Detecting systems with life


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Profile Bob DeWoody
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Message 1129144 - Posted: 18 Jul 2011, 12:01:08 UTC

I'm sure this has been mentioned before but I couldn't find any references. When the Voyagers have looked back toward earth have they detected anything like gases in earths atmospheric spectra that wouldn't be there without our presence? If so wouldn't that be a good starting point in looking at other star systems for potential SETI study?
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Message 1129330 - Posted: 18 Jul 2011, 17:35:10 UTC - in response to Message 1129144.

Exoplanet Spectroscopy is indeed about the only way of determining whether a planet is supporting some kind of life similar to that on Earth (unless there's a technological civilization sending detectable signals).

I don't know if the Voyager instruments were ever pointed back at Earth, if so it must have been early. They wouldn't be able to resolve Earth separately from the Sun now.

ESA has preliminary planning for a possible mission at http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=47036.

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Message 1129413 - Posted: 18 Jul 2011, 20:05:20 UTC

Hmmmm... I don't think Voyager was ever designed with instruments for for doing that type of spectral analysis.

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Message 1129416 - Posted: 18 Jul 2011, 20:11:25 UTC - in response to Message 1129413.
Last modified: 18 Jul 2011, 20:11:42 UTC

Hmmmm... I don't think Voyager was ever designed with instruments for for doing that type of spectral analysis.

John.


http://en.wikipedia.org/wiki/Voyager_program#Scientific_instruments
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Message 1129548 - Posted: 19 Jul 2011, 1:57:27 UTC - in response to Message 1129416.

Hmmmm... I don't think Voyager was ever designed with instruments for for doing that type of spectral analysis.

John.


http://en.wikipedia.org/wiki/Voyager_program#Scientific_instruments

I guess i was wrong. Thanks Jason!

John.

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Message 1129556 - Posted: 19 Jul 2011, 2:14:24 UTC

Such a shame that most of the instruments that have the possibility of making such a detection have ceased to operate now.
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Message 1129564 - Posted: 19 Jul 2011, 3:12:30 UTC - in response to Message 1129556.

Such a shame that most of the instruments that have the possibility of making such a detection have ceased to operate now.

Yea. But when you think about it, when they launched the Voyager space probes in 1977, zero planets had been detected around other stars. Back then astronomers were still very skeptical about anyone claiming they were seeing planets around other stars.

Exoplanet hunting was a fringe science back then. See how times change! Today Exoplanet hunting would have to be ranked as one of the most exciting new area's of science!

John.
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Message 1129671 - Posted: 19 Jul 2011, 12:42:11 UTC - in response to Message 1129564.

do realize that the instruments weren't meant for extra solar inspection if planets. Voyagers instruments for looking at planets were meant for close in inspection.
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Profile Bob DeWoody
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Message 1129829 - Posted: 19 Jul 2011, 22:28:08 UTC

OK, how about this for a proposed mission? Build a probe with whatever is felt to be the correct instruments to do the job of detecting compounda in the atmosphere of a planet that are most likely due to the presence of life and more specifically intelligent life and as soon as it is far enough out aim it at the only planet that we know of that fits the criteria. Then start looking for the unique signature. Then reaim the probe to look at candidate systems that are closest to ours.
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Message 1130996 - Posted: 23 Jul 2011, 15:52:04 UTC - in response to Message 1129829.

OK, how about this for a proposed mission? Build a probe with whatever is felt to be the correct instruments to do the job of detecting compounda in the atmosphere of a planet that are most likely due to the presence of life and more specifically intelligent life and as soon as it is far enough out aim it at the only planet that we know of that fits the criteria. Then start looking for the unique signature. Then reaim the probe to look at candidate systems that are closest to ours.


Why they don't do that is beyond me. Seems NASA is all about sending probes to asteroids, and planets within our solar system, but have little to no interest in sending them outside our system. Makes me wonder if they are afraid of what they might find. Then again, who is to say they haven't already done this and are just not telling us? That is very possible.
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Message 1131413 - Posted: 24 Jul 2011, 17:15:04 UTC - in response to Message 1130996.

NASA and other space agencies should use Earth as basis for life signs in atmospheres of exoplanets. Exoplanets that show life markers in the atmosphere, such as mathane, oxygen, nitrogen, water vapor. Telescope designers should think what Earth would look like if some one was watching us from another star system; for example from the Alpha Centauri system. Why is NASA spending so much money in sending probes to Mars? Clearly, Mars does not have habitable conditions, unless NASA plans to Terraform it, which is never. The question is, how are austronauts going to the Space Agency? if the shuttles are no longer running; clearly another vehicle should already have been in existence as replacement to the shuttles. But going back to the question of detecting life signs in other planets. Clearly, telescopes should incorporate techonologies which are capable of detecting life markers on exoplanets thousands of light-years way. For example, why is not the Keppler telescope pointed at the Alpha Centauri system? a short 4.5 light-years away from the Sun. With Sun like stars, who knows what is in that system. Too many resources are spent on local space exploration and not on new technologies, such as fusion propulsion, antimatter propulsion; technologies that would allow actual human flight to other star systems. I think to date, the best money spent on space exploration have been the Galileo probes, money well spent. As those probes enter interstaller space, perhaps one day another civilization will detect the radio signal of the probes.

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Message 1131491 - Posted: 24 Jul 2011, 20:46:49 UTC - in response to Message 1131413.
Last modified: 24 Jul 2011, 20:48:01 UTC

I think finding life on Mars--evidence of primitive life--past or present would be a tremendous piece of knowledge to acquire. At our current state of technological development a manned mission to Mars along with a moon base would be next logical steps and would probably result in new advances in the realm of materials and many other branches of science. Science makes slow but steady progress--in less than 100 years we went from Kitty Hawk to the moon. In another 50 we could possibly have permanent Lunar and Mars bases as well as a proper Space Station. Probes to nearby, promising planets will probably await a propulsion system that can achieve speeds that approach perhaps 15% of the speed of light. let's hope that we can find one or more within less than 100 light years distance (don't think so --time will tell)

Antimatter propulsion and reaching other galaxies and star systems won't happen in your or for many many lifetimes.

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Message 1131622 - Posted: 25 Jul 2011, 7:29:01 UTC

This week I watched Morgan Freeman's "Through the Wormhole" and saw some interesting theories on how we might someday get around the speed of light. But we have a lot of time until then to search for interesting placed to go.

I could write a book on what is so wrong with the decision to terminate the space shuttle program before a replacement was ready. And the Orion was not the answer. The Orion vehicle would have been well suited to go the the moon or Mars but not as a LEO space taxi.
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Message 1132118 - Posted: 26 Jul 2011, 4:55:23 UTC - in response to Message 1131491.

I could imagine in a not so far future, fusion propulsion as a means of interstellar traveling. It is something that NASA should really think about, fusion propulsion technology. Yes, there is not even an experimental fusion reactor capable of sustaining fusion yet. But NASA being the premiere space agency, should focus on technologies that will propel human flight beyond the Solar System. NASA should start thinking in phasing out chemical propulsion as a means of space flight; too expensive and bulky and highly ineficient. I dont think Congress would fund a mars trip in a rocket propelled by chemical propulsion. Highly ineficient, extremely expensive, gigantic rocket, and such a trip in a chemical rocket would cost more than the entire NASA budget. It is like someone competing at the Indy 500 in a Model T, that driver would never win it. Time for NASA to focus on eficient techologies of propulsion, develop new ones, continuing inproving current ones such as ionic propulsion. Antigravity techology, magnetic propulsion systems. These may sound exotic, but radical or exotic propulsion ideas are the antidote to the current dryhole of propulsion systms for space exploration. Space exploration cannot be just sending probes to planets in the solar system again and again with the same scientific purpose. Kudos to the probe that is orbiting Vesta and then will go to Ceres, that is great space exploration; but the ultimate goal is for one day for humans to be able to travel to other stars, such as to the Centauri system and beyond. For that to happen, future propulsion systems will have to achieve 20 to 30 percent light speed.

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Message 1132165 - Posted: 26 Jul 2011, 10:36:15 UTC

Dawn is using ion propulsion. It took 4 years to reach Vesta, but it is also going to Ceres after one year.Too slow for human flights. There was a project to use nuclear explosions for interstellar travel in the Sixties but it was abandoned after the treaty forbidding nuclear explosions in the atmosphere. As for fusion reactors, they are much too big for space travel, needing huge magnets with superconducting coils.
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Message 1132166 - Posted: 26 Jul 2011, 10:38:47 UTC - in response to Message 1132118.
Last modified: 26 Jul 2011, 11:16:07 UTC

Yes that's right. To achieve those speeds we would have to accelerate at 1 g for the better part of a year. That means a 100,000 lb. space craft would have to generate 100,000 x 32 pounds of thrust for this period of time. The shuttle with it's payload weighs about 250,000 pounds. Yet; at liftoff it weighs 4.5 million lbs--it's all chemical fuel. Chemical rockets are out of the question for the length of time required to achieve these near-light speeds for any object that is big enough to carry an exploring or colonization team. The fuel would weigh some incredible amount. At the moment Ion propulsion units are incredibly weak. Fusion will require temperatures that exist at the center of the sun; probably also not feasible.

Anti-matter might be the ultimate answer in terms of efficiency. So far we have been able to make a few grams or so for a few microseconds of existence. I have no idea how it could be stored and throttled.

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Message 1132313 - Posted: 26 Jul 2011, 21:49:46 UTC - in response to Message 1132166.

Currently, fusion techonology is more feasible that anti-matter techonology, diferent ways of capturing energy release by particles. I wonder if any though has been given to the hybridezation of an Ion/fission propulsion system. Obviously fission energy release would happen in space, thus avoiding any radiation fallout onto Earth's atmosphere. Would make sense incorporating an ion/fission engine; both techonologies are currently available. I dont know what kind of speed a craft would generate with such a machine. If anyone knows, would love to read it; if such thing is feasible. I dont think an hybrid engine of ionic/fission propulsion is in the realm of the exotic. I could see a spacecraft fitted also with a ion engine and fission propulsion seperately. The fission engine could propell the craft very fast, while the ion engine would serve as breakes when aproaching a star such as Alpha Centauri B, for example.

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Message 1132317 - Posted: 26 Jul 2011, 21:56:53 UTC - in response to Message 1132165.

There is more than one way of sustaining fusion in a reactor, other than magnets with supeconducting coils.

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Message 1132417 - Posted: 27 Jul 2011, 4:23:27 UTC

Even so, travel beyond our system depends on getting around the speed of light, not getting close to it. OK, say the crew only ages 10 to 20 years on a trip to a nearby star system. Back on earth hundreds or thousands of years will have passed by the time that first crew would get back home. Most likely by that time either man will have figured out a totally different means of travel or just as easily we will have gone extinct. We have gotten too used to SciFi fantasy communications where time dilation has been totally side stepped. Talking across the quadrant is just like talking across the planet. It ain't gonna happen. Sending a message 5 LY is going to take 5 years if even possible.

I'm afraid the only way we will leave our system will be in some sort of generations ship and it will be a one way trip. And it will only be funded if all hope of continued survival on earth is gone.
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Message 1132490 - Posted: 27 Jul 2011, 9:38:57 UTC - in response to Message 1132313.

you can find info on ion propulsion on the internet. They produce paltry amounts of thrust. On the order of one one thousandth of the force of gravity.

So if this were the power source it would take forever to accelerate a massive space ship.

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