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Space

Jupiter-Sized Planet Orbits Epsilon Eridani 226

Phrogman writes: "SpaceRef is the first to report that a Jupiter-sized planet has been discovered orbiting the star Epsilon Eridani which is located about 10.5 light years from Earth. The planet is oribiting the star at roughly 300 million miles - about the same distance as earth's asteroid belt. The discovery was made by astronomers at McDonald Observatory in Texas in collaboration with other astronomers around the world."
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Jupiter-sized Planet Orbits Epsilon Eridani

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  • So you've never heard of the prime directive in star trek have you?
  • I've got connections - I know ;)
  • Believing something to not be extraordinary is not conceited, unless my perception is skewed. Please correct me if I'm wrong, but most average things aren't too special compared to the above-average (or even the below average).
  • Mars is bereft of atmosphere because it its escape velocity is low enough that the atmosphere can boil off - solar influence has nothing to do with it.

    I'm not talking about the piddling little difference between a Marslike atmosphere and an Earthlike atmosphere, I'm talking about the difference between a gas giant atmosphere and a rock planet atmosphere. The point was that a Mercury-distance planet might be a rock planet like Mars is.

    I was explaining why there might be rock planets for the gas giant to throw around. That should have been obvious.

    With a Jupiter-mass planet at the distance of the asteroid belt, you'd have stable planetary orbits from Earth-distance on in.

    Just what are you basing that specific distance on? You just pulled it out of your hat, didn't you?

    Even that effect has nothing to do with the sun "blowing away" the atmosphere

    Ugh, as if "blowing away" meant anything other than "removing". If you want to write a short statement about astrophysics, you have to use imperfect analogies to terrestrial phenomena, and it takes quite a jackass to point out how the analogy isn't an accurate literal description.

    ---
    Despite rumors to the contrary, I am not a turnip.
  • Sol is the name of our sun; therefore, the system that orbits around it should be the Solar system. Similarly, the system that orbits around Epsilon Eridani should be the Eridanic system or the Epsilonic system. The only thing you have to change is capitalize Solar; otherwise, the "solar system" might tend to mean a generic group of planets orbiting a generic star.

    --
  • Oh god... please don't tell me we've reached the point that we're going to start seeing things like the the "Pepsi Supercolider -- The choice of the next generation of physics majors" or Wendy's logo emblazoned on the side of the Space Shuttle next?!?

    ;)

  • Well, technically, neither the sun nor the earth orbit each other. They both orbit their mutual centre of gravity. Seeing as this imaginary point in space is actually located inside the sun (as it is so much more massive than the earth), then it would seem more appropriate to say the earth approximately orbits the sun.
  • I'm sure that if you took a poll of normal English speaking people, they'd identify 'solar system' as the general term for a star and its satellites. It seems quite engrained into the English language and would require some effort to change. If it is to be called the Solar system, then what is the generic term for a star and its satellites?

    I myself have been found of the grammatically incorrect 'Sol system;' the solar system around any star would be referred to by the star's name, without transforming it into an adjective. Then again, as people seem fit to refer to our sun as the only Sun, we might as well call it the Sunny system. ;)

    --
  • Well, you have the mass and kinetic energy of the probe, which might amount to that of a fair-sized nuclear device if it did not decelerate. If it aimed itself appropriately, it might return important data to sensitive receivers, perhaps several bits:

    Signature of impact originating from Epsilon Eridani: Rocky, earth-type planet detected.

    Signature of impact including spectral lines of chlorophyll: Earth type planet bearing strong signs of life.

    Signature of impact including spectral lines of chlorophyll and return volleys of relativistic weapons: Earth type planet bearing strong signs of intelligent life.

  • You're missing the point. We don't concern ourselves with the effect one body has on the other. It is irrelevant WHY the objects move as they do when we choose a reference point. We can pick any point in space and say the entire universe orbits around it and be no less correct than if we calculated the perfect center of the universe around which everything in the universe orbits with a basically circular pattern.

    And anyway, your argument (if I understand what you're trying to say) falls apart when you realize that gravity from one object affects every other object in the universe, making it perfectly logical that objects don't orbit other objects in a perfectly circular fashion, and thereby making it moot what orbital patterns are changed by changing our reference points (if you understand what I'm trying to say =-) ).
  • and the planet itself gives off heat

    I don't think this is strictly true. The gas giant itself would not give off much heat - what does come into play is the constant stretching and compressing of a natural satellite by the massive tidal forces involved in orbiting such a monster. This process, in turn, can generate the heat in the satellite to kick off all kinds of interesting stuff....

  • Actually, Jupiter does *kind of* have a surface. After you get so far down in the atmosphere, the pressure forces the gases into liquid form, IIRC. Then again, IANAA (I am not an astronomer).
  • You don't. We'll contact you if we have a use for you.
  • Perhaps he is referring to the 100 year period starting now ('now' referring to the time at which the post was conceived).
  • Our star is as average as one could get.

    The belief that the Sun is "as average as one could get" is as conceited as believing that Earth is the center of the universe. In your case, it is just at the center of the universe of all possible star sizes.

  • but the craft doesn't think it's moving near the speed of light. I think it was meant near the speed of light, relative to the earth.
  • Since no alien race has contacted us yet, they're probably all less advanced than we are.
    Either that, or they're bright enough not to get mixed in with the wrong crowd...

    --Lenny
  • Hey,

    Henceforth, my worldview shall be yo-centric.

    My world is already yoyo-centric. It's funny to see the look on peoples' faces when you tell people:

    Me: "My world's yoyo centric."
    Them: "I don't understand."
    Me: "That's because your brain is only a half-yoyo."

    Try it yourself! a yoyo-centric world.

    Michael Tandy


    ...another insightless comment from Michael Tandy.
  • What's the big deal ? With the equipment available to astronomers these days the best we can do is to spot glimpses of Huge ( Jupiter Sized and larger ) planets around nearby stars.

    My unscientific guess is that the Galaxy is literally swarming with small rock planets ranging in size from Mars up to 2X Earth. Manyt of these planets will have oceans of water and some life. With 200,000,000 Stars in our Galaxy and 1 in ten for planets, water, life ( as we know it ) and intelligence we would still have 200,000 sets of aliens to find.

    Even if my above math ( very bad math at that :) was off by a couple orders of magnitude we would still have enough for a star trek like future.

    This is a theory based on nothing whatsoever but alas. For years scientists held that the planets around Sul were such a massive fluke we would be lucky to find even 1 other star with planets in our Galaxy.

    PS : Scientists tend to disagree loudly on things not yet proven. :)
  • Shouldn't that be "FIRST CONTACT!!!" instead? Mal-2
  • by jason22 ( 191200 ) on Friday August 04, 2000 @08:17AM (#880650)

    From browsing this thread, I have the idea that this discovery of distant planets is being taken as a first-time thing by some people. I thought it imperative to fill that void in the collective knowledge base.

    We've found approx. 35 such planets to date: here's one found in Nov 1999 [sciencenews.org], a whole system found in April 1999 [sciencenews.org], one in 1998 [sciencenews.org], and here [sciencenews.org], and here [sciencenews.org]...

    We've found Jupiter-sized planets at Jupiter-like distances, which is neat because it means we could detect our own solar system...

    -Jason

  • yeah, what are we expected to say! woo-hoo?
  • 'm not talking about the piddling little difference between a Marslike atmosphere and an Earthlike atmosphere, I'm talking about the difference between a gas giant atmosphere and a rock planet atmosphere. The point was that a Mercury-distance planet might be a rock planet like Mars is.

    *Sigh*. For the nth time - this is because of fractioning of the protoplanetary disk *BEFORE* planets formed!

    Just what are you basing that specific distance on? You just pulled it out of your hat, didn't you?

    This is the distance at which the relative gravitational influences of the star and the jupiter-sized planet would be comparable to the relative gravitational influences of Jupiter and Sol. Not difficult to estimate.
  • by baywulf ( 214371 ) on Thursday August 03, 2000 @06:50PM (#880653)
    If aliens do contact us by radio signals, it will probably translate to "FIRST POST!!!"
  • by CodeSlave ( 207133 ) on Thursday August 03, 2000 @06:52PM (#880654)
    Me & my wife are under the paranoid delusion that the Star Trek shows have been getting the Earth's population ready to make a "First Contact" sorta thing. Or maybe I've just been watching to much Star Trek lately. But look when Star Trek first aired. Wasn't that after Roswell. Gotta go, have to find my Haldol. "Honey did I put that on the shelf next to your Lithium?".....
  • They just finished the Shadow War. And the war with Earth is starting. Should be about a month, then it will re-cycle.

    Plus Star Trek Voyer will start next week! Mmmmmm! Seven!

  • by LNO ( 180595 )
    There's GOTTA be some kinda way to slashdot that planet.
  • Hey!

    I don't see how Antigravity (Boots, ship or other wise) will help in the real problem.

    Well, at the current costs of launching 1kg into space (About "£2000 / $3000 IIRC), to launch parts to build, say, the 'Starship Enterprise' would cost the GDP of every nation on earth, all added together (On top of that, you have the cost of actually making the components). If an antigravity conduit into space could be established using a spinning disk (Which could probably be done quite cheaply if the theory is as it sounds), getting things into space would be cheaper.

    I think....

    Michael Tandy


    ...another insightless comment from Michael Tandy.
  • What's the problem with "solar system" vs "Solar system?" If you were a farmer on Mars, would you call the stuff you're plowing "mars" instead of "earth?"
  • by TheDullBlade ( 28998 ) on Thursday August 03, 2000 @06:54PM (#880659)
    I know, they said Jupiter-type, but there is lots of speculation here that there might also be smaller ones.

    There won't.

    We've got rock planets here in the inner solar-system because our manly yellow star blew off most of the atmosphere of the nearest planets.

    Epsilon Eridani is a little pansy orange dwarf that couldn't blow the atmosphere off of this Jupiter-type planet as close as the asteroid belt.

    With a gas giant in the inner solar system, no tiny little rock planet is going to find a stable orbit. It would get tossed out into an eccentric orbit, assuming it didn't just get tossed into the sun.

    Of course, by Earthlike planet, I mean a rock planet with a gaseous atmosphere in a stable, near circular orbit at a near-constant distance from the sun (yes, dammit, I call Epsilon Eridani the sun, meaning the big hot ball). There might be an Earthlike planet if you're willing to accept a really big unlivable asteroid like Pluto as "Earthlike".

    ---
    Despite rumors to the contrary, I am not a turnip.
  • No, Sector 000 would be even better...
  • How about sector 001?

    :^)
  • I'd say it was all of those things, and the one thing it isn't is "aliens from Epsilon Eridani-ly"
  • the movie looked to me like they'd blown the special effects budget - I mean, using the actor who played her father as the alien? how much of a cop-out is that? the least they could have done was put some latex on his forehead...

    <g>
  • that galaxy

    Because while EE is only 10.5ly away, it's in a differant galaxy :)

  • by vertical-limit ( 207715 ) on Thursday August 03, 2000 @06:22PM (#880665)
    Hello! Earth doesn't an asteroid belt -- our sun has an asteroid belt, and the Earth orbits the sun.
  • any life that might have evolved is going to either be very, very strong, or very, very short.

    No, it'll be very, very, balloony looking. This planet is a gas giant (anything that big has to be) so it has no surface (not one life could live on anyway). Any life form would have to be able to float in whatever atmospheric layer it can survive in. If it goes too high, it asphyxiates, explodes, or gets poisoned. If it goes to low, it asphyxiates, implodes, or gets poisoned. A balloon is the most efficient way for a large organism to stay in a layer. This is pretty unlikely to happen, but if there is any life it will most likely have balloon-like structures.

    I know the article doesn't say that the planet is jovian, but I'm pretty sure any solid planet that size would probably never form, and if it did, it would probably collapse and turn into a black hole or something. Or maybe it would generate a lot of heat? I'm to lazy to figure out the physics so I'll just shut up.
  • More of an appendix.

    Stars are found (usually) by measuring an irregular pulse coming from the star. E.G: we look at a pulsar, and determine that based on its size and distance it should be pulsing at X rate. Instead, it is pulsing at Y rate, therefore there's something orbitting it.

    Also, if there's irregular pulses coming from a star that shouldn't be pulsing......

    There's a few different ways of finding planets, Red Shift, etc. I don't know them all....

    TTFN
  • Indeed the earth is motionless, with the entire rest of the universe orbitting around us... but since everything on out to the furthest star is in perpetual motion, the end result is that it appears that we too are in motion...

    I could go on with this theory for a bit more, but i need to finish my coffee...
  • How'd they find it? Pertubation? Occlusion? Something else?

    Bruce

  • Vulcan is also supposed to be in the 40-Eridani system. I'm not certain which is more widely accepted, but I'm pretty sure it's 40, not Epsilon...
  • In ours, Jupiter is the "vacuum cleaner" - it attracts many potential meteors away from inner planets so that they are much less likely to have catastrophic impacts. Now if we could just spot the smaller planets from so far away... and transwarp engines would be nice too...
  • > Hello! Earth doesn't an asteroid belt -- our sun has an asteroid belt, and the Earth orbits the sun.

    Heretic! The Sun orbits the Earth, along with all other planets.
    The Earth is the center of the universe

    People are so easliy led astray by the likes of Copernicus.

  • by gatz ( 121608 ) on Thursday August 03, 2000 @06:24PM (#880675) Homepage
    The star trek planet Vulcan is supposedly supposed to be in the Epsilon Eridani system, and this corresponds almost perfectly with everything trek says about Vulcun (except that its a Jupiter sized planet, but thats all we can detect so who knows.), and its only 10.5 lightyears away. What are the chances of life ! (hehe. admittedly slim. but still. it would be so cool)
  • by rockwall ( 213803 ) on Thursday August 03, 2000 @06:25PM (#880676)
    This is great news, for two primary reasons.

    First off, it's more or less in our cosmic neighborhood. 10.5 lightyears!! We could quite conceivably send a probe in that direction well within the next century. Knowing that extrasolar planets exist this close to earth is a very good sign indeed.

    The planet is also at a very moderate distance from its parent star -- although I see no data regarding the shape of its orbit. It might well be extremely elliptical, but we can always hope for something vaguely circular. In any case, it should make for some interesting viewing.

    For more information about extrasolar planets, consult your local library. No, just kidding, try this site here. [obspm.fr]

    First one there gets to name it!

    yours,
    john
  • by kevin805 ( 84623 ) on Thursday August 03, 2000 @09:24PM (#880677) Homepage
    My dad's like that too. He says (jokingly) "They're getting us ready."

    Always makes me wonder, where do I apply to become one of They?
  • Except E.E. is half as bright as the Sun, so this planet gets less solar radiation than Jupiter.

    Steven E. Ehrbar
  • I believe they detect planets by looking for doppler shifts in the light emitted by the star. The planet causes the star to wobble in a periodic manner.
  • The problem is that you need a power source, transmitter and antenna to transmit the results back to Earth. They are going to have to be much heavier than a gram to get a high enough ERP and a reasonable data rate.

  • the movie looked to me like they'd blown the special effects budget - I mean, using the actor who played her father as the alien? how much of a cop-out is that? the least they could have done was put some latex on his forehead...

    Actually, that came from the book. Except that in the book, Jodie Foster's character (Ellie Arroway) is part of an international, five person team, and the "aliens" are more like automated tour guides that are welcoming the human race into space. The aliens take on the form of the team members relatives by scanning their memories. This turns out to be a mixed blessing -- another female in the group realizes that her late husband wasn't all that great a guy by interacting with the alien who takes on his form.
  • *Sigh*. For the nth time - this is because of fractioning of the protoplanetary disk *BEFORE* planets formed!

    Look, jerk, stop misinterpreting what I'm saying to make me look stupid. I don't know whether you're doing it on purpose or you just think I'm a moron because you can't grasp what I'm saying, but it's bloody annoying. If it doesn't make sense the first time you read it without thinking about it, read it again and think for a minute before you post back to "correct" me.

    It doesn't matter whether the gasses were blown away before or after the planet formed. I've never cared about that, and it's never made a speck of difference. I only ever mentioned it to establish what planets could form at which distances.

    We know that E.E. is a small star with weak radiation. I didn't infer that from the existence of the gas giant; it's known from other observations. Everything we know about the formation of the solar system says that the gas giant could have, and probably did, form in the orbit it is currently in (where the radiation is weaker than that at Jupiter), and any rock planets would have to form much closer in (and my original post on the topic admitted the possibility that they could, at least, form). That only leaves the question of whether any rock planets between E.E. and the gas giant could have a stable orbit.

    As for that, I think your analysis of the possibility of stable orbits is naive. Your conclusion might be right, but your method isn't valid. Whether an orbit in a many-body system are stable over millions of cycles is not trivial to calculate, and the effects of a perturbing force like a large planet do not just scale linearly with the force of its gravity.

    We're talking about a gas giant close enough and big enought to make the star wobble noticably. That's a very rough gravitational environment for a small planet to find a stable orbit in.

    The point can certainly be argued, but can't be resolved with quick back-of-the-envelope calculations.

    ---
    Despite rumors to the contrary, I am not a turnip.
  • How do you know the sun is a man? have you checked? If so, what did you check for?

  • by kevin805 ( 84623 ) on Thursday August 03, 2000 @09:39PM (#880707) Homepage
    We're going to run into a terminology problem soon. It's sort of self-centered, and problematic in science fiction, to call the solar system which Earth happens to be in, "our solar system". But what should we call it? Some of the possibilities I can think of are:

    Sol would seem to be the best, if we didn't have all romance languages to worry about. It even looks like a proper name ("Saul", "Solomon"). Not going to work out, though, because if I'm on a planet in Epsilon Eridani, and I'm speaking spanish, you'd have to differentiate based only on whether I used it with or without an article ("Sol" vs. "El sol").

    Any other ideas? "Earth System", "Terran System" both seem wrong because it's the star, not earth, that we're refering too. "Human system" or similar science fiction stuff sounds totally wrong because the whole idea only matters if we get to another star. You don't call Europe "the white man's continent".

    I sort of like "home system" or something with that sort of meaning, but I can't think of anything that works. We could always just steal a word for sun from a dead language (is "helios" a word in modern greek?).

    The we have the whole problem of renaming a good portion of the natural sciences as soon as we get to Mars: Geology, Geography, Geophysics, and so on.
  • by TheDullBlade ( 28998 ) on Thursday August 03, 2000 @07:06PM (#880709)
    Second question: do we find their females attractive? (hey, you never know!)

    Third question: do we have better weapons than they do?

    Fourth question: are they an enlightened, peaceful society that has evolved beyond the memory of war?

    If you have answered yes to one of questions 1 or 2 and yes to one of questions 3 or 4, the obvious indicated action is invasion.

    I've seen a lot of old movies about contact with aliens, and I they all pretty much go the same way. I think that we, as weird space aliens, have a duty to run amok, eat a few of them, and kidnap the most attractive of their females.

    Oh, I forgot a few very important questions.

    5) is their version of the common cold a deadly disease to us?

    6) (if you answered "yes" to 4) do they have an an ancient weapon of great power which can be reactivated by an epic quest undertaken by one of their most dashing young males whose favorite female we kidnapped and a sufficient number of expendable henchmen?

    ---
    Despite rumors to the contrary, I am not a turnip.
  • by Christopher Thomas ( 11717 ) on Thursday August 03, 2000 @07:06PM (#880710)
    Generally planets are so much smaller than the star they orbit that any affect they have on the stars brightness is very minimal, if any...

    What's actually being detected isn't a brightness change - it's a doppler shift in the star's emission lines as it moves towards and away from us due to the influence of the orbiting planet.

    You have the right reason for nondetection; it's just a different parameter being measured :).
  • Since no alien race has contacted us yet, they're probably all less advanced than we are.

    Wow. Is humanity really this cocky?

    • How do you know we haven't been contacted by an alien race?
    • Assume temporarily that we have not been contacted. Maybe that's because they're more advanced than we are. For instance: Aliens:Humans::Humans:Roaches. Everything's relative here.

    Should we educate them, and perhaps send religious missionaries? Or are these other lifeforms even capable of salvation?

    I think that statement proves that all aliens are much more advanced than us! :)

  • As for that, I think your analysis of the possibility of stable orbits is naive. Your conclusion might be right, but your method isn't valid. Whether an orbit in a many-body system are stable over millions of cycles is not trivial to calculate, and the effects of a perturbing force like a large planet do not just scale linearly with the force of its gravity.

    You can most certainly resolve this with "back-of-the-envelope" calculations.

    It is only the _relative_ masses and positions of the objects that matter. Absolute scale is irrelevant - it just imposes a scaling factor on time. This means that I can make valid conclusions by comparing the Eridani system to the Sol system.

    The only variable in the Eridani system that differs from the Sol system is the relative masses of the star and the gas giant planet, and this doesn't change much - Epsilon Eridani is about 0.75 solar masses, according to a quick web search.

    Thus, I would be very surprised if my conclusion _didn't_ hold.

    We're talking about a gas giant close enough and big enought to make the star wobble noticably. That's a very rough gravitational environment for a small planet to find a stable orbit in.

    The key word is "noticeably".

    We've had spectrographs for many, many decades, and *only* *now* have instruments sensitive enough to detect the extremely slight perturbation of spectral lines due to planetary nudging of parent stars.

    The effects of a gas giant planet are not as severe as you make them out to be.
  • by Hard_Code ( 49548 ) on Friday August 04, 2000 @03:38AM (#880723)
    Trekkies will recognize Epsilon Eridani as the sun of Spock's home planet Vulcan. I propose we name the planet Vulcan.
  • It is only the _relative_ masses and positions of the objects that matter. Absolute scale is irrelevant - it just imposes a scaling factor on time. This means that I can make valid conclusions by comparing the Eridani system to the Sol system.

    With comments like this, I don't see any point in continuing this discussion. You obviously have no conception of the complexities of planet formation and orbital dynamics and how fragile a stable orbit is if you think you can just make a few linear extrapolations and come up with valid answers.

    ---
    Despite rumors to the contrary, I am not a turnip.
  • by Christopher Thomas ( 11717 ) on Thursday August 03, 2000 @07:12PM (#880731)
    We've got rock planets here in the inner solar-system because our manly yellow star blew off most of the atmosphere of the nearest planets.

    Actually, according to the literature I went through when writing a project on star systems in high school, the gasses are blown out of the inner solar system _before_ planets start to form.

    Blowing the atmosphere off of an already-formed planet won't happen under anything short of very extreme circumstances. Jupiter could be sitting in Venus's orbit and still remain intact. In the primordial disk, however, there's nothing to hold gases in one place, so they can be moved easily.

    So, I think that there is a very good chance of finding rocky planets around Epsilon Eridani.
  • Just don't be the guy wearing the red shirt when you land on their planet. :-)
  • Of course, the meat stage is the first step in the evolution of a prime grade-A machine intelligence. Until they've made that step, we might want to talk to them.

    I personally suspect that the radio phase of civilization is fairly short. If you only have a 2 or 3 century window after which a civilization discovers quantum communications or something, chances of actually finding a civilization based on RF would have to be vanishingly small. However, once you discover quantum communications (Or whatever) you can instanteously tune in to the furthest reaches of the Universe. And THEN you find out that the universal internet is clogged with live qkpth porn and make vlbork fast schemes and tune out in disgust.

  • There's still the little problem of a gas giant in the inner solar system pulling any smaller planets out of their orbits. If you recall, that's the real reason I said there won't be a rocky planet in a stable orbit.

    While I didn't mention it, obviously a weaker star can still blow out the gasses from closer-in planets (a Mercury-distance planet there might get the treatment Mars did here). That's why I left the possibility of Pluto-like (or even more eccentric) planets.

    The relevance of the weak gas-pushing power is that it left a Jupiter where it would make a real mess of any sort of inner solar system (and I do believe that it formed there and wasn't thrown in by near passes of several distant gas giants; E.E. is only about half as bright as Sol).

    ---
    Despite rumors to the contrary, I am not a turnip.
  • Real civilizations use Xkkqpli-based (sorry, I know your primitive mouth-parts can't form this sound) communications to access their massive computer archives of goat porn.

    ---
    Despite rumors to the contrary, I am not a turnip.
  • by Wise Dragon ( 71071 ) on Thursday August 03, 2000 @07:48PM (#880743) Homepage
    The thing about big planets like this is that they tend to have a lot of moons. In our system, one of the moons (Europa) has water on it, which may be liquid. Now think if Jupiter was closer to the sun. More solar radiation, more tidal forces. Perhaps there could be a livable world in orbit around this planet!!! This is definitely worth sending a probe after. I just wish we were spending more money on space. I really do. It's sad how unimportant it seems to be.
  • by istartedi ( 132515 ) on Thursday August 03, 2000 @07:48PM (#880744) Journal

    Epsilon Eridani is a little pansy orange dwarf that couldn't blow the atmosphere off of this Jupiter-type planet as close as the asteroid belt.

    No, but it could blow the atmosphere off one of the closer-in smaller planets. Like the planet Vulcan, where it is hot and the atmosphere is thin. Obviously the atmosphere is not thin because most of it was blown off. The atmosphere was blown off during the early stages of the Epsilon Eridani system formation. Later, gases were released from the planet's interior as it cooled.

    Now hurry up and invent the warp-drive.

  • Anyone who is not convinced by now that a star having planets orbitting it is the norm, and not the exception, needs to have their head examined. As telescopes continue to get better, we're going to find more and more. It won't be a worthy headline until we're able to detect earth-sized/earth-like planets orbitting nearby stars. Which, probably isn't as far in the future as most think...
  • by Christopher Thomas ( 11717 ) on Friday August 04, 2000 @04:52AM (#880754)
    There's still the little problem of a gas giant in the inner solar system pulling any smaller planets out of their orbits. If you recall, that's the real reason I said there won't be a rocky planet in a stable orbit.

    At asteroid-belt distance hardly counts as "in the inner solar system". All that this gas giant does is make the band in which stable orbits can occur a little narrower. Inner planets can most certainly still exist stably.

    While I didn't mention it, obviously a weaker star can still blow out the gasses from closer-in planets (a Mercury-distance planet there might get the treatment Mars did here).

    Mars is bereft of atmosphere because it its escape velocity is low enough that the atmosphere can boil off - solar influence has nothing to do with it.

    The only planet that has had substantial solar influence on its atmosphere is Mercury, because it's *extremely* close to the sun. Even that effect has nothing to do with the sun "blowing away" the atmosphere - on the contrary, it _heats_ the atmosphere so that individual molecules can more readily reach the planet's escape velocity.

    With a Jupiter-mass planet at the distance of the asteroid belt, you'd have stable planetary orbits from Earth-distance on in. The star is cooler, so atmospheres will be cooler, and more easily retained unless you're *really* close to the star.

    I'm afraid that your arguments about atmospheres being "blown away" just don't make any sense. See above.
  • For an observer on the yoyo it would appear as if the world around it is in a constant state of extremely annoying motion while it (the observer) seriously tries to hold on to the yoyo, develops a cause of nausea, and feels too sick to figure out the math.

    You'd wonder what relativistic time-effects any Einsteinian observer would have on a yoyo.

    Anyone ever brought a yoyo aboard a space shuttle trip?

  • Since no alien race has contacted us yet, they're probably all less advanced than we are.

    And who says we are already in contact with beings from other worlds.

    What about

    1. Area 51 (Groom Lake AFB, Nevada)
    2. Something like Stargate (GO SGC!)
    3. Roswell, New Mexico
    4. Heaven's Gate
    5. UFO's (in general)


    I'm not saying that any of these are anything but a ficticous story, but it still is an alternative to saying that we are have never been contacted by "aliens". Of course you need to believe that the US government is capable of a "grand conspiracy".
  • I say wrap up some very hardy bacteria or virii in suspended form, and fire it off. Since we're screwing up this planet so badly, we might as well give evolution a shot on another one. I suspect the teeny ethical issue of pre-existing life on another planet might arise, but hey -- nobody believes in that crap anyway. It's gotta be empty, for sure.
  • Although you can say that everything orbits the Earth from a certain perspective, there is a small problem with this mathamatical model:

    The Sun is so much more massive than the Earth (about 99% of the mass of the entire solar system... including Jupiter, Saturn, Uranus, and Neptune) that you need to keep track of the gravitational effects of all of the other planets at the same time.

    With a heilocentric viewpoint you can simplify the calculations (at least on an initial basis) to only take into account the mass of the sun. In fact, you don't even have to take into account any planetary body when you are calculating rough orbits. Only when you are trying to determine the possibility of other objects (such as what was used to discover Neptune... and erronously used to discover Pluto) is the mass of the other planets even used. And you have to use many significant digits in your calculations for this to be even remotely useful.

    None the less, this is a valid viewpoint to suggest that the Sun and everything else in the universe orbits the Earth.
  • I'm a big fan of Isaac Asimovs sci/fi writings, and in one of his books (in the Foundation series I think, but I could be wrong - I'm at work now) they're searching for the Earth. According to that story, one of the very first systems colonized by man had the old poetic name of 'Epsilon Eridani'.

  • > This raises an interesting moral question: would it be wrong to assimilate extrastellar life? Suppose they're just little above chimpanzees, and really don't have any real cognizant thought. They're not human; would diverting their limited thought to improve life on Earth be truly harmful? Should we educate them, and perhaps send religious missionaries? Or are these other lifeforms even capable of salvation?

    Why aren't we asking these questions about the chimpanzees, whom we know to actually exist?

    --
  • by Greyfox ( 87712 )
    Could the Earth type planet orbit the gas giant?
  • by Sunlighter ( 177996 ) on Thursday August 03, 2000 @07:31PM (#880774)

    Epsilon Eridani, located at right ascension 3h33', declination -9 47', range roughtly 10.7 LY, which works out to sol-centered galactic-aligned cartesian coordinates (- 7.641i - 0.2749j - 7.485k) LY (over-precise), is spectral class K2, so this planet, at Earth's distance out, would be somewhat colder than Earth. There is hope that other, more useful planets are in the system, but I wonder if the gravitational influence of the gas giant would have swept that area clean...

    -- Sunlighter

  • It isn't "elephantly" or "whalely" or "enormous subterranean fungusly" but it is definitely manly.

    ---
    Despite rumors to the contrary, I am not a turnip.
  • by CMU_Nort ( 73700 ) on Thursday August 03, 2000 @07:32PM (#880777) Homepage
    The folks at Burger King observatory in Oklahoma report that the McDonald observatory in Texas has misidentified the new planet. They claim it is simply an spaceborne Whopper which they launched several years ago.

  • by deglr6328 ( 150198 ) on Thursday August 03, 2000 @07:53PM (#880778)
    In December of 1999 astronomers in Britain announced they directly observed the extrasolar planet of Tau Bootis by analyzing what is thought to be starlight reflected from the surface of the planet(with a 1/20 chance of error). this was the first time ever for such an observation. now considering some facts about the tau bootis system, the Epsilon Eridani system should be FANTASTIC for this kind of spectroscopic analysis (ie. we might be able to see what it's atmosphere is made of right now!). tau bootis is 51 light years away from earth (roughly 5 times the distance of Epsilon Eridani, the star in question for this article) and it's planet orbits the star at an average distance of 20 times closer than earth from our sun (not a good situation for the resolving power of hubble, for instance, yet they were still able to extract the reflected surface light of the planet from the light of the star using a doppler shift trick) while the planet orbiting Epsilon Eridani is at a distance of about 3 times the radius of earths orbit about the sun (much better for the resolving power of current telescopes). IANAA (astrophysicist) but couldnt we use hubble or keck right NOW to do these observations and for the first time study the atmospheric contents of extrasolar planets?
  • I think it's really interesting that recently we're discovering so many planets. Just think, in the 80's, there were NO known planets orbiting other stars. Of course they can most easily detect large planets because they have the largest effect on the stars brightness (whis I believe is how they detect them). There may be just as many undiscovered planets about the size of the earth.

    I really hope they'll discover some form of life somewhere...even some sludge sucking germ on Titan would have drastic implications.

    Dennis
  • But look when Star Trek first aired. Wasn't that after Roswell.

    Yeah, 22 years after Roswell.

    *EVERY* TV show is after Roswell. Hell, is "I Love Lucy" supposed to prepare us for an invasion of Cuban nightclub singers?

    --
  • Remember too that the higher the frequency, the smaller the antenna required. Terahertz frequencies would need only a microscopic antenna.

    Of course, you'd have to figure out how to transmit without vaporizing your antenna...

  • Okay, now I know the chances of there being intelligent life on this planet is very slim; I know all about Carlson's Equation. But it's still a very intriguing situation, and we should be prepared for the discovery of intelligent life should it ever occur.

    Since no alien race has contacted us yet, they're probably all less advanced than we are.

    This raises an interesting moral question: would it be wrong to assimilate extrastellar life? Suppose they're just little above chimpanzees, and really don't have any real cognizant thought. They're not human; would diverting their limited thought to improve life on Earth be truly harmful? Should we educate them, and perhaps send religious missionaries? Or are these other lifeforms even capable of salvation?

  • by d_glob ( 210401 )
    well, hopefully within time we will find an earth sized planet .... jupiter sized planets don't hold much interest. but this one is about the same distance from its sun as our asteroid belt is from ours. there is a possibility that there may be an earth sized planet or two revolving as well. life?
  • You're right, at great depths the hydrogen gas in Jupiter's atmosphere is forced into a liquid metallic state by the immense pressure. However, Jupiter does actually have a core made of rock that is believed to be about four times as heavy as the Earth. I think it would probably be liquid at those temperatures and pressures though (like the core of the Earth).

    The hydrogen can act as a metal as it can lose an electron to empty its innermost electron shell (remember the periodic table, where hydrogen appears twice - it can also gain an electron to complete its innermost electron shell, so it acts as a non-metallic element too). The large swirling mass of liquid metal is believed to be the cause of Jupiter's immense magnetic field and strong radio emissions.

  • by Black Parrot ( 19622 ) on Thursday August 03, 2000 @07:33PM (#880807)
    > There's GOTTA be some kinda way to slashdot that planet.

    Well, now that one has been found so close, everyone on the planet is going to start directing radio broadcasts there in hopes of getting a SETI response. I think that qualifies as spam.

    I wonder whether their response will be a cease-and-desist from the galactic equivalent of the FCC. What's the penalty for a RF DoS attack on a solar system?

    ps - If any Epsilon Eridanites are reading this... MAKE MONEY FAST!

    --
  • Well, its always nice to know that there's further evidence that there are worlds orbiting other stars.. It gives creedence to our current thoeries regarding the creation of our own solar system, and helps us fine-tune the methods to which we'll find more such planets in the future.

    So this thing is Jupiter-sized, and pretty far away from its sun, so its probably a gas giant. "Duhh, so what, we cant land on it then." Well, yes, thats correct..we can't land on it. It doesnt have a surface..Just like with Jupiter, if you tried to land on it, you'de go straight through it. Its made entirely out of gas, not rock, or ice. The big deal about this, is that most Jupiter-sized planets also have Jupiter-like characteristics, i'm guessing, which means they more than likely have a large number of satellites, and the planet itself gives off heat. The same as Europa may harbor life sustained by Jupiter's heat, the moons of this newly discovered planet also have a chance of sustaining life.

    Then again, even if we had the technology to span such distances in person, it would take hundreds of years to even build up a decent speed... we'd have to accellerate the spacecraft in a way that was survivable by human beings, mind you. I dont know anyone who wants to spend the next hundred years with their cheeks plastered to their skulls, trying to strain like theyre on the toilet... minute after minute, hour after hour, month after month.

    I think i'll stay here..but I get first dibs on real estate. :)

    My 48,500 rupees,
    Bowie J. Poag
  • I didn't even think of that. With the way gas giants pick up moons, I'd almost say it's likely.

    It wouldn't be too comfortable, though. Not lots of light for photosynthesis, but with enough greenhouse gasses in the atmosphere it could probably be warm enough for liquid water.

    Damn, there might be somewhat Earthlike life on a satellite of E.E.!

    ---
    Despite rumors to the contrary, I am not a turnip.
  • But look when Star Trek first aired. Wasn't that after Roswell.

    Actually, I'm under the impression that all television was aired after Rosewell...

  • Mr Cowing noted in the article that they discovered a large dust cloud orbiting Epsilon Eridani back in 1998, and noticed a large bright spot they thought might indicate a large planet. I sincerely hope they have managed to capture an actual image of the planet itself. There will be more information forthcoming on this issue very shortly I am sure.

  • Well, technically the Earth doesn't have to be defined as orbiting the Sun. Since we are on the Earth, relative to us the Sun orbits the Earth, and so do all the other planets AND the asteroid belt (albeit in sort of a silly elliptical orbit).

    It's all a question of frames of reference. Since it's all moving in directions we can't really perceive anyway, it is just as logical to define Earth as the fixed point as it is to define the Sun as such. We simply say the Sun is fixed in space as a matter of convenience for us, since it being the fixed object allows us to describe every planet as maintainig a (more or less) circular path in space.
  • by PD ( 9577 ) <slashdotlinux@pdrap.org> on Thursday August 03, 2000 @06:34PM (#880822) Homepage Journal
    I agree. Suppose that the future space probe is a 1 gram mass consisting of a power source, computer, sensors, radio, and attitude control.

    We sent a multi-ton spacecraft out of the solar system. Two of them in fact. We sent a further two somewhat lighter spacecraft out of solar system as well.

    Think of the speed you could get if you put a nuclear type rocket behind a 1 gram fully functional payload.

    Perhaps you could reach a substantial fraction of the speed of light, allowing a mission to be completed within 100 years.

    That would make it just possible for someone being born today to still be alive when our first stellar probe is radioing the results back to earth.

    When you consider that there are people alive who existed before cars, it's simply astounding.
  • by def ( 87618 ) on Thursday August 03, 2000 @06:36PM (#880828) Homepage
    Generally planets are discovered by a "wobble" that they induce in the star that they orbit that is caused by the gravitational attraction between the sun and the star. This is also why a large number of the known extrasolar planets are also in relatively close orbits, both due to the increased gravitational force and the fact that an orbit takes place in a much smaller amount of time.

    Generally planets are so much smaller than the star they orbit that any affect they have on the stars brightness is very minimal, if any, and thus differences in relative brightness are not a good way to detect extrasolar planets.
  • Anyone ever brought a yoyo aboard a space shuttle trip?

    Yep, one of the original "Toys in Space" experiments. Back in the 1980s they did a mission that included bringing up a bunch of toys that demonstrated different physical principals, and filming them for use in classrooms. In the 90s they did a similar mission with some different toys.

    Other toys (than the yoyo) on the Toys in Space experiment included magnetic marbles, a ball and jacks, a motorized 'Hot Wheels' car in a loop of track, a 'Wheelo' disk held to a wire frame track with a magnetic axle, a paddle ball (or whatever it's called -- wooden paddle with a rubber ball held by an elastic cord), and a couple of others.

    Some (including the yoyo) worked just fine in zero-gee (yoyo's don't really rely on gravity, you have to throw them to give them enough energy to overcome drag on the string), others didn't (the ball and jacks were problematic).

    The video is available from NASA, I've seen it a couple of times.
  • by redhog ( 15207 )
    You are all a bounch af lazy trained monkeys :)

    Anyway, we CAN notify that the earth is orbiting the sun, not vise-versa. And a Jojo-sitizen could easily notise he's livinging on a moving jojo :)

    Motion is arbitrary, sine motion is relative. However, that goes only for _linear_ motion. Motion without acceleration/retardation.
    Acceleration has the same effect on mass as has gravity. It is, in contrary to mere motion, significant, that is, the refference points are NOT arbitrary.

    And orbiting is equal to acceleration (Directed at the center of the orbit).

    --The knowledge that you are an idiot, is what distinguishes you from one.
  • Woah there, cowboy. This is only an announcement of the forthcoming announcement. They won't release the details until they've torqued off 75% of the people who want to know first.
  • Panspermia theories don't have to be true for aliens to have similar biochemistries. (At least similar to some Earthly life form, not necessarily humans.)

    It's not unreasonable to assume that the rules of chemistry are pretty much universal, and within those bounds, carbon/hydrogen/oxygen/nitrogen based biochemistries are the most probable (variations on those, eg subbing silicon for carbon, or fluorine for oxygen, tend to produce insufficiently interesting variety of compounds, at least in the sort of environment we'd be interested in occupying.) And from that it's a safe bet that the biochemistry that evolved on Earth is the most probable (if not the only) one that can evolve under those conditions.

    But even within the bounds of DNA/RNA and recognizable amino acids, there's a heck of a lot of room for variation in proteins and relative amounts of the other elements that lifeforms depend on. So your answer to (1) is probably correct, ditto your answer to (5). (After all, how many people get infected by, say, tobacco mosaic virus or Dutch elm disease?)
  • by jabber ( 13196 ) on Thursday August 03, 2000 @06:38PM (#880849) Homepage
    IIRC B5 is supposed to orbit the 3rd planet in Epsilon Eridani, Epsilon 3.

    BTW: All those interested: B5 will be rebroadcast on Sci-Fi starting Sept 25th. 7:30pm, daily, I think. :)
  • "On Monday 7 August 2000, an announcement will be made at a meeting of the IAU (International Astronomical Union) that a Jupiter-sized planet has been discovered orbiting the nearby star Epsilon Eridani."

    The problem is that a jupiter sized star is most likely all gas, hydrogen mostly. What i am waiting for is a earth or mars sized planet only about 10 light years away! Then we could send some probes! (i am not talking right now, but within the next century)

    Isn't is amazing that we can debate planet exploration but none of us will ever live to see the 'Star Trek' vision of space in our lives?

  • Since no alien race has contacted us yet, they're probably all less advanced than we are.

    What if bombarding us with tons of space dust every day is an alien culture's idea of "communication"? They're sending us messages in the patterns of dust which falls into our atmosphere every day!

    And here we sit, ignoring it day in and day out. "Damn those earthlings, they don't understand our language at all!"

"Just think of a computer as hardware you can program." -- Nigel de la Tierre

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