That would require 1g of gravity, if we can produce that, we have effective artificial gravity for spaceships. Prehaps it will be much easier in a small space than a whole ship, but you're in a similar order of magnitude. At the moment they're many orders less.
But is ease of reception the same per watt at each wavelength? I was thinking that number of photons is what is important for recieving rather than the power.
Shorter wavelengths are more energetic, so I would expect it takes more energy to transmit light than radio. The energy required to transmit a signal from another star that we can pick up with our radio telescopes is enormous, so you can expect them to use the more efficient method. Also, there are key frequencies in the radio spectrum, like the 21 cm line and multiples of it, that an ET might think to use and we can look at more closely.
The improvement with interplanetary communications is caused by the detector being better rather than anything inherent to the wavelength - I don't think it applies to interstellar communications.
There's lots of evidence supporting inflationary theory - the fact that measurements show we're in an almost flat universe is the first one to spring to mind.
The speed of light in air is only marginally less than in a vacumn (refractive index of air at sea level: 1.0002926, says wikipedia) and the atmosphere drops in pressure very rapidly on a lunar scale. The exosphere starts at, at most 1000km from the earth's surface, and that's the "beginning of the end" of the atmosphere. The moon is around 400000km away. The light is travelling through the atmosphere for only 0.25% of its journey. The difference in light time from the surface of the earth and the exosphere would be a tiny fraction of a second.
Do those robots of yours work in the extreme range of temperatures you get on the moon? A better comparison would be to existing space probes - say the Mars rovers. Apparently they cost a little short of a billion dollars for 2. Getting to the moon is slightly cheaper than to Mars, and mass production reduces costs, so you're talking a billion or 2 for a lunar mining operation - much higher than your prices.
You also need to factor in the cost of getting whatever you mine back to Earth. Chances are you're going to be sending cargo ships back and forth - you might as well have some supplies on the outward journeys, so no extra cost for sending the required food (and we're already ignoring hydroponics etc).
As for repairs - you can normally tell what is most likely to go wrong with a machine and prepare for it. It is easier for a human to repair such things than another robot.
Admittedly, the almost realtime communications possible with the moon make remote controlled repairs a possibility, but I was thinking about mining asteroids, rather than the moon. If you're going to have people living in the asteriod belt, you might well want to lunar base for a launching platform.
I think your ratio of initial setup to per person is off by quite a bit. The extra cost of making a 2 person base rather than a 1 person base is quite small relative to the cost of the first person. The living space doesn't need to be twice the size. The square-cube law means you need less materials to build a larger dome (proportionally). Atmosphere cycling needs to be increased linearly, but I expect the cost of it isn't linear.
Also, even taking into account that most of your last sentence was an exaggeration, you are overestimating the value of 1.2 billion dollars. Setting up a simple, robotic mining mission will run into the 10s of billions at least, I would guess - adding some people will increase it significantly, but not overwhelmingly.
The cost of having a human technican on site is a constant, regardless of scale. The benefit, however, increases as the number of things for him to fix increases. There becomes a point where the money saved by not having to bring things back to be fixed or even completely replace them outweighs the cost of keeping a human there. Exactly where that point it does indeed depend on costs of things like launches, but the point is somewhere. (Of course, at current costs that point might require more mining than is possible on a single asteriod, so effectively doesn't exist, but oh well.)
Of course, if we get a working space elevator, pretty much everything becomes viable... Hopefully that dream will become a reality sooner or later...
"Yes, there are "tons of resources". Now address why, as the gp mentioned, you think humans should be involved in gathering them at all, given that robotic missions usually are a 20th the price of an equivalent manned mission."
Small scale mining missions would probably be cheaper with robots, yes - once the scale gets larger it becomes economically viable to have technicians on hand to fix things that go wrong. Once the scale gets larger still, it becomes viable to have entire colonies to do the mining.
We'll probably start with robots, but people have a purpose in space too.
Upload speeds years ago were far lower than they are now. The slowest upload speed you get on British ADSL is 256kB/s which works out at just over 9 hours per gig. That's not great, but anyone wanting the upload gigabytes of data on a regular basis would probably have a faster connection (SDSL with 1 meg up isn't too expensive for the kind of business likely to have that much data - and that's just on a phone line. Special lines can get much higher). Leaving your photo collection to upload over night (maybe over a few nights) isn't that much trouble.
It's meant to do all kinds of clever things - I took a look, even read the FAQ, and after a couple of minutes gave up. I couldn't work out how to make it do anything other than be a standard search engine that seemed to give worse results than google. A SE that I have to spend ages working out how to use isn't worth the hassle.
Road signs in London are in miles. They rarely actually specify units, so what made you think they were kilometers?
Speed limits that are explicitly stated are usually either "30" or "40" - both meaning mph. 30kph is very slow...
But yes, supermarkets have everything in metric, by law. I think you can specify imperial units as well, but everything has to be sold in metric units. For example, we get 568ml bottles of milk (although most milk is now sold in integer or half integer numbers of litres - it's just delivered milk [which is getting quite rare] that's still pint bottles).
I expect he meant private - he'd have said "State school" is he meant a government funded school - it's the standard term in England and one that's easy to understand despite "common languages".
I'm sure MS has enough revenue in euros to cover the fine, so changing currency rates won't make any difference. If they were having to pay the fine in dollars, it would mean they were making a loss in Europe, so would just cut the market off completely.
Actually, 2 billion kelvin corresponds to a peak at 1.5pm - someone near the near end of gamma rays, only slightly shorter than x-rays.
I doubt they'd have something in place to measure that normally, but TFA says they repeated the experiment multiple times - they probably went and got an appropriate detector once the one they had started crying. Such detectors aren't hard to come by.
Re:Yeah, we don't have enough junk in orbit
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Golf in Space
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· Score: 1
11 minutes? That would be a height of about 1600km above the centre of the Earth - well within the Earth itself (R=6400km). What did you mean?
Actually cold is good for telescopes - it reduces the amount of infra-red the telescope and surrounding objects emit so there's less interference. I expect it's more of an issue with radio scopes than optical, but I know a lot of effort goes into cooling telescopes (and we're talking liquid helium, not just nitrogren - very cold!).
You throw stuff out the back of your rocket while you're near ground, that stuff is going to hit the ground and transfer its momentum. Until you're far enough away for the exhaust to disperse before reaching the ground you effectively push against the ground - you'd get the same thrust without the ground there, certainly, but the ground still recoils. It's a pretty small consideration, though - you can launch from alternate sides of the asteroid if you have to.
Why is this asteroid of yours in Earth's orbit? Seems like an odd example... It probably wouldn't even impact - co-orbital objects usually avoid eachother by one speeding up and one slowing down and thus changing orbits slightly (I believe their are moons of Saturn that do exactly that - try Wikipedia). It would have to be very close to Earth to start with for there not to be time for it to move round.
You pull something towards Earth, yes, it'll speed us. Just as a space shuttle does on re-entry, just as meteors do, it's a simple matter. We use aerobraking to slow things down at the moment, we can do that with the mined goods - just put them inside a reusable heat shield and let them lose their extra speed against the atmosphere.
Re:Odds of an impact are better than you think
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Golf in Space
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· Score: 1
Those numbers are for any piece of junk hitting, I was talking about a particular golf ball. Obviously if you have hundreds/thousands of bits of junk the chances are increased over just a single bit.
Re:Yeah, we don't have enough junk in orbit
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Golf in Space
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· Score: 1
A polar orbit would increase the respective speed, yes, but it also decreases the chance of a collision quite drasticly.
Re:Yeah, we don't have enough junk in orbit
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Golf in Space
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· Score: 1
If you're stationary at that altitude you should be more worried about falling back down than about the very slim chance of getting hit by a golf ball. If you're in orbit you'll be moving at roughly the same speed as the ball - the only way you could have a large difference in speed is if there is a large difference in eccentricity of your orbits, however I expect both you and the ball will be in roughly circular orbits (if you get hit during the short time before you circularise your orbit you're *very* unlucky).
Maths may involve calculating the trajectory (actually it involves *how* to calculate it rather than the actual calculation, but examples are a useful learning tool), it doesn't involve actually projecting anything - that's physics. Physics is using maths to predict the results of experiments - if you're actually doing an experiment it's physics, maths is abstract.
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That would require 1g of gravity, if we can produce that, we have effective artificial gravity for spaceships. Prehaps it will be much easier in a small space than a whole ship, but you're in a similar order of magnitude. At the moment they're many orders less.
But is ease of reception the same per watt at each wavelength? I was thinking that number of photons is what is important for recieving rather than the power.
Shorter wavelengths are more energetic, so I would expect it takes more energy to transmit light than radio. The energy required to transmit a signal from another star that we can pick up with our radio telescopes is enormous, so you can expect them to use the more efficient method. Also, there are key frequencies in the radio spectrum, like the 21 cm line and multiples of it, that an ET might think to use and we can look at more closely.
The improvement with interplanetary communications is caused by the detector being better rather than anything inherent to the wavelength - I don't think it applies to interstellar communications.
There's lots of evidence supporting inflationary theory - the fact that measurements show we're in an almost flat universe is the first one to spring to mind.
The speed of light in air is only marginally less than in a vacumn (refractive index of air at sea level: 1.0002926, says wikipedia) and the atmosphere drops in pressure very rapidly on a lunar scale. The exosphere starts at, at most 1000km from the earth's surface, and that's the "beginning of the end" of the atmosphere. The moon is around 400000km away. The light is travelling through the atmosphere for only 0.25% of its journey. The difference in light time from the surface of the earth and the exosphere would be a tiny fraction of a second.
Do those robots of yours work in the extreme range of temperatures you get on the moon? A better comparison would be to existing space probes - say the Mars rovers. Apparently they cost a little short of a billion dollars for 2. Getting to the moon is slightly cheaper than to Mars, and mass production reduces costs, so you're talking a billion or 2 for a lunar mining operation - much higher than your prices.
You also need to factor in the cost of getting whatever you mine back to Earth. Chances are you're going to be sending cargo ships back and forth - you might as well have some supplies on the outward journeys, so no extra cost for sending the required food (and we're already ignoring hydroponics etc).
As for repairs - you can normally tell what is most likely to go wrong with a machine and prepare for it. It is easier for a human to repair such things than another robot.
Admittedly, the almost realtime communications possible with the moon make remote controlled repairs a possibility, but I was thinking about mining asteroids, rather than the moon. If you're going to have people living in the asteriod belt, you might well want to lunar base for a launching platform.
I think your ratio of initial setup to per person is off by quite a bit. The extra cost of making a 2 person base rather than a 1 person base is quite small relative to the cost of the first person. The living space doesn't need to be twice the size. The square-cube law means you need less materials to build a larger dome (proportionally). Atmosphere cycling needs to be increased linearly, but I expect the cost of it isn't linear.
Also, even taking into account that most of your last sentence was an exaggeration, you are overestimating the value of 1.2 billion dollars. Setting up a simple, robotic mining mission will run into the 10s of billions at least, I would guess - adding some people will increase it significantly, but not overwhelmingly.
The cost of having a human technican on site is a constant, regardless of scale. The benefit, however, increases as the number of things for him to fix increases. There becomes a point where the money saved by not having to bring things back to be fixed or even completely replace them outweighs the cost of keeping a human there. Exactly where that point it does indeed depend on costs of things like launches, but the point is somewhere. (Of course, at current costs that point might require more mining than is possible on a single asteriod, so effectively doesn't exist, but oh well.)
Of course, if we get a working space elevator, pretty much everything becomes viable... Hopefully that dream will become a reality sooner or later...
"Yes, there are "tons of resources". Now address why, as the gp mentioned, you think humans should be involved in gathering them at all, given that robotic missions usually are a 20th the price of an equivalent manned mission."
Small scale mining missions would probably be cheaper with robots, yes - once the scale gets larger it becomes economically viable to have technicians on hand to fix things that go wrong. Once the scale gets larger still, it becomes viable to have entire colonies to do the mining.
We'll probably start with robots, but people have a purpose in space too.
Upload speeds years ago were far lower than they are now. The slowest upload speed you get on British ADSL is 256kB/s which works out at just over 9 hours per gig. That's not great, but anyone wanting the upload gigabytes of data on a regular basis would probably have a faster connection (SDSL with 1 meg up isn't too expensive for the kind of business likely to have that much data - and that's just on a phone line. Special lines can get much higher). Leaving your photo collection to upload over night (maybe over a few nights) isn't that much trouble.
It's meant to do all kinds of clever things - I took a look, even read the FAQ, and after a couple of minutes gave up. I couldn't work out how to make it do anything other than be a standard search engine that seemed to give worse results than google. A SE that I have to spend ages working out how to use isn't worth the hassle.
Road signs in London are in miles. They rarely actually specify units, so what made you think they were kilometers?
Speed limits that are explicitly stated are usually either "30" or "40" - both meaning mph. 30kph is very slow...
But yes, supermarkets have everything in metric, by law. I think you can specify imperial units as well, but everything has to be sold in metric units. For example, we get 568ml bottles of milk (although most milk is now sold in integer or half integer numbers of litres - it's just delivered milk [which is getting quite rare] that's still pint bottles).
I expect he meant private - he'd have said "State school" is he meant a government funded school - it's the standard term in England and one that's easy to understand despite "common languages".
I'm sure MS has enough revenue in euros to cover the fine, so changing currency rates won't make any difference. If they were having to pay the fine in dollars, it would mean they were making a loss in Europe, so would just cut the market off completely.
Actually, 2 billion kelvin corresponds to a peak at 1.5pm - someone near the near end of gamma rays, only slightly shorter than x-rays.
I doubt they'd have something in place to measure that normally, but TFA says they repeated the experiment multiple times - they probably went and got an appropriate detector once the one they had started crying. Such detectors aren't hard to come by.
11 minutes? That would be a height of about 1600km above the centre of the Earth - well within the Earth itself (R=6400km). What did you mean?
Actually cold is good for telescopes - it reduces the amount of infra-red the telescope and surrounding objects emit so there's less interference. I expect it's more of an issue with radio scopes than optical, but I know a lot of effort goes into cooling telescopes (and we're talking liquid helium, not just nitrogren - very cold!).
You throw stuff out the back of your rocket while you're near ground, that stuff is going to hit the ground and transfer its momentum. Until you're far enough away for the exhaust to disperse before reaching the ground you effectively push against the ground - you'd get the same thrust without the ground there, certainly, but the ground still recoils. It's a pretty small consideration, though - you can launch from alternate sides of the asteroid if you have to.
Why is this asteroid of yours in Earth's orbit? Seems like an odd example... It probably wouldn't even impact - co-orbital objects usually avoid eachother by one speeding up and one slowing down and thus changing orbits slightly (I believe their are moons of Saturn that do exactly that - try Wikipedia). It would have to be very close to Earth to start with for there not to be time for it to move round.
You pull something towards Earth, yes, it'll speed us. Just as a space shuttle does on re-entry, just as meteors do, it's a simple matter. We use aerobraking to slow things down at the moment, we can do that with the mined goods - just put them inside a reusable heat shield and let them lose their extra speed against the atmosphere.
Those numbers are for any piece of junk hitting, I was talking about a particular golf ball. Obviously if you have hundreds/thousands of bits of junk the chances are increased over just a single bit.
A polar orbit would increase the respective speed, yes, but it also decreases the chance of a collision quite drasticly.
If you're stationary at that altitude you should be more worried about falling back down than about the very slim chance of getting hit by a golf ball. If you're in orbit you'll be moving at roughly the same speed as the ball - the only way you could have a large difference in speed is if there is a large difference in eccentricity of your orbits, however I expect both you and the ball will be in roughly circular orbits (if you get hit during the short time before you circularise your orbit you're *very* unlucky).
Maths may involve calculating the trajectory (actually it involves *how* to calculate it rather than the actual calculation, but examples are a useful learning tool), it doesn't involve actually projecting anything - that's physics. Physics is using maths to predict the results of experiments - if you're actually doing an experiment it's physics, maths is abstract.
How is that maths? It's tech or physics. Maths doesn't involve physical experiments...
And those that can't teach inspect schools.