EPTScientists discover *life* on another galaxy. - Page 2
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liosama
Australia843 Posts
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Zoler
Sweden6339 Posts
On March 14 2010 04:39 liosama wrote: Also our bias of what life is causes us to think there is only one type of chemistry by which 'life' can exist. For all we know there could be beings who are made of entirely different chemistry than our own - As the great Carl Sagan mentioned I bet they're all made of Starcraft and they play koreans (I know makes zero sense) | ||
intrigue
Washington, D.C9933 Posts
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VorcePA
United States1102 Posts
On March 14 2010 04:29 LuCky. wrote: The only way to travel farther than our solar system is through time travel. Therefore, we need the technology to "grab" light and pull it back. The speed of light is what limits our ability of time-travelling. Errrr... no it doesn't. We theorize that it does because of our understanding of physics, but we've never been able to test it. We understand a significant portion about the world we live in, including electromagnetic energy, physics, and chemistry. But the one thing we haven't really got a grasp on that would be relevant to this discussion is gravity. All of our math seems to be wrong when it comes to that force, and it's theorized that if we ever make a breakthrough that complements or replaces our theory of general relativity, we can bend space to our will (funnily enough, much like the Protoss :p /nerd ) | ||
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zer0das
United States8519 Posts
On March 14 2010 04:34 DefMatrixUltra wrote: [1] Short answer: yes. Spectrum analysis is, in theory, a way to identify any compound. Now, the things that we can actually measure practically very easily are things like single atoms or 'small' compounds (compounds made up of a small number of different elements). So stuff like Hydrogen, Helium, Nitrogen etc. is easily identified 100% of the time. Getting into larger compounds sort of stretches the limits of computational power. The calculations required to determine what spectra a compound produces are enormous and extremely complicated (lots of very advanced quantum mechanics). However, once you have the spectra (once you've spent your couple of weeks time on a supercomputer), you have it. You know it, and it will always be correct. The cool thing about atomic spectra is that quantum mechanics gives an enormous amount of constraints on what spectra can be produced - so each atomic configuration + energy configuration can only have a single spectra. This is why spectrum analysis can give 100% identification of a compound, assuming you've already calculated the answer and can relate it to something you've measured. While nothing you say is really wrong, I think you're kind of oversimplifying things. There are many different types of transitions that molecules can undergo. The ones that are generally examined are: Rotational (less than 0.01 of an electronvolt, or eV) Vibrational (a few tenths of an electronvolt) Electronic (several eV) The vibrational excitation of molecules happens into the IR region (IR also is known as thermal energy) of the electromagnetic spectrum. However, the molecule must have a dipole moment, or else it will not absorb infrared energy. So you would never see nitrogen in an IR spectrum, nor would you see individual atoms. However, even something as simple as water can be seen (at around 3200-3500 wavenumbers, which is just an inverse centimeter and a unit of energy). Electronic transitions correspond to the visible and ultraviolet part of the electromagnetic spectrum. If you wanted to look at emissions of atoms though, you'd put everything in a flame or furnace. I somehow doubt that emission spectroscopy of atoms in space would be an easy thing. Although after reading the documentation about the instruments, apparently there are some metastable atomic transitions in the near IR... which I was not aware of (I can't imagine these are easy to see though). As far as accuracy goes, as long as the absorption is strong enough, then you know something is there, so long as you already know its absorptions. Although generally speaking, IR is only used for identifying what functional groups are present, each individual spectrum is unique, so you can back out what is present based on known spectra, to some extent (although there are generally easier methods, if you have a purified sample to work with... nuclear magnetic resonance spectroscopy (NMR) or mass spectrometry, for example). But in this case, everything is so simple, it would be fairly trivial to look at a spectra and say "oh, water and carbon dioxide is there!" | ||
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SpiritoftheTunA
United States20903 Posts
On March 14 2010 04:57 VorcePA wrote: All of our math seems to be wrong when it comes to that force, and it's theorized that if we ever make a breakthrough that complements or replaces our theory of general relativity, we can bend space to our will (funnily enough, much like the Protoss :p /nerd ) Um, our math is only wrong when it comes to trying to mix gravity/generalrelativity with quantum mechanics. It also doesn't fully explain the behaviors of some galaxies, but that's where dark matter (mass distribution of galaxies) / dark energy (accelerated expansion of the universe) / dark flow (some parts of the universe going in a weird direction) come in, just placeholders until we understand what the hell's going on there. To say that "all of our math seems to be wrong when ti comes to that force" is a bit of an exaggeration... | ||
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DefMatrixUltra
Canada1992 Posts
On March 14 2010 04:57 VorcePA wrote: Errrr... no it doesn't. We theorize that it does because of our understanding of physics, but we've never been able to test it. We understand a significant portion about the world we live in, including electromagnetic energy, physics, and chemistry. But the one thing we haven't really got a grasp on that would be relevant to this discussion is gravity. All of our math seems to be wrong when it comes to that force, and it's theorized that if we ever make a breakthrough that complements or replaces our theory of general relativity, we can bend space to our will (funnily enough, much like the Protoss :p /nerd ) I am a physicist. Almost everything you are saying is nonsense. We have a really great understanding of gravity. Even just using plain old Newtonian gravity solves pretty much any problem that we could be presented with. Gravity was the first of the forces that we started studying, look at the n-body problem. General relativity already shows us that solutions exist where we can 'bend space to our will' by warping spacetime in order to travel 'globally' faster than light (but not locally). The only thing we don't have is a quantum theory of gravity, which as far as we can tell is primarily of interest for understanding the early formation of the universe. I'm not saying that we know everything and we've got this shit figured out, but please don't post garbage like this without even trying (like pointing at some crackpot's paper [Null physics anyone?]). On March 14 2010 05:07 zer0das wrote: While nothing you say is really wrong, I think you're kind of oversimplifying things. [1] There are many different types of transitions that molecules can undergo. The ones that are generally examined are: Rotational (less than 0.01 of an electronvolt, or eV) Vibrational (a few tenths of an electronvolt) Electronic (several eV) The vibrational excitation of molecules happens into the IR region (IR also is known as thermal energy) of the electromagnetic spectrum. However, the molecule must have a dipole moment, or else it will not absorb infrared energy. So you would never see nitrogen in an IR spectrum, nor would you see individual atoms. However, even something as simple as water can be seen (at around 3200-3500 wavenumbers, which is just an inverse centimeter and a unit of energy). Electronic transitions correspond to the visible and ultraviolet part of the electromagnetic spectrum. If you wanted to look at emissions of atoms though, you'd put everything in a flame or furnace. I somehow doubt that emission spectroscopy in space would be an easy thing. [2] [1] Answering a post on a non-physics forum, it's pretty much impossible to not oversimplify things. It seems like you are speaking from a chemistry/thermodynamics perspective. I have actually worked with astrophysicists on these spectral analysis problems (correcting for redshift and everything). [2] It is very difficult. That's why we can't do a simple analysis on most of the things we're looking for. You have to calculate the spectra from quantum mechanics (you can't just assume your particles are in a boiler or whatever). Once you correct for redshift and doppler effect, you can get an identification 100% of the time, assuming the spectra is something familiar or something you have calculated already. I addressed most of your explanation in my "atomic configuration + energy configuration can only have a single spectra" without trying to explain the different modes that complex compounds can have. | ||
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VorcePA
United States1102 Posts
On March 14 2010 05:07 SpiritoftheTunA wrote: Um, our math is only wrong when it comes to trying to mix gravity/generalrelativity with quantum mechanics. It also doesn't fully explain the behaviors of some galaxies, but that's where dark matter (mass distribution of galaxies) / dark energy (accelerated expansion of the universe) / dark flow (some parts of the universe going in a weird direction) come in, just placeholders until we understand what the hell's going on there. To say that "all of our math seems to be wrong when ti comes to that force" is a bit of an exaggeration... I'm pretty sure making up placeholders for over 95% of the mass in the universe constitutes us being more wrong than right. | ||
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SpiritoftheTunA
United States20903 Posts
On March 14 2010 05:16 VorcePA wrote: I'm pretty sure making up placeholders for over 95% of the mass in the universe constitutes us being more wrong than right. No, because saying that gravity doesn't account for that "mass" is like saying "wtf gravity is so strong between two electrons, AND IT REPELS." What I'm saying is that that 95% of missing "mass" might not necessarily be governed by our existing theories of gravity and relativity. Just because we say "adding invisible mass in these locations would make gravity make sense" doesn't mean that it has to be gravity that's the inconsistency. | ||
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starfries
Canada3508 Posts
Spectroscopy is nice but just finding organic molecules is not life; they are a prerequisite but there are many others. It's like digging up some iron ore and saying HEY GUYS I FOUND A CAR. To find signs of actual life in other galaxies you'd need to be able to resolve a planet to do spectroscopy on it, which is really really hard. Planets are something like 10^-10 arcseconds at most and the best we can do is 10^-3 or so. Otherwise we would probably have to find evidence of actual civilizations, which means they either have to be aiming a signal directly at us or have a power output close to that of a star. | ||
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{CC}StealthBlue
United States41117 Posts
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SpiritoftheTunA
United States20903 Posts
On March 14 2010 05:21 starfries wrote: oh thank god, i was gonna give up on this thread :/ Spectroscopy is nice but just finding organic molecules is not life; they are a prerequisite but there are many others. It's like digging up some iron ore and saying HEY GUYS I FOUND A CAR. To find signs of actual life in other galaxies you'd need to be able to resolve a planet to do spectroscopy on it, which is really really hard. Planets are something like 10^-10 arcseconds at most and the best we can do is 10^-3 or so. Otherwise we would probably have to find evidence of actual civilizations, which means they either have to be aiming a signal directly at us or have a power output close to that of a star. Luckily for us, the Earth would appear as a huge anomaly in certain frequencies, so if there's any other intelligent life in the universe, they might look at us and go "wtf is going on there." (Not counting the fact that if they were millions of light years away, then they'd only receive that information millions of years from now) | ||
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goswser
United States3519 Posts
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synapse
China13814 Posts
On March 14 2010 03:47 konadora wrote: But does having all the necessary elements -> life? I'm pretty shitty at chemistry but my thinking is that having the 'materials' there doesn't necessary mean the end products will exist. Having all the necessary elements is still a breakthrough; does having all the DNA needed for humans make a human? probably not, but over time.... | ||
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HnR)hT
United States3468 Posts
On March 14 2010 04:37 L wrote: 1) That 'pull back light' post is hilarious. 2) Scientists have been pretending that finding methane in any atmosphere is a sure sign of life because they don't believe that methane can be produced without being degraded without life. Once you learn how extrapolation and assumption heavy astrobiology is you kinda get a distaste for the entire thing. That said, as instrumentation gets better and we get more planetary samples for analysis things will shape up considerably. Astrobiology is not a real scientific discipline.  Also, AFAIK there can't possibly be life as we understand it in a region of young stars and interstellar gas. Aside from the fact such stars presumably had not had the time to aquire planetary systems with Earth-like planets, they occupy a region well on the left on the main sequence strip of the Hertzprung-Russel diagram, i.e. they are blue-hot and extremely luminous and their radiation would be absolutely lethal at distances in the AUs. | ||
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starfries
Canada3508 Posts
On March 14 2010 05:16 VorcePA wrote: I'm pretty sure making up placeholders for over 95% of the mass in the universe constitutes us being more wrong than right. Just because the theory doesn't explain everything doesn't mean that there are amazing space-bending abilities to be had. When Einstein came up with relativity it wasn't like we started building time machines since the previous theories were basically right EXCEPT in high gravitational fields and at near-light speeds. So any new theory of quantum gravity will look basically the same, except for very small things in high gravitational fields/high speeds. Even if it allows things like teleportation, it would probably only work on particles, certain quantum states, or exotic matter. None of which would apply to spaceships. So we would still have to get there the long way. Even being able to make wormholes still means we have to get the thing out there somehow, which is limited by the speed of gravitational waves (= c). | ||
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zer0das
United States8519 Posts
On March 14 2010 05:14 DefMatrixUltra wrote:[[2] It is very difficult. That's why we can't do a simple analysis on most of the things we're looking for. You have to calculate the spectra from quantum mechanics (you can't just assume your particles are in a boiler or whatever). Once you correct for redshift and doppler effect, you can get an identification 100% of the time, assuming the spectra is something familiar or something you have calculated already. Yeah, I realize you have to simplify things a bit, I just think you went a little overboard.  Also, you must calculate the spectra? Is there any particular reason for this? Are real spectra too noisy? (actually now that I think about it, probably since IR detectors have this issue :S Although I suspect there's probably other reasons too..). | ||
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Slow Motion
United States6960 Posts
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Tenryu
United States565 Posts
On March 14 2010 05:46 Slow Motion wrote: I think we should launch a preemptive nuke. It should reach by the time intelligent multicellular life develops. | ||
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Maenander
Germany4926 Posts
 It is just the nearest big star formation region. That is also the reason why it is so prominent in the sky. Massive young stars are very bright. Herschel is pretty new though, and I am certain it does produce the best spectra ever in far-infrared. It´s pretty amazing to have a european 3.5m-telescope in space, that has a larger mirror than Hubble after all. A far-infrared-telescope is a little different from an optical telescope though. | ||
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