Amazing Pictures from Hubble
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Steve_Harris wrote:
I have to disagree. We know that amino acids are widespread and easy to build, but we just don't know the likelihood of them self-assembling into self-replicating structures, so we don't know how likely life is. It could be so vanishingly improbable that we are the only planet where it happened, or it could be widespread. We simply don't know.
Knowing the likelihood is irrelevant, if the universe is infinitely huge then no matter how small the probability, it will have happened. The difficulty lies with us finding it.
My current favourite word is: Delicious!
-SK Genius
Well it's not infinite so the probability matters. Possible and probable aren't the same. It's possible for the chemical reaction in an explosion to reverse but it's so improbable that it has never happened anywhere and never will.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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Steve_Harris wrote:
Our elements heavier than hydrogen are supernova ejecta
Nit: heavier than Helium.
Steve_Harris wrote:
why would they come here anyway?
Counterarguments: 1) Von Neumann (self replicating) probes are the only practical way to survey a large fraction of a galaxy. There's no reason not to keep a few of them in each surveyed system to continually update the creators data. 2) Even at .01c (this is a very low value for a laser sail ship) it would take an expanding lifeform only a few million years to spread across every habitable planet of the galaxy. This is a very small amount of time vs the amount of time life has existed on the Earth. Ego if they existed they should be here already.
The latest nation. Procrastination.
Dan Neely wrote:
Even at .01c
Even at this speed some of the jumps between habitable worlds where new material could be gathered would be thousands, tens or even hundreds of thousands of years. No system in a ship can last this long, things wear out, no life-support system is 100% closed so eventually they would run out of resources (that is, if the enforced confinement hadn't driven them all mad, or to kill each other, or both, long before they got here).
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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Mustafa Ismail Mustafa wrote:
Its a statistical certainty
I have to disagree. We know that amino acids are widespread and easy to build, but we just don't know the likelihood of them self-assembling into self-replicating structures, so we don't know how likely life is. It could be so vanishingly improbable that we are the only planet where it happened, or it could be widespread. We simply don't know.
Mustafa Ismail Mustafa wrote:
We just haven't found them or been found by them yet.
Our elements heavier than hydrogen are supernova ejecta, and as this takes time to accumulate enough to form planets like Earth, we must be one of the first advanced(-ish) civilisations to arise *anywhere*. Interstellar travel without breaking the lightspeed barrier is infeasible due to the timescales involved, and why would they come here anyway? The Solar System is totally unremarkable, there are far more interesting places to visit - globular clusters, the Orion Nebula etc. Our radio transmissions are going to fade to below background noise long before reaching any other star systems so they will have no idea that we have even that level of technology, even after the thousands or millions of years it will take for the signals to reach them, and the same is true for their transmissions heading our way. We will never pick up their stray transmissions. I would love for intelligent aliens to turn up on Earth, or at least evidence for them, but I just don't believe it will happen in the forseeable future.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
Steve_Harris wrote:
I have to disagree. We know that amino acids are widespread and easy to build, but we just don't know the likelihood of them self-assembling into self-replicating structures, so we don't know how likely life is. It could be so vanishingly improbable that we are the only planet where it happened, or it could be widespread. We simply don't know.
OK, I'll grant you that we don't know. But, the sheer vastness of space can't but keep on nudging me to the certainty part.
Steve_Harris wrote:
Our elements heavier than hydrogen are supernova ejecta, and as this takes time to accumulate enough to form planets like Earth, we must be one of the first advanced(-ish) civilisations to arise *anywhere*.
The estimated age of the Universe is 13.5 - 14 Billion years[^] and the estimated age of the Earth is, in comparison, a measly 4.54 Billion years[^]. Nearly 10 Billion years is a loooooooooong time by any measure. We as of yet do not have any "precise" measure of the ages of other planets. The numbers are staggering; 30 - 70 Sextillion[^] I can't even begin to imagine how massive that number is! I'm no cosmological expert, but I'd guess with such a massive field to play with, there's almost bound to be other intelligent life in the universe and even better likely that there are several, regardless of the stage of their technological development.
If the post was helpful, please vote, eh! Current activities: Book: Devils by Fyodor Dostoyevsky Project: Hospital Automation, final stage Learning: Image analysis, LINQ Now and forever, defiant to the end. What is Multiple Sclerosis[^]?
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Steve_Harris wrote:
I have to disagree. We know that amino acids are widespread and easy to build, but we just don't know the likelihood of them self-assembling into self-replicating structures, so we don't know how likely life is. It could be so vanishingly improbable that we are the only planet where it happened, or it could be widespread. We simply don't know.
OK, I'll grant you that we don't know. But, the sheer vastness of space can't but keep on nudging me to the certainty part.
Steve_Harris wrote:
Our elements heavier than hydrogen are supernova ejecta, and as this takes time to accumulate enough to form planets like Earth, we must be one of the first advanced(-ish) civilisations to arise *anywhere*.
The estimated age of the Universe is 13.5 - 14 Billion years[^] and the estimated age of the Earth is, in comparison, a measly 4.54 Billion years[^]. Nearly 10 Billion years is a loooooooooong time by any measure. We as of yet do not have any "precise" measure of the ages of other planets. The numbers are staggering; 30 - 70 Sextillion[^] I can't even begin to imagine how massive that number is! I'm no cosmological expert, but I'd guess with such a massive field to play with, there's almost bound to be other intelligent life in the universe and even better likely that there are several, regardless of the stage of their technological development.
If the post was helpful, please vote, eh! Current activities: Book: Devils by Fyodor Dostoyevsky Project: Hospital Automation, final stage Learning: Image analysis, LINQ Now and forever, defiant to the end. What is Multiple Sclerosis[^]?
I don't remember the name of the book, but Stephen Baxter discusses the "if they are there why don't we see them" question in one of his novels, and the conclusion was that it was because of the violent events (Gamma Ray Bursts etc) which occur, with decreasing frequency as their energy increases. These events sterilise or at least destroy all higher life within their sphere of influence. Baxter argues that the high-energy events happen frequently enough to send life through a whole galaxy (or a large chunk of one) back to the primordial soup if not destroy it completely, so all intelligent species can only survive a finite time before being destroyed. These "life reboot" events prevent any species surviving long enough to develop far enough to escape the events, which is why the galaxy isn't populated by intelligent space-faring species.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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I don't remember the name of the book, but Stephen Baxter discusses the "if they are there why don't we see them" question in one of his novels, and the conclusion was that it was because of the violent events (Gamma Ray Bursts etc) which occur, with decreasing frequency as their energy increases. These events sterilise or at least destroy all higher life within their sphere of influence. Baxter argues that the high-energy events happen frequently enough to send life through a whole galaxy (or a large chunk of one) back to the primordial soup if not destroy it completely, so all intelligent species can only survive a finite time before being destroyed. These "life reboot" events prevent any species surviving long enough to develop far enough to escape the events, which is why the galaxy isn't populated by intelligent space-faring species.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
Steve_Harris wrote:
"if they are there why don't we see them"
I'd simply hazard the guess that size of space is massive. Intelligent life, regardless of their level of technology, might not neccessarily be in our galaxy which would effectively label them as our neighbors. They could just as easily be in a whole other galaxy, millions if not billions of ly away. Beyond that, I couldn't say other than anything is possible.
If the post was helpful, please vote, eh! Current activities: Book: Devils by Fyodor Dostoyevsky Project: Hospital Automation, final stage Learning: Image analysis, LINQ Now and forever, defiant to the end. What is Multiple Sclerosis[^]?
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I don't remember the name of the book, but Stephen Baxter discusses the "if they are there why don't we see them" question in one of his novels, and the conclusion was that it was because of the violent events (Gamma Ray Bursts etc) which occur, with decreasing frequency as their energy increases. These events sterilise or at least destroy all higher life within their sphere of influence. Baxter argues that the high-energy events happen frequently enough to send life through a whole galaxy (or a large chunk of one) back to the primordial soup if not destroy it completely, so all intelligent species can only survive a finite time before being destroyed. These "life reboot" events prevent any species surviving long enough to develop far enough to escape the events, which is why the galaxy isn't populated by intelligent space-faring species.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
That would be Manifold Space. It's predecessor Manifold Time was also enjoyable despite having a completely different premise (we were the first and only intelligence). The 3rd book Manifold Origin is crap. He's written an anthology on the same theme Manifold Phase Space that I've not read, and can't comment on.
The latest nation. Procrastination.
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Dan Neely wrote:
Even at .01c
Even at this speed some of the jumps between habitable worlds where new material could be gathered would be thousands, tens or even hundreds of thousands of years. No system in a ship can last this long, things wear out, no life-support system is 100% closed so eventually they would run out of resources (that is, if the enforced confinement hadn't driven them all mad, or to kill each other, or both, long before they got here).
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
Who said the colony ships had to be crewed during the transit. Just include genetic information in a von Nuemann probe's database and have it build uterine replicators and nannybots along with it's own successors. For that matter i lowballed the speed, .1c is probably feasible for laser sails, which would put uninhabited systems that could be mined for supplies a few decades apart. A civilization using space habitats wouldn't need a terrestrial planet in the first place, and the evidence that all non giant stars have planetary systems of some sort is becoming overwhelming. Studies of angular momentum had made it very likely even before the first extra solar planet had been spotted: Smaller stars didn't have enough in their own spin, the sun's spin momentum + orbital momentum of the planets (mostly Jupiter) added up to the expected value.
The latest nation. Procrastination.
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It may just be me, but why is it that the images (stunning as they are) always seem to have at least one star that has a "star" burst filter effect applied to it (compass like light rays emanating from the star)? Is this deliberately applied by Nasa or is this some sort aberration of the equipment they use? To me this effect is very distracting.
Peter Hayward Ngarkat Technologies South Australia,
They're Diffraction Spikes[^]. Any standard configuration reflecting telescope will have them, and none of the variants that don't scale to larger sizes. The correctors that Schmidt and Mastsukov cassegrains use suffer the same problems that limited the size of refractors: the far greater difficulty of creating a volume of perfect glass vs a perfect surface, and that eventually the glass distorts under its own weight and can no longer maintain a proper optical figure. Off Axis designs are either made by making a giant mirror and cutting smaller chunks out of it's side (impractical for bigger scopes) or use rube goldberg optics to try and correct for the astigmatism caused by tilting the primary mirror. These also tend to have much slower focal ratios (~f/10) to aid in that, while the giant research scopes have extremely fast ratios (as low as f/.1) to keep the image scale/field of view reasonable and to reduce weight.
The latest nation. Procrastination.
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Well it's not infinite so the probability matters. Possible and probable aren't the same. It's possible for the chemical reaction in an explosion to reverse but it's so improbable that it has never happened anywhere and never will.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
You wrote: it's so improbable that it has never happened anywhere and never will. A bit of nit picking: how does "so improbable that ... never will" differ from impossible? Impossible and improbable aren't the same thing either.
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Who said the colony ships had to be crewed during the transit. Just include genetic information in a von Nuemann probe's database and have it build uterine replicators and nannybots along with it's own successors. For that matter i lowballed the speed, .1c is probably feasible for laser sails, which would put uninhabited systems that could be mined for supplies a few decades apart. A civilization using space habitats wouldn't need a terrestrial planet in the first place, and the evidence that all non giant stars have planetary systems of some sort is becoming overwhelming. Studies of angular momentum had made it very likely even before the first extra solar planet had been spotted: Smaller stars didn't have enough in their own spin, the sun's spin momentum + orbital momentum of the planets (mostly Jupiter) added up to the expected value.
The latest nation. Procrastination.
How do you think the vat-born offspring of such a species would feel, being brought up to know that they were cast adrift in space, never to know their parents or home planet, or if they even still existed? How would you protect a "laser sail" and its crew from collisions when running at 0.1c?
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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I do not totally disagree with your statement, but to discuss this further will result in my having to turn this into a political conversation, which I'd rather not turn this into, however, there is no doubt that politics were a major, driving force behind our going to the moon; and "yes", our differences with Russia played a key role in the decisions made back then. But 'petty differences' are also what keeps us from achieving even greater things, and I firmly believe that those challenges must be met by everyone on this planet, and not just one nation, and until we can put these child like differences aside and work together, we'll never truly accomplish what we could. ... and I seriously hope, for the continued survival of our species, that one day, our children are able to look past all that, and reach out to the stars, before this planet's time is up, because regardless of what you believe, think, say or do ... Earth will eventually die, and all life on it will die with her, and we cannot stop it.
:..::. Douglas H. Troy ::..
Bad Astronomy |VCF|wxWidgets|WTLAmém!
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Just wanted to make certain that the space enthusiasts here, saw the latest jaw dropping Hubble images: http://www.spacetelescope.org/images/html/heic0911c.html[^] http://www.spacetelescope.org/images/html/heic0911b.html[^] Just incredible stuff. (make certain you click on the images to enlarge them)
:..::. Douglas H. Troy ::..
Bad Astronomy |VCF|wxWidgets|WTLOh man, I love this stuff as much as the universe is not understood. I wish that when we die, God gives us a free ride through the universe.
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How do you think the vat-born offspring of such a species would feel, being brought up to know that they were cast adrift in space, never to know their parents or home planet, or if they even still existed? How would you protect a "laser sail" and its crew from collisions when running at 0.1c?
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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low power forward firing lasers to ionize the ISM and a magnetic field to deflect the charged particles.
The latest nation. Procrastination.
Not much help if you meet one of these![^] At 0.1c even a pea-sized rock is going to do serious damage. 10g at 0.1c has a kinetic energy (0.5*m*v*v) of (thanks to Google): 0.5 x 0.01 kg x 0.1 * c x 0.1 * c = 4.49377589 × 1012 joules I wouldn't want to get in the way of it.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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Not much help if you meet one of these![^] At 0.1c even a pea-sized rock is going to do serious damage. 10g at 0.1c has a kinetic energy (0.5*m*v*v) of (thanks to Google): 0.5 x 0.01 kg x 0.1 * c x 0.1 * c = 4.49377589 × 1012 joules I wouldn't want to get in the way of it.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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Once the lasers convert them to plasma any gravel they run into can be defected as easily as single atoms. Larger objects would need to be dodged, but are correspondingly much easier to detect.
The latest nation. Procrastination.
My mistake, you said "low power lasers", I think you meant "lasers powerful enough to turn stone to plasma". Running those, and the magnetic deflectors, for decades if not millennia isn't going to come cheap...
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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My mistake, you said "low power lasers", I think you meant "lasers powerful enough to turn stone to plasma". Running those, and the magnetic deflectors, for decades if not millennia isn't going to come cheap...
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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Everything is relative. They are low power vs the amount of energy needed for the lasers at the launch site pushing the sail itself.
The latest nation. Procrastination.
But not inconsiderable in their own right. If they can turn stone to plasma, how does the craft avoid being vaporised by the much more powerful pushing laser?
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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You wrote: it's so improbable that it has never happened anywhere and never will. A bit of nit picking: how does "so improbable that ... never will" differ from impossible? Impossible and improbable aren't the same thing either.
One has a finite but vanishingly small probability, one has a probability of zero.
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine
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But not inconsiderable in their own right. If they can turn stone to plasma, how does the craft avoid being vaporised by the much more powerful pushing laser?
I hope you realise that hamsters are very creative when it comes to revenge. - Elaine