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Science

Extrasolar Planet's Light Observed 143

Posted by jamie from the insanely-precise-spectral-analysis dept.
Last week we ran a story about a visually-detected planet orbiting HD 209458 - its star dimmed when the planet passed before it. Today, Richey points us to a "a BBC story about how astronomers have actually picked up light reflecting off an extrasolar planet. They've managed to perform a basic analysis of its atmosphere from it." Check out the three elements they believe they found.
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Extrasolar Planet's Light Observed More

Extrasolar Planet's Light Observed

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  • I am very much shooting from the hip here, but if I had to guess I would say that it's because spectral lines from reflected light are of necessity absorption lines. Now, in order to see absorption lines in a spectrum you have to have some light in that part of the spectrum to begin with, but H and He absorption lines should be saturated (or nearly so) in the star's photosphere; hence, there would be no possibility of seeing absorption lines in those elements from the planet, no matter how abundant those elements happen to be in the planet.


    Now, Si and Mg should be pretty rare in the star, so that could account for being able to see those elements, but I would have thought O (along with C and N) would be at least somewhat abundant in the star. In this case I would guess the possibilities are that the O lines don't saturate, or that the stellar O is mostly OII or OIII (singly and doubly ionized, respectively), so that the stellar lines don't coincide with the planetary lines.


    As a side note, I think the conventional wisdom of "oxygen as an indicator of life" wouldn't apply here because this planet is likely hot enough that the gas is mostly atomic rather than molecular. Remember that the reason why elemental oxygen is supposed to be so uncommon in planetary atmospheres is that it is so reactive. Thus, the argument goes, if it is there some sort of process (like life) must be replacing it. On the other hand, if the environment is hot enough to dissociate most molecules anyhow, then oxygen's reactivity is less important, so it's not surprising to see it fairly abundant.


    -r

  • It is known that suns will swallow up planets. This one is not the first gas giant found to be very close to its parent sun. Scientists discovered a gas giant 1/2 of Jupiter's size, and it was close as Mercury's orbit - in fact I found the URL for details about this: http://earthsky.worldofscience.com/1998/es980809.h tml My best guess is that these planets are spiraling in towards their parent sun and will be gobbled up. Neither planet could have formed at this close distance. They have to be spiraling in.
  • A paper is being refereed for Nature. The BBC actually broke an embargo on the news (as the Sunday Times did a few weeks ago).

    I've been to a few talks by the guy who did the work (his office is just across the corridor from mine) and their basic expertise is in very detailed analysis of time-variations in the exact shape of spectral lines. A spectral line from a star is not actually a line. It gets broadened by Doppler shift where the atoms emitting (or reflecting or absorbing) the light are moving towards, or away from, the observer.

    To take an example from another project of theirs, consider a rapidly rotating star with a dark "sunspot" at its equator. As the spot comes into view around the side of the star, the blue-shifted part of the spectral line will get a little dimmer, then, as the star rotates, the "dimming" will shift to the centre of the line, and then towards the red-shifted side.

    What they do is to use a very precise spectrometer to record the distribution of light across the line at regular intervals. This gives them a big two-dimensional data set (dimensions are frequency and time). They then crunch this with some fairly serious computational power (I asked Prof Cameron why they had got in first on this, and he said that they were the only group with the software) to extract a best guess at the distribution of spots on the star. Phrases like "least squares deconvolution" and "maximum entropy" often appear on his noticeboard.

    The same technique applies to detecting the light from the planet. Such light would move through the spectrum in a predictable way, and they could use their software to search for it. The fact that they saw the same pattern in several spectral lines is a good confirmation of the real planet.

    Crucial to success in this case was (a) a fairly bright star (b) a big planet (c) a planet moving fast in its orbit.

    To digress a little, the increasing number of extrasolar planets being discovered is, in a way, encouraging to those who hope that we are not alone, but also troubling. The planets being detected at present are (a) big (b) close to the star (c) often in quite eccentric orbits. Earth-like planets might have real problems co-existing with these monsters. Also, I heard a suggestion that magentic and tidal effects from big close planets may cause occasional "hyper-flares" which would sterilise Earth-like planets quite effectively.

    Steve Linton
  • I'll grant you the point about hydrogen and helium, but why no carbon? Why no nitrogen? If it were a gas giant it would have appreciable amounts of methane and ammonia in its atmosphere. Nitrogen has about the same atomic weight as oxygen. It should be present in similar amounts.

    As far as it being vapor: you may know more about this than I do. I just have a general science education. However, consider this. When you see the Earth from space, almost all of its light is reflected from the sun. It's white light when it strikes the earth. The image you see, though, isn't white. The oceans are distinctly blue-ish and the land is various shades of brown. The color of the light changes because of the absorption lines of the stuff on the ground.

    AFAIK, scientists do surface spectoscopy by scattering light off solids all the time.
  • There's a big difference here though. They're not looking at a planet, like you'd look at Mars. They're looking at a star.

    The difference of angle between the star and the planet from over 50 light years away is way too small to see. So, they point the instruments at the star, then record everything. The stuff that varies on a cycle of 3.3 days they say is from the planet or due to it. Then it's a matter of analysis.

    Do you know all the crazy stuff that happens in a star? The fusion cycle is ridiculous. All kinds of wacky things happening. Carbon exists in stars (albeit for a very short period of time) sometimes. You get all sorts of wacky spectral lines from different stars. Anything that star is putting out is going to cancel the signal we can say is from that planet. Probably the only reason we can see O, Si, and Mg is that that is extremely unlikely stuff to find in a star.

    Yes, if you can see the planet directly, get reflected light directly, then you can analyse the hell out of it. But we're not seeing the planet. We're seeing the star, and filtering the planet out of that.


    ---
  • Probably the only reason we can see O, Si, and Mg is that that is extremely unlikely stuff to find in a star.

    I hear you. I don't place too much stock in these results either BTW. Those three elements should be relatively easy to detect. Nitrogen shouldn't be harder to detect than oxygen, though. It's not much more common in stars.
  • The next step, obtaining an actual image of a planet, will probably have to wait for the next generation of space observatories that will come into operation in about 10 years' time.

    Hey, we can do the math how large that telescope
    is going to be. I don't know the formula, but we have all the numbers.

    We'd like about 100 pixels across the planet, but
    will settle for 20. Jupiter sized planet which is 11 times earth. So the diameter is about 1.3*10^8m . So pixel size comes to 6.5*10^6m.

    The distance to that planet is 50*3*10^8*3600*24*365=4.7*10^17 . So each pixel represents an angle of 1.4 * 10^-11 (in radians).

    Now from this and the wavelenght of the light we can calculate the minimum size of the telescope. I don't know the formula anymore, so I'll probably miss out on a few factors of 2 and PI.

    But lambda (wavelength of the light, 500nm)divided by the arc becomes 36km. So, my estimate is that this telescope that can take pictures of this planet is at least 36km (22 miles) in size.

    Either that physical size, or some coupled telescopes. As far as I know, they are already working on getting this to work. But mirror accuracies will probably have to be phenomenal. Like in less than the size of an atom.

    Roger.
  • > With "proofs" like yours, I hope that you're not in any way associated with science.

    Not that I agree with the way he originally posted that 'no life in the universe proof' reply (though I do believe it), you just said that you hope everyone who believes evolution is fact is not involved in science also!

    FYI (currently) there is no physical, observable, demonstratable evidence for evolution, just as there is no physical, observable, demonstratable evidence for life on other planets, just as there is no physical, observable, demonstratable evidence for the existence of God other than the visible change in people's lives that can be explained no other way and the faith of those who believe.

    Therefore, it is a 'belief' in life on other planets, a 'belief' we evolved from dirt, and a 'belief' that God exists; it is simply a choice of what you believe - being as scientific as you like to decide which is more reasonable, and believable.

    Personally, I don't believe in evolution, but I believe in God, and I believe life - in it's simplest form - exists by God on other planets, so I obviosously believe in the existence of other planets. I do believe we are the only intelligent life. And until we get an intelligent response from an extra-terrestrial body, no one can say I'm wrong. I'm very objective and base everything I believe on what I experience, see, and understand to be true based on what is provable. And I love astronomy :)
  • > Same could be said for primitive tribes of aliens, maybe yesterday they invented the wheel. Abscence of evidence isn't evidence of abscence

    (I like that last line BTW :)

    Now if the universe is billions of years old, what are the chances
    1) that an alien race would coincidentally begin evolving at the same time as us, or even, say, within 1000 years of us?
    2) based on that assumption and people's estimate of the number of possible intelligent civilizations out there, that we haven't contacted anyone yet (sorry, they're all hiding from us until we're advanced enough ala Star Trek)

    I think, personally, that sci-fi shows, like Star Trek, Star Wars, Lexx, B5, etc (which I'm fans of BTW), have given us such appealing possible explanations for our universe, that we've come to believe that it's the only possible explanation. No one wants to believe that we are alone, that the universe is a vast, amazing phenomenon created by God (no, not us). I know most people think 'how could you be so closed minded' - well, vice versa? I never said that life DOES NOT exist on other planets - I simply believe it doesn't because I don't see how it could. Until we come up with proof, I choose not to because I think it degrades our existence, and frankly, scares me. Plus, I've experienced things that prove to me that it's the only reasonable choice.

    Just for the record, I believe in other planets, and I believe life exists by God on other planets, but I believe we are the only intelligent life we will ever find (and we'll be lucky sometimes with that :)
  • My theory on how this planet formed goes something like this:

    1) This star system had at one time at least 2 planets(could have more than two right now, just can't see them). This planet and another smaller(yet still very large) rocky planet, let's say with 10 to 20 earth masses.

    2) One of these planets had a slightly eliptical orbit that came fairly close, or even crossed into the other planets orbit. With the gas giant being the outer planet of the two.

    3) Eventually after hundreds of millions of years orbiting each other, the gas giant and the rocky planet collided and this collision sent the gas giant hurtling in towards the sun. And what we see today is the remanents(sp) of those other two planets. This is a possible explaination of why there is silicon, magnesium, and oxygen.

    It is possible for there to be oxygen on this planet and not contrast with its formation theories, the oxygen could be in the form of SiO2(silicon dioxide), or Mg2O3 (dimagnesium trioxide), etc.

    A reason it might not have any hydrogen of helium(they don't believe so because it would be so easy to detect, but the planet must be imaged again to account for experimental error) is because with such large tidal fluctuations in a gas giant type of planet the more massive elemets are going to naturally be drawn to the sun by gravity and the lighter elements like helium and hydrogen are going to be forced to the exact opposite side of the planet, the side without the reflection of light. So obviously since the only way we detected it was through its light and that had to originate from the sun side of the planet, then naturally the heavier elements are going the be the ones we detect.

    {P.S the earth doesm't work like this because we are 93 millions miles from the sun and not directly next to it.}

    With an orbit of 3.3 days, temperatures that would seem to be in the thousands of degrees(at least), massive tidal fluctuations caused by its proximity to the sun, I would have to say there is a 99.99...% that no life exists on this planet.

    But then again what do we know about how extra-terrestrials might look and have evolved.

    --And the number of extra solar planets is much higher that anyone else has posted it is at a minimum of 17 or 18, as of the beginning of this year, and this number does not include pulsar planets.

    --A. Bugg--

  • The equation for g is not g=G*(m1*m2)/r^2, that is the equation for gavitational force. F=G*(m1*m2)/r^2. From this the equation m2*g=G*(m1*m2)/r^2 can be made, m2 cancels from both sides, leaving the equation g=G*m1/r^2.
  • Not to disagree with the basic point (journalists are yahoos) but don't most gas giants radiate slightly more energy than they receive?
  • The proof of extrasolar planets, the attention being given to string theory, and the revitalized possibility of extraterrestrial life, is all proof that there is still more to this universe than we think.

    Maybe there's more to this universe than we even hoped and dreamed. Who's with me on that!! hehe
  • Actually i believe the signal comes from the radio, which sends it to the antenna, which meerly distributes the radiation to a wider area :)
  • An atmosphere that contains silicon in vapor form indicates that it's too hot for silicon to combine with oxygen.

    At these temperatures, there is zero possibility of silicon-based life--the molecules wouldn't stay together!

  • The same reason why there's no hydrogen on Mercury, or much on Earth or Venus (at least in comparison to other elements). When the solar system was forming, the force of the solar wind was enough to drive lighter elements far away from the sun (this is why Jupiter et al have so much hydrogen, and it is also the origin of the Oort cloud of comets), but heavier elements stayed in the inner solar system.

    I knew all those geology classes would come in handy someday.
  • At any given temperature, the average energy of an element is independent of its mass. More mass => slower. Less mass => faster => may exceed escape velocity.

    Or it may just be they couldn't get past the 'noise' of the star, as seems to be the common hypothesis.

  • The planet was discovered a few years ago. What is important about this is that they were able to determine some of the elements on the planet (by analysing the spectral lines of the reflected light). The technique they used to isolate the reflected light from the glare of the star is the real advancement.

  • Oxygen? (Score:3)

    by rde ( 17364 ) on Monday November 22, 1999 @08:38AM (#1512313)
    Woo, oxygen. If I remember my astrobiology correctly, this would be taken as a sign of life if it weren't on a planet four times the mass of jupiter, and with a year of less than four of your Earth days.

    Note to everyone who reads science fiction: silicon has a lot of the properties of carbon; this does not mean that silicon-based life (as we sort of know it) is possible. Don't jump to conclusions.

    You've got to wonder, though, what the astronomers have discovered when they refuse to talk to the BBC.
  • We know there's oxygen there, and where there's oxygen there's water, and where there's water there's life. Now it's just a matter of finding out how much the life wants to donate to the Republican party.

    More seriously, why couldn't they detect hydrogen and helium? Would the amount of light with hydrogen and helium spectra in it be overwhelmed by the huge amount of light from the star (also filled with helium and hydrogen)?

    George
  • That settles it. I've seen that STTNG episode.

    It's just a matter of time before the silcon-based alien life forms arrive and start calling us ugly bags of mostly water.
  • Despite taking it almost for granted that planets existed outside our solar system, and having a rough understanding of the measurements that had previously confirmed planetary existence, I find myself saying "Well, now we really know that these planets exist."

    Is this just the standard layman seeing-is-believing reaction, or do scientists know have firm belief in something that they once doubted? Personally, I would be a little scared if those British astronomers were unsure of the existence of that planet until the moment they "saw" reflected light.

    An unrelated question: can they use the same technique to search for moons of that planet?

  • hrm.. (Score:2)

    by Haven ( 34895 )
    Could someone tell me why there are heavier elements like Silicon and Magnesium and no Hydrogen?
  • First off, I'll assume that you are taking an artistic license in order to fit the info into a headline when you attribute the light to the planet ("planet's light", indeed).

    Secondly, isn't this about the 3rd or 4th time this has happened (for the first time each) in the last 10 years?
    ---
  • Please try to use a modicum of basic scientific knowledge when writing your headlines. The light is the reflected light from the star, it is NOT the planet's light!

    I know that common usage (such as moonlight would have you believe that planetary bodies produce their own light, but except for earth, and perhaps some theoretical planet made of radium, I doubt many do, and if they did, I doubt they would be perceptible at these distances using current technology.

  • Why oxygen *is* revelant (Score:3)

    by Enoch Root ( 57473 ) on Monday November 22, 1999 @09:47AM (#1512321)
    Now, a lot of people have pointed out that it's somewhat useless to wager that there is life (As We Know It (tm) anyway) on that planet. Of course, being 4 times the size of Jupiter, and with a revolution of 3 *days*, it must be a bit hectic up there, to put it mildly.

    But: the presence of oxygen is revelant, in the sense that it's a pretty high coincidence that oxygen can be found there, if it is indeed due to chance. This is the same argument than when the first exoplanets were discovered: people pointed out they were large, surely lifeless masses of gas, but the point is not that. The point is, planets *do* exist out there, around other stars. That's mighty big, as it shows that planet formation is universal, and not a freak accident.

    From there, it only looks good. If now we can observe the light off a planet (though I bet the specific conditions for observing such a light is in the range of probabilities of seeing a gravitational lens effect), it means we're moving forward to the day we'll be able to observe an Earth-type planet up there somewhere. And from there, it's a simple question of sending a radio signal directly at that planet.

    So, stop saying it's irrevelant. It's a small step, but it's revelant as hell. Ten years ago, I could only dream that scientists would pick out the signs of an extra-solar planet. Now the possibility of finding a planet the size of our own is becoming more and more a reality. And if that's not something to celebrate, I don't know what is.

    "The wages of sin is death but so is the salary of virtue, and at least the evil get to go home early on Fridays."

  • Think about it.. They say there is a planet. They are able to see light reflecting from it. They say they found Oxygen. That means that life like ours could be capable on that planet. Taking both of these statements as true, then why cant we "hear" anything from this planet? If we can see it, we should be able to hear it. It must be that, THERE IS NOTHING TO HEAR! And if thats the case, then there is no life, or at least intelligent life. To prove my theory that WE ARE THE ONLY LIFE IN THE UNIVERSE! -matt


    Lessee... Planet is 50 lightyears away from earth, assuming a nice round estimate of Radio waves being 100 times slower (Which is wrong and giving radio waves a much higher speed than they deserve) it would take 5000 years for anything to be audible here. If they were broadcasting Radio waves 5000 years ago then they've either blown themselves up or moved past radio waves long ago. And likely abandoned the planet or developed in a manner which we can not guess. Also, since they would of neccesity be silocon based I imagine they may not have any concept of many things we take for granted, sight and sound being 2 of them. As they would be VERY VERY close to their sun and going VERY VERY Fast. A rather harsh environment, eh?

    Kintanon
  • Why is oxygen such a big deal? Life isn't dependent on atmospheric oxygen.. observe the plethora of anaerobic bacteria. Also oxygen doesn't mean diatomic oxygen - for all we know the atmosphere could be gaseous glass. Plus the environment is SO different from Earth, who knows what sort of life would develop? Obviously not like on earth, although I wouldn't rule out autonomous replication completely.

    Anyway, me, I think it's all just hooey until they find a class-M planet, which they never will until we develop IST. So everyone mail their congressman to pursue fusion research! (also it will solve problems like having to burn petroleum for making fertilizers and other heinous things).

    SA
  • I guess we can't call it "moonlight" either, since *that* light belongs to the Sun.

    Well, it should have been called sunlight, but then the Moon went ahead and patented the million year-old technology first.

    "The wages of sin is death but so is the salary of virtue, and at least the evil get to go home early on Fridays."

  • Re:Oxygen? (Score:2)

    by Yarn ( 75 )
    I believe its *free* oxygen that means life is present. It wouldnt be much use to 'life as we know it' if its bound up with silicon for example.
  • You've got to wonder, though, what the astronomers have discovered when they refuse to talk to the BBC.

    Jesus. Let's hope it's not something like this:

    http://www.theonion.com/on ion3541/frightening_study.html [theonion.com]

    Admittedly off-topic, but hey, it's amusing. And the world needs laughter, especially when there are studies like that out there.

    -jay
  • Popular media science articles are often difficult to interpret, as they have been dumbed down either deliberately by the reporter or through the reporter not understanding the subject. I strongly suspect that 'contains the elements magnesium, silicon and oxygen' is the result of this process.

    It is most unlikely (see below) that there is elemental magnesium and silicon in the planet's atmosphere - so it must be that they detected molecules containing magnesium, silicon and oxygen (i.e. almost certainly MgO and SiO.) The reporter has reported the elements but not the molecules.

    MgO and SiO are so stable that they are present as molecules in the atmospheres of cool stars - around 3000K. For them to be in elemental form in the planet's atmosphere, it must be hotter than this.

    Here is a back-of-the-envelope calculation: The relationship between orbital radius and period is P^2 proportional to a^3 (a=semi-major axis of the orbit) (This is one of Kepler's laws.) Strictly speaking, we need the mass of the star in there also, but we are told the star is 'slightly larger and brighter than the sun', so I will assume it has solar mass and luminosity for simplicity.

    The period is about 0.01 that of the earth around the sun, therefore the orbit radius is about cube root(1e-4) approx equals 0.05 that of the earth - i.e. 1/20 AU. The incident energy from the star goes as inverse r squared, so will be 400 times brighter than on Earth. The equilibrium temperature for a black body goes as the fourth root of this, so will be about 5 times greater than for the Earth.

    The black body equilibrium temperature of the earth is below freezing - say 250K (we gain from the greenhouse effect) so this planet will be around 1250K - short of what is needed to dissociate MgO and SiO by a factor of about 3. (This is somewhat of an underestimate as the star is more luminous than the sun. This is partly counteracted by the fact that with a more massive star, the planet is further away for the same orbital period.)

  • Re:Oxygen? (Score:3)

    by Bearpaw ( 13080 ) on Monday November 22, 1999 @10:21AM (#1512332)
    Woo, oxygen. If I remember my astrobiology correctly, this would be taken as a sign of life ...

    IIRC, it would need to be a high concentration of "free" oxygen (O2). It wouldn't be conclusive, but it would be strong evidence. O2 is so reactive that in order for a high concentration of it to exist, there would need to be some source constantly replenishing the supply. (In Earth's case, the source is the large quantity of life that produces oxygen as a by-product.)

    I don't remember if spectroscopy is able to distinguish between the existence of free oxygen and oxygen in combination with other things.

  • (a) Does it run Linux? (b) If life is discovered there, will Microsoft move to include it as evidence that they don't have a monopoly? Daniel
  • Two words for ya: Pons and Fleschman.

    The two guys who decided to go to the press with their discovery of cold fusion before getting the research peer reviewed. Now whatever you think of their work, one giant lesson was learned about the importance of peer review before a press announcement. Since then scientists have been almost paranoid about talking to the press before an article is in review.
  • Let's assume, for the sake of argument, that silicon CAN perform the same functions as carbon in being an integral part of life.
    Let's also assume that it DOES have the same side always facing the sun.
    Would it be at all possible for life to evolve on the cooler side of the planet, still maybe warm enough to support life? Of course, there's no sunlight for photosynthesis, but that may not be the only method of creating oxygen in the atmosphere...
    Of course, I'm probably completely wrong on this. And it'll be moot when the planet does the big sun-dive.
  • Lessee... Planet is 50 lightyears away from earth, assuming a nice round estimate of Radio waves being 100 times slower (Which is wrong and giving radio waves a much higher speed than they deserve) it would take 5000 years for anything to be audible here.

    One-hundred times slower than the speed of light? Ummm, no, sorry, light's nothing but electromagnetic radiation at a lower frequency than that which we commonly associate with the use of "radio." It's all the same thing, ergo, moving at the same speed.

    If they were broadcasting Radio waves 5000 years ago then they've either blown themselves up or moved past radio waves long ago.

    I'm by no means a physicist, but as far as I know, the electromagnetic spectrum is all there is. There's no faster, more efficient way to communicate than that. So they may well have moved on to higher frequencies (x-, micro-, gamma rays, etc.) than what we normally use but they would still be detecable by our instruments.

    -jay
  • Lessee... Planet is 50 lightyears away from earth, assuming a nice round estimate of Radio waves being 100 times slower

    Light and radio are made of the same thing, photons, which all travel at the same speed, speed of light. It is a constant speed in a vacuum (which space is pretty close to being). When they say that the planet is 50 lightyears away, it would take 50 years to send a radio signal there, or 50 years to get a radio signal from there. (Radio in this context is simply a specific frequency range, I'm not suggesting ANYTHING to do with life.)

    Sound, on the other hand, isn't going anywhere off planet, from our planet or that one.

  • Exactly. They probably have something known as scientific integrity that compells them not to make public announcements until their results have been peer-reviewed.
  • If a complete solar system is discovered, can we run it as a Beowulf cluster with our own?

    "The wages of sin is death but so is the salary of virtue, and at least the evil get to go home early on Fridays."
  • Is it just me, or do other people have a problem with the dynamics of these planet systems? I generally like the idea of extrasolar planets, but have an issue with the calculations.

    In this case (thanks to the calculations of Mr. Woodhams in post #58) we're looking at a really large ball of gas that's about 7.5M km from it's sun. That means it's traveling around 165 kps - that's pretty darn quick. At that distance the solar wind would be relatively dense. So how long would it be before the tidal forces and effects of drag totally smeared that ball of gas along its orbit?

    I have to believe they are seeing something besides simple on-planet systems out there.

  • The word you're looking for is "extrasolar" - outside the solar system (the planetary system of our sun, Sol). All planets other than Earth are "extraterrestrial", including the local ones like Mercury and Jupiter.

    And in response to a different message, Jupiter's surface gravity is about 2.5 G. Yes, Jupiter has way more than 2.5 times Earth's mass, but it has a much larger radius, too; g = (G*m1*m2)/r^2
  • do scientists know have firm belief in something that they once doubted?

    I think the importance of this is that a spectral analysis is being performed of an extrasolar planet. This has never been done before, and if it turns out to be practical, it will open the door to learning about the chemical makeup of planets in other star systems. Up until now, the best anyone had managed was to determine the mass of such planets, not their chemical compositions.

    --

  • Oxygen w/o carbon will get you nowhere, in terms of "Life as we know it".

    Carbon is FAR MORE important than oxygen, in that regard.

    I wish I had a nickel for every time someone said "Information wants to be free".
  • Well, the audio signal came from my mouth. The microphone picked it up, the radio amplified it and frequency-modulated it onto an AC radio-frequency electrical curent. But it wasn't EM *radiation* until it got to the antenna--in fact the *driver* element of the antenna, if I'm using my satellite Yagi...since the other elements are merely reflectors, and thus unworthy of mention.

    Any radiation that occurs before that (like leakage from the cabinet or the feedline, ferinstance) doesn't count.

    73 de KB3DXS. :-)

  • >And in response to a different message, Jupiter's surface gravity is about 2.5 G.

    That is at the surface of the atmosphere, since we don't actually know if or how deep the solid ground might be. If you measured the gravity of earth at the top of the visible atmosphere, it would be less than 1 G.

  • If I remember correctly, Oxygen is formed in the last few hours (days, years, not sure which) of a star's existence. Therefore oxygen should be pretty rare relatively speaking.

    All the heavy elements that the planets of our solar system are formed of were produced in a supernova which occurred before the sun was formed. Since this other system is pretty close, I guess we can assume that the heavy elements there were formed from the same exploding star.
  • If discovery of life in other solar systems leads to "unification" of Earth to reach out to our neighbors, would this be like the "unification" of Northern Europe for the crusades (to kill and pillage) or like the "unification" of the United States to relocate and kill native people. Or the "unification" of the Soviet Socialist Republic for the good of the workers?

    Personally, I get worried when everyone gets together to unite under the one, true cause...
  • AAANI (An Astronomer Am Not I)

    Are we really sure this thing is a planet ? I always thought that when something got to about the size of Jupiter it stood a chance of being a star of sorts itself.....anyone care to fill us in ?
  • don't ask me where I read this but our solar system seems to be rich in carbon, and other star systems aren't suspected to be so abundant in carbon, and we need it as much as oxygen to support life. I wish I had the newspaper article I read that from..darn.. anyways that's my 2 cents!
  • I really don't think the major significance of this is in "confirming" the existence of the extrasolar planet -- the science that underlies those (prior) detections is pretty damn hard to poke big holes in, while the work described here in some ways assumes the existence of a planet. Let me try to explain a bit more. We know a whole hell of a lot about gravity, and the way things under its influence move -- this is why, to pick a "gee whiz" example, we can send satellites on fantastically accurate trajectories through the solar system. Given that knowledge, by far the simplest way to explain observered Doppler shifts in the spectra of some stars is to posit the existence of other bodies orbiting around those stars. And this is really a marvelous thing: that given our knowledge of the way things move under gravity, we can deduce all kinds of things about the mass of the orbiting object, its period of rotation, etc (all up to some factor of the inclination angle -- this is why the recent detection of a transit was so neat).

    Now, the current endeavour. What they've done here is to take a spectrum of the star and, since there is supposed to be an orbiting planet, said that the part of the spectrum which is variable on the same timescale as the planet's supposed orbit is the reflected light from that planet. This seems a perfectly reasonable thing to do. But note that there are lots of other ways to explain simple variability -- the supposition that this is reflected light from the planet depends on the prior work.

    The detection of elements in the atmosphere works because atoms have discrete transitions in energy -- each of these transitions corresponds to some wavelength photon, more or less. We know these transitions very, very well, and we use them a lot -- so for instance, I can tell you that a prominent forbidden-line transition of Oxygen [OIII] happens at 5007 angstroms, or that Halpha (a transition from the 3rd to the 2nd energy levels of H) occurs at 6563. You get the idea. So if you look at the spectrum and you see certain transitions, you know the elements which can produce those transitions must be present (modulo certain other concerns, which I'm ignoring here).

    Finally, this is almost precisely the sort of thing that the Terrestrial Planet Finder (and later, the TP Imager) -- basically a space-based interferometer -- are designed to do. They'll go up, hopefully, in the next decade or so. The idea is that with high enough resolution, you could actually discern light from the star vs. light from the planet, without resorting to this "subtracting out the variable component" stuff -- then you could do the same sort of spectral analysis, and come up with a determination of what's in the planet's atmosphere. This would, you see, be cool.

    Man that was a long post. Hope it helped, though.

  • that "we're explorers" line is a load of crap. We're capitalists. If it can be proven that we can make buttloads of money (without any scary, risky, large up-front costs), humans will do it.

    Why did we go to the moon?
    As I mentioned in the Chinese space program discussion; cold-war posturing. But I left out the all important (and highly profitable) pork-barrel spending, where large corporations maneuver their own politicians (as in, they 0WN them), into taxing the bejeezus out of the middle class, to buy nice big rockets to scare the bejeezus out of the Ruskies (now the Chinese), the fact that we got to send people to the moon was kind of neat, but beside the main point of: "Capitalism kicks ass, and you sorry Russians couldn't land a man on the moon because you're all lazy slobs wanting a handout".

    We don't HAVE to go to Mars. Because there are only two imperitives in life, Death and Taxes. And unless we "go" to Mars in the afterlife, Mars doesn't look to be in the plan.

    So until it's cheap enough to go there, or unless some economic incentive can be found to justify the cost, it isn't going to happen, no matter how many little boys (and girls, sorry for being so sexist!) stand outside in their backyards with thier dads (or moms), pointing at a small, twinkling red dot in the sky, and dreaming.

    I wish I had a nickel for every time someone said "Information wants to be free".
  • "pointing at a small, twinkling red dot in the sky, and dreaming."

    That's it.

    I'm inclined to agree with you, that we're capitalists, interested in gaining things, but the things that we deem as valuable are set by society.

    When a child dreams of going to another planet, who tells them they can't (not that it's hard, but that they CAN'T). An older adult. Now, the adult is trying to be realistic.

    We're gonna change what we see as valuable, hopefully soon. I want to live in a society where money is pretty irrelevent because needs are all met and the things that we want are, uhh, less materialistic.

    Would you help in that? I would. I want to. I want to raise the money for a private space venture (Mars, probably, maybe the moon). Would you contribute? Seriously. Estimates (if I remember correctly) that a privatly funded space program would run about 1 billion dollars.

    Until we find out about things more valuable than money, we'll stay here unless the advantages outweigh the cost, you're right. Columbus wasn't an explorer, he was a marketer.

    It makes me sad; it makes me realize that we haven't gotten that far. It makes me want to change the world again, like I did, when I wanted to walk on the moon instead of writing or dreaming about it.

    bye
  • ...and they aren't standing out at normal threshold! Moderators, are you listening?

    I haven't had the chance to read either of the papers mentioned, but I was wondering (idle curiosity) where the (deeply scientifically respected) BBC got the idea of O, Si, Mg detection in the observations.

    Of course, if you beleive theories, ...

    Sure, I'll believe theories; even 2sigma ones, so long as I don't actually have to bet my dog....

    Hopefully, we'll see a similar headline in the future that is more beleivable.

    Having spent time in physics and general journalism, the aims of the two are in fact mutually exclusive. I'm pretty sure that if the headline is scientifically believable, it will never appear in the popular press (Somebody's Law). (Too bad /. is sucked into the same trap too often.)


  • Maybe there is intelligent life out but they know that the rest of the universe is made up of amoeba such as yourself. They do not want to have themselves heard by you ignoramuses otherwise you may start making more nonsensical and utterly stupid pronouncements



  • You're missing the point of the scientific method.. scientists don't believe in "proof" but rather *absence of disproof*. In other words, the way this experiment is designed is like so: astronomer predicts that if there's a planet in orbit around star A, then there will be light fluctuations in sync with the orbit of the planet. The spectra of these light spikes will be unlike that emitted by the star. If these spikes are not seen or if they resemble something other than the chemistry expected of a gas giant, we take this as the beginning of DISPROOF of the existence of the planet in question.
  • What the fuck are you talking about? Stay on topic
  • Well, this planet is also very near the star, (3.3 day orbital period - Mercury is 66 days), and very large (4x Jupiter Mass). I'm betting that it's not anything close to spherical, and I'm also betting that it has no moons, and I'm also betting that it's far LESS hospitable to life than our Jupiter is, and I'm less certain, but I also think it's not likely that there are any intelligent or advanced life-bearing worlds in this solar system.

    But I haven't been there, so what do I know?

    I wish I had a nickel for every time someone said "Information wants to be free".
  • Has any one looked for planets in the Centari (sp?) system? I haven't been able to find any info either way. To me it makes sence that you'd look for planets closer to the Sol system then 50 light years away.

    SeeYa,
    Fyre
  • As I read this article, I had an interesting thought come to mind... what if we do discover a distant planet, and what if we do observe parameters indicating some form of life on that Planet?

    In 10 years time, we'll supposedly have the technology to start taking pictures of distant planets - what if we eventually take a picture of a planet that definitively indicates that life exists on that planet (hey, are those *cities*?)?

    What do we, as a species, do next?

    We know we have distant neighbours. They're definitely some sorta life form, say. It'll take us 10,000 years to get there, at least using modern technology - what do we do about it?

    I personally don't have a hard time envisioning a massive shift in cultural focus were this to happen - mankind may in fact become more unified around the goal of reaching out to our neighbours and establishing trade with them, or some sort of Unification of species (cultural, trade, religious, sexual, etc).

    The ramifications are interesting - do we as a species make it a goal to contact this distant civilization in some fashion, or do we just leave it at that and go on pretending they don't exist, since for all intents and purposes, the existing Earth generation will never have contact with them? Well, I can imagine our own species undergoing massive shifts too - perhaps Earth wars will be fought over whether to contact our neighbours or not, who knows?

    I'm sure there have to be some pretty good speculative fiction pieces on this sort of subject - do any Slashdotters know of authors that have treated this subject in any particular degree of quality or style? I'm inclining towards writing a short story myself, based on this subject... but surely there have to be some fairly decent authors out there who have already approached this same issue from a "what effect does it have on mankind *now* as we know it?" stance.



  • Unfortuantely, this story was very premature. Hopefully, we'll see a similar headline in the future that is more beleivable.

    First, the group has submitted a paper to a scientific Journal, and it has been accepted, however several changes (mainly deletions) were made between the version they submitted and the version that will be published.

    Second, another group of respected astronomers tried a very similar observation of this same system and published a paper claiming to have an upper limit on the light reflected off the planet. Their upper limit is below the claimed detection. Of course, either could be incorrect, but this detection is still controversial until the discrepancy is resolved, even if all their data and analysis looked convincing.

    Third, I've seen both versions and discussed them with other respected astrophysicts. Their data is good, meaning they have performed a very precise observation. However, most astrophysicists that I discussed this paper with disagree with the interpretation that they have detected light reflected off the planet. The statistical analysis that led to that conclusion is questionable, and the signal is significant at no more than the 2 sigma level. I'm not saying they haven't detected light from the planet, only that they did not present the data and statistical analysis that is necessary to convincingly show they detected light from the planet. I would call this a "probable detection", meaning that they probably detected light reflected off the planet, but can't be very confident.

    Finally, there is NO detection of oxygen in this atmosphere, or silicon, magnesium, or any specific elements. If you beleive their data and analysis, then you do learn that the radius of this planet is on the order of the radius of Jupiter (there's a non-trivial dependance on the albedo). This would be very convincing that the planet is a gas giant and not a terestrial planet. However, there is no evidence that there is any oxygen in the atmosphere. Now most reasonable people would imagine there's probably lots of hydrogen and helium, probably some lithium, berrilium, boron, carbon, nitrogen, oxygen, flourine, neon, sodium, magnesium, etc., but there is no observational evidence that this planet has oxygen or any other individual element in it's atmosphere. Of course, if you beleive theories, I can give you lots of those...

    Sorry for the disappointment.
  • Don't worry. People have thought about all the issues you bring up. The solar wind isn't very significant to the orbit of the planet, although it can affec it's atmosphere. Tidal forces are important and may very well cause the planet to spiral into the star in several billion years. It is likely that they already "spun-up" the star so that the star's rotation period matches the planet's orbital period.
  • Actually, more electromagnetic radiation is radiated off of Jupiter than it receives. Although this radiation doesn't take the form of visible light, it radiates more than it receives nonetheless. This is due to Jupiter's massive rotation speed.
  • We're all dancing around the answer here. It's not a gas giant, because of the solar wind, high temperature, yadda yadda. Besides, how many gasses can you think of that contain magnesium? The article is a bit vague on just what the spectra showed, but it's probably the three elements in plasma, or else in solid form.

    Quick quiz: what are the three most common elements in the earth's crust?

    Answer: Oxygen, Silicon, Aluminum

    (Note that aluminum is right next to magnesium on the periodic table, and magnesium is in the top ten elements for the earth.)

    The planet is made out of MgSiO3 and related minerals. It's a big ball of rock with little or no atmosphere (it would boil off at those temperatures.)

    I think THIS is the big news they won't discuss yet. AFAIK, astronomers didn't think it was possible to have a rocky planet that big - they were guessing the limit was a bit larger than the Earth.
  • I understand what you're trying to say about spectroscopy, but you're wrong. There are two types of spectral lines: emission lines, from something that's hot enough to glow, and absorption lines, from every other type of matter. If the light really is reflected, then they must be measuring absorption lines. On the other hand, if parts of the planet are hot enough to glow (seems plausible) it could be rock just as easily as gas. Hot lava glows nicely in the dark.

    It can't be a gas giant for a few reasons:
    1. No Hydrogen
    2. No Carbon
    3. No Nitrogen

    The nitrogen is most telling. It has about the same atomic weight as oxygen, so it should be present in similar amounts, regardless of the planet's temperature or gravitational pull. It's not there because it does not react strongly with metals to form minerals.

    Actually a free oxygen atmosphere is pretty fishy to start with. Oxygen is extremely reactive - almost as corrosive as chlorine gas. The only reason the Earth has free oxygen is because the plants keep dumping it there. On the other planets in our solar system it is always seen in a compound - carbon dioxide, water vapor, etc. Since we don't see hydrogen or carbon, it is probably in rock form.
  • Last night, all the self-proclaimed Wise-Men of /. derided NBC for broadcasting the Y2K movie, calling it meaningless hysteria and irresponsible broadcasting. Tonight, there is a snippet of news on a possible discovery of light being reflected off a gas giant near Tau Boote 50 light years away, and some of you same wise men (though not all, some of these posters know of what they speak) are talking about silicon based life-forms and asking why we haven't heard radio communications from this planet?!?! Geez, haven't these particular /.ers taken an elementary course in Astronomy? In any event, I expect the pace of these discoveries to increase. At first, we were able to detect a planet by the gravitational 'wobble' it produced on its star, then we were able to look at how the light from a star dimmed when a planet passed nearby it. According to one of my astro books, we've discovered 6 or 7 planets. Only a few are smaller than Jupiter while the rest are much larger. The interesting thing is, and the question to be answered is, how does such a planet like the one formed around Tau Boote survive the intitial formation of the star? Most astronomers think there is some sort of solar gale when the star is initially formed, and such a gaseous planet could not survive. In any case, it will be even more difficult to detect earth sized planets since they are much smaller and won't radiate near the electromagnetic energy of these gas giants. As for extra-terrestrial life- Well, hopefully Hubble 2, or whatever it will be called, could point its camera at these objects and take some nice snap-shots. If something proves interesting enough, it's not that difficult to move the VLA in New Mexico or some southern Radio 'scope to look at the object. The next century will be a very exciting time for all astronomers.
  • The $64,000 question is though, as Science used to be of the opinion that OUR solar system was what you could characterize as a "normal" one - small, life-bearing rocky inner planets, big, radioactive, cold, dead gas giants, farther out; which type of solar system is "normal", and how does the distribution of such "normal" solar systems affect the chances of finding intelligent life?

    Now, pretty much every extrasolar planetary system we've observed is NOT structured in that way (the way ours is). Granted, because of the methods we're using for observation, (star-wobble, spectrographic filtering), observing a solar system built like ours is probably beyond our current technology, and maybe that's why we haven't observed any yet. Not only can we not detect larger gas-giant planets that orbit relatively far out (like our own solar system), but I also believe that we can't yet detect smaller planets like Earth in other solar systems, wether they're in close-in or far-out orbits. But I also think it's safe to say that a solar system like the ones we've observed other than ours, would not be as likely to bear intelligent life. The presence of such a large mass, in the "goldilocks-zone" of the inner planets, would be very disruptive. Smaller objects would tend to get swept away by the larger objects' periodic influence. The scale of distances among inner planets is much smmaller than among the outer planets, Mercury is many many times closer to Earth than Jupiter.
    I don't think Science even today has a good model for how these "inner gas giant" systems form. It contradicts the model they came up with to explain OUR solar system. But to say that they don't exist would contradict current observations, so it's the model that has to go. And with it, a lot of suppositions on the distribution of "life-friendly" solar systems in the Universe. At least until we have the technology to detect solar systems that are formed more like ours - and from that we can come to more of a conclusion as to whether there is intelligent life out there. Because if there is, I think it's not likely to be found in solar systems such as those we've observed to date.

    So if OUR solar system is "normal", then we can say it's pretty likely that there is a lot of intelligent life out there. If our solar system is *not*, then I'd say it's pretty unlikely that we'll find a LOT of intelligent life out there, but not necessarily NO intelligent life out there. Though our solar system may be an oddball model, it can't be unique.


    I wish I had a nickel for every time someone said "Information wants to be free".
  • I don't remember if spectroscopy is able to distinguish between the existence of free oxygen and oxygen in combination with other things.

    IIRC from astronomy courses at university, spectroscopy cannot distinguish free oxygen from oxygen bound in a molecule with something else.

    If you read the article, you'll notice that these guys have pulled together a very smart hack from the star's spectroscopy data. However, with a dim object like a planet they are likely to miss most of the elements in the atmosphere.

    The oxygen they found could be bound to anything. I guess the most likely molecule would be carbon dioxide, but even if it was water they wouldn't be able to tell. It's unlikely to be O2, which would be an indicator of life.

  • Sorry no evidence for Mg, Si, or O, yet. See my earlier top-level post.

    In any case, this planet does not pass directly in front of or behind it's star as viewed from Earth. Actually, the orbital plane is inclided a good bit (probably 30-60 degrees) to our line of sight. They claim to have detected a signal by looking where they would expect to find reflected stellar lines slightly shifted due to the planet's doppler shift. Again, see my previous top-level post, as this is not yet a clear detection of any light from the planet.

  • Conincidentally, just a few weeks ago, the professor for an imaging class I'm taking discussed the method of detecting planets by measuring the reflected light off the planet. Basically, we wait for a period of increased solar activity (which causes a spike in the received signal), and then take the autocorrelation of the received signal. We should then see 2 spikes in the autocorrelation function: one corresponding to the direct emission from the star, the other from the reflection off the planet.

    In practice however, it doesn't work that well (and in fact hadn't been applied sucessfully before this) since the reflection off the planet is very weak and drowned by noise.

  • Re:Oxygen? (Score:3)

    by DanaL ( 66515 ) on Monday November 22, 1999 @08:55AM (#1512380)
    You've got to wonder, though, what the astronomers have discovered when they refuse to talk to the BBC

    They are probably just being cautious with there discovery. I imagine they don't want to over-hype stuff, get everyone's hope up and then say, "Oops, we made a mistake, the results were false."

    Apparently, they hadn't sent the results to any journals, so their results probably have not been peer-reviewed yet.

    Dana

  • The obvious questions... (Score:3)

    by Hanno ( 11981 ) on Monday November 22, 1999 @08:55AM (#1512381) Homepage
    ...will the Chinese send a manned craft [slashdot.org] there?

    ...will the Chinese launch a cyber attack [slashdot.org] against that planet? Of course, using modified, evil closed-source seti@home clients?

    ------------------
  • do scientists know have firm belief in something that they once doubted?
    Although scientists were pretty sure about the existence of planets, they weren't positive; as you said, seeing is believing. There were other explanations for the phenomena, but of all the possible answers, a planet was by far the most plausible. You can consider this a confirmation that is nice, but wasn't really necessary for proof.
    I doubt the same technique would find a moon as well, but you never know.
  • An object four times the size of Jupiter orbiting a Sol-sized star with a period of 3.3 days? That thing is really booking and must be quite close to the star. Mercury's orbital period is 88 days. Aren't we looking at some sort of hybrid binary system? Is it any wonder the thing is hot.

  • Could someone tell me why there are heavier elements like Silicon and Magnesium and no Hydrogen?

    From the article, it sounds like they looked at the spectra of the star and planet, and saw what varied over 3.3 days. I'm assuming the hydrogen and helium spectra from the star was so much higher in magnitude than the hydrogen and helium from the planet that differences caused by the planets orbit were undetectable.

    Oxygen, silicon and magnesium must be rare enough in the star to allow a noticeable difference in the spectra when the planet rotates.

    George
  • >Could someone tell me why there are heavier
    >elements like Silicon and Magnesium and no
    >Hydrogen?
    I think you just answered your own question.
  • Woo, oxygen. If I remember my astrobiology correctly, this would be taken as a sign of life if it weren't on a planet four times the mass of jupiter, and with a year of less than four of your Earth days.

    Just in case...
    Given that is 'only' 50 light years from earth we should start beaming Linux advocacy right away ;-)
  • Possible explanation: (I'll use our solar system as an example)
    Jupiter slows down a bit, and begins spiraling in towards the sun...
    20 million years go by, and the asteroid belt becomes part of Jupiter. A few million years later, mars is gone... then earth, venus, mercury... Soon, you have a MASSIVE ball of gas circling around the sun with a period of 3.x days... you also have the huge quantities of oxygen from all of the absorbed planets. Note that neither this discovered planet nor the fictional jupiter is likely to have much oxegen in O[2] form, as it's HOT and reactions with oxygen are easy to set off.
  • http://origins.jpl.nasa.gov/missions/sbobs.html These projects seriously rock - real cutting-edge science. I can only dream of what they'll find.
  • ... as posted on the LANL astrophysics preprint server a few days ago:

    http://xxx.lanl.gov/ps/astro-ph/9911314 [lanl.gov]

    The URL above gives the abstract in ASCII, but the article itself is in Postscript. If you look at the main article, pay special attention to the figure which shows the REAL "signal" of reflected light from the planet, and the signal from a fake planet inserted into the data. The fake signal is clearly there, but I'm not confident that the claimed signal is.

    How did they do it? The basic idea is: they took spectra of the star with very high resolving power, which spread out light into different wavelengths; or, equivalently, spread out light at different velocities. They knew when the planet ought to be coming towards us, and going away from us, in its orbit around tau Bootis, and with what speed. That meant that they could examine _very carefully_ spectra to find hints of spectral features which were shifted -- ever so slightly -- from their ordinary positions. They found weak evidence that some spectral features were shifted to the blue when the planet was coming towards us, and to the red when the planet was going away from us.

    But, if you ask me, it's a two-sigma result. Needs more observation.

    As for the claims of specific elements ... well, my guess is that the authors saw the weak, time-varying features in spectral lines produced by some element, and the press misinterpreted this to mean that that element was present in/on the planet. If the planet is simply reflecting light like a perfect mirror, it will produce these weak, time-varying features for ALL lines of ALL elements. Given the signal-to-noise ratio in the spectra I saw in their paper, I don't think that the authors are really advocating the presence of any specific elements in/on the planet.

    And if they _were_ (which I emphasize is unlikely), it would be elemental oxygen, not atomic oxygen.

    A good idea, certainly, but _really_ tough technically. I think that the press is running away with the story.

    Michael

  • Three elements detected by astronomers:
    Oxygen, Silicon, Magnesium

    Three most common elements in the Earth's crust:
    Oxygen, Silicon, Aluminum (Mg in top ten)

    Various people below made the right points; the oxygen can't be atmospheric; the planet can't be a gas giant that close to the sun; the lack of hydrogen and helium is significant.

    The planet is a big ball of rock with no atmosphere. That's pretty remarkable; AFAIK astronomers didn't think a rocky planet that size could form. That may be what the astronomers won't talk about yet.
  • good points, i retract my earlier comment


    (i do think the leakage should count though, but you've obviously actually worked with ham radio and i'm just faking it :)
  • in my bio. class earlier this year we learned earth didnt have much pure O2 but somehow we made it....it may have had ammino acids and other forms of organic compounds. we had no atmosphere and the early life was hellish at the time. even though humans and most other organisms that live on earth cant hold up to the heat and pressure like on that planet but rember there are different plants and animals in trenches that can "hack" it, why not on the other planet. also in reply to the person who said something about no "intellegent life" maybe they were tired of not getting an answer so they stopped before we started
    i would like to hear more about this
  • Hmmmm... one of the odder posts I've seen in a while.


    Pro-troll evidence:
    Obvious logical fallacy, grandiose statements, AC & AOL-STYLE SHOUTING TEXT!!!.


    Anti-troll evidence:
    Generally earnest tone, not overtly antogonistic & name is signed at end.

  • Its most likely in gaseous form. I doubt that the gasses would "boil off" (although hydrogen can "evaporate" -for lack of a better word- from a planets atmosphere by being subjected to solar winds and other effects.) The sheer mass of this planet makes it likely that the gas would remain, or at least the heavier elements would. Given its size it probably heats itself (Hydrogen fusing core similar to Jupiter? Perhaps.)

    The proximity to the star it orbits coupled with its own internal heat would make the elements detected most likely be present in a gaseous form.

    This is coupled with the fact that a gas spectograph was most likely taken of the planet. This is how spectograpy (sp) works. AFAIK, unless they used the amount of light NOT reflected by the planet, but then that would not rule out a great deal of elements, so how could they have detected these three?

    The answer is again A light spectograph of gasses.
    The reason is because the article cleary states that they detected reflected light not absorbed. Thus, it IMO is not a rock. Given its mass, I would favour a gas giant.

  • Tau Bootis is the weirdo among the exoplanet stars.

    1. It's the youngest of the set: 2 Gyr, whereas most are older than 5 Gyr. This is due to a selection bias because younger stars have bigger star spots which can ``ape'' the spectral signature of an exoplanet.

      This has happened a couple of times already, but in each case follow-up photometry has shown that the variations aren't planet induced.

    2. The radial velocity variations have a much larger amplitude than the other exoplanet stars, about 450 m/s.

    3. The orbital period is about the same as the rotation period of the star. This is a problem because the star is under "active" for it's rotation. So, does the planet influence the star's orbit here (but not for any of the other 51 Peg-type planets???) or vice versa.

      The period I *expect* from stars of Tau Boo's mass and age is 5 days, not 3.3 days. But I've been monitoring the rotation for 15 years and it's definitely shorter than 5 days. Weird, weird, weird.

    4. Tau Bootis has a weird other period that doesn't "fit" with anything I can think of. I'm still writing a paper on this, but the punch line of "duhhhhh I don't know" isn't very interesting :-)

    Interested parties can get our papers at http://cfa-www.harvard.edu/~donahue/P reprints/ [harvard.edu]. In the newest paper (I'll put it up on the page tomorrow, PROMISE), we definitely show that there's NO transit of the planet across the stellar disk.

    The St. Andrews group are REALLY good people. And, I"m saying that not just because they said nice things about my research recently! :-)

  • Are we really sure this thing is a planet ? I always thought that when something got to about the size of Jupiter it stood a chance of being a starof sorts itself.....anyone care to fill us in?

    Err, no. Jupiter is only about 1/80th of the mass required to achieve become a star. This object is four times bigger than Jupiter, but that still puts it well below the minimum mass required to achieve fusion.

    --

  • Yeah, at either pole days are a year long.
    6 months of light, 6 months of darkness.
    At the equator, days go by the fastest.

    Who knows? This guy could be a scientist working in Antartica.
  • If this is o2, then that means plants, or at least alage or something. And yes, i know i cant spell the latin for "microscopic plants"


    This news item might as well have been titled "logical fallacies from hell". If it is molecular oxygen (which it almost certainly is not), it doesn't even come close to proving the existance of life on that planet. Virtually every other piece of evidence indicates that life similar to that of the Earth would be impossible: Never mind the fact that the planet is insanely hot, its made of GAS for Christ's sake! Where do you suppose the organic molecules which constitute the necessary precursors of life would have accumulated? In thin air? And if you posit that "life could have evolved differently", then the presence of oxygen is no longer strong evidence for life anymore anyway.

  • Every time I ask why aren't we colonizing other planets I get the same response. "There is no economic incentive to go." But I say there is. What if a company existed that offered a package that gave you the ability to live on another planet. (I.E. Recycling Food supply, Water, Air and the tools to expand your living area.) And you would get all this for a mere $50,000,000 a person. Would you agree that there is a market for this? (Countries, Very Rich people, All Microsoft employees) The profits this company could generate would be extreme. And best of all it would pave the way for them to control interplanetary trade, Policing, etc. Sooner or later a Company will see this opportunity. And if the economy keeps going the way it is, this time will be soon. Capitalism will pave the way to the stars.
  • Has any one looked for planets in the Centari (sp?) system? I haven't been able to find any info either way. To me it makes sence that you'd look for planets closer to the Sol system then 50 light years away.

    Our stellar next door neighbor, the Centauri system, is actually a trinary star system. Alpha Centauri A and B circle fairly close, and the C component (sometimes called Proxima since it happens to be closer to us at the moment than any other star save our own) circles fairly far out. Now, my understanding is that they're less hopeful of finding planets in binary or trinary star systems than orbiting a single star. I don't doubt that they've checked, and I'm not surprised that nothing has been found. There may be planets there anyways, but not the big wonkin gas giants we can spot today.

    --

  • Nope. The astronomers aren't hiding something, like the secret of the blue laundry balls. They are gagged by the usual agreement with the science magazine Nature, which requires that they don't talk about the article until AFTER it's published. Science mags aren't like People or Time. They take publication seriously. Scientists anyway tend to squirm when they have to answer the questions of liberal arts grads. who aren't exactly masters of physics. Even if once speaks slowly and distinctly, you'd get a silly musunderstanding 9 outta ten times.

  • Exploration (Score:3)

    by The Good Reverend ( 84440 ) <michael AT michris DOT com> on Monday November 22, 1999 @09:00AM (#1512408) Journal
    I remember reading books on astronomy when I was growing up; there are 9 planets, many moons, and they're all in our solar system. Scientists think there are probably other planets out there, but they can't be sure.

    The books I was reading, in class and outside, were written in the late 80s and early 90s. An now, 10 years later, we've discovered scores of planets, and even seen light from one of them! It's amazing! I remember being angry to hear that funding for space travel/exploration was being cut every year; I could never say why I knew we needed to continue this research, but I just knew we did. We HAVE to go to Mars. We HAVE to send out more deep space probes. We HAVE to go back to the moon.

    We're explorers. We always have been. These findings of planets have made it to the late night talk show monologue jokes, Comedy Central's The Daily Show, and most major media outlets. There's interest again. I just hope we keep it up and make sure we don't stop exploring because "there's better things we could be doing with our money"

    The Good Reverend

  • Wow. (Score:3)

    by Otto ( 17870 ) on Monday November 22, 1999 @09:02AM (#1512410) Homepage Journal
    Okay, let's summarize:

    -Magnesium, silicon and oxygen found (no proportions given out).
    -Huge planet. 4 Jupiter masses
    -3.3 day year

    Well, if it's 4 J-masses, and whips that fast around it's sun, I'd bet it's always facing the same side towards the sun. Probably causes some pretty damn spetacular tides on that sun too (think solar matter waves 1000 miles high :-)...

    Now oxygen != life guaranteed. They give no clue on how much O^2 has been found, nor if it's cool enough to be O^2 in the first place. If the place is too hot, molecules might not be an option. This is a possibility since it's mighty close to the sun, remember?

    Still cool. Probably the only reason they can get any light off it it because it is so close to it's sun, and gets enough light to reflect well. Also, it's damn lucky that the ecliptic planes cross just right to see it at all.

    Life is probably out. Jupiter is what, 20 G's? and this thing is around 80? Nah. My best guess: it's so damn hot and massive that it's nearly a star anyway. Give it a few hundred years or so, it'll crash into the star itself, and give the astronomers some real eye-candy.


    ---

  • Vaporized Rock, or, Oxygen != Life (Score:4)

    by ENOENT ( 25325 ) on Monday November 22, 1999 @09:03AM (#1512411) Homepage Journal
    In this case, the presence of oxygen in the atmosphere does not indicate the presence of life. In fact, given the two other elements detected (silicon and magnesium), it indicates a climate that is singularly inhospitable to any biology at all.

    The atmosphere is vaporized rock. Now that's hot.

    Rocks, at least the crustal rocks on Earth, consist mainly of oxygen, silicon, and magnesium, with a few trace elements to make things interesting.

    Given that this planet is so close to its star, it's not surprising that the surface tempurature is hot enough to boil rocks.

  • ... so I don't know a whole lot about these things. But I think it's a very interesting development for them to find Oxygen. Very, very interesting. It makes me ask an important question, though:

    Why?

    I don't know a whole lot about planetary formation, but I seem to recall there was a reason that Oxygen isn't usually found in the big gas giants, and things like Hydrogen and helium are. So one asks the question: Why is there oxygen there? Why is there, of all things, silicon there?
    The current theory, I think, about how this particular planet formed is that it was created way out where it ought to have been, and then gravitated (so to speak) inward. But would that account for these odd elements in the atmosphere?

    Again, I don't know much about the creation of the universe, so if there's any astrophysicists out there, I'd love to find out what's going on here :)
  • If we had the wherewithal to communicate rationally with a completely alien species, wouldn't we have done it already here on earth? There are loads and loads of lifeforms around, and yet the extent of our communication with them has been domestication (with the exception of a couple of signing primates). Would aliens become our pets or our food? Would we become theirs?

    Or suppose the life on planet X is intelligent but huge and slow - like million-year lifespans and taking a year just to get a word out. Would we have any incentive to talk to them? Would we even know to try?

    Or will it really turn out that all intelligent life in the galaxy is just English-speaking humanoids with wrinkled noses?

  • One-hundred times slower than the speed of light? Ummm, no, sorry, light's nothing but electromagnetic radiation at a lower frequency than that which we commonly associate with the use of "radio." It's all the same thing, ergo, moving at the same speed.

    If they were broadcasting Radio waves 5000 years ago then they've either blown themselves up or moved past radio waves long ago.

    I'm by no means a physicist, but as far as I know, the electromagnetic spectrum is all there is. There's no faster, more efficient way to communicate than that. So they may well have moved on to higher frequencies (x-, micro-, gamma rays, etc.) than what we normally use but they would still be detecable by our instruments.



    My mistake if everything travels the same speed.

    As to the second point you make the erroneous assumption that we have discovered everything there is to discover. I'd not be so quick to hop on that horse if I were you.

    Kintanon
  • In 10 years time, we'll supposedly have the technology to start taking pictures of distant planets - what if we eventually take a picture of a planet that definitively indicates that life exists on that planet (hey, are those *cities*?)?

    What do we, as a species, do next?



    Simple, we go to war.

    Kintanon
  • No details of the work? No peer review?

    It's exciting news, but I think we should really wait for some more information and confirmation.

    What's interesting is the note in the article regarding observation with the next generation of telescopes and astronomical equipment. Aside from confirming this, what else might be done with the next generation of observation equipment?

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