Note that the report is from the IPCC - Intergovernmental Panel on Climate Change.
No doubt there are some valuable findings in the report, and I know it draws on the results of multiple climate models, but it is still a group commissioned by a political group (the UN) amid very intense political pressure under the presumption of climate change. My understanding is the lead investigators of the group are paid by the panel...paid quite a bit more than $10,000 I'd wager.
I don't want to debate the conclusions of the report here and I certainly disapprove of bribery (I wouldn't consider hiring scientists to independently review the report a bribe, btw, anymore than the IPCC "bribed" a different group of scientists to write the report). I just think if people are going debate bias in the findings of such and such a study, they should be honest in recognizing where it may be working its way.
I know a bunch of people are going to misinterpret my comment as a viscious attack on the IPCC, so I'm going to stop there and close with this quote from a researcher in the organization that was looking to hire these scientists to review the report:
"Right now, the whole debate is polarised," he said. "One group says that anyone with any doubts whatsoever are deniers and the other group is saying that anyone who wants to take action is alarmist. We don't think that approach has a lot of utility for intelligent policy."
1.) You can see in visible light from the ground, and several modern telescopes beat the hubble in that respect.
2.) Ultraviolet (another capability that will be lost with Hubble) isn't as interesting to astronomers as infrared. JWST will far outperform Hubble in IR. Some capabilities you just can't afford, otherwise we'd probably have half a dozen variations on the Hubble in orbit.
3.) JWST will also produce stunning images. They just won't be true color. For that matter, neither are most of the Hubble images. Moot point.
Actually, although the Advanced Camera for Surveys produces some of the deepest and highest resolution images, especially of distant objects, it is the wide-field planetary camera that produces a lot of the most memorable images, such as the "Pillars of Creation" in the Eagle Nebula.
Hubblesite.org has a good layman's description of the instruments on the Hubble.
Also, we're still getting many fine images of the planets, stars, galaxies, and nebulae around us from the Spitzer and the multitude of ground-based scopes that make great backgrounds. And don't forget the fantastic Mars rovers or Cassini.
Agreed. More hypothetical numbers.
on
Water From Wind
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· Score: 1
Let me know what you think.
I was going to point out basically the same thing. The effect is likely negligible, even with large numbers of them. The volume of the air that passes through the turbine is tiny compared to the volume of air that passes above or even around the turbine.
However, I'm also rather skeptical that he gets a significant amount of water from this. I'd love to see some numbers for air flow rates, incoming and exiting temperatures, and relative humidities. A couple simple data points and a psychrometric chart could tell you a lot real quick. Unfortunately, the article (buried in its fawning praise) seems to suggest that he's only gotten to the point of building a desktop prototype (paraphrase: "even a colleague opening the office door caused it to spin")
If he removes 20% (optimistic, I would think) of the water vapor in one pass, in a 5 m/s wind (stiff breeze) with a 10 m^2 swept area (about the size of a two car garage...pretty big for any form of compressor) at 25 degrees C with a 40% relative humidity (comfortable conditions), then he'll be getting about 1 gallon per minute. That's actually much better than I expected when I started my calculations, but still only about enough to supply one lawn sprinkler at a time. You'd need a lot of these things to irrigate a field. I see it as at best a niche product for water supply to houses in remote, dry areas, not really a major agricultural solution. It could potentially be better coupled with a generator so you can get electricity from it, too.
If it works anything like I suspect, it also won't work well, if at all, below freezing because the condensation would just ice up the blades.
The Advanced Camera for Surveys wasn't installed until the third servicing mission in 2002. It's been problematic since then. If it can be installed on a spacewalk, it can be replaced on a spacewalk.
Also, the Hubble servicing mission has been approved. Barring some act of God or Congress, Atlantis will conduct this mission on STS-125 in May of 2008. The ACS was not on the itinerary for service, but it might still be possible to add it to the agenda or push back the mission date if need be. On the other hand, it might be possible to work around whatever problem caused the latest shutdown, the third according to Wikipedia.
I should point out the foot dragging was largely spurred on by calls for the retirement of the shuttle as soon as possible (even immediately) and some general hysteria following the Columbia incident (as opposed to the rational re-examination that also took place). There is also the issue of the cost, which is in the range of hundreds of millions and had not been provided for, and a difference of philosophy between O'Keefe (administrator until 2005) and Griffin (current admin). Mission development is fully provided for in 2007, and should be in the 2008 budget, too.
If Hubble was going to roll over and play dead, it should've done so back in mid-2005, before more money had been spent on the servicing mission.
There's plenty of good jokes here about Darwinism, and some useful discussion about how to actually sterilize a sponge (boiling water, dishwasher, eliminating the sponge as a middleman and simply cleaning plates in the microwave, etc.), but what about the reasons for sterilizing the sponge in the first? Does it even make sense?
Remember, we're talking about a species that used eat stuff raw that had been sitting out in the sun for a couple hours, and beat it into edible sized pieces with sharp rocks. It's a species that still does eat stuff off the floor, picks its nose, and thinks nothing of touching computer keyboards or the handrail on city bus. And here we are worrying about ordinary household bacteria in a sponge that probably gets used in conjunction with some form of antibacterial detergent anyway.
Seriously, how many death certificates note "Cause of death: Scotch Brite scrubber sponge?" How much clinical evidence is there that disinfecting sponges increases longevity or improves your health?
At the same time, there is mounting evidence that moderate exposure (without overdoing it, of course) to microbes may bolster the immune system, and questions about whether antibacterial products might kill only the weakest pathogens, leaving no resource competition to stifle the growth of chemical-resistent bacterial strains.
Don't be paranoid. Most of the microbes out there never hurt anyone.
The challenge of getting the data from Pluto, once it's acquired, is definitely non-trivial.
New Horizons has a total of 8 GB of redundant solid state (flash) memory to save data as it's taken. Divide that by the the 450 baud the parent mentioned, and you can see that to broadcast all of that data to earth would take about 7 months, not including overhead related to operating the probe and previewing the most important data.
In fact, New Horizons will perform it's observations of Pluto and Charon nearly continuously for several weeks before and after the closest approach, then spin to point at earth and broadcast nearly continuously for 9 months.
All of this to take what we've been able to discern of Pluto from this to essentially as good as this.
The bottom line is that NASA has rocket engines that can do everything they want. The relevant point is, different rocket engines do some tasks better than others. Methane has its selling points, which the article notes, but it doesn't simply put all other fuels to shame or anything like that.
NASA has wanted to have a methane engine option for quite a while, but since they have other functional options, they haven't been willing to take money away from other projects to develop it. It's a risk in the sense that it's not a proven design (see my final two paragraphs). As such, they haven't made a commitment to it for any particular project. Now they've finally funded ATK (who sub-contracted X-Cor) to develop the engine, I believe with funding from the Constellation program.
The first studies that NASA did for the Orion CEV had it using a methane/oxygen engine for the extra performance. However, because of the timeline involved and the challenge in getting reliable performance from a non-hypergolic engine in deep space, they chose the safer and cheaper route from an engineering perspective of using a proven hydrazine fueled engine (from the Boeing Delta 2 upper stage) like the shuttle and apollo craft. It sounds like a methane engine may still be used for the new Lunar Surface Access Module (lander), which is on a slower development timeline than the Orion, and as an upgrade to the CEV.
I want to note that almost all flight-restartable rocket engines (off-hand, the only exception I know of is the old Saturn V J-2 second stage engine) use hypergolic fuels. Hypergolics are fuels which spontaneously ignite when combined. The shuttle uses methyl-hydrazine and nitrogen tetroxide, which has a performance not far below kerosene and oxygen, the major drawback being its instability and toxicity.
The reason for accepting the drawbacks of hypergolics is they ignite with incomparable reliability. Before NASA is willing to commit to having a manned mission 150,000 miles from earth depend entirely on a non-hypergolic engine, they have to be absolutely sure that when they pour frigid oxygen and methane together together in the cold of space and throw a spark that it will ignite reliably and controllably. You can't just send an astronaut back there with a Zippo and a can of carb cleaner and hope for the best.
How is this insightful? It's idle speculation, at best.
The underlying assumption is completely baseless. The US has never shot down another country's satellites. We did shoot down one or two of our own in the 80's to test an anti-satellite system that would be used in time of war, but right now multiple other countries operate a variety of spy satellites that fly over the US freely. Russia, China, Japan, Israel, the UK, and I think India, Italy, and France all have launched spy satellites.
And terrorism? What the heck? Does shooting down satellites inspire terror in anyone? It could properly be interpreted as an act of war, in violation of existing space treaties, but that goes beyond stretching the limits of the definition of terrorism.
The article links to a downsized picture. If you really want in on the fun, download the 6.2 MB full size image from the MRO website.
The Pathfinder lander itself is labeled MPF. It's about 2/3 of the way across the image (to the right) and perhaps 500 pixels from the top. It appears lighter than the surrounding material, roughly triangular in shape, and has a slight shadow to the right.
I'm not sure which point they think is the adorable little Sojourner (pic of mockup next to Spirit and Odyssey on earth), but I think it's the two light grey pixels with a shadow about 15-20 pixels north of Pathfinder. That may just be one of the rocks it studied, though.
The parachute and backshell are also labeled. The round object is the aerodynamic backshell that covered the top of the lander during entry. It is attached to the parachute, which is draped over the ground a few meters northeast.
The think the heatshield fragments are pretty self-explanatory, although I'm unsure why it's so scattered. It must have broken up, probably tumbling, shortly after being released.
The distribution of parts around the landscape makes some sense if you know how it landed. Pathfinder entered the Martian atmosphere at about 17,000 mph. It aerobraked using the heatshield down to about 900 mph. After two minutes, the parachute deployed and the heat shield was released. The lander was then lowered on a tether so it would be clear of the backshell. 8 seconds before touchdown, the airbags inflated and retrorockets fired. 2 seconds before touchdown, the tether was cut, with the retrorockets carrying the backshell safely away from the lander, and the Pathfinder bounced down onto its airbags.
I think the Pathfinder payed for itself just in coolness (come on...airbags! Who thinks this stuff up?). Add science and engineering lessons learned, and this mission is priceless.
It wasn't one engineer. It was a team effort. And it wasn't a very simple matter of "forgetting". Several factors combined, including re-use of code from the MGS mission (a conversion factor was in the old code, but not recognized when the code was adapted for the doomed MCO) and budget constraints that limited pre-flight testing (so bug was missed...and in fact might have still been missed even with more testing). The effects of the bug were also subtle enough that 3 minor main engine firings were conducted without enough error showing up to reveal the problem. It wasn't until the long orbital insertion firing that the error in the trajectory became noticeable, and by then it was too late. The team's first clue something was wrong was when the spacecraft didn't radio home after the engine burn.
The details are really convoluted, but the Wikipedia page on the mission has a decent write up explaining how the mistake was made, with additional resources cited. The PDF paper giving a perspective from the MCO team is particularly revealing, if you've got some time on your hands.
Correction: In case you're a highly experience aerospace engineer.
I already checked. They don't seem to be doing a Google style "young talent" hiring search or accepting those with marginally-related experience. If you look through the jobs page, they're generally asking for 10 years experience with some very specific skills (like direct experience with RS-68's or RL-10's). Your chances probably aren't very good if you're looking to break into aerospace, even with an advanced degree. *sigh*
With good reason, I'd wager. I would attribute a large part of SpaceX's rapid pace of development of the Merlin engines to having recruited the same kind of talent directly off of Lockheed and Boeing. They didn't have to figure out many of the details of how to build a working rocket because they people they hired had already built them.
This is probably critical for Blue Origin. Space.com's reported that their current test vehicle is powered by catalytically decomposed hydrogen peroxide. If they're going to achieve the payload and altitude they want, suborbital though it may be, I doubt they're going to get there without a bipropellant; fuel + oxidizer. Just switching to H2O2 + kerosene would double the theoretical specific impulse, or energy they can get per mass of fuel. On the downside, burning a bi-propellant increases the complexity of the engine significantly and complicates throttling, and if they're planning on using turbopumps instead of a pressure-fed system (a scheme their jobs page supports), it gets even more complicated.
You know...I figured they were out there, and I was just looking in the wrong places. Thanks for the tip, although I suspect these Stamp modules are a little simpler than I'm looking for. My interest is not so much in building the electrical interfaces as the mechanical parts. So if I can upload a program easily and just connect sensors, switches, and loads or relays directly to the I/O, I will be a happy person.
They also sell just the command module seperately. Same for the power pack. From that you could build up your own device.
I've been looking around for an affordable controller for a while that is a complete unit, but programmable, so I could build a custom chassis with quite a bit of versatility. This looks like it might fit the bill, although I'm still digging through the website trying to find information about the I/O. At $60 for the controller, it might be what I'm looking for.
Someone in an above thread posted a link to a NASA animation of the orbit.
If you give the Java Applet (before anybody complains, I'd like to see you do something like this via AJAX) a minute to load and fiddle around with the controls, you can rotate around and see the comet's path relative the earth, adjusting the date a day at a time.
As you can see, between now and Jan 15th, the comet moves almost directly between the sun and the earth, and is completely lost in the glare. As the earth moves around a little further in it's orbit, the sun, comet, earth no longer form a nearly straight line, so it becomes visible again, but because it's orbit is highly inclined (it flew basically over the sun's north pole), the comet at the same time passes below the ecliptic plane. Unfortunately, this will probably be when it's at it's brightest. The upshot is our friends in the southern hemisphere should be able to catch some twilight glimpses of it then. lso, if the comet does get as bright as some of the optimistic estimates (Magnitude -8), it will even be faintly visible during the day (all over)! It will fade out of sight through February.
With an perihelion of only 0.2 AU and an aphelion of over 5000 AU, we can bet that it will be a long time before this comet swings back through the inner solar system.
Add all the veggies you want, there is nothing "healthy" about that.
Ummm...how about 7 grams of protein, 25% of your daily iron, and 300 grams of carbohydrates (They aren't evil. The body uses carbs effectively for energy. There have been health problems linked to low-carb diets), and 25 grams of fiber?
And sodium is critical in maintaining water balance in your cells and and also allowing nerve and muscle activity. I personally get really bad headaches if I get dehydrated from physical activity because of low sodium levels. Because of the way food is generally prepared these days, low sodium is less of a problem than high sodium, but it still is necessary.
Nobody's claiming ramen is a health miracle, and a diet based on it would be very poorly balanced, but it can definitely be part of a healthy diet.
However, the submission and the article are still a little strange in their word choices (mostly the submission...If you re-read the article a few times, it makes more sense). They seem to suggest that the assymetric shockwave gives the pulsars their sping, when according to the theory, it actually takes away spin. I clicked on the article wondering how in the world they were postulating massive, exploding objects with very low or possibly non-existant angular momentums.
If I'm reading it right, the ejected debris from the rebound should spiral more in this case to account for the net loss of angular momentum, no?
Anyway, the worst part was this line:
According to three-dimensional simulations they performed at the Leadership Computing Facility, located at ORNL, the spin of a pulsar is determined not by the spin of the original star, but by the shock wave created when the star's massive iron core collapses.
What they really meant is the original spin plus the shockwave, not just the latter instead of the former. Other than that though, the press release is a fresh breath of clear writing.
As someone who grew up on a big stack of Popular Mechanics, I hate to say it, but "in-depth" and "Popular Mechanics" are two terms that haven't worked well together in a sentence for years, arguably decades.
A much better source of information is www.globalsecurity.org or fas.org. In fact, looking through their section on North Korea's WMD, I see that the Popular Mechanics author basically paraphrased their write-up, giving his article all the quality and broad research base of any good internet blog.
Another nice aspect of globalsecurity and the Federation of American Scientists, is that both maintain rather extensive databases of information on weapon systems. For example, if after reading the article, I want to know how far a chemical weapon-equipped Scud could deliver it's payload, I can look that up, too.
Actually, magnitude 6 is generally the faintest stars visible to the naked eye (under good viewing conditions, of course). Magnitude 6 is where the scale actually comes from. M1 is the brightest stars in the sky. M6 is the dimmest. The modern scale is defined by extrapolating these definitions logarithmically in both directions.
In fact, I can say conclusively that a magnitude 9 flash could be detected in a 14" telescope. Clyde Tombaugh discovered Pluto (max magnitude 13) with a 13" telescope.
However, it is inappropriate for the submitter to compare this project too closely with SETI@home or even Stardust@home. It sounds like the researchers developed this software for their project, and decided to release it as a bonus for enthusiasts. If people pick up on it and find things, great. If not, no major loss. The other @home projects I mentioned depend much more on outsiders.
Whether or not a suburban setup could hope to find anything, I couldn't say.
At the compression ratio achieved by a scramjet, I don't believe the thin atmosphere is a problem. Effectively, the shock wave compresses the air for you.
However, the X-43 was a very, very far cry from a commercially viable transport. It was 12 feet long and had something like a 100 pound usable payload, dedicated entirely to instrumentation. It was a single use, throw away, test plane. The engine only ran for just over 10 seconds (the goal was not to accelerate the plane to Mach 10, but to prove it is possible to operate the engine at Mach 10...imagine a candle in a hurricane). It required a $30 million Pegasus rocket to accelerate it to stated speed.
When NASA first started toying with scramjets, they created the X-30 concept, which would've been basically what the article is describing but more realistic. Then they got to look at actually making a scramjet work and haven't really talked about the X-30 since. The X-43 is far less ambitious, but is still a tough project.
Aside from the very substantial technical hurdles, what do you think the commercial market is for a 2 hour flight to anywhere in a cramped capsule moving so fast that if there were an accident, there might not even be teeth left to identify you with? Even the Concorde couldn't pay for itself, and it cut the trip time for a very busy route in half. For comparison, Virgin Galactic is planning on offering suborbital joyrides that peak out at 3000 mph and don't actually get you anywhere for $200,000 each. Supposing that $200,000 per ticket were achievable, I doubt anyone can justify saving 10 hours at that price, even really important business executives. Even if they're time were that valuable, it's not like they couldn't get work done in the air on a suitably equipped business jet.
Perhaps I'm misreading it, but from my understanding, the point of this experiment was not really verification of the Milgram study in less direct form, but rather to investigate how subjects perceive the wrongness of acts, or at least complicity with wrongful acts since they're acting under instructions, in conjunction with virtual personalities as opposed to real people.
So esentially, they're trying to determine how people respond to virtual world situations and compare that to real world situations. While I don't think parallels should be assumed very closely (for one, the conscious is being driven to apply real world ethics to fake situations, instead of vice versus), those interested in the "video games do/don't cause violence" debate should be at least interested in the findings of this study.
I remember watching a video on the original study in sociology class. It was surprisingly unsettling. Even after the test subjects had explained to them that they hadn't actually caused any pain to anyone, and that the study was their reactions, not the actor's, they still had to go to bed that night knowing that regardless of the reality of the pain, they had made a decision to inflict it on another human being.
Well, it's all estimates at some point. You can't genuinely collect all the data.
More importantly, the mileage estimates are intended to help the average consumer make an informed decision. They want to know what they can reasonably expect. In effect, the mileage estimate should more accurately represent the mode, not the mean. Newspaper delivery is not the typical use and will skew the mean downward, but the mode stays the same. Having the numbers would certainly be interesting (and useful if you're a fleet manager), but it's a lower priority than the numbers for typical use.
The current tests actually tend to be skewed in favor of hybrids. They don't represent the modal performance well. Some people get advertised mileage, but from what I've been hearing, most fall quite a bit short because of more typical driving habits.
Before I go, I thought I'd compliment you on a clever, non-typical application for your car. I had never even thought about it, but a hybrid is quite well suited to that purpose. It's not quite as efficient as a purpose-built generator because the engine is oversized and there's non-trivial charge-discharge losses, but it's more economical than buying a generator for a day or two of use per year when you already have the car. As you noted, it's quite wasteful to run an engine significantly below capacity, since most of the energy just goes to keeping it idling, especially a car engine with 50kW or more of capacity when you're only maxing at perhaps 2 kW and averaging a quarter of that. The same is true to a lesser degree for generators, as well. When your Prius is running to charge the batteries, the "overhead" of the engine makes a much smaller percentage of the total power produced.
I'm curious if you just used a cigarette lighter inverter or wired one into a higher capacit circuit.
Amen. I've watched a couple of them courtesy of NASA TV. Now that the end is tangibly near, I'm hoping to plan a trip to KSC to see one myself before they're all done.
Of course, when we get that far (2016 or so), the massive Ares V's should be able to put on a pretty good show, but without the glamor of hanging that pretty white glider off the back of the stack.
Several posters seem to think that because we haven't directly studied giant squids very much that we don't have even a remote clue how many there are. However, it is quite obvious from the fact that sperm and other species of whales eat these animals in abundance that they're numbers are not insignificant.
Sacrificing a specimen for research may be long term beneficial for the health of the species. As the parent noted, we may learn something from this that will allow them to be successfully studied in captivity. Furthermore, by dissecting the animal, researchers can look for any clues of human factors influencing their health or habitat, and thereby understand what activities may adversely affect their populations.
Slashdot Mirror
No doubt there are some valuable findings in the report, and I know it draws on the results of multiple climate models, but it is still a group commissioned by a political group (the UN) amid very intense political pressure under the presumption of climate change. My understanding is the lead investigators of the group are paid by the panel...paid quite a bit more than $10,000 I'd wager.
I don't want to debate the conclusions of the report here and I certainly disapprove of bribery (I wouldn't consider hiring scientists to independently review the report a bribe, btw, anymore than the IPCC "bribed" a different group of scientists to write the report). I just think if people are going debate bias in the findings of such and such a study, they should be honest in recognizing where it may be working its way.
I know a bunch of people are going to misinterpret my comment as a viscious attack on the IPCC, so I'm going to stop there and close with this quote from a researcher in the organization that was looking to hire these scientists to review the report:
Your point gets made a lot, but:
1.) You can see in visible light from the ground, and several modern telescopes beat the hubble in that respect.
2.) Ultraviolet (another capability that will be lost with Hubble) isn't as interesting to astronomers as infrared. JWST will far outperform Hubble in IR. Some capabilities you just can't afford, otherwise we'd probably have half a dozen variations on the Hubble in orbit.
3.) JWST will also produce stunning images. They just won't be true color. For that matter, neither are most of the Hubble images. Moot point.
Actually, although the Advanced Camera for Surveys produces some of the deepest and highest resolution images, especially of distant objects, it is the wide-field planetary camera that produces a lot of the most memorable images, such as the "Pillars of Creation" in the Eagle Nebula.
Hubblesite.org has a good layman's description of the instruments on the Hubble.
Also, we're still getting many fine images of the planets, stars, galaxies, and nebulae around us from the Spitzer and the multitude of ground-based scopes that make great backgrounds. And don't forget the fantastic Mars rovers or Cassini.
I was going to point out basically the same thing. The effect is likely negligible, even with large numbers of them. The volume of the air that passes through the turbine is tiny compared to the volume of air that passes above or even around the turbine.
However, I'm also rather skeptical that he gets a significant amount of water from this. I'd love to see some numbers for air flow rates, incoming and exiting temperatures, and relative humidities. A couple simple data points and a psychrometric chart could tell you a lot real quick. Unfortunately, the article (buried in its fawning praise) seems to suggest that he's only gotten to the point of building a desktop prototype (paraphrase: "even a colleague opening the office door caused it to spin")
If he removes 20% (optimistic, I would think) of the water vapor in one pass, in a 5 m/s wind (stiff breeze) with a 10 m^2 swept area (about the size of a two car garage...pretty big for any form of compressor) at 25 degrees C with a 40% relative humidity (comfortable conditions), then he'll be getting about 1 gallon per minute. That's actually much better than I expected when I started my calculations, but still only about enough to supply one lawn sprinkler at a time. You'd need a lot of these things to irrigate a field. I see it as at best a niche product for water supply to houses in remote, dry areas, not really a major agricultural solution. It could potentially be better coupled with a generator so you can get electricity from it, too.
If it works anything like I suspect, it also won't work well, if at all, below freezing because the condensation would just ice up the blades.
The Advanced Camera for Surveys wasn't installed until the third servicing mission in 2002. It's been problematic since then. If it can be installed on a spacewalk, it can be replaced on a spacewalk.
Also, the Hubble servicing mission has been approved. Barring some act of God or Congress, Atlantis will conduct this mission on STS-125 in May of 2008. The ACS was not on the itinerary for service, but it might still be possible to add it to the agenda or push back the mission date if need be. On the other hand, it might be possible to work around whatever problem caused the latest shutdown, the third according to Wikipedia.
I should point out the foot dragging was largely spurred on by calls for the retirement of the shuttle as soon as possible (even immediately) and some general hysteria following the Columbia incident (as opposed to the rational re-examination that also took place). There is also the issue of the cost, which is in the range of hundreds of millions and had not been provided for, and a difference of philosophy between O'Keefe (administrator until 2005) and Griffin (current admin). Mission development is fully provided for in 2007, and should be in the 2008 budget, too.
If Hubble was going to roll over and play dead, it should've done so back in mid-2005, before more money had been spent on the servicing mission.
There's plenty of good jokes here about Darwinism, and some useful discussion about how to actually sterilize a sponge (boiling water, dishwasher, eliminating the sponge as a middleman and simply cleaning plates in the microwave, etc.), but what about the reasons for sterilizing the sponge in the first? Does it even make sense?
Remember, we're talking about a species that used eat stuff raw that had been sitting out in the sun for a couple hours, and beat it into edible sized pieces with sharp rocks. It's a species that still does eat stuff off the floor, picks its nose, and thinks nothing of touching computer keyboards or the handrail on city bus. And here we are worrying about ordinary household bacteria in a sponge that probably gets used in conjunction with some form of antibacterial detergent anyway.
Seriously, how many death certificates note "Cause of death: Scotch Brite scrubber sponge?" How much clinical evidence is there that disinfecting sponges increases longevity or improves your health?
At the same time, there is mounting evidence that moderate exposure (without overdoing it, of course) to microbes may bolster the immune system, and questions about whether antibacterial products might kill only the weakest pathogens, leaving no resource competition to stifle the growth of chemical-resistent bacterial strains.
Don't be paranoid. Most of the microbes out there never hurt anyone.
The challenge of getting the data from Pluto, once it's acquired, is definitely non-trivial.
New Horizons has a total of 8 GB of redundant solid state (flash) memory to save data as it's taken. Divide that by the the 450 baud the parent mentioned, and you can see that to broadcast all of that data to earth would take about 7 months, not including overhead related to operating the probe and previewing the most important data.
In fact, New Horizons will perform it's observations of Pluto and Charon nearly continuously for several weeks before and after the closest approach, then spin to point at earth and broadcast nearly continuously for 9 months.
All of this to take what we've been able to discern of Pluto from this to essentially as good as this.
The bottom line is that NASA has rocket engines that can do everything they want. The relevant point is, different rocket engines do some tasks better than others. Methane has its selling points, which the article notes, but it doesn't simply put all other fuels to shame or anything like that.
NASA has wanted to have a methane engine option for quite a while, but since they have other functional options, they haven't been willing to take money away from other projects to develop it. It's a risk in the sense that it's not a proven design (see my final two paragraphs). As such, they haven't made a commitment to it for any particular project. Now they've finally funded ATK (who sub-contracted X-Cor) to develop the engine, I believe with funding from the Constellation program.
The first studies that NASA did for the Orion CEV had it using a methane/oxygen engine for the extra performance. However, because of the timeline involved and the challenge in getting reliable performance from a non-hypergolic engine in deep space, they chose the safer and cheaper route from an engineering perspective of using a proven hydrazine fueled engine (from the Boeing Delta 2 upper stage) like the shuttle and apollo craft. It sounds like a methane engine may still be used for the new Lunar Surface Access Module (lander), which is on a slower development timeline than the Orion, and as an upgrade to the CEV.
I want to note that almost all flight-restartable rocket engines (off-hand, the only exception I know of is the old Saturn V J-2 second stage engine) use hypergolic fuels. Hypergolics are fuels which spontaneously ignite when combined. The shuttle uses methyl-hydrazine and nitrogen tetroxide, which has a performance not far below kerosene and oxygen, the major drawback being its instability and toxicity.
The reason for accepting the drawbacks of hypergolics is they ignite with incomparable reliability. Before NASA is willing to commit to having a manned mission 150,000 miles from earth depend entirely on a non-hypergolic engine, they have to be absolutely sure that when they pour frigid oxygen and methane together together in the cold of space and throw a spark that it will ignite reliably and controllably. You can't just send an astronaut back there with a Zippo and a can of carb cleaner and hope for the best.
How is this insightful? It's idle speculation, at best.
The underlying assumption is completely baseless. The US has never shot down another country's satellites. We did shoot down one or two of our own in the 80's to test an anti-satellite system that would be used in time of war, but right now multiple other countries operate a variety of spy satellites that fly over the US freely. Russia, China, Japan, Israel, the UK, and I think India, Italy, and France all have launched spy satellites.
And terrorism? What the heck? Does shooting down satellites inspire terror in anyone? It could properly be interpreted as an act of war, in violation of existing space treaties, but that goes beyond stretching the limits of the definition of terrorism.
The article links to a downsized picture. If you really want in on the fun, download the 6.2 MB full size image from the MRO website.
The Pathfinder lander itself is labeled MPF. It's about 2/3 of the way across the image (to the right) and perhaps 500 pixels from the top. It appears lighter than the surrounding material, roughly triangular in shape, and has a slight shadow to the right.
I'm not sure which point they think is the adorable little Sojourner (pic of mockup next to Spirit and Odyssey on earth), but I think it's the two light grey pixels with a shadow about 15-20 pixels north of Pathfinder. That may just be one of the rocks it studied, though.
The parachute and backshell are also labeled. The round object is the aerodynamic backshell that covered the top of the lander during entry. It is attached to the parachute, which is draped over the ground a few meters northeast.
The think the heatshield fragments are pretty self-explanatory, although I'm unsure why it's so scattered. It must have broken up, probably tumbling, shortly after being released.
The distribution of parts around the landscape makes some sense if you know how it landed. Pathfinder entered the Martian atmosphere at about 17,000 mph. It aerobraked using the heatshield down to about 900 mph. After two minutes, the parachute deployed and the heat shield was released. The lander was then lowered on a tether so it would be clear of the backshell. 8 seconds before touchdown, the airbags inflated and retrorockets fired. 2 seconds before touchdown, the tether was cut, with the retrorockets carrying the backshell safely away from the lander, and the Pathfinder bounced down onto its airbags.
I think the Pathfinder payed for itself just in coolness (come on...airbags! Who thinks this stuff up?). Add science and engineering lessons learned, and this mission is priceless.
It wasn't one engineer. It was a team effort. And it wasn't a very simple matter of "forgetting". Several factors combined, including re-use of code from the MGS mission (a conversion factor was in the old code, but not recognized when the code was adapted for the doomed MCO) and budget constraints that limited pre-flight testing (so bug was missed...and in fact might have still been missed even with more testing). The effects of the bug were also subtle enough that 3 minor main engine firings were conducted without enough error showing up to reveal the problem. It wasn't until the long orbital insertion firing that the error in the trajectory became noticeable, and by then it was too late. The team's first clue something was wrong was when the spacecraft didn't radio home after the engine burn.
The details are really convoluted, but the Wikipedia page on the mission has a decent write up explaining how the mistake was made, with additional resources cited. The PDF paper giving a perspective from the MCO team is particularly revealing, if you've got some time on your hands.
Correction: In case you're a highly experience aerospace engineer.
I already checked. They don't seem to be doing a Google style "young talent" hiring search or accepting those with marginally-related experience. If you look through the jobs page, they're generally asking for 10 years experience with some very specific skills (like direct experience with RS-68's or RL-10's). Your chances probably aren't very good if you're looking to break into aerospace, even with an advanced degree. *sigh*
With good reason, I'd wager. I would attribute a large part of SpaceX's rapid pace of development of the Merlin engines to having recruited the same kind of talent directly off of Lockheed and Boeing. They didn't have to figure out many of the details of how to build a working rocket because they people they hired had already built them.
This is probably critical for Blue Origin. Space.com's reported that their current test vehicle is powered by catalytically decomposed hydrogen peroxide. If they're going to achieve the payload and altitude they want, suborbital though it may be, I doubt they're going to get there without a bipropellant; fuel + oxidizer. Just switching to H2O2 + kerosene would double the theoretical specific impulse, or energy they can get per mass of fuel. On the downside, burning a bi-propellant increases the complexity of the engine significantly and complicates throttling, and if they're planning on using turbopumps instead of a pressure-fed system (a scheme their jobs page supports), it gets even more complicated.
You know...I figured they were out there, and I was just looking in the wrong places. Thanks for the tip, although I suspect these Stamp modules are a little simpler than I'm looking for. My interest is not so much in building the electrical interfaces as the mechanical parts. So if I can upload a program easily and just connect sensors, switches, and loads or relays directly to the I/O, I will be a happy person.
They also sell just the command module seperately. Same for the power pack. From that you could build up your own device.
I've been looking around for an affordable controller for a while that is a complete unit, but programmable, so I could build a custom chassis with quite a bit of versatility. This looks like it might fit the bill, although I'm still digging through the website trying to find information about the I/O. At $60 for the controller, it might be what I'm looking for.
Someone in an above thread posted a link to a NASA animation of the orbit.
If you give the Java Applet (before anybody complains, I'd like to see you do something like this via AJAX) a minute to load and fiddle around with the controls, you can rotate around and see the comet's path relative the earth, adjusting the date a day at a time.
As you can see, between now and Jan 15th, the comet moves almost directly between the sun and the earth, and is completely lost in the glare. As the earth moves around a little further in it's orbit, the sun, comet, earth no longer form a nearly straight line, so it becomes visible again, but because it's orbit is highly inclined (it flew basically over the sun's north pole), the comet at the same time passes below the ecliptic plane. Unfortunately, this will probably be when it's at it's brightest. The upshot is our friends in the southern hemisphere should be able to catch some twilight glimpses of it then. lso, if the comet does get as bright as some of the optimistic estimates (Magnitude -8), it will even be faintly visible during the day (all over)! It will fade out of sight through February.
With an perihelion of only 0.2 AU and an aphelion of over 5000 AU, we can bet that it will be a long time before this comet swings back through the inner solar system.
Ummm...how about 7 grams of protein, 25% of your daily iron, and 300 grams of carbohydrates (They aren't evil. The body uses carbs effectively for energy. There have been health problems linked to low-carb diets), and 25 grams of fiber?
And sodium is critical in maintaining water balance in your cells and and also allowing nerve and muscle activity. I personally get really bad headaches if I get dehydrated from physical activity because of low sodium levels. Because of the way food is generally prepared these days, low sodium is less of a problem than high sodium, but it still is necessary.
Nobody's claiming ramen is a health miracle, and a diet based on it would be very poorly balanced, but it can definitely be part of a healthy diet.
Thanks for explaining that.
However, the submission and the article are still a little strange in their word choices (mostly the submission...If you re-read the article a few times, it makes more sense). They seem to suggest that the assymetric shockwave gives the pulsars their sping, when according to the theory, it actually takes away spin. I clicked on the article wondering how in the world they were postulating massive, exploding objects with very low or possibly non-existant angular momentums.
If I'm reading it right, the ejected debris from the rebound should spiral more in this case to account for the net loss of angular momentum, no?
Anyway, the worst part was this line:
What they really meant is the original spin plus the shockwave, not just the latter instead of the former. Other than that though, the press release is a fresh breath of clear writing.
As someone who grew up on a big stack of Popular Mechanics, I hate to say it, but "in-depth" and "Popular Mechanics" are two terms that haven't worked well together in a sentence for years, arguably decades. A much better source of information is www.globalsecurity.org or fas.org. In fact, looking through their section on North Korea's WMD, I see that the Popular Mechanics author basically paraphrased their write-up, giving his article all the quality and broad research base of any good internet blog.
Another nice aspect of globalsecurity and the Federation of American Scientists, is that both maintain rather extensive databases of information on weapon systems. For example, if after reading the article, I want to know how far a chemical weapon-equipped Scud could deliver it's payload, I can look that up, too.
Actually, magnitude 6 is generally the faintest stars visible to the naked eye (under good viewing conditions, of course). Magnitude 6 is where the scale actually comes from. M1 is the brightest stars in the sky. M6 is the dimmest. The modern scale is defined by extrapolating these definitions logarithmically in both directions.
In fact, I can say conclusively that a magnitude 9 flash could be detected in a 14" telescope. Clyde Tombaugh discovered Pluto (max magnitude 13) with a 13" telescope.
However, it is inappropriate for the submitter to compare this project too closely with SETI@home or even Stardust@home. It sounds like the researchers developed this software for their project, and decided to release it as a bonus for enthusiasts. If people pick up on it and find things, great. If not, no major loss. The other @home projects I mentioned depend much more on outsiders.
Whether or not a suburban setup could hope to find anything, I couldn't say.
Wait...such as what? I, admittedly as a Catholic, am having a hard time thinking of examples of this.
At the compression ratio achieved by a scramjet, I don't believe the thin atmosphere is a problem. Effectively, the shock wave compresses the air for you.
However, the X-43 was a very, very far cry from a commercially viable transport. It was 12 feet long and had something like a 100 pound usable payload, dedicated entirely to instrumentation. It was a single use, throw away, test plane. The engine only ran for just over 10 seconds (the goal was not to accelerate the plane to Mach 10, but to prove it is possible to operate the engine at Mach 10...imagine a candle in a hurricane). It required a $30 million Pegasus rocket to accelerate it to stated speed. When NASA first started toying with scramjets, they created the X-30 concept, which would've been basically what the article is describing but more realistic. Then they got to look at actually making a scramjet work and haven't really talked about the X-30 since. The X-43 is far less ambitious, but is still a tough project.
Aside from the very substantial technical hurdles, what do you think the commercial market is for a 2 hour flight to anywhere in a cramped capsule moving so fast that if there were an accident, there might not even be teeth left to identify you with? Even the Concorde couldn't pay for itself, and it cut the trip time for a very busy route in half. For comparison, Virgin Galactic is planning on offering suborbital joyrides that peak out at 3000 mph and don't actually get you anywhere for $200,000 each. Supposing that $200,000 per ticket were achievable, I doubt anyone can justify saving 10 hours at that price, even really important business executives. Even if they're time were that valuable, it's not like they couldn't get work done in the air on a suitably equipped business jet.
Perhaps I'm misreading it, but from my understanding, the point of this experiment was not really verification of the Milgram study in less direct form, but rather to investigate how subjects perceive the wrongness of acts, or at least complicity with wrongful acts since they're acting under instructions, in conjunction with virtual personalities as opposed to real people.
So esentially, they're trying to determine how people respond to virtual world situations and compare that to real world situations. While I don't think parallels should be assumed very closely (for one, the conscious is being driven to apply real world ethics to fake situations, instead of vice versus), those interested in the "video games do/don't cause violence" debate should be at least interested in the findings of this study.
I remember watching a video on the original study in sociology class. It was surprisingly unsettling. Even after the test subjects had explained to them that they hadn't actually caused any pain to anyone, and that the study was their reactions, not the actor's, they still had to go to bed that night knowing that regardless of the reality of the pain, they had made a decision to inflict it on another human being.
Well, it's all estimates at some point. You can't genuinely collect all the data.
More importantly, the mileage estimates are intended to help the average consumer make an informed decision. They want to know what they can reasonably expect. In effect, the mileage estimate should more accurately represent the mode, not the mean. Newspaper delivery is not the typical use and will skew the mean downward, but the mode stays the same. Having the numbers would certainly be interesting (and useful if you're a fleet manager), but it's a lower priority than the numbers for typical use.
The current tests actually tend to be skewed in favor of hybrids. They don't represent the modal performance well. Some people get advertised mileage, but from what I've been hearing, most fall quite a bit short because of more typical driving habits.
Before I go, I thought I'd compliment you on a clever, non-typical application for your car. I had never even thought about it, but a hybrid is quite well suited to that purpose. It's not quite as efficient as a purpose-built generator because the engine is oversized and there's non-trivial charge-discharge losses, but it's more economical than buying a generator for a day or two of use per year when you already have the car. As you noted, it's quite wasteful to run an engine significantly below capacity, since most of the energy just goes to keeping it idling, especially a car engine with 50kW or more of capacity when you're only maxing at perhaps 2 kW and averaging a quarter of that. The same is true to a lesser degree for generators, as well. When your Prius is running to charge the batteries, the "overhead" of the engine makes a much smaller percentage of the total power produced.
I'm curious if you just used a cigarette lighter inverter or wired one into a higher capacit circuit.
Amen. I've watched a couple of them courtesy of NASA TV. Now that the end is tangibly near, I'm hoping to plan a trip to KSC to see one myself before they're all done.
Of course, when we get that far (2016 or so), the massive Ares V's should be able to put on a pretty good show, but without the glamor of hanging that pretty white glider off the back of the stack.
Well said. Exactly the point I was going to make.
Several posters seem to think that because we haven't directly studied giant squids very much that we don't have even a remote clue how many there are. However, it is quite obvious from the fact that sperm and other species of whales eat these animals in abundance that they're numbers are not insignificant.
Sacrificing a specimen for research may be long term beneficial for the health of the species. As the parent noted, we may learn something from this that will allow them to be successfully studied in captivity. Furthermore, by dissecting the animal, researchers can look for any clues of human factors influencing their health or habitat, and thereby understand what activities may adversely affect their populations.