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The Science Of Planet Detection 67

Posted by emmett from the inspector-detector dept.
Black Dog writes: "It seems like we're hearing about the 'Extra-Solar Planet of the Week" lately. I thought it might be useful for everyone to bone up on planet detection techniques. Two of JPL's projects are at: The Terrestrial Planet Finder and techniques for planet detection."
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The Science Of Planet Detection More

The Science Of Planet Detection

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  • Re:But can we get there? (Score:1)

    by Anonymous Coward
    With current technology, the trip would take more like 250,000 years, which is quite a while even in the great scheme of things.

    Not necessarily. There were some very *hot* ideas that were presented at the 1999 breakthrough propulsion symposium.

    Robert Forward went back and revised his calculations for "Star Wisp". This set on the track for a new idea - "Gray Sails". You make a light sail out of carbon mesh. As it swings in close to the sun ( about 3 solar diameters ) it's termperature will go to about 4000 kelvin and act as an efficient black-body radiator.

    The thrust per unit mass for a gray sail is far better than for a reflective light sail. The calculations indicate that it would start with an acceleration of about 17 gravities and achieve a velocity of between 2.5% - 5% of light speed. That's not as good as you can get with fusion, but we don't have fusion yet and this could be used to send a probe to Alpha-Centauri in less than 100 years.

    One of the other ideas that caused considerable interest was "plasma sails". You generate a magnetic field around the vessel. Then release some ionised material into it ( say Xenon ). This will "pump" the field up so that it will expand like a blow-fish. The particles in the solar-wind then hit the field and accelerate the vessel.

    From memory, the calculations indicated that a solenoid producing a field of 0.1 Tesla and a couple of kilograms of Xenon would produce a magnetic field/ion halo of about 50 kilometers in diameter. This would interect with the solar wind to produce a thrust that could propel a probe of about 100 kg up to a velocity of just over 100 kilometers per second ( 360,000 kilometers per hour ). Not to shabby for a solenoid, a solar power array and a couple of kilograms of Xenon.

    It's still early days with these ideas. My only point here is that we may be a lot closer to a solution than you think. It's all just a question of how you slice a problem up and try to solve it.

  • Unfortunately, the fact that a dimmer star might have a terrestrial planet very, very close could result in a very high periodic shift...

    Sorry, but these aren't good prospects. For a terrestrial planet to be in the habitation zone ( liquid water on it's surface ) for a star of less than half a solar-mass, tidal locking with it's star will rob it of all rotational motion in a couple of hundred million years.

    The same side of the planet would be in perpetual sunlight with the other in perpetual darkness. The volatiles ( including water ) would all migrate and freeze on the dark side.

    In the case of a star of more than two solar masses, it's fusion rate of hydrogen into helium is *much* faster than in the sun ( fusion rate is not a linear function of mass ). Stars of this type will leave the main sequence and become red-giants within about 500 - 1000 million years.

    In comparison, the sun has been going for about 4300 million and has about 5000 million to go before it leaves the main sequence. So stars of more than about two solar masses probably aren't very good prospects either.

    Likewise with double and triple stars - gravitational interactions would make a planets orbit more eliptical over time so that they would swing between scorching heat and freezing cold.

    My point here is simply that we can narrow our search *very* dramatically. We would certainly want to pick a few "unlikely" prospects in our nearby vicinity simply to make sure that we haven't overlooked something simple in our existing theories ( and also because they are likely to be easier to make accurate observations off ), but once they were confimed, we would start concentrating our efforts on stars which would be more likely prospects.

    As to the technical difficulties involved - yes, they are considerable. However, I'm fairly optimistic that we will have begun to detect terrestrial sized planets before 2020 and possibly as soon as 2010.

    In addition, by that time we will also have accumulated enough data from the existing gravity doplar shift programs to have included gas giants that aren't in close and/or highly eccentric orbits around their parent star.

    Exciting stuff, but it's irritating to have to accept that you have to be patient while the data accumulates.

  • Eclipse detection is great if the planet's orbit
    is sufficiently well aligned with the line from the star to Earth that we get eclipses.

    Unfortuately, this gets less and less likely, the smaller the planet is, and the further from the star.



  • "Two of JPL's projects are at:

    The Terrestrial Planet Finder and
    Techniques for planet detection."

    The obvious next step is to find ways to get to those planets, but first, NASA has to be careful that their engineers don't mix up "inches" with "centimeters" anymore. :)

  • I appreciate the above being moderated up as funny, but whoever got it up to 4 did so in the past 5 or 6 hours and therefore had to have seen that it was already sitting at 3. That's a mod point that could have been put to better use elswhere.

    All of this assumes that I am incorrect in my paranoid theory, based on strange and/or hours after the fact moderations, that there is a plot afoot to manipulate my karma up and down like a yo-yo just to mess with my head.
    Kind of like the guy whose new car kept getting better and better gas mileage and then worse and worse until one day his friends couldn't contain themselves or their laughter anymore and admitted to first adding extra gas to his tank and then later siphoning more and more out.

  • Then who built the window?

    Well, first we have to determine whether the window exists, or is simply a figment of the baseball receiver's imagination. Certain quantum theories also suggest that the glass really never broke in an alternate multiverse, hence there is no need to worry about who designed it because, having not broken, you have not yet noticed (observed) it, as it were.

    t's much more likely that the baseball has always been traveling and, through a series of random events and natural forces on the ball has happened to smash through the window.

    Which is consistent with my theory. Afterall, something had to set it in motion.

    I'm pretty sure the fossil record supports me on this if baseballs could fossilize.

    Unfortunately, it does not, so conjecture will not do us much good at this point.

  • The gravtitational force of a planet accelerates
    the star a few meters per second,
    turning its color redder or bluer than before.
    The earlier threshhold was about ten Jupiter masses.
    The current is about a half Jupiter mass,
    or change in accerleration of 3 m / sec^2.
    You got to measure these color changes with
    respect to a good fraction of the orbit - months
    or years apart. Because this technique is so
    young, we have only observed the faster planets
    now. The slower ones, i.e. as far out as Earth
    will come in time.
  • San Francisco State University's Physics and Astronomy department [sfsu.edu] is doing a lot of the work on finding extrasolar planets. The lead investigator is Geoff Marcy [sfsu.edu], who has a page of extrasolar planet news notes [sfsu.edu] and a page of links to other extrasolar planet sites [sfsu.edu].
  • from my perspective they seem about the same size, so, no.

    --
  • original comment: Even better, why not a gas tax for space exploration.

    Errr... how is this not picking my pocket?

    You forget: under a capitalist system it's my job to exploit the workers for my personal gain. So, it's in society's best interest to tie a long-term reward to a short-term reward for you. We use your desire to drive an SUV to pay for the continuation of the species (space exploration) and, if we get enough revenue, perhaps a free vasectomy for you. As a bonus.

    You assume I don't want to tax you. I do. It's to both my and our species survival. I could care less about what your copy of the constitution says to you, only in what the Supreme Court says I can get away with.

  • You're committing the common error of assuming that what's mine is ours. If everyone who had a project that required just $10 of every citizen's income got what they wanted, we'd have... Oh wait; we're already there.

    No, what's yours is mine. What's mine is mine. [grin]

    As for this project, ask me nicely, you can have 10 times that $10 -- but try to pickpocket me, and I'll rip your liver out.

    Even better, why not a gas tax for space exploration. Then, the more you drive, the more exploration we do as a nation. In that way, even though you're doing harm to the environment, you're helping our species get off this rock. We could even call the bill "The Law of Intended Consequences".

  • Trust me, they will keep making amazing little announcements three times a week until interest in the Mars Polar Explorer fiasco report dies down. NASA may not be able to control half of its space probes, but it does a masterful job of controlling the science news headlines.
  • Yikes, I knew I should have previewed, I meant Mars Polar Lander of course.

  • rux (Score:1)

    by atma ( 68232 )
    The detection of extra-solar planets is exciting.. the fact that there are planets in those same systems that are possibly habitable by some sort of organism.. whew! :D
  • No. It takes very different techniques to detect small bodies very far from a star and a planet orbiting within a few AU, and we just happen to be improving the technology for detecting planets around other stars faster than the technology for finding iceballs in the Kuiper belt.
    --
  • Scientist: "Mister President, these aliens sent this message to us, using photons, from a distance of 666 million light years. This means it was sent over a half-billion years ago, long before the first animals came out of the waters to live on land on Earth. They obviously have time travel!"

    President: "Is that so? And they're afraid of us. This means we can use the threat of coming to visit them as a way to get their secret of time-travel. And since they're looking into our present, which was their future at the time, all we have to do is wait for them to tell us."

    <weeks pass>

    Scientist: "Mister President, we have the secret of time-travel reduced to practice."

    President: "I'll take that, thanks. There are a few things I want to clean up. As Freud should have said, sometimes a cigar should only be a cigar..."
    --

  • One of the other ideas that caused considerable interest was "plasma sails". You generate a magnetic field around the vessel. Then release some ionised material into it ( say Xenon ). This will "pump" the field up so that it will expand like a blow-fish. The particles in the solar-wind then hit the field and accelerate the vessel.
    Unfortunately, this can only get you moving as fast as the solar wind. This is not nearly fast enough for interstellar missions to be completed within one person's lifetime, let alone one researcher's scientific career. This would probably be just the thing for Kuiper belt probes, though.
    --
  • God is, of course, the brat kid that broke your window in this analogy.

    This doesn't explain anything. Then who built the window?
    It's much more likely that the baseball has always been traveling and, through a series of random events and natural forces on the ball has happened to smash through the window. I'm pretty sure the fossil record supports me on this if baseballs could fossilize.
  • Sometime around last year, the field was very excited and happy because a planet was found where there was actually definitive evidence that it existed. It was something about the light or certain waves bouncing off of it during an eclipse. Could someone explain that a bit better? And how it was different from catching other new planets, which is done by sensing gravitational pulls??? I don't know, i'm clueless.

    please enlighten me :)

    Mike Roberto (roberto@soul.apk.net [mailto]) - AOL IM: MicroBerto

  • planets (Score:1)

    by eel ( 91514 )
    Yes, Beculs we all know that earth like planets mean the posibility of life. cuz this one has life. Why must we jump to conclusions based on a experimental data set of 1. We only know of one planet that has life on it. and one that one planet the life we have found so far is so diverce that it is easily imaginable that ther may be life (just based on this one) that may be on planets (or not even planets) that are nothing like ours. We know absolutly nothing about life that may or may not exest elseware (i.e. not on this planet). Yes it may be on earth like planets or It may not. Anybody ever read "Dragons Egg"? Not just flufy sifi but an interesting premis by a well know astrophisisist. Any way Forward (I think it was him) layed out a premis that had inteligent life on a nutron star. Yes it is true that life (probably) needs complex chemacal reations. But that does not mean That it has to be liqued H2O at about 1g. Ok enough ranting basicly what I am saying is that we don't know. and I am a fan of if you don't know don't say that you do!
  • Knowlage is the first step. e=MC^2. Is a pritty good example. 35 Years AFTER he came up with that they actualy made energy out of mass. Of cource he wished that he'd a' never came up with it but hay that is progress for you. Every time sombody askes "But what is it good for?" shows that they have no understanding of how science works. I usaly lump those people in with the "But it is just a thery" folks. I am sory I did not mean to get bitter but the fact is that most of the great progreses that we as a specis have made at the time that it was thought up sombody was saying that is cool, but what is it good for.
    Y=MX+B
    What use is that?
  • Alot of the earths oceans are unexplored and remain a mystery also.
    --
  • Well, it has the practical use for humanity as a whole in that it gives us some perspective on the Universe and our place in it. For now, we only know that other planets exist, and that most of them are nothing like the nine we are accustomed to. That in of itself is something amazing: ten years ago the entire idea we'd be detecting things with at the level of Saturn's mass would have been (and was) laughed at. Now, we actually doing it.

    With time we'll catalog more of the "zoophony" of planet types, and hopefully will start finding some object that bear a resemblance to those with which we are most famliar. As that happens as a race we become part of that community (I know that sounds very Sagan-esque, but it's the best I could come up with on short notice). That's valuable because it's at least something that unites us planet-wide --- we're now starting to think as a planet when comparing ourselves to other systems. I find that a very positive step for the future, and that to me has a practical use.

  • It seems we are finding planets around stars over 100 light years away. That's great, but are we finding planets around starts closer to our Sun, like within 20 light years? We have many stars close by, like the trinary Alpha Centauri (Alpha, Beta, Proxima) system right next door. Have we noticed any wobbles around nearby stars?
  • Energy is directed towards either the most necessary or the most profitable research at any given point.

    If it ever becomes necessary to get off this planet, the chances of our finding out how to do it will increase a thousandfold.

    I just hope that by the time it becomes necessary, we're not too far away from the required discoveries that it takes more time than we have left to find out how to do it.

  • what? they cleard up the 'Ketchup'/'Catsup' Fiasco?
  • Now if only I ever went outside...
  • Yet we are intruiged by the substance you call 'CHEESE' Prepare to surrender all stores!
  • Amen to that... d00d :-D
  • Data for the most recent discoveries can be found at an associated webpage at Berkeley:
    http://astron.berkeley.edu/~gmarcy/planetsearch/hd 46375/hd46375.html

  • No new information in this post really. I just had to mention that when I first read the headline while scanning the front page, I was sure the headline read "The Science Of Planet Destruction." Now I thought that would be pretty cool. What a great stress reliever! But, I was disappointed that upon closer inspection it actually said "Planet Detection." Maybe detonating those planets would make them easier to detect. =) What do you think?
  • Am I the only person who at first glance thought that is what it said? Why did I expect to see something like that on /.?

    The Science Of Planet Destruction

    Posted by emmett on Thursday March 30, @04:38PM
    from the inspector-detector dept.
    Black Dog writes: "It seems like we're hearing about the 'Extra-Solar Planet of the Week" lately. I thought it might be useful for everyone to bone up on planet destruction techniques. Two of JPL's projects are at: The Terrestrial Planet Finder and techniques for planet destruction."

    "the JPL has positioned 7 nuclear charges in a parabolic pattern inside the moon. When detonated the bombs will form an explosive 'lens.' This lens will turn the iron core of the moon into an explosively formed projectile. while JPL hopes to position the Iron core at a LaGrange point for later use as raw materials for a space station, they could miscalculate it's trajectory (as they have done with how many mars missions now?) and send it hurtling toward the earth."
  • Someone tried to insult me yesterday by saying "(my actions) qualify me to work at nasa"

    Sigh, I don't suppose anyone else has gotten this one.

    Is it just me or are all the brains in the world concentrated in just 2% of the population...

    Jainith
  • Around the 1700's or so a scientist, I believe it was Faraday, was asked by the Queen of England of what use were his studies of useless phenomenon like electricity and magnetism. To which Faraday replied "Of what use is a baby?"

    Only in the 20th century could anyone really appreciate his comment. The chances of us actually seeing an end-use for some of this in our lifetimes is almost nil. But we do it anyway because we (or at least some of us) care what kind of world our descendants inhabit.

  • Robert Forward is a very good Hard Science Fiction writer, but he suffers from a significant achilles heel. Look at any book he's written; Dragon's Egg and its sequel Starquake had life on virtually all the neutron stars in the sky. Not only did Flight of the Dragonfly (AKA Rocheworld) have life on one of the Rocheworlds, but the sequels placed complex life forms on most of the star's other planets. A small cometlike planet past Pluto has complex life in Camelot 30K, and Saturn is an active biosphere, with carbon based life, in Saturn Rukh. In all of the above, the life has at least one sapient form, capable of relating to humanity (though often with severe *physical* restrictions, not psychological) and somewhere in a level approximating humanity in the last 10,000 years. Even the ones that aren't, in this sense, formulaic, aren't terribly far from the model. Martian Rainbow doesn't actually bring the sapients into the picture - and it has a large focus on the science vs military politics - and it is far more subtle in Timemaster - but it isn't as subtle as, say, Charles Sheffield. And I wouldn't call Sheffield a master of subtlety.
  • There is a simple solution to relative motion of satelites, thanks to the computing power now available. As of this point in time, laser ranging is good to a couple of milimeters at a distance of about 100km (hence the usefulness of c as a standard for distance), with our best wavelength limiting filters. This is impossible to achieve in atmosphere, but should not be a problem for a satelite. Additionally, directional calibration can be achieved by near-star placement. Some filtering for far-removed satelites can be achieved by EGM matrix computations of orbit path, allowing a refined positions-relative-to-earth map that can be constantly updated alongside the detector data. All of which is great for the interferometry component.

    As for the spectroscopy components, there's no such issue. Mass data compilation from multiple sources just generates a huge time-dependant spectral chart, which can be constantly analyzed for signatures of known compounds. It doesn't matter *where*, as long as you've got the entire terrestrial disk of the star in question. It's a far more brute-force approach than the interferometry, but that's not a big issue. We're just looking for certain blues and greens and infrareds... Particularly the likes of H2O(l), which should *only* exist on one of these terrestrial planets.
  • Yes not to metion the asteriods that are so called planets. If an asteriod enters orbit for a day or so I guess we could call it a planet. I think they need to be a bit more choosy.

    oh look it has maybe some gravity well call it a planet

    If you havent read the uplift trilogy do"
  • However, note this: 200 years to go 10 light years is 5% of the speed of light, or roughly 54 million kilometers per hour. Current spacecraft travel around one thousandth of this, or in the neighborhood of 50 thousand kilometers per hour. With current technology, the trip would take more like 250,000 years, which is quite a while even in the great scheme of things.

    Ah, but what about relativity? There's no limit (beyond acceleration * amount of fuel you can carry) to how "fast" you can go, really... I remember reading in Analog (way back when) that it would take less than a lifetime of "subjective" time to reach the center of this galaxy at 1 gee acceleration; we need lighter fuel and better drives, but not exponentially better ones.

    Not for credit: If in the ?illions of years you're taking, earth-time, we build a 2 gee ship and chase you down, are you younger, older, or the same age as you would have been if you'd waited and gone with the second crew? Or does it depend?

  • As for this project, ask me nicely, you can have 10 times that $10 -- but try to pickpocket me, and I'll rip your liver out.
    Even better, why not a gas tax for space exploration.

    Errr... how is this not picking my pocket?

    To review: taxation (for purposes outside of the stated Constitutional responsibilities of protecting the citizenry from the application of force or fraud) is theft. Full stop.

  • How do you breathe while performing a colon examination upon yourself that way? I don't think that's what Ms. Couric meant...

    So, to review, you're taking the position that capitalism somehow embodies justification for outright theft, and that if the Supreme Court is asleep at the switch, that makes it all okay? Hello? McFly?

    Never mind that you're talking about then taking my pilfered money and handing it over to a gov't whose track record is, to put it mildy, abyssmal, and instructing them to use it to ensure the survival of the species.

    Looking at history, they'd take that as a mandate to continue the welfare program practices of paying people who are unable to hold down productive jobs to have more children, who'll in all too short a time, join their mothers in the same cycle. Hey! It's increasing the species, right?

    Or, the money could be applied towards procuring more big-hair bimbos for our Lech in Chief, thus increasing the species another way.

    I actually don't assume that you don't want to tax me -- to the contrary, I proceed from the assumption that you and your spiritual brethren are all about. This is why I lock my car... and why I vote.

  • But we would rather spend the money on fueling up our SUVs and creating military forces to get fuel for those SUVs. For only $10 a year per capita, we could (the US or the EU) easily create enough detection equipment and the scientists to analyze it.
    You're committing the common error of assuming that what's mine is ours. If everyone who had a project that required just $10 of every citizen's income got what they wanted, we'd have... Oh wait; we're already there.

    As for this project, ask me nicely, you can have 10 times that $10 -- but try to pickpocket me, and I'll rip your liver out.

    Besides all of that -- what's more wasteful: a private citizen spending his own hard-earned money to gas up a fuel hog, or a gov't that spends my money to pay farmers not to farm, addicts to use, and lawyers to slice away more of our freedoms daily?

  • A lot of the time, cutting edge science produces something totally off-the-wall that we hadn't thought about. I think that there's a lot of value in just taking one topic, any topic, and exploring the hell out of it. Patterns are everywhere. Mother nature loves to cross-reference.

  • looking for trouble (Score:2)

    by Anonymous Coward
    Sometime in 2001:
    [NASA] Yes, we have visual confirmation of another earthlike planet at a mere distance of 666 Million light years from Earth!

    several months later:
    [SETI] After focusing our efforts on that section of the sky, we've intercepted what appears to be a possible signal. We've began our analysis.

    months pass...
    [SETI] Our scientists have finally unveilled the meaning of the alien transmission. It appears that they are sending us this message, looped over and over again:

    Stay away from us you silly humans, you already fucked up your planet.
  • No one seems to have mentioned the probable direct detection of reflected light from the planet around tau Bootis. This is reported in Nature, vol 402, 16 December 1999. The main author's office is just across the corridor from me.

    This was mainly, a monumental data processing achievement. They described it on a recent TV program as "like detecting a firefly sitting on the edge of a searchlight 10 miles away". As I understand it, they modeled the way that the reflected light would change with both orbital geometry and Doppler shift and used very sophisticated processing to extract a signal with those characteristics from the background time-resolved spectrum of the star.

    One bonus of this work is that the planet's signal is much stronger in green light than in red or blue, giving an idea of its colour. The same approach might eventually allow for detection of the presence or absence of specific compounds on the planets surface.

    The authors don't see this approach generalizing to find Earth-like planets. They are too dim, and their orbital velocities are low enough that the Doppler shift is lost in the shifts due to movement of gas on the Sun's surface. On the other hand, they thought that interferometric work in the medium IR stood a good chance. You would need a flottile of perhaps 4 8m space telescopes, with supercooled detectors and extremely accurate station-keeping (to with 1 micron over extended periods) but you could then use interference to cancel the image of the star almost completely, while preserving any light from the planet.

  • Considering those particles are a few nano-meters away from the detection apparatus, while planets are a few billion light-years away, no.

    Do you notice the baseball that just landed in your lap first, or the kid at the end of the block that put it through your window? Okay then, that's why we detect particles first. God is, of course, the brat kid that broke your window in this analogy.


  • DARWIN [rl.ac.uk] from Europe, and Kepler [nasa.gov] another proposal from the US.

    --

  • Oh, I agree, there are some exciting ideas in space propulsion technology. However, I don't consider something to be "current technology" until somebody has gone out and built one and proven that it works.
  • Most cutting-edge science has no immediate practical use. We will find uses for it in the future, assuming that we keep up with the cutting-edge science. We cannot predict what uses may come of it now, but you can rest assured that they will come in time.
  • That in turn reminds me of a short SciFi story I read a while ago..

    The gist of it was that Earth's first extra solar, manned mission gets shot into deep space, to land on a far away planet. Years later, they arrive, only to be met by (much younger) explorers from Earth, who had left Earth much more recently....
  • I think the SIM or Space Interferometry Mission has good goals in searching for new planets. But what new information is there to learn about Earth from these other planets. What are the pratical gains from this?

    I think is great that they have discoved that a planet around some near by star creates a "wobble" that they can dected. But sences Space travle is far from getting anything to a distint planet in other Star System. Thus we can't go and see for ourselves if this planet even exists that we think we dedcited by "indirict means"

    I'm not trying to belittle the scinces of this. Or deny that just having new information about the univerise is a gain in and of itself. But how can we benfit from this in pratical ways. AKA how does this make my box run faster? Or How can this help world hunger? That kind of thing.
  • Whereas most (extra-solar) planets have been detected by the gravitational pull on the neighboring star, the one last year was visually detected. This was done by noting a small, regular dimming of the star. So...basically, we had a stellar eclipse.

    This is important because a earth-sized planet has almost zero gravitational effect on the sun, but, it does block light (however small the amount). Indeed, this might be a way of detecting smaller, more earth-like planets.

    Grades, Social Life, Sleep....Pick Two.
  • So arguably, on the basis of this proposition, Ceres should be classified as "a minor planet" rather than an asteroid.
    They already are called "minor planets". The term "asteroid" refers to their visual appearance from Earth; they are unresolvable points of light like stars (aster - star), not showing discs like the other planets do.
    Likewise with some of the larger moons...
    No. All the planets of Sol, major and minor, orbit Sol. Any body orbiting a planet is by definition a moon of that planet.
    --
  • That's funny, I misread 'planet detection' as 'planet destruction', and thought to myself "so NASA has a Death Star..."
  • Yes, but even if we do find "Earthlike" planets, and we manage to find our way to the stars, and actually find an advanced species, let's all face the fact that it is highly unlikely we will be welcome.
    More likely we'll be treated as the interstellar equivalent of a first time AOL user and face some massive interplanetary LART for simply being what we are: A species who may conquer time and space, but can't make a toupee that doesn't get big laughs.
  • If we _do_ find an earth-like planet within 10light years - do we actually have enough technology to send a probe ship into orbit around it?

    I appreciate it might take 200 hundred years - but that's not long in the grander scheme of things.

    Do we have the technology that will get it that far and slow it down - and not break??? :)

    (August 2231: "I can't believe they put NT on that probe ship - oh my fscking god!)

  • Does anyone think it's ironic that we're better at detecting new sub-atomic particles than new planets?

    kwsNI
  • At first I thought your posting was a troll, but reading your last paragraph, you seem to be merely curious how the masses could benefit from this.

    This research has to do with the ultimate survival of the human race. Right now we only live on one rock. If we mess it up by crossing AIDS with the common cold, or some external force like an ice age or falling rock messes it up, we're screwed.

    If human race lives on 2 rocks in the solar system, such as moon or mars, then any (one) planet destryoing event would not remove us from the universe.

    If any news item or research generates more interest in people to push towards space travel, this is, IMHO, a Good Thing (TM).

    Not sure about world hunger, but in the past, space race research has made boxen go faster. :o)

    --
    Do you think Hemmingway would have written so many novels if his typewriter had been capable of Open GL hardware-accelerated 3-D graphics?
  • WTF are you talking about? NASA isn't involved in the extrasolar planet detections -- it's mostly universities [berkeley.edu]. They were doing it long before the last two Mars probes vanished, too.

    I'm not an apologist for NASA (heh -- you ought to hear some of the stories I can tell), but you ought to realize that there's plenty of science done without them (yes, even space and planetary science), and plenty of science interest independent of NASA on the part of the media.

    If you want to bash 'em, do it on reasonable grounds; don't try to link it to something else entirely...

    ---

  • Popular Science has some recent articles discussing planet detection as well.

    They cover the announcement of the two smallest extra-solar planets discovered to date (announced Wednesday) here [popsci.com].

    They also have an article that summarizes techniques for planet detection (including SIM and the TPF, among others) here [popsci.com]. This article also offers some insights into the challenges of actually sending probes to these remote places, with some possible (and definitely futuristic) suggestions.

  • Re:What are the pratical uses for this? (Score:3)

    by Bill Currie ( 487 ) on Thursday March 30, 2000 @02:16PM (#1159972) Homepage
    The practical use of discovering planets we can't get to is to generate motivate to figure out how to get to them.

    Just think about befor boats were invented:

    "ooh, look there's an island over there"

    "yeah, but it's too far to swim"

    a log floats by...

    I'm sure you get the idea.

  • Re:But can we get there? (Score:3)

    by HeghmoH ( 13204 ) on Thursday March 30, 2000 @04:06PM (#1159973) Homepage Journal
    I'm reminded of the article on slashdot a while back about how delaying the start of an enormous computational task can actually make it so the task finishes sooner, because of the march of computational technology.

    I suspecet that the same is true here. Drive systems will continue to get better, though not at the same rate or with the same regularity as computing technology. An ion drive system will help, as would fusion drives.

    However, note this: 200 years to go 10 light years is 5% of the speed of light, or roughly 54 million kilometers per hour. Current spacecraft travel around one thousandth of this, or in the neighborhood of 50 thousand kilometers per hour. With current technology, the trip would take more like 250,000 years, which is quite a while even in the great scheme of things.

  • Check out the BOSS!! (Score:3)

    by The Iconoclast ( 24795 ) on Thursday March 30, 2000 @04:03PM (#1159974)
    There is a group at my university's [cwru.edu] physics [cwru.edu] department working on a design for a cool planet detecting satillite. It is called BOSS. [cwru.edu] Check it out, cool stuff.

    A wealthy eccentric who marches to the beat of a different drum. But you may call me "Noodle Noggin."

  • Needle in a Forest (Score:3)

    by WillAffleck ( 42386 ) on Thursday March 30, 2000 @02:29PM (#1159975)
    Our basic problem is that we are getting fairly good at finding planets, but not terrestrial ones. Gas giants, no prob. But Earth-sized, we're not quite there yet.

    Additionally, the ones we do find that might be earth-sized we find only because they are erratic in orbit or receive too much radiation (which is how we can find them).

    We need to start sending out packages above or below the solar plane, with sufficient telemetry and telescope size (e.g. Hubble), and in greater number. And we need to start sending drone ships with basic measurement devices towards some of the more likely candidates, to extend the search range.

    But we would rather spend the money on fueling up our SUVs and creating military forces to get fuel for those SUVs. For only $10 a year per capita, we could (the US or the EU) easily create enough detection equipment and the scientists to analyze it.

  • The joys of optical interferometry (Score:3)

    by tjwhaynes ( 114792 ) on Friday March 31, 2000 @03:23AM (#1159976)

    My old astronomy lab have a group working on optical interferometry, and have a working optical interferometry complete with four (or possibly now five) telescopes linked together. If you are interested in the details, there is a good introduction [cam.ac.uk] and more detailed information here [cam.ac.uk]. Now the interesting thing here is that it is very important to keep the telescopes at exactly the same distance apart or compensate in some way (here there are trolleys running up and down a long (30m) optical bench and the telescopes are concreted into the ground. The problems inherent in doing optical interferometry in space present many of the same problems examined in this project, plus the limitation that you can't just stick an optical bench on a satellite and hope to get it off the ground. On the other hand, ten years ago people were highly sceptical of getting optical interferometry working on anything more than a rudimentary basis and felt that map making was many years away, so maybe those problems can be solved too.

    Cheers,

    Toby Haynes

  • I took a good look at the proposed detector, which is essentially a directional spectroscopic satellite. It looks feasible enough, given enough time and enough satellites, if the initial assumption (that terrestrial planets are common) is correct. It won't produce quick results, I expect.

    This is actually a very interesting line of investigation, and one that is highly popular in SF. Instead of the current approach of scanning stars for the results of gravitational perturbations (which I was surprised to see finding sub-Jovian planets), the TPF scans for light in specific emission spectrums - water, maybe oxygen and ozone, perhaps ammonia and methane, nitrogen... I'd assume this would mean using a time-based saturation filter to screen out everything from the star and all the stars behind it, loose ice and dust and complex non spectral light sources and reflectors.

    If they're smart, they'll find a way to factor the red/blue shift of the target bodies into the filter, as well as shifting the spectrums. Given enough time, they could build up the period of the target body, and therefore determine its orbital radius...

    Of course, that would entail finding the signatures in the first place. Unfortunately, the fact that a dimmer star might have a terrestrial planet very, very close could result in a very high periodic shift (relatively), which might cause problems if a very narrow wavelength filter were being used to stamp out undesirable light sources.

    Lots of things for them to think about when building this... and all relying on getting a tremendous amount of ultra-sensitive electronics into orbit. Shame we don't have orbital industry yet.

  • My personal planet detection technique (Score:4)

    by unitron ( 5733 ) on Thursday March 30, 2000 @02:02PM (#1159978) Homepage Journal
    1. go outdoors
    2. look down

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