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SETI Finds Interesting Signal
Several readers sent in notes about an interesting signal discovered by SETI. No real evidence of Someone Out There, but not fully explainable either. Another reader submits a blurb suggesting that aliens should send spacemail, not signals: "Rutgers electrical engineering professor, Christopher Rose, has an article on Nature magazine's cover today describing the most efficient way for our civilization to be discovered by aliens. On this question of better to 'write or radiate', his conclusions: better not to send radio transmission, when physical media like DNA on an asteroid can declare a terrestrial presence. Similar to what motivated Voyager scientists to attach a plaque for the outbound trip. Rose has some great information payload sizes as examples (like the entire information equivalent for our global genome fitting on a 100 pound laptop!)."
Well, the problem with radio signals is that they degrade so fast, and the fact that what we transmit will probably not be intelligible to any foreign species, they may get the drift that we are semi-intelligent, but probably not enough information to decipher where we are from or our purpose. With physical artifacts, as long as the beings can see visible light, there is a good chance that they can get a good jist of what we are trying to convey. We can draw pictures of humans and animals and plants on our planet, and possible draw basic symbols and graphs to make out basic mathematical concepts, and possibly the general location of Earth. While it would be much more difficult to locate a physical object than a radio signal, the short range of a radio way probably makes it impractical for long distance communication in space. Of course, there is the possibility of physical objects degrading with time, but with proper materials this should be pretty limited.
thisnukes4u.net
The first assumption I make is that it has to be water-based organic life. It has to be water...
Not necessarily. On a somewhat cooler world than ours with 4-5% flourine in the atmosphere, water would be immediately broken down into oxygen and hydroflouric acid, which is liquid in the -83 to 19.4 C range.
This works because "plants" could function by photosynthesis with HF in place of water and carbon tetraflouride in place of carbon dioxide to produce H-C-F chain compounds and liberate free flourine, with nickel as the catalyst in place of the magnesium in chlorophyll. We'd have to postulate higher UV energy levels as well to provide enough decomposition energy, but that goes along with a thinner atmosphere and lower temperatures without much of a stretch.
"Animal" soft tissues in this scenario would be about the same as the plants, but hard tissues would be produced by the reaction
{ H-C-F } + F2 -> { F-C-F } + HF
resulting in a teflon boned and shelled organism, probably one muther-tough sonofabitch. His main energy reaction would be
{ H-C-F } + F2 -> CF4 + HF
with a blood catalyst metal of titanium, which would result in colorless arterial blood and violet veinous, as the titanium flips back and forth between tri- and tetra-valent states. So he'd probably be a good deal more energetic than us 02-running organisms as well.
Given what we know about vulcanism on the outer moons and so forth, I wouldn't be surprised to find that a scenario along these lines is rather more probable around the universe than the local one we're familiar with.
Their technology would be rather different than ours too, since no terrestial style organic matter is possible, and there wouldn't be much around except flourides; no oxides, sulfides, silicates, or chlorides. All metallurgy would have to be electrical. Oh, and they probably wouldn't be good mountain climbers either, since flourides are structurally weak; nothing tough like granite to make mountains out of. So technological progress seems a trifle unlikely. But *shrug* they'd probably think that about Earth, too...