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Extrasolar Planet Detected Visually

Posted by jamie on from the nice-painting dept.

"etphonehome" was the first of many to submit this. Astronomers at UC-Berkeley measured a star decreasing in brightness as its planet crossed in front of it. This is the first known planet whose orbital plane crosses Earth, making this measurement possible. It's great to see independent confirmation of the "wobble" which until now has been the only evidence of extrasolar planets. There's a splendid artist's rendition on the astronomers' webpage; see also the story on CNN or the technically-challenged Washington Post ("the planet had indeed cast a shadow over the star").

71 of 96 comments (clear)

  1. cant wait... by matman · · Score: 1

    it'll be neat to see what kinda observations are made with the new hubble in planning. it's supposed to be able to actually photograph the planets themselves. :)

  2. question by nick+the+man · · Score: 1

    im not an astronomer, so can some one explain this. how did they see a shadow of the planet on the sun?

    -nick

    --
    "by doing just a little each day, I can gradually let the task overwhelm me."
    1. Re:question by astrophysics · · Score: 3

      They monitor the intensity of light from the star as a function of time. They saw the star dim a little bit just when predicted by the group who discovered the planet. If correct, it will transit (pass in front of the star) again today and people will be looking to confirm this.

    2. Re:question by shogun · · Score: 1

      They didn't, what they saw was the actual amount of light being received at Earth by the star being reduced. This is caused by the planet crossing the line between the star and Earth so that some of the light from the star was being blocked, hence making the star appear slightly dimmer.

    3. Re:question by Anonymous Coward · · Score: 1

      how did they see a shadow of the planet on the
      sun?

      Instead of emitting light, the planet emits dark (y'know, like "dark matter"). Thus, it can cast a shadow on anything it wants to.

      (Since Calvin's Dad wasn't around to provide the answer, I figured I'd better step in :-)

    4. Re:question by Tony+Towers · · Score: 1

      They didn't exactly. What they saw was a decrease (of about 1.7%) in the light received from that star, i.e. that planet was blocking some of the light.

      The link above is to an "artist's impression" of what would have been seen with a powerful enough telescope.

  3. Re:question about 'shadows' by Anonymous Coward · · Score: 5
    They did not, properly speaking, see a shadow on the sun. That was a bit of ignorant journalism in the Washington Post article, I guess. I didn't read that one.

    What happened is that a very large planet moved in its orbit of the other star into a position between that star and Earth. Thus, it blocked some of the light from the star from reaching earth, making the star appear to dim for a few moments...think of it as a very partial eclipse of that star by one of its planets, much like our moon occasionally gets between us and the sun, causing partial or total eclipses, blocking or dimming it briefly.

    This dimming of the star, predicted by the astronomers, proved that they had inferred its orbit coreectly, and that there are indeed other planets. Even if they are obscenely close to thier stars. A 3-4 day orbit means that thing is very very close to its sun - the weird thing is they've detected a lot of planets with about the same distance from various stars...

    Where are all the planets that have nice, decent, life supporting orbits? (ok ok , life-as-we-know-it style? I don't want to emigrate to Mercury or its distant kin!!)

  4. New planets, how do they look like? by fReNeTiK · · Score: 1

    I've been really excited by the discovery of planets orbiting around other stars. This news seems to confirm the very strong evidence gathered already by direct observation. What I'd really like to know is this: Have astronomers already found out something about the planetary structure of those planets, i.e. are these all Jupiter like gas giants or can we expect something more earthlike?
    --

    --
    I strongly believe that trying to be clever is detrimental to your health. -- Linus Torvalds
    1. Re:New planets, how do they look like? by astrophysics · · Score: 1

      That's why this planet made slashdot and not the other six that were recently announced. For this planet, because we saw a transit, we know the mass to within a few percent and the radius to better than ten percent. So we finally know that at least this planet is a gas giant and not a humoungous terestrial planet.

    2. Re:New planets, how do they look like? by Skip666Kent · · Score: 1

      Most 'new planets' will fall into the 'gas giant' category and/or be in a very close orbit around their central star. This is simply due to the fact that, currently, these extra-solar planets are the easiest to locate, because they affect the appearance/motion of their parent star to a MUCH larger and more visible degree than small, earthlike planets at earthlike distances from the central star.

      --
      **>>BELCH
  5. Re:CNN scientifically challenged too by aenea · · Score: 1

    I was scratching my head over that sentence too. How exactly do you get a gas giant into a 4 day orbit?

  6. Re:question about 'shadows' by Anonymous Coward · · Score: 1

    I don't want to emigrate to Mercury or its distant kin!!)

    Good. It's not really an option at the moment.

  7. Re:CNN scientifically challenged too by astrophysics · · Score: 3

    What this was probably intended to say was...

    Ever since the first extrasolar planet around a sun-like star was discovered (1995) to be in a 4 day orbit, astronomers have theorized that that planet (and recently several others like it) were not massive terrestrial planets, but rather gas giants like Jupiter (but much closer to their parent star). This discovery is the first where we accurately know both the mass and radius observationally. The observations show that this is indeed a gas giant as predicted (for similar type planets) years ago.

    The bit about it not forming so close is a little more technical. But basically, we beleive that gas giants begin to for a few AU (distance from Earth to Sun, Jupiter is at 5 AU) from their parent star (based on our estimates of the temperature of the disk and at what distance different elements and molecules will condense). An alternative is that these close massive planets are accutally humoungous rocky planets (like Mercury, Venus, Earth, Mars). While this observation does not prove that it didn't form there, it does prove it's a gas giant. That is a triumph of astrophysical theory.

    BTW- Some of the difficulties with forming gas giants at several AU are: How do you move them in to 0.04 AU? Why do they stop right there and not continue to migrate into their parent star?

  8. On Earth-like extra-solar planets.. by ToastyKen · · Score: 2

    The majority of the planets we've been able to detect so far are gas giants because their mass makes them easier to detect. Doesn't mean there aren't any Earth-like planets out there, though.

    In fact, there was a recent discovery of a possibly more Earth-sized planet: http://news.bbc. co.uk/hi/english/sci/tech/newsid_446000/446360.stm

  9. Extrasolar Planet by waldeaux · · Score: 5
    Actually, the transit that was reported was discovered by Greg Henry, of TSU using telescopes at Fairborn Observatory (south of Tuscon, AZ).

    These telescopes do the most precise photometry ever achieved, working to about 0.001 magnitudes on a night-to-night basis, and about 0.0002 mags for long-term variations. That's ALMOST good enough to montior irradiance changes for stars that vary as little as the Sun does. On a very good night, with lots of overlapping data, these telescopes could almost detect a transit of an Earth-sized planet.

    There are two published papers on using these telescopes to look for transits in exoplanet systems. A third has been accepted for publication by the Astrophysical Journal and will come out in the March 10, 2000 issue. (I'm one of the authors.) Preprints of the papers are all available on one of my webpages:

    (I'll get the preprint of the 3rd paper up there on Monday.)

    It's great to see that a transit has finally been observed! We were starting to get worried... The search for transits is being done in collaboration with a long-term program to better understand the stars they orbit also done at Fairborn and with Mount Wilson's HK Project.

    Bob Donahue

    1. Re:Extrasolar Planet by astrophysics · · Score: 2

      Sunspot: Extremely unlikely, since the time of the transit matched the time of the maximum radial velocity. Also the observed radial velocity variations are way to large to be a sunspot.

      Solar Prominence: This would be brighter, not dimmer

      Brown dwarf: Depends on what your definition of a brown dwarf is. If it includes 0.6 Jupiter mass objects, then you can call it a brown dwarf. However, most astronomers are reserving the term brown dwarf for object that fuse dueterium, but not hydrogen.

      Indeed, noone has physically touched the planet, like an early explorer finding a new island. They've only infered it based on visual observations. But that's good enough for me to beleive with >99.99% confidence that there really is something pretty massive about 0.045 AU from that star.

      I'm not sure what you think is necessary to "prove" the method. If we have to touch the planet, then it almost certainly won't be proven in our lifetimes. I think may people would say that this observation of a transit gives independant evidence for this planet's existance, making the method even more credible than before.




    2. Re:Extrasolar Planet by hendric · · Score: 1

      Bob,
      How much more capability would be needed to detect an atmostphere of the planet passing in front of the sun? Has this been done before for, say, Venus?

      --
      "Though it may take a thousand years, we shall be FREE."
    3. Re:Extrasolar Planet by waldeaux · · Score: 1
      You can rule out sunspots.

      The star is inactive compared to the Sun. I can't give specifics (yet) --- I only got a copy of MY data for this star on Friday, but I can tell from the raw data that it's probably at the level the Sun was at during the Maunder Minimum.

      However, sunspots can mimic the RV variations if they are large enough. We looked into this problem in our first paper on the subject (Henry et al. 1997, ApJ, 474, 503), and in more detail in another paper (Saar & Donahue 1997, ApJ, 485, 319).

      And there is a case where this happened!

      The star HD 166435 is young, has a 3.8-day rotation, and the motion of the spots across the surface cause enough photocenter wander to influence the radial velocity variations that it mimic the effects of an exoplanet. We (Henry with precision photometry, and the HK Project at Mount Wilson with spectrophotometry) were able to show (before the paper was submitted for publication) that the variations coincided with variations in the photosphere and the chromosphere of the star with the same period.

      The chromospheric variation is the exoplanet killer since the flux variations that are observed have to come from stellar activity.

      Needless to say we're trying very hard to keep up with all exoplanet announcements, and even rumours to get a handle on the properties of the stars they orbit.

      Bob Donahue

    4. Re:Extrasolar Planet by waldeaux · · Score: 1
      Well, as for Venus, I don't know of any papers doing this in terms of spectroscopy, but there is a very famous example of how you can see Venus' atmosphere and show that it is VERY dense:
      During transits of Venus just as the ingress phase is ending, you see a "tab" of darkness extending from the edge of the solar disk to Venus' disk that's caused by the dense atmosphere.

      Coincidentally, there is a transit of Mercury tomorrow which can be seen from the West Coast. Transits of Venus are much more infrequent, but have the weird property that two occur within a few years of each other, then not again for something like 200 years. The next two are in 2004 and (I think) 2012, so lucky us! :-)

      -----------

      Paul Butler had an interesting comment in the newspaper article suggesting that it would be possible to detect the planet's atmosphere during a transit.

      What I suspect he's referring to would be the appearence of extra lines in the star's spectrum during a transit caused by absorption of starlight by the planet's atmosphere. The problem with this is that there isn't much light being absorbed, so the effect will be incredibly tiny. But with a LOT of photons it might show up. You could co-add all the in-transit spectra you get over time.

      Heh. Having said this, it occurs to me that the widths of the spectral features of the star are much wider than the variations in wavelength shift that are used to detect the planet, but I don't have a clue what the widths of these "overlayed" features would be!

      BUT if it's an atmosphere and it's cold (compared to the star's photospheric temperature, which even at the small orbit is completely reasonable) molecular bands would be where I'd look. They'd be broad because of all the many rotational and vibrational lines.

      It's still a long shot, but three years ago, so was the entire idea of detecting exoplanets this way!

      And, the chances of this working (IMHO) are a lot higher than the people who are looking for variations in the photometric light curve due to reflected stellar light from the close-in planet. (But the information gathered from this star will provide a better estimate of the expected flux amplitude --- I haven't tried to calculate it yet.)

      Work is going to be VERY INTERESTING tomorrow and Tuesday!

      Bob Donahue

    5. Re:Extrasolar Planet by rew · · Score: 1

      ... beleive with >99.99% confidence ...

      ...proven in our lifetimes. ...

      Well, I can tell you that with higher than 99.99999% confidnece: We need einstein proven wrong first....

      Roger.

  10. Cool. If we start walking now... by DragonHawk · · Score: 2

    Cool. If we start walking now, how long will it take us to get there?

    (I remember figuring out how long it would take to walk to the sun in high school, just as an experiment in imagination.)

    --

    dragonhawk@iname.microsoft.com
    I do not like Microsoft. Remove them from my email address.
    1. Re:Cool. If we start walking now... by Griim · · Score: 1

      What is that? Approximately 9 lifetimes? I remember reading once that the average person walks 11 million miles in their lifetime.

    2. Re:Cool. If we start walking now... by retep · · Score: 1

      Cool. If we start walking now, how long will it take us to get there?

      Very very long... The distances in the universe are just incredible. When you look in the night sky most of the points of light you see aren't stars, they're complete galaxies. The universe is huge. Trillions or stars are in it. It'd take quite a few billion lifetimes to even get to the closest stars by walking.... Just a lifetime going at the speed of life. Although the relitivistic effects would make it seem like a few days.

    3. Re:Cool. If we start walking now... by jonnythan · · Score: 1

      Well, assuming you walk an average of 2 meters/second from now til eternity, it would take on the order of 22,934,123,036 years.

    4. Re:Cool. If we start walking now... by Anonymous Coward · · Score: 1

      The universe is probably expanding at a fast enough rate that the distance between Earth and that planet is increasing faster than you can walk.

    5. Re:Cool. If we start walking now... by orionbelt · · Score: 2

      > When you look in the night sky most of
      > the points of light you see aren't stars,
      > they're complete galaxies.

      This is actually not quite true. All the stars that you see in the night sky are indeed stars like our Sun, and all belong to our Milky Way galaxy. The only other galaxy that we can see with the naked eye from midnorthern latitudes is the Andromeda galaxy, which appears as a dim little cloud if you know where to look at, on a dark, clear, moonless night. From a more southern location one can also see the two Magellanic Clouds, which are small satellite galaxies of our own Milky Way (Andromeda is actually bigger in size than the Milky Way, and something like 25-30 times further away than the Magellanic Clouds).

      Although we can see, with the naked eye, some of the brightest individual stars in the Magellanic Clouds because they are relatively nearby, we cannot see any individual stars in Andromeda (with the naked eye). All we can see is the collective glow of the hundreds of billions of stars that make up that galaxy. We need telescopes to see individual stars in nearby galaxies. And even the largest telescopes are no help for more distant galaxies.

      It is estimated that there are something like a trillion galaxies in the observable universe.

    6. Re:Cool. If we start walking now... by orionbelt · · Score: 1

      > The universe is probably expanding at a fast
      > enough rate that the distance between Earth and
      > that planet is increasing faster than you can
      > walk.

      In fact, the expansion of the universe is relevant only for distances between galaxies that are far apart. It has no noticeable effect inside the Milky Way.

      However, it is still true that, because both the Sun and that star orbit around the galactic center with different velocities, they are moving one with respect to the other.

    7. Re:Cool. If we start walking now... by D|sturbed · · Score: 1

      Hrm. At a lifespan of say, 75 years, you'd have to walk approximately 400 miles a day to walk 11 million miles in your life. Even if you were walking 16 hours a day, you'd have to go at an average speed of 25mph. That makes me tired just thinking about it...

      Get fragged @ Lone Star Quake

    8. Re:Cool. If we start walking now... by PD · · Score: 2

      Hop in your car, and drive straight to the sun. Our sun is 93 million miles away, just a short 8 light-minutes from Earth. A hop, skip, and a jump in cosmic terms.

      Anyway, hop in your car and start driving to the sun. Go straight to the sun, and drive 100 miles an hour.

      It will take you more than 100 years to get there!

      --
      If tits were wings it'd be flying around.
  11. Artist's Rendition... by HiRes · · Score: 3

    Forgive me if I'm missing the point, but why include an artist's rendition of the planet/star system on a page that otherwise contains scientific information? You can disclaim 'til you're blue in the face, yet someone is going to surf on over there and think, "man, those scientists sure can take clear pictures of faraway stuff these days!"

    Seems to me that when you expect the unwashed masses to visit your site, you should consider that many folks really don't have a good grasp on the state of the technology. Monitoring the brightness of a star and noticing a 1.7% dip is a lot different from peering through an eyepiece and looking at Saturn's rings. I think in this case, the picture only obfuscates the situation.

    But maybe I'm nitpicking...

    --
    wcb
    1. Re:Artist's Rendition... by MajorBlunder · · Score: 2
      I understand your point, but no matter what you do, there are going to be a fair amount of the "unwashed masses" who will take things out of context, misinterpret what your saying, and generaly bug the hell out of the rest of us. All in all, it doesn't matter what morons think since they don't (think that is).

      If nothing else, the Artist's Rendition helps to inspire our imaginations, and and give us something more to ponder than calculations and figures on paper.

      --

      "I'm making perfect sense, you're just not keeping up."

    2. Re:Artist's Rendition... by Anonymous Coward · · Score: 1

      Yes. I suggest we dumb down the content of the internet. Don't provide artist renderings--their verisimilitude is a threat to a literalist, imagination-free internet.

      Furthermore, let's distribute soap to the great unwashed masses. Frankly, they're dirty, and need a clean up a bit.

      Only once the unwashed have scrubbed down and proven themselves intellectually capable of critically consuming information will we dare show them things like art, which otherwise masks reality.

      (What an asshole the original poster was, BTW.)

    3. Re:Artist's Rendition... by Anonymous Coward · · Score: 1
      Looks like this Australian newspaper didn't read very carefully.

      LONELY PLANET: Scientists in California have used a radio telescope in Arizona to capture this startling image of a planet passing in front of star HD 209458 in the constellation of Pegasus. It is the first independent confirmation of the existence of planets outside our own solar system.

      Lol!

    4. Re:Artist's Rendition... by Dandre · · Score: 1

      Even worse, in the Oakland Tribune, they put the image on their front page, with a caption identifying it as a depiction of an image of the planet from the Berkeley astronomy site. It was not at all mentioned that it was simply an artist's rendition. Claiming that it was "seen" is also a bit odd -- more like it was detected using a visual medium. It's not like a human is sitting there, staring at the star, waiting for a shadow to cross over it. In any case, it's still cool, but once again we see the difficulty of presenting scientific discoveries in the popular press.

      Cheers,

      David Andre

  12. Don't get discouraged by vipw · · Score: 2

    Alot of people seem to be discouraged that the only other planets we can find are gaseous and close to the star they orbit. However people are forgetting that those are the only type of planet that is able to block a significant amount of the light traveling from a star -- and this one only blocked 1.7%. If an planet the size and distance from the star were in revolution with a long year(more than a few days at least) there would be alot smaller and less frequent windows of blockage and the amount of blockage would be so miniscule that it would be nearly impossible to detect. That we are finding concrete evidence of any planets is important, and makes the chances of earthlike planets much more likely, this is definitely good news.

    Just think of living in that solar system, there would be killer eclipses : )

    1. Re:Don't get discouraged by jafac · · Score: 1

      IANAAP (I am not an astro physicist), but I think that a solar system, with a large gas giant with an orbital period of 3 days, would not harbor any intelligent life. (not making an absolute statement, I'm saying probably here).

      The gravity field from the gas giant is very strong - it's a very massive object, a very large world, and would tend to greatly perturb the orbits of other planets nearby. Especially the small, rocky inner ones that would otherwise sustain life long enough to evolve intelligence. Basically, what I'm saying, is if a planet that size occupied Mercury's orbit in this solar system, probably Venus, Earth, and Mars would not be occupying stable orbits, and would likely have either been catapaulted out of the solar system, or into the sun, or broken up.
      Inner planets (from what little I understand of astrophysics) tend to be grouped relatively close together, and outer planets, farther apart, which is why Jupiter and Saturn don't perturb the orbits of Mars, Venus, Earth, or Mercury (to any significant degree - by significant, I mean, catastrophically).
      But then again, the fact that a gas giant exists so close to a star, kind of turns a lot of astrophysics on it's ear. That was not what has been thought of as a "normal" solar system, yet pretty much all of the extrasolar planetary systems we've observed so far have had what modern astrophysics would consider "abnormal". On the other hand, it's a lot harder to observe these smaller rocky planets (like Earth, Mars, Venus, Mercury) at these distances, because they don't perturb the Sun gravitationally as much, so we really don't know what's "normal" and what is not. What we do know, is that there are certainly planets out there, and my feeling is that in these systems, where a gas giant is close-in to the star like that, it's not likely that there are any close-in small rocky planets capable of bearing intelligent life.
      (for the record, I do believe that there is likely life on Europa, and probably Mars too, and therefore it's possible that life may exist in one of these extrasolar systems, on small moons or stray planets, etc. - just not intelligent life. Whether there are planetary systems configured like ours, bearing intelligent life out there, remains to be seen - but I believe it's likely).

      So yeah, there would be killer eclipses (especially since the star's photosphere might be stretched out into space by the gravitation from the inner planet), but no comfortable place to view them from.

      I wish I had a nickel for every time someone said "Information wants to be free".

      --

      These are my friends, See how they glisten. See this one shine, how he smiles in the light.
  13. eek, should have proofread better by vipw · · Score: 1

    If an planet with size and distance from the star like earth's were in revolution with a long year(more than a few days at least) there would be alot smaller and less frequent windows of blockage and the amount of blockage would be so miniscule that it would be nearly impossible to detect.

  14. Re:Thank you Bob by Money__ · · Score: 1
    I just want to tell you how much we all apreciate all your hard work and dedication to the extrasolar planet search. This changes man kinds view of the solar system, and this is indeed an historic day.

    I hope that all of the people in your field continue there diligent, results producing, undertaking. Thanks !

  15. Astronomy/Physics Question by Dolohov · · Score: 1
    From the information I've seen so far, it looks like this thing is larger in size to Jupiter, but not nearly as massive, and orbiting at a phenomenal speed. How is it, then, that it stays intact? That is, why is it still a discrete planet-type-thing that can block sunlight instead of flattening out into a ring or just dissipating altogether? I don't really know much about planetary physics, but it seems to me that something that insubstantial moving that fast has got to have some serious drag on it, even in a near vacuum.

    Or, conversely, is it possible that these values indicate an error in measurement or assumption?

    1. Re:Astronomy/Physics Question by Chandon+Seldon · · Score: 1

      I think the way it works is that all the matter that would be causing the drag on it becomes part of the planet...

      --
      -- The act of censorship is always worse than whatever is being censored. Always.
    2. Re:Astronomy/Physics Question by astrophysics · · Score: 2

      It's 0.6 Jupiter Masses, that's still more than enough to keep it gravitationally bound even in a 3 day orbit around a ~1.2 solar mass star.

  16. Definite Interest Perker-Upper by KaosDG · · Score: 2

    This is one of those things that I read and say "Wow..."

    The one paret that I find so discouraging (at least in our current state of tech) is that what we saw happened 153 years ago. Think about that.
    Even at our fastest possible (theoritcally speaking) speed of light, it would take 153 years to go and poke around that system. Man, now where'd I leave the keys to the Enterprise?

    So all this actually happened around 1846. Makes you see how miniscule we all really are...

    --
    "Fuzzy Wuzzy was a bear, Fuzzy Wuzzy had no hair... Fuzzy Wuzzy wasn't fuzzy was he?"
    1. Re:Definite Interest Perker-Upper by Cironian · · Score: 1

      >The one paret that I find so discouraging (at >least in our current state of tech) is that what >we saw happened 153 years ago. Think about that. >Even at our fastest possible (theoritcally >speaking) speed of light, it would take 153 years >to go and poke around that system.

      Why would you want to poke around there? As they said the planet is most likely a gas giant and so you might as well do research on Jupiter. (Which has the added advantage that you can reach it within your lifetime, if the flight just werent that damn expensive)

    2. Re:Definite Interest Perker-Upper by KaosDG · · Score: 1

      I dunno... I guess I'm just curious. There is also the possibility that there could be other planets in that system that we can't readily detect, so it would be great to "go have a look see." All this is fantasizing, for now.

      "if the flight just werent that damn expensive"

      Good point there. Makes you wonder how the whole financial/political/scientific infra-structure of space exploration works. Meaning: If it's for the benefit of Human-Kind, Why (or more importantly, WHO) do we have to pay?

      --
      "Fuzzy Wuzzy was a bear, Fuzzy Wuzzy had no hair... Fuzzy Wuzzy wasn't fuzzy was he?"
    3. Re:Definite Interest Perker-Upper by wik · · Score: 1
      Another wow, at least to me, is the orbit period of 3.523 days, 1/100th that of earth! On top of that, it isn't too much more massive than earth (I don't have any numbers with me right now).

      I would have thought that something orbiting like that would have a very eccentric orbit, but the eccentricity is ~.001. I'm rather surprised that a gas giant planet can survive as such, so close (0.045AU) to a star that's about as hot and as massive (at least as far as gravity goes) as our sun. Neato.

      --
      / \
      \ / ASCII ribbon campaign for peace
      x
      / \
    4. Re:Definite Interest Perker-Upper by astrophysics · · Score: 1

      Actually, it's 0.6 Jupiter masses which places it at 200 Earth masses.

      The low eccentricity is likely a result of tides being raised on the planet by the star.

    5. Re:Definite Interest Perker-Upper by jamesc · · Score: 1
      Good point there. Makes you wonder how the whole financial/political/scientific infra-structure of space exploration works. Meaning: If it's for the benefit of Human-Kind, Why (or more importantly, WHO) do we have to pay?

      WHO/WHY: Why, ourselves of course. The fuel and building materials and electronics aren't free. Nor do the engineers and technicians work for nothing. (OK, grad students on university projects excepted. ;-)

      Contrary to the late (and notorious) US Senator Proxmire's short-sighted harping, we have never launched a rocket full of dollar bills or gold coins into space. Every dollar spent was spent on Earth.

      The question is: How much gets spent for space exploration vs. say, paper clip budget overruns amongst the myriad of gov. paper-pushers? (Am I biased? Certainly not! 8-)

      --
      "You've crossed my Line of Death!" "What? No! Where is it?" "Here in the fine print...."
  17. Why is it not a binary system? by lars · · Score: 1

    I'm not sure of the details of these systems (how big is the star?), but is it possible that the system formed as a binary system, only there wasn't enough mass in the smaller "star" for fusion reactions to begin? This seems to be the obvious explanation, but I assume since there's no mention of this that it has been ruled out. Why? Is the mass ratio between the objects too great for them to have formed as a binary system?

    1. Re:Why is it not a binary system? by astrophysics · · Score: 3

      The reason it's not called a binary system is that the mass of the "planet" is 0.6 times the mass of Jupiter. This is not massive enough for it to fuse hydrogen or even deuterium. To answer your question, the star is probably about 1.1 to 1.3 times the mass of the sun (not based on careful analysis, only it's spectral type), so the mass ratio is approximately 2000:1.

      Of course how massive it is does not necessarily determine how it formed. Indeed, one hypothesis is that it did form by direct gravitational collapse from the protostellar nebula similar to the star it surrounds. However this hypothesis is no longer favored by most astrophysicsts for rather technical reasons related to turbulence in the protostellar disk. Additionally, models (see papers by Alan Boss who favors this approach) have difficulty doing this at less than a few AU (AU=distance from Earth to Sun, Jupiter is at 5 AU, this planet is at 0.045 AU).

      (Other hypothesis exist about ways to form a planet at several AU and then migrate the planet to a small distance. I'll answer another question related to this after lunch, so you can read more there.)

  18. Re:question about 'shadows' by amorsen · · Score: 1

    If the planets were further from their suns, they would be undetectable to us. Only a very massive planet in a very small orbit makes a star wobble enough to let us detect it.

    One can only hope that the fact that there are so many planets of the kind we can detect means that there are also many planets of the kind we cannot detect, such as Earthlike planets. Then again, one can also hope for the opposite.


    Benny

    --
    Finally! A year of moderation! Ready for 2019?
  19. Re:question about 'shadows' by astrophysics · · Score: 3

    In fact current radial velocity surveys could detect Jupiter mass planets out to several AU (AU=distance fom Earth to Sun, Jupiter at 12AU, this planet orbits at 0.045 AU) . In fact some have been detected as far as 3 AU from their star (see Marcy & Butler's list

  20. Wow by extrasolar · · Score: 3

    Just think. Say you have a flashlight pointed at the wall and you put your hand in front of the flashlight; you get a shadow on the wall. Anyone remember that image posted on slashdot with the shadow of moon on the earth. Now we have single planet hundreds of lightyears away casting a shadow for a brief moment; covering our entire solar system, perhaps a lot more. Just think how many star systems are in this planet's shadow! All the many cubic light-years of space, probably millions, in the shadow from a single point in the sky.


    ***Beginning*of*Signiture***
    Linux? That's GNU/Linux to you mister!

    1. Re:Wow by Andreas+Bombe · · Score: 1
      All the many cubic light-years of space, probably millions, in the shadow from a single point in the sky.

      No, not really. The sun is most certainly much bigger than the planet. In eclipses, the moon is only able to cast a core shadow because it's so near to earth. At longer distances the core shadow would become smaller until there is no core shadow anymore. What remains is a partial shadow which only decreases brightness of the light source, but does not completely block out light.

    2. Re:Wow by dillon_rinker · · Score: 1

      Exactly. When observing a transit, you get an effect much more like an annular eclipse than a total eclipse.

  21. Extrasolar Planet by imamonkey · · Score: 1

    I seems to me that this is way, way too early to call this a confirmation of a planet. Other possibilities are:
    Sunspots - Solar Prominence - "Brown Dwarf" Star
    The "Wobble" method of Planet discovery is not yet a proven method. These planets are not "discovered"; just inferred.















    Besides, it seems too wacky to have large planets that close to a star without being destroyed by tidal force.

  22. Re:CNN scientifically challenged too by astrophysics · · Score: 4

    Good question. If current theories are correct then they did not form there, but rather migrated after forming at several AU. The fact that one is observed to be a gas giant supports this since gas giants are beleived to form at several AU.

    How did they move? At the moment, there are several hypotheses, each with it's own problems. To summarize:

    1. Interaction with a gaseous disk to transport angular momentum outward and mass inward by exciting spiral density waves at Lindblad resonances (distance at which the orbital frequency matches the frequency of radial oscilation of the planet in an epicyclic approximation) on both sides of the planet's orbit. Big problems: Effects of additional planets, how to stop the migration right before it falls into the star

    2. Interaction with a planetessimal disk in which many small bodies at orbital resonances (where ratio of the two orbital periods is a rational) have their eccentricities excited so they can be kicked out of the system by the planet in a close encounter. Big problems: Effects of additional planets, need a very massive disk for the process to be unstable (and thus significant migration).

    3. Interation with other planets so that one planet gets kicked farther out (sometimes out of the system entirely) and another planet closer in, or two collide. Big problems: Can this send enough planets so close to their star to match observations?

    4. Interactions with another (more distant) star that induces a long term secular increase in the eccentricity until tidal effects before important and circularize the orbit at a small radius. Big problems: Quadrupole moment of star may limit eccentrity. Some planets are around star with no observed wide binary companion.

    If you want references to any of these, I can provide them.

  23. Re:joke by Cassandra · · Score: 1

    I thought they both did... ;)

  24. The nature of "confirmation" in science by DrRobin · · Score: 2

    Here is the sense in which it is confirmation:

    1) The existence of the planet was _inferred_ from spectography of the star, showing doppler shifts consistent with a wobble caused by an unseen planetary companion.

    2) The size and periodicity of the wobble allowed the researchers to _predict_ the size, and period of the planet's orbit.

    3) The existence of the planet was _confirmed_ by finding a photometric dimming of light from the star, consistent with transit of a gas giant planet, at exactly the time and periodicity _predicted_ by the spectography.

    The chance that two _independent_ means of detection would give the _same_ predictions for the inferred planet is remote and provides very strong evidence for the reality of the planet. This is a very important result and a very nice piece of science.

    Speaking as a working scientist, I think it is also a very nice demonstration of how how science works in the real world, too often misunderstood even by the techies on slashdot.

    1. Re:The nature of "confirmation" in science by rew · · Score: 1

      2) The size and periodicity of the wobble allowed the researchers to _predict_ the size, and period of the planet's orbit.

      The physical size was determined from the dip. The mass was determined from the period in the wobble.

      3) The existence of the planet was _confirmed_ by finding a photometric dimming of light from the star, consistent with transit of a gas giant planet, at exactly the time and periodicity _predicted_ by the spectography.

      Periodicity? They sighted the dimming effect once, and Sunday the second one was supposed to happen. What did happen, was that the measurement was spoiled by clouds. Three days till the next possible measurement. So? Just wait it out? Good science. "OH, Observatory shuts down for the winter, no more measurements till next spring."

      This sounds to me as if they are rushing ahead with publishing the things without allowing enough time to evaluate correctly what they are seeing. Maybe a bird flew over the observatory during the measurement around the right time.

      The graph of the wobble looks like a perfect sine, extrapolated from the 6 shown dots. That's highly inaccurate. Sure you can fit a sine to any number of random dots. Jot down a number of random points between -30 and +60 and tell the computer to find a fitting sine. I'm sure it will find one. Now try the following: randomly pick 6 x-values between 0 and 250. Calculate 50 * sin (x_i). Now add 6 random values, say between -2 and +2, to the calculated "measurements", and tell the computer to find the sine wave. I expect you'll find wildly different values from the amplitude 50 (100 top-top), and the period 2PI.

      The gif shows 6 points, but has a heading saying something about 2000 points. I'm not sure what to make of that. 2000 measurements is WAY too labor-intensive. I don't believe they made 2000 spectra.

      Speaking as a working scientist, I think it is also a very nice demonstration of how how science works in the real world, too often misunderstood even by the techies on slashdot.

      Speaking as a techie on slashdot, I think this is a nice demonstration of "release early and often" which applies to open source, and not science.

      Publishing in a peer-reviewed magazine, means that the reviewers had the chance of asking all kinds of nasty questions, and they were able to ask for supporting documentation, for example the raw data.

      If you publish on the internet, you can make the raw data available, so that those interested can verify the data on their own.

      Roger.

  25. Eclipses by Cassandra · · Score: 1

    Just think of living in that solar system, there would be killer eclipses : )

    Longer eclipses perhaps, but our eclipses are special in that the moon happens to cover the solar disk almost exactly. This allows us to view the corona (the solar atmosphere) which I think is the most fascinating aspect of an eclipse. Just a partial eclipse, or total blackness are not as visually astounding.

  26. Eclipse cont. by Cassandra · · Score: 1

    Just think of living in that solar system, there would be killer eclipses : )

    Just had a second thought on this:
    Wouldn't the planet allow some light to shine through it's body since it is a gas giant? This would give an effect like the one when you put your finger on a lit light bulb--glowing edges of the planet! And the effect can be further enhanced if the planet has a large dense atmosphere. Wow!!

    1. Re:Eclipse cont. by orionbelt · · Score: 1
      Wouldn't the planet allow some light to shine through it's body since it is a gas giant?

      Not really: it may be a gas giant but the gas is so thick and dense that it is opaque. Besides, even gas giants (at least of the Jupiter variety) are believed to have metallic cores due to the extremely high pressures near their centers.

      This would give an effect like the one when you put your finger on a lit light bulb--glowing edges of the planet! And the effect can be further enhanced if the planet has a large dense atmosphere. Wow!!

      Do you mean seing a "glowing ring" surrounding the planet due to its dense atmosphere? Well, even assuming we could resolve the planet from such a big distance (which we cannot), the glowing ring could not be seen against the much brighter star disk. To see the ring one has to use the planet's disk to cover the star itself (which happened with spacecraft we sent to Jupiter and other giant planets). But to do this one would have to be much closer to the planet!

    2. Re:Eclipse cont. by Cassandra · · Score: 1

      I certainly did not mean looking at an eclipse in that solar system from Earth. This is what the astronomers just did!

      The posting I replied to talked about living in that solar system and watching an eclipse. A totally different siduation.

  27. photos of the planet by daWulf · · Score: 1

    why not use the gravity of sun as lens and take some very nice photos of the planet...
    but that would need a telescope to be sent to the outer rim of our solar system and so we would have to wait a few years for some nice pictures

    1. Re:photos of the planet by orionbelt · · Score: 1
      why not use the gravity of sun as lens and take some very nice photos of the planet...

      Our Sun would be too bright and would block even the amplified light of the planet...

  28. Re:It might not be a planet by orionbelt · · Score: 1
    The decrease in brightness could very well be from an orbiting brown dwarf.



    Not really. The planet's mass was deduced to be only 0.6 Jupiter masses, which makes it too small to be a brown dwarf. Brown dwarfs are believed/defined to have a minimum of about 80 Jupiter masses. This is how much mass is needed to barely ignite *some* fusion reactions in the center, but not enough to really call it a star.

  29. Re:ANTI-GOD squad by daala · · Score: 1

    "There isn't ONE SPECK of evidence for such nonsense, but people keep on talking about it as being "inevitable" .. yeah, right"

    "God might have some surprises in store for these "SETI" types in the afterlife .."

    MMMM....Now who is getting spiteful.

    And you call yourself a Christian person or someone who believes in God! Pretending to be an all knowing Pharisee such as yourself with all of your blown up self-importance. Guess what matey you sound like the type of Christian that I keep running into! (one that has never read a word of the Bible and relies on others to spoon feed it to him like your corrupt Church leaders more interested in power on this plane rather than in heaven. My evidence for this is thousands of different Christian groups out there all fighting with one another)

    I myself although not a Christian have studied the Bible and Christianity at Univesity. You see I wanted to expand my knowledge not limit it like you seem to be proposing for the rest of the world and the scientific community

    Oh and by the way. NO EVIDENCE FOR EXTRA-TERRESTRIAL life. Hey do you know what the this word even means. NOT OF THIS EARTH in LOOSE TERMS. Does that not apply to the HOLY GHOST, SERAPHIM, CHERUBIM and DEMONS. There was an part-extra-terrestrial in the Bible he was CALLED JESUS unless you are now telling us that he was totally human then you yourself are not a Christian!!!!

    How do you know that GOD made the Universe just for us. Where does it state this. You could argue quite extensively from passages in GENESIS that he made the EARTH for us but not the whole UNIVERSE. There is no mention of it in the Bible at all. Are you speaking directly to the source if so could you ask him to contact me so I can RUN THIS EVIDENCE past him and ask him the truth

    Now I am not saying that SCIENCE is the be all and end all I just hate seeing these types of RELIGIOUS IGNORAMUSES on the NET who have no idea of their religion or of the Bible that they all claim they truly cherish.

    Mate- Pick up the BIBLE and begin reading. You will probably find that being an opinionated bigot will not get you into HEAVEN either. THERE WILL BE A SUPRISE for SOME OF YOU SO CALLED CHRISTIANS AS WELL WHEN YOU WORK OUT WHO THE REAL MASTER IS THAT YOU HAVE BEEN SERVING!

    And before you take the twig out of my eye take the log out of your own!!

    Guess what it doesn't talk about the Theory of Relativity in the Bible or LINUX does that mean they don't exist either

    --
    "The way she used to say Rimmer as if it rhymed with scum" Red Dwarf
  30. Re:no doubt by daala · · Score: 1

    Sorry, sorry I know this continues matters.

    What was the intended point of this little pearl of wisedom.

    What is your need to attack other people because of their religious beliefs. I know many Christian people (not that theres anything wrong with that!) hell the guitarist in my band is studying to be a minister. He is NOT ARROGANT, studied SCIENCE and PSYCHOLOGY at UNI and believes in EVOLUTION and would laugh his ass off at the GOD SQUAD.

    Yes I agree there is IGNORANCE and ARROGANCE on BOTH sides of this "GOD" debate. Hell it has gone on for time immemorial and I challenge anybody to give me proof from EITHER side disproving the existence of GOD or proving it!!!

    In a time before people where considered cultured when they where versed in both PHILOSOPHY and SCIENCE. A healthy combination of the 2 will provide us with the biggest understanding.

    INTOLERANCE OF ANY KIND IS POINTLESS AND VIOLENT whether that be RELIGIOUS or INTELLECTUAL both have caused more conflict in human kind than any other factor.

    Please don't continue this stupidity.

    Peace

    All Hail Discordia, All Hail Eris!

    --
    "The way she used to say Rimmer as if it rhymed with scum" Red Dwarf
  31. Re:ANTI-GOD squad by daala · · Score: 1

    Ok I have my BIBLE in front of me. Come on Book and Verse show me all the places where it says the UNIVERSE was made for us. Come on where is it?

    Your friend also mentioned that he believed in other planets but not in other life-forms. Ok that is cool. But he goes on to say that nothing that is not mentioned in the BIBLE exists. Come on that is just plain stupidity. How then may I ask does this PLANET get a special dispensation for existence and everything else doesn't. Come on again where does it mention this PLANET in the BIBLE.

    It is universally agreed by scientists and theologians alike that the bible is divinely inspired - OH I MUST HAVE BEEN ASLEEP WHEN THIS ANNOUNCEMENT WAS MADE. I am sure if the Scientific community proved or diproved something like this it would be BIG BIG news. Now I am not talking about a bunch of CRETINISTS here (yes I deliberately mispelt it CREATION SCIENTISTS)
    It doesn't talk of alot of things in the BIBLE does that mean they do not exist here as some from the top of my head:

    GRAVITY, COMPUTERS, UNITED NATIONS, MODEMS, BRITNEY SPEARS, TELEPHONES this list is endless.

    Does the BIBLE tell Chrisitians to go onto USENETS and blindly defend things that they know absolutely nothing about. Does it tell you to behave as if you are the better person and everyone else is a scumbag.

    Listen buddy - Jesus spent his time with prostitutes and criminals attempting to save them from themselves. In your definition he died for all of us to save us from our SINS. You as a Christian have to RESPECT everybody no matter how you are treated by them (including me!!!)

    LOVE, FORGIVENESS and CHARITY do those things ring any bells..... The Christians that I know all display these tendancies. I respect them and love them for who they are and they do the same for me. Much of what I have learnt about Jesus has come from my own reading and then asking them sparking intense but always fulfulling arguements.

    I do not see SELF-IMMORTALISATION, SELF-WORTH, PRIDE or ARROGANCE like I see in your "GOD" squad.

    I think you guy's should switch sides you already seem to be batting for the other team!

    --
    "The way she used to say Rimmer as if it rhymed with scum" Red Dwarf
  32. I'm just wondering... by Anonymous Coward · · Score: 1

    After reading the Washington Post story, I have to ask: Is it the light from our sun that's causing the planet to cast a shadow on its star, or were the astronomers using really big spotlights? :)

    Actually, what I'm really wondering is: Is the state of scientific literacy in this country really so bad that the editors at a major newspaper (published in the nation's capital, no less) don't understand that stars *emit* light, or is the state of journalism so bad that reporters and editors don't care about actually "getting it right"?

    Either way, it's bad.

  33. Proof of a sort. by Darby · · Score: 1

    OK, how about this one.
    God is good, infallible, and all powerful.

    Babies are born deformed or dead.

    That to me is a contradiction.

    Given that the second statement is a fact, God must be either evil, fallible, or not all powerful.

    Granted this isn't a mathematical "proof", or
    even a really good scientific argument (which is impossible given the subject), but it works for me.


    ---CONFLICT!!---