can only be described as sad.
Everyone knew from the beginning that JSP was Sun's copycat reaction to ASP, which became popular for some strange reason but is also riddled with these problems. It thoroughly mixes logic and presentation. This is OK if you're in a hurry, but if you have the time and ability to come up with something that will work better, you should just stick to servlets- which is what JSPs are pretending not to be anyway. Simplicity is a virtue.
"Anti-Patriot" has taken on a new meaning lately. It used to be an English phrase, and it meant antipathy or disobedience toward one's country. Now, "anti-patriot" and "anti-patriotic" are Newspeak phrases. They merely imply that. According to current usage, they refer to disagreement with or opposition to the Bush Administration and its political allies.
There have been a lot of scary people asserting themselves as being the only "patriots", so no, "anti-patriot" no longer scares me. Once you realize how people have been playing games with the language you were taught in grade school, you realize how much the things you learned about patriotism when you were growing up no longer apply.
"Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism." How stupid are we to swallow this shit? I'm sure they could have made an acronym to spell "QUISLING" or "TRAITOR" if they wanted, but smart traitors know to drape the flag around themselves and everything they do. When they introduce the anti-subversion bill, it's going to have an acronym like "MOM" or "APPLEPIE".
Lamely replying to my own post:
The difference in radiation temperatures between incoming and reflected radiation is where the mirror gets its momentum.
This is not even required. A reflected photon will always impart a momentum of 2h*mu/c on the mirror. Always hit "Preview".
Comparing prescription drugs to a standard commodity such as gold by weight is likely to produce very skewed results, for two reasons. First, gold is a commodity. You can buy it from anybody and there is no patent-protected monopoly on it. Second, the masses of effective doses for most pharmaceuticals are extrememly variable and can vary by something like six orders of magnitude from one compound to another.
To get really ridiculous, why not talk about the cost of software per gram? It approaches either positive or negative infinity, depending on whether a blank CD gains or loses mass when they stamp it.
Agreed... I think if you showed this guy a windmill he'd argue that it couldn't exist and he'd go into explaining why it won't ever turn.
The flaws in his argument are right there on the page:
But what will be the performance of the mirror as a heat engine? If the mirror receives heat energy from the Sun and converts some of this into free energy, namely the kinetic energy of its motion, it falls into the strict definition of a heat engine, and Carnot's rule defining the maximum efficiency for this energy conversion must apply. We can determine the incoming temperature of the radiation by measuring the temperature an absorbing (black) body would reach when exposed to the radiation being sent to the mirror, and the temperature a black body would reach exposed to the outgoing radiation from the mirror, both measurements carried out in common motion with the mirror. Carnot's rule would then give the maximum efficiency as that fraction of the heat flow trough the mirror, given by the difference of the two temperatures, divided by the input temperature. It would be that fraction of the heat flow that could maximally appear as kinetic energy gained by the mass of the mirror. If this was a perfect mirror, the two temperatures will be the same, and it follows that the mirror cannot act as a heat engine at all: no free energy can be obtained from the light. The proposed solar sail cannot be accelerated by sunlight.
The bold sentence has two flaws. The first is a minor grammatical point- he mixes tenses and should be using the subjunctive ("If this were a perfect mirror..."). But that's just a smartass observation.
The reason it's wrong is that the two temperatures are NOT the same. They are different. Unless the mirror is infinitely massive, the photons will lose energy from their elastic collision with it, and recoil with a slightly longer wavelength. This is true in the mirror's own reference frame. The difference in radiation temperatures between incoming and reflected radiation is where the mirror gets its momentum. He implicitly assumes that the differences in the two temperatures are zero. No wonder he can't get his solar sail to work!
Would it be better to place a black sheet there instead of a mirror-faced one? Unlike the mirror, this could absorb energy and the momentum associated with that. But it would do this only from the moment of its exposure until it reached thermal equilibrium with the available radiation. Then energy absorption would cease, and with that the delivery of momentum to the sheet would also cease. For any lightweight sheet, this time would be only seconds.
This would be a rather elegant proof that you can't construct a sail powered by cosmic microwave background radiation. Unfortunately, he thinks he's talking about the sun, which is a point source. The Sun shines on one side of the sail, not both sides! One side is exposed to radiation with a temperature of 300K. The other side sees only 3K radiation. The sail temperature will rise to some intermediate temperature between 3 and 300K and reach thermal equilibrium with all available radiation. But this means nothing for momentum transfer! Once it reaches thermal equilibrium, the sail is receiving X watts of radiation coming from one direction, and radiating X watts thermally in all directions! While the wattages are the same for both, the radiated energy has no overall momentum, while the incoming energy has a very definite momentum. He seems to be confusing the sail's kinetic energy of motion with its internal thermal energy.
And this guy is from Cornell! I only have a B.A. from Rutgers. Man, I wish I'd gone for the PhD instead of trying to get into med school.
I see where he's coming from. Here's how you would set it up as a perpetual motion machine.
Get two solar sail ships facing away from each other with focused perfect mirrors. Set off a light bomb in between them. Watch them accelerate forever without any additional energy imparted to the system as the photons from the light bomb bounce back and forth between them without loss of energy.
First of all, as they recede, the light loses energy upon each reflection because of the doppler shift. So the wavelength gets longer and longer. Second, this is not a reversible engine. How do the mirrors come back to each other so you can do it again?
The same thing happens with the solar sail. I read Gold's paper and don't see how this guy's argument applies. A solar sail system doesn't constitute a perpetual motion machine. You could construct something with a cyclic process, maybe. The solar sail unfurls inside the orbit of Mars until the sun pushes it away with radiation. Then as it passes Mars, the sail is folded up, and you wait for the sun's gravity to pull it back in again. Then you could connect a long chain to it, and perhaps make it do work as it travels in and out.
And in theory, this will work. According to Gold's paper, this would be a perpetual motion machine. But it isn't. "Perpetual" means "forever". It doesn't mean "until after I'm dead". The sun is running down!
A real perpetual motion machine runs perpetually. This one is going to work for a few billion years and then stop. People always overlook the fact that the entropy of the sun is increasing as heavier elements build up in its core!
If you replaced the sun with a giant magic lamp that would keep burning forever, then he would have an argument. Yeah, the magic lamp + solar sail system constitutes a perpetual motion machine, and the place where it doesn't work is the magic lamp which keeps shining with no loss in entropy. Real suns don't do that. He is making the same damn mistake that the creationists make when they yap about how the Second Law of Thermodynamics forbids evolution- ignorant of the fact that a local loss of entropy on earth is more than counterbalanced by the entropy gain within the sun. The sun isn't going to shine perpetually.
Your solution does not solve the problem. Sure, YOU aren't seeing the spam physically with your eyes, but it is still coming, consuming bandwidth and ISP resources. From the ISP's point of view, once the email has been handled and forwarded to the end user, the damage is done. Client filtering makes little difference afterwards. What is the signal to noise ratio in your private mailbox? How many spams arrive per legitimate email? 1000? 10000?
it's not a big deal for ISPs to implement the same service on their mail servers.
Ha! Have you ever done tech support at an ISP? They'll have to hire 400 Bombay phone bank workers just to field the phone calls from people who can't understand why they're not getting email from their grandchildren.
Don't you think that someone who has the resources that Intel has would not need to resort to this? That is, if their sys admins are any good. Find this whole thing a bit odd.
Well, you're looking at this from a system administrator's perspective (i.e. a techie's perspective). That is, you'd want to find out how it happened, and set up some sort of filter in the firewall or SMTP server so it won't happen again. At that point you will consider the problem effectively solved.
Intel's management and legal department clearly don't think that's enough. From their viewpoint, preventing similar emails from arriving is merely a first step. Once that's been done, problems still remain that need to be rectified. After all, this !@#$ smartass has just gotten away with using our infrastructure to defame us in front of all our underlings! He must be smashed, to serve as a warning to others. You've solved the technical problems, but the social problems remain, and they can be made into legal problems for greater effect.
When this happened at the company I worked at, no technical remedies were taken (we didn't bother). The "social remedies" consisted of a few debunkments and jokes at the weekly company meeting, and that was it. No legal action was even discussed. Small companies are great to work for. I thank my lucky stars every day I don't work for a company like Intel.
A better analogy would be putting a "NO TRESSPASSING" sticker on your mailbox. Remember, the mailbox's intended use is a receptacle for incoming mail. (Note that this does not extend to flagrant abuse of the mailbox, say by stuffing it with thousands of flyers, especially if measures have been taken to prevent mass emails from clogging the mailbox. That does not fall within intended use.)
The mailman arrives, and puts ten letters in the mailbox. I read nine letters which concern my usual business. The tenth distresses me emotionally- so I sue the sender, claiming that they have trespassed my mailbox! But the sender has used it as intended, the mailbox functioned properly as a receptacle for the letter, and no damage was done to it. You cannot define the intended use of your mailbox as "a receptacle only for letters that you like".
Can you imagine the legal consequences if this summary judgment were allowed to stand? Sending even a single handwritten email to anybody would open you up to a lawsuit for "mailbox trespass"- if the recipient decided he doesn't like you or your message, he could sue you for trespass and cite this case as precedent!
It's a good thing Intel was told to get bent. They may have had a case if they built their case differently (like, where did this guy get everyone's email addresses?) but the precedent they sought to create would have been a disaster. What is truly scary is the fact that someone in the lower courts actually granted Intel's motion for summary judgment.
I got one once. One of our sales guys was secretly trying to get his own competing startup company going (after the boom was over- mistake #1), but he accidentally submitted his cellphone bill to the company for reimbursement (mistake #2) and they noticed the calls. When it hit the fan, he quit and sent a "swan song" email to the company and badmouthed a whole bunch of people in it (mistake #3). Most of us didn't know a thing about it until we came in one morning, checked our mail, and found the "fond farewell" in our inboxes. It didn't advertise any open positions in his new company (I guess that would make it commercial speech). It was just an emotional rant, with some badmouthing of a few specific individuals. Clearly he wasn't exercising good judgment when he sent it. But it blew over rather quickly. Nobody wasted too much time talking about it, other than to remark "well I guess X isn't working here anymore."
I've never deleted that email. Every so often I open it again just to imagine the balls it must take to send something like that. If a court were to rule that such an email constituted "electronic trespass", I would be very upset. That having been said, I cannot stress enough that SENDING AN EMAIL LIKE THAT IS A MISTAKE. If you're ever tempted to do it, DON'T. Once you send it they'll be talking about what an idiot you are forever. If you're in a small industry, you'll forever be meeting people who have heard about it.
He got work with another company after his startup failed. Ironically, we signed a deal with that company recently, so he'll be selling our products again. When he's not stabbing you in the back, he's a pretty good sales guy.
If that connection is made, then some companies are in trouble. One is Symantec. I got plenty of spam offering Symantec products in a notorious spam campaign that happened some time ago. Recently a new campaign started where you get a too-good-to-be-true offer on Symantec products. Except the download isn't from Symantec, it comes from the spammer- meaning you could be running a trojan.
Reminds me of a nasty one I got a few weeks ago that claimed to be from "update-notification@paypal.com":
Not to imply that PayPal itself isn't a scam outfit, but this particular email obviously comes from a scam outfit that is not PayPal.
It's obvious you don't contribute anything to the world. Your country probably doesn't either, unless you're a traitor the U.S. and are posting from within its borders. If so, why don't you move to france so you can get buggered by other smelly people that think like you?
He can move to any other country in the world, really. They feel the same everywhere now. France was just the one with the balls to speak up.
I'm going to a conference there in two months. If you give me the money, I'll buy a bottle of French wine and pour it down the gutter for you.
This is how I would do it. During the period where only subscribers can see the story, Slashdot would quickly build a cache of the site.
Then, every minute, it would send a small HTTP request (like for robots.txt) and keep track of the response time. Maybe it could even generate a small postage-stamp sized log-scale graph of the response time as a PNG and insert or link to it from the front page, so you'd know how the site is holding up before clicking on the links.
Once the response time has increased by a certain factor, the bot assumes the site has crashed under load. It then automagically posts a comment to the story with the subject "uhhh... it seems to be slashdotted" and then spits the site (stripped of HTML) into the comment body. This would save karma whores a lot of time.