Boffin: Earthlike worlds within 30 lightyears of here A heavyweight American boffin says that Earthlike worlds will soon be discovered within 30 light-years of our Solar System, and that such worlds' abundance across the universe means that the existence of alien life is a racing cert. Speaking in advance of the American Association for the Advancement of Science annual meeting, …
There's plenty of evidence that planetary systems are relatively common around normal (and some abnormal) stars. Nearly all those observed so far, however, have been Jupiter-sized or larger in very close proximity to the star - there's a lot of observational bias (this type of planet is much easier to detect using current methods), but still it appears that nice, orderly solar systems like the one we live in may be the exception. Gas giants tend to form further out than rocky planets like the Earth - if they then somehow migrate inwards, the aforementioned earth-like planets will get skittled out of the way, into a zone that is not habitable.
Any theory that proposes a significant number of 'advanced' civilisations in the galaxy must find a plausible method of dealing with Fermi's paradox:
http://en.wikipedia.org/wiki/Fermi_paradox
Just wondering, as Erich Von Daniken made the same conclusions years ago in his books. If you consider that there are billions upon billions of stars then even with a relatively low probabilty of any given star having an orbiting planet which can support life, there are still likely to be millions of inhabited worlds.
Well, that's the very basics of it, but probabilty alone would dictate that it's pretty likely that other intelligent species exist elsewhere.
I look forward to seeing the images of the night-side of an alien civilisation. It'll be pretty and also revolutionary for us.
Less looking forward to seeing some snapshot of an epic space battle (although if anything would galvanise the human race to stop its petty squabbling, that would)
But how would "radio signals", "evidence of water", "X% oxygen" etc... be proof of life? I find it increasingly amusing that scientists consider our form of existence to be the only form possible; ignoring sea life, plant life, ozone life.. all these things which could support life far more complex and intelligent than our own.
...working quantum entanglement, which it appears is well on its way, means that we could conceivably have a satellite orbiting a planet 10 light years away, and sending back live images, within 50 years or so. Maybe even less, if the republicans stop crushing science spending.
Kind of mind boggling, innit?
It's a fair point but partially it's to do with chemistry - life is a series of chmical reactions and the physics required for biological reactions favours certain elements more than others. That's not to say other possibilities aren't out there though.
The big problem with the 'there's loads of stars so there must be loads of Earths' theory is taht it ignores several low-probability things that have effected how the Earth develop. Firstly, we were hit by a mars-sized object in our early history which ahs provided us with a truly massive moon for our size. Due to its size the moon has been able to stabilise a lot of the orbital eccentricities that effect other planets. These eccentricities would have lead to extreme climate variation which would in turn have made it very difficult for life to get a foothold.
We also exist in a fairly narrow band of space where water is neither frozen all year or boiled off into the atmosphere.
On top of that, we have a liquid iron outer core and solid inner core. The geomagnetism produced by this gives us a protective shield which reduces the ability of the solar wind to a) irradiate us all and b) strip away our atmosphere.
There's a whole host of other peculiarities. The other thing people forget is that there is an observer bias here. It may seem odd that there are no other planets like ours, but if very special conditions are required to get life then life can only evolve to observe those conditions. As a result you then take those conditions for granted and assume they must be common.
"Any theory that proposes a significant number of 'advanced' civilisations in the galaxy must find a plausible method of dealing with Fermi's paradox:"
The plausible method is known. And simple. And depressing: 'advanced' civilisations do not last very long.
Fermi's question (it's only a paradox if you start from the totally unfounded assumption that intelligent life is common. If you admit that it's unfounded, the paradoxical part vanishes) has two basic answers: Either intelligent technic civilisations are extremely rare, or they don't last long.
An arxiv paper a few weeks ago gave an upper bound: if an advanced civilisation lasts 1000 year before vanishing (as "advanced civilisation", we're still at a bit less than a century), then there are less than 350 advanced civilisations in the galaxy.
It sounds like a great idea, but the problem with quantum entanglement is you'd need to create a large number of entangled particles (enough to send data packets), somehow store them on the probe for say, 60 or more years (accelerate to close to the speed of light if possible, then decelerate from the halfway point), all the while keeping them secure and free from any contamination. And keeping the probe safe from micro-meteors and even elementary particles at a large fraction of the speed of light) And of course expecting everything to still work after a journey that lasted the better part of a century. Oh, and keeping the entangled particles' counterparts on Earth safe as well. Our probes still need to come a long way to reach that kind of reliability, not counting Voyager 1&2. It'd be almost as cool to point the spacecraft back at Earth and look back in time.
I'm certain there's earth-like planets out there, but maybe expecting any to be within comparatively easy reach is a bit much. Amazing how far away 30 light years really is.
Sorry to add another downer to this idea, but quantum entanglement wouldn't help in the slightest. Entangled particles can flip states simultaneously over an arbitrarily large distance, but nature has ensured that no useful information can ever be transmitted at faster than the speed of light. Entanglement is a private process between the particles concerned... any attempt to actually measure the state of one of the particles buggers up the quantum mechanics good and proper. Sorry.
There are many proposed solutions to the Fermi paradox/question - for 50 of them, see "Where is Everybody?" by Stephen Webb. None of them (to my satisfaction, anyway) addresses the issue that if just one technological civilisation discovers (during its 1,000 year lifetime) a means of breaking free from its original solar system, it can 'easily' colonise a galaxy within a few hundred million years (no warp drive necessary, though it would be nice).
Well, first of all, that wouldn't be "proof". Boss loses a great deal of credibility in my eyes by misusing that word so blatantly.
It would, however, be evidence, because the only cause for such phenomena that we have observed is life. It would not be proof because we haven't eliminated the possibility of other causes.
More important to your question, though, is that this is not a strict one-to-one relation as you infer. In other words, if we don't find those things, that does not prove that there isn't life there. It simply means that we don't have evidence of the easiest*-to-detect form of life.
In short, just because a => b, that doesn't always mean that !a => !b.
* Easiest for us, that is.
But perhaps it's possible to entangle the states of two particles at a distance? It would mean "smearing out" the synchronisation apparatus over the vast distances involved, but if quantum mechanics allows for the possibility of entanglement in the first place and also really counter-intuitive results such as non-destructive bomb testing, quantum cryptography and the like, who knows what else is theoretically possible? Of course, it would still take in the region of 40-60 years to synchronise the first qubit or batch of qubits, and there might not be much worth discussing over the comms channel at that point.
is left undefined. There are a number of characteristics, some of which have been mentioned: size, distance from sun, length of day, magnetosphere, temperature, elemental composition, etc. Any of those could be used to claim a planet is 'earth-like'.
They also make some big assumptions about what life has to be like. Most lifeforms we see use oxygen or carbon dioxide and sunlight. There are also microbes that eat methane and other hydrocarbons. Whole ecosystems thrive around deep ocean hydrothermal vents, metabolizing sulfur compounds and such. Similar colonies exist around mineral-rich cold water seeps coming out of continental landmasses. There are even bacteria living in rock more than a mile deep, powered by radioactive elements. So the presence or absence of certain atmospheric gasses is not a reliable indicator of life. Even water might not be necessary; ammonia has similar properties.
That said, I do think that extrasolar planets will turn out to be fairly common. There are currently 321 known extrasolar planets, 287 of which are within 1000 light-years, so planetary formation clearly isn't an unusual process. Our solar system ended up with four rocky planets, an asteroid belt with enough material for a fifth, four gas giant planets, and a large field of debris. It would actually be surprising for a star to form from a cloud of dust and not have any large pieces left in some sort of orbit.
They also make some big assumptions about what life has to be like.
Agreed. I would suggest that there are more strictly anaerobic bacteria than there are strict aerobes. Most bacteria grow perfectly well under anaerobic conditions, even when they are classified as aerobes. (One of the distinguishing features of an aerobe is the presence of an enzyme called catalase, although aerobic streptococci do not possess this enzyme!). No-one could suggest that bacteria are rare, so how anyone could make these statements without having some small knowledge of their characteristics shows a lack of forethought.
"""
Less looking forward to seeing some snapshot of an epic space battle (although if anything would galvanise the human race to stop its petty squabbling, that would)
"""
Aye, It would! In a swift and summary manner: Those Gamma Ray Bursts will be found to be the alien equivalent of Somali technicals lighting up some competing home boyz ;-)
They haven't been able to "prove" if life does or does not exists on Mars (part of the reason for sending the probes), how are they going to prove life exists on planets 30 (or more) light years away without going there?
Science is the new religion and the scientists are the priests
We really don't need yet another class of self promoting elitists accusing us of heresy anytime we question any of their proclamations.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2024
