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Comment Re:Isn't it widely accepted... (Score 1) 104

It's not that simple. Mercury also has a magnetic field. Which is a real head-scratcher, as it's even smaller than Mars.

Internal planetary dynamics are complicated. To get a dynamo you need fluid flow. But whether something is liquid or solid depends on both temperature and pressure - temperature increasing melt, pressure decreasing it. So there's a very complicated interplay.

Comment Re:Isn't it widely accepted... (Score 3, Informative) 104

Very little energy reaches the Venusian surface - Venus's albedo is twice that of Earth's, so most light gets reflected from the cloud deck, and what does enter gets quickly absorbed in the clouds and thick atmosphere. Also, the crust is not what drives a dynamo, the core does. Nuclear decay is what drives terrestrial planet cores, not solar input.

Also I don't know what you mean by "rapid crust recycling", unless you mean Venus's global resurfacing events. But those only happen once every several hundred million years. And they take about 100 million years to complete, they're not rapid.

Comment Isn't it widely accepted... (Score 4, Interesting) 104

... that because of Mars' small size, it cooled faster, thus freezing its outer core and shutting down its dynamo? Isn't Venus the far greater mystery? Nearly the same size as Earth, yet no magnetic field and what appears to be occasional whole-crust overturn rather than plate tectonics? Isn't that the one we need to solve?

Comment Re:core point (Score 1) 150

I agree. The field of extraterrestrial linguistics has seriously advanced beyond then, thankfully, with communications systems based on logic system, and even a transmittable operating system that explains how it should be run (inputs, outputs, etc), enabling one to send interactive programs along with it.

It's funny, but there's a concept I've never seen before in science fiction: that of multiple alien species living amongst each other, but whose homeworlds are vast cosmic distances apart and who have never gotten anywhere close to each other due to the difficulties of approaching relativistic velocities in spacetravel. How? Bit by bit we understand more of "what makes us tick". Not just how DNA codes for proteins, but the whole complex interplay of these proteins in keeping a cell operating. We now understand how to turn skin cells to pluripotent stem cells, stem cells to primordial germ cells, and are approaching being able to turn them into eggs and sperm without having to implant them in testes or ovaries. Some day, probably somewhere between several decades to a century or so from now, we may well have developed the ability to create a fertilized egg completely from scratch - including all of the organelles necessary to keep it alive - and an artificial womb to carry it in. Once one has transmitted the means to convey information and technology, plans can be transmitted (ala Contact, but with technology for biological creation, not communication). One could send to another world every last step needed to create and nurture a human being in-situ, along with a interactive computerized childrearing "system" for the child's early years, along with a discussion of exactly what is being done at each stage. And other species could do this as well in their transmissions to us.

Of course, if the "singularity" people are right, one could just transmit a sentient program to other worlds and be done with it far simpler. Either way, whether anything gets done with a signal depends on whether they're 1) actually out there, 2) close enough, 3) receive the message, 4) detect it, 5) recognize it as carrying information from sentient beings, 6) decipher it, 7) and perhaps most importantly, decide whether they want to actually risk trusting this transmission from an alien world. Lots of "ifs", to say the least.

Comment Re:core point (Score 1) 150

To be able to hold a pointing orientation in space, one has to be able to understand 2D. To be able to understand changing positions in space, one has to be able to understand 3D. To interact with physical objects, they must have some method to perceive their shape. If they're interacting with spacecraft, they have to be able to do some pretty damned precise things in regards to all three of these things The methods used to be able to do these things may be alien to us, but they have to be able to understand them in some sort of form. They essentially have to be able to perceive the voyager plates, perceive that there's information of some form on there, and have the mental wherewithal to convert it into whatever coordinate space / representation system their minds use, and to begin to make deductions about its meaning.

They could reach the wrong conclusions. But if they're spacefaring, they have to at least be capable of advanced reasoning, so they're going to have a shot at it.

Comment Re:...uhh (Score 5, Interesting) 150

Every signal that we have sent out requires them to be visually oriented. Do you think the TV signals we beam into space will make any sense to beings that communicate ultrasonically? An encoded 2D image interlaced with alternate lines 30 times a second won't be of much use to intelligent vampire bats.

Okay, first off...

1) Vampire bats do not work that way.

2) Humans take information that our senses can't perceive all the time and turn in into forms that we can. That's what false-color images and the like are.

3) A species that can pick up the signal (as the GP posited) is most definitely able to transform signals between mediums. It's pretty much a fundamental part of any receiver technology - you take a propagating signal, turn it into data, then turn the data into a form that you can perceive.

Obviously no species is going to inherently have the recipe for demodulating the signal just handed to them - they'll have to figure it out, even if their senses are precisely the same as ours. They'll have to recognize, "hey there's a signal here, and by its pattern it doesn't appear to be naturally generated and seems to be storing data in some manner". They'll then have to reverse engineer how to pull the data out of the signal. Then they'll have to figure out how the data is structured (probably the hardest part, esp. with modern compressed digital formats). All of these apply to all beings. But once you've figured all of that out, turning it into a form that you can perceive is the easy part.

Say there's a species with no vision that can only experiences the world through ultrasound echolocation, as in what you probably intended to be your example? Once you understand that the signal is, say, periodic frames representing an array of triplet values (what we know to be RGB) and know how to decode it to that, the species may play it back by, say, an "ultrasound screen" that creates the perception of a 3-dimensional surface, with the height representing pixel intensity. Maybe they might combine all three RGB values into one height, maybe they might present them as side by side heightfields, maybe they might use one value to represent height, another to represent surface roughness, another to represent sound absorptive properties of the surface, or somesuch. They'll pick whatever is most convenient for them.

I'm not going to humour your "liquid methane temperature" communication concept because that's far too low bandwidth for a sentient species to practically use. Pheromones also. And "interference patterns of UV radiation", that depends on what you mean by "interference patterns" - you're either talking about a UV equivalent of echolocation, as above, or just visible data shifted into the UV, which is just a frequency shift on the RGB image into their visual range. We as humans do frequency shifts of astronomical data all the time, that's what every image made from a UV, X-ray, IR, radio, etc telescope is.

For any species to be able to get to the phase of being able to receive and demodulate communications, it must have at least the concept and ability to perceive 2D orientation (if not 3D), because it has to be able to align receivers with the right patch of sky. That perception can be of some unthinkably bizarre form by our standards, but it has to exist. Whatever perception of 2D it has, 2d images can be presented in that form.

Your Pi/Tau example is clearly pointless. We as humans clearly know of both constants. Sure, Pi "stands out" more to us at first glance, but if we received something that appeared to be of non-natural origin, you really think nobody would notice if the data was Tau?

Circles are no more "rare in water" than on land. The cross section of a sphere is a circle. What do you think bubbles are? Rounded rocks? Round sea life? Heck, lava underwater, unlike on land, tends to produce round structures called pillow lava. And again, if this to the point of being able to isolate faint radio transmissions from the cosmos and recognize natural from manmade, then it's familiar with all sorts of other concepts - stars, planets, moons, orbits, and countless other macroscopic round things, as well as microscopic / subatomic round things, both 2d (circles) and 3d (spheres). And how exactly are their mathematicians (which they fundamentally must have to be able to be able to demodulate these signals) not figuring out what shape has the least surface to area (or in 3d, surface area to volume) ratios? How are they dealing with radio transmissions without understanding sines/cosines and the like?

There is no such thing as "a constant that describes the relationship of the volume of a sphere to its radius/diameter". To its radius/diameter cubed, yes, but not its radius/diameter. And you really think that mathematicians trying to figure out a transmission from another world wouldn't be able to figure out that a number was 3/4 Pi? Seriously?

In your last example (gravity waves), you've switched to something entirely else entirely. You're responding to a post based on the premise " If they have the ability to pick up the signal". So why are you talking about a situation where they can't pick up the signal because they communicate by gravity waves and we don't? And seriously, if they can manage something as difficult as gravity wave communication, radio wave communication is going to be laughably simple to them.

Comment Re:A Rover? (Score 1) 46

We don't have the post WWII impetus and properly taxed corporations of the 1960s anymore. We have a fractured populace entertained to death, and any increased productivity or technological gains are immediately funneled up towards the rich.

Funny how a society with single income families and no cell phones was able to put people on the Moon, hm?

And this is generally treated (even by people concerned about it) as a fact of nature, something like the drought in California or dust storms on Mars.

Comment Re:Righthaven (Score 1) 64

What is right wing about filing a lawsuit to unmask a doe, suing that person, then settling for a much smaller amount. It seems this is used by many different trolls, and likely doesn't have any political ideology behind it. It is sleazy though. Filing a lawsuit with the intention of settling just to get a payout is wrong. It is short circuiting the justice system for personal profit.

Yeah that's neither right nor left, it's the universal language of greedy bloodsuckers.

Comment Re:Righthaven (Score 3, Interesting) 64

What is right wing about that process? The Democrats support the movie industry, not the Republicans.

The fact that Democrats support something doesn't negate the possibility of something being right wing. The Democrats are not ideologically pure, or ideologically homogenous, and very few of them can be considered "left".

To me, pretending that copyright is only about property rights, and ignoring the fact that copyright was also supposed to be about free speech and about making material available for free to the public after a limited time, is definitely "right wing".

A right is not what someone gives you; it's what no one can take from you. -- Ramsey Clark