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Space Science

Planck Telescope Is Coolest Spacecraft Ever 196

Posted by timothy
from the that's-certainly-what-the-moon-rabbits-think dept.
Hugh Pickens writes "Launched in May, BBC reports that Europe's Planck observatory has reached its operating temperature, a staggering minus 273.05C — just a tenth of a degree above what scientists term "absolute zero." and although laboratory set-ups have got closer to absolute zero than Planck, researchers say it is unlikely there is anywhere in space currently that is colder than their astronomical satellite. This frigidity should ensure the bolometers will be at their most sensitive as they look for variations in the temperature of the Cosmic Microwave Background (CMB) that are about a million times smaller than one degree — comparable to measuring from Earth the heat produced by a rabbit sitting on the Moon. Planck has been sent to an observation position around the second Lagrange point of the Sun-Earth system, L2, some 1.5 million km from Earth and Planck will help provide answers to one of the most important sets of questions asked in modern science — how did the Universe begin, how did it evolve to the state we observe today, and how will it continue to evolve in the future. Planck's objectives include mapping of Cosmic Microwave Background anisotropies with improved sensitivity and angular resolution, determination of the Hubble constant, testing inflationary models of the early Universe, and measuring amplitude of structures in Cosmic Microwave Background. 'We will be probing regimes that have never been studied before where the physics is very, very uncertain,' says Planck investigator Professor George Efstathiou from Cambridge University. 'It's possible we could find a signature from before the Big Bang; or it's possible we could find the signature of another Universe and then we'd have experimental evidence that we are part of a multi-verse.'"
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Planck Telescope Is Coolest Spacecraft Ever

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  • comparable to measuring from Earth the heat produced by a rabbit sitting on the Moon

    Is anyone else dissapointed we don't already have this capability? I can stream Top Gear in HD from youtube in faster than real time but we lag this far behind in (optical? thermal?) imaging? I know the atmosphere creates a lot of optical distortion... but really? Not even a rabbit (which have unusually high body temps if I recall correctly)?

    • Re: (Score:1, Informative)

      by Anonymous Coward

      Uh, yea. Atmopheric distrotion is bad enough for visible radiation...thermal would basically be a second level of distortion.

    • by Valdrax (32670) on Saturday July 04, 2009 @05:58PM (#28582837)

      I just want to know how long the rabbit's been sitting there. I mean, is it still a living rabbit, and does it get hotter for a few seconds as it thrashes around without breath in the moon's almost nonexistent atmosphere?

      Or do scientists just know how hot SPACE RABBITS get? When will the invasion come?

    • by Anonymous Coward on Saturday July 04, 2009 @06:32PM (#28583005)

      I'm just disappointed they couldn't find a way to turn it into a car analogy instead of rabbits.

    • Re: (Score:3, Funny)

      by El Cubano (631386)

      comparable to measuring from Earth the heat produced by a rabbit sitting on the Moon

      Is anyone else dissapointed we don't already have this capability?

      I'm actually a little disappointed that this wasn't expressed in standard metric terms. I thought here on Slashdot, the agreed upon standard was something in terms of libraries of congress. Is there a conversion factor or something we can apply here?

      • Re: (Score:3, Funny)

        by Asclepius99 (1527727)
        20 rabbits = 5 hares
      • by tylerni7 (944579) on Sunday July 05, 2009 @01:26AM (#28584611) Homepage
        Well, let's say 1 Library of Congress is about 20TB, a measure of information. If we want to convert that into Rabbits * arc length, a unit of temperature * arc seconds, we can use the laws of entropy.

        We know that entropy=k*ln(O) where k is the Boltzmann constant and O is the number of microstates of the system. If we really wanted, we could express the number of microstates as 1 LoC, since both are really just measuring information in one way or another.

        Now if you recall temperature = change in heat/change in entropy. The average body temperature of a rabbit is about 312 degrees kelvin according to google.

        To get a change in entropy and heat, we can look at both over an arbitrary time step t, so 312 K [one rabbit]=(heat/t)/(k*ln(2TB [one Library of Congress])/t)

        Solving for one Library of Congress, we get one Library of Congress = e^(k*heat [in joules]/312 degrees K)=e^(4.4252x10^-26 joules^2/(degree kelvin)^2)

        Now assuming a rabbit is about 0.2 meters in diameter, at a distance of about 384,000 km, that's about 3*10^-8 degrees.

        So, putting that all together, the conversion factor is about e^(4.4252x10^-26 joules^2/(degree kelvin)^2)*1.1*10^5 arc seconds.

        Hope that clears things up for you!
    • by thrawn_aj (1073100) on Saturday July 04, 2009 @10:34PM (#28584017)

      comparable to measuring from Earth the heat produced by a rabbit sitting on the Moon

      Is anyone else dissapointed we don't already have this capability? I can stream Top Gear in HD from youtube in faster than real time but we lag this far behind in (optical? thermal?) imaging? I know the atmosphere creates a lot of optical distortion... but really? Not even a rabbit (which have unusually high body temps if I recall correctly)?

      Actually, that's an interesting question. It has been answered in this thread but I'd like to address a deeper issue here. Technical challenges usually come in two flavors, one which can be solved simply by making a device better and better and the other, which has to do with the signal you're trying to measure just not being there (or is otherwise masked by "noise"). I put "noise" in quotes because people always assume the signal can be separated from the noise. Not so. In most cases, you have to know the source of the noise to reliably subtract it out. In other cases, you can be lucky and the noise will be random so that greater averaging of the data filters out the noise automatically. For ALL other cases, people have to resort to making assumptions about the noise, which means that the "filtered signal" you end up with has (sometimes huge) contributions from the person who made the assumption. Is it a rabbit or an artifact of my assumptions?

      This particular question you raise is in that final category. There just isn't enough signal there that is distinguishable from the surrounding crap for you to tell with any certainty that you have rabbits on the moon and not a migratory bird flock here in the sky. You could always throw money at the problem (in principle) by having a dozen weather satellites constantly monitoring the patch of atmosphere in direct line of sight between you and the moon and feeding you detailed real-time data of temperature, pressure, index of refraction, chemical composition of air(/dust) in there (affects absorption/reflection/transmission). THEN, you MIGHT stand a good chance of catching a glimpse of your elusive rabbit.

      Technology can always be improved. Ambient conditions will always be the ultimate threshold for the actual utility of that technology.

      That is not to say that a particular phenomenon always stays of out of reach. One simply realizes that certain constraints stated in the problem are actually ridiculous. For instance, if the goal was really to observe rabbits on the moon, the constraint that the instrument be on the earth is highly artificial. Instead, one would relax that constraint, put a satellite above the atmosphere, satisfy one's rabbit fetish and the problem's solved :).

    • Well as we all know:

      Hey diddle diddle,
      The cat and the fiddle,
      The cow jumped over the moon,
      The little dog laughed to see such fun,
      And the dish ran away with the spoon.

      It seems to be well within the capability of current measurement techniques to determine whether bovines are leaping over natural satellites, so we should be able to figure out if a rodent is sitting on one.

      • we should be able to figure out if a rodent is sitting on one.

        As any fule knoe, rabbits are considered to be leporids or lagomorphs.

  • by nebaz (453974) on Saturday July 04, 2009 @05:47PM (#28582795)

    They call that a cool space craft? It doesn't even have warp drive, let alone quantum torpedoes. It doesn't even have anything onboard to which you could apply the phase "reverse the polarity". Cool. Bah!

    • It might actually have one or more peltier devices, which could definitely merit the phrase "reverse the polarity".(though, given the needs of the experiment, I suspect that reversing the polarity would be a terrible plan...)
    • They call that a cool space craft? It doesn't even have warp drive, let alone quantum torpedoes. It doesn't even have anything onboard to which you could apply the phase "reverse the polarity". Cool. Bah!

      Dude, you can reverse the polarity on anything with a DC circuit. Sometimes, with spectacular results.

      • Re: (Score:2, Funny)

        by Mitchell314 (1576581)
        In other news, the coldest telescope became the hottest telescope upon the discovery of two coincidental mistakes where all analog switch were labeled backwards and the purchased fuses closed on failure.
    • by Greyfox (87712)
      Hmm... If you reverse the polarity of the bolometers, you might be able to CAUSE galactic background noise rather than measuring it! This would disturb the subspace plextrons the borg craft uses for propulsion, causing it to self destruct!
      • Re:Don't think so. (Score:5, Interesting)

        by Artifakt (700173) on Saturday July 04, 2009 @08:07PM (#28583403)

        Neat idea, taken a little farther. An advanced civilization prevents a more primitive one from developing advanced physics by making astrophysical observations look funny locally. The primitives assume the weak anthropic principle holds, come up with all these really strange theories about cosmic strings, dark energy and such, and never become competition.

    • by jmv (93421)

      It doesn't even have anything onboard to which you could apply the phase "reverse the polarity"

      Of course it does. I heard it's powered by AA batteries.

    • by syousef (465911)

      It doesn't even have anything onboard to which you could apply the phase "reverse the polarity".

      You can reverse the polarity on anything electrical. Just swap the positive and negative terminals. Don't ever expect to use many of those things you do that to ever again though. Most of the things that die will wimper but some higher voltage things will get dangerous and explode.

    • by BitZtream (692029)

      In a device like this, I'm certain they can reverse the polarity on something for some useful purpose. Its just too complex for there not to be SOMETHING.

  • That's a pretty small telescope you have there, and it doesn't last very long either ; ).

  • Signature (Score:1, Funny)

    by Anonymous Coward

    "Sorry for the Inconvenience"

  • by Bromskloss (750445) <(moc.liamg) (ta) ... erdda.yrailixua)> on Saturday July 04, 2009 @06:03PM (#28582855)

    The Planck telescope is the smallest telescope that, according to our current understanding of nature, it is meaningful to speak about. This property sets the Planck telescope apart as the natural unit (also called Planck unit) for telescopes.

    • Re: (Score:3, Funny)

      by Eudial (590661)

      The Planck telescope is the smallest telescope that, according to our current understanding of nature, it is meaningful to speak about. This property sets the Planck telescope apart as the natural unit (also called Planck unit) for telescopes.

      I think the technical term is telescope quantization. Telescopes can only exist as integer multiples of the Planck telescope.

    • by Maelwryth (982896)

      And we can call the first repair job, "Walking the Plank".

  • by mellon (7048) on Saturday July 04, 2009 @06:07PM (#28582871) Homepage

    A rabbit sitting on the moon will be at a much different temperature than its surroundings, not a millionth of a degree kelvin. The only thing interesting about measuring the temperature of a rabbit on the moon is resolution, not sensitivity. So essentially completely the opposite of what the Planck telescope does.

    Sorry, just had to release my inner pedant - this was too good to resist.

    • Re: (Score:3, Funny)

      A rabbit sitting on the moon will be at a much different temperature than its surroundings

      Not for very long. How's that for pedantry?

      • by mellon (7048)

        Presumably the rabbit is protected somehow, or else it wouldn't be sitting. Of course, that protection would probably smooth out the variance in the amount of energy being radiated, and so make the measurement process more interesting...

    • Re: (Score:3, Informative)

      by Anonymous Coward

      heat != temperature.

      The summary said "heat produced by a rabbit sitting on the Moon". Somehow that went through your brain and came out as "measuring the temperature of a rabbit on the moon". So the problem is you, not the metaphor.

      • by mellon (7048)

        Er, no. The variation in temperature between the rabbit and its surroundings is substantial. The variance being measured in the microwave background are tiny. The distinction between heat and temperature here doesn't matter (or if it does, you haven't yet explained why).

    • by Ambiguous Coward (205751) on Saturday July 04, 2009 @06:18PM (#28582937) Homepage

      The only thing interesting about measuring the temperature of a rabbit on the moon is resolution

      Well yeah, that and the obvious question of "what the hell is a rabbit doing on the moon, and how did it get there?"

      • Re: (Score:2, Funny)

        Maybe its measuring the temperature of a human on earth?

      • by Lehk228 (705449)
        obviously it is suffering an agonizing demise since it doesn't have a pressure suit, O2 supply, or thermal protection.
        • obviously it is suffering an agonizing demise since it doesn't have a pressure suit, O2 supply, or thermal protection.

          Won't somebody please think of the MoonRabbits

      • Re: (Score:2, Funny)

        by Mogster (459037)

        Well yeah, that and the obvious question of "what the hell is a rabbit doing on the moon, and how did it get there?"

        Obviously it should've taken that left turn at Albuquerque =)

      • by ozbird (127571)

        Well yeah, that and the obvious question of "what the hell is a rabbit doing on the moon, and how did it get there?"

        The Goodies [wikipedia.org] dunnit.

      • That's fairly obvious - it's a Suicide Rabbit [wikipedia.org]. Obviously it hitched a ride on the LRO [wikipedia.org]

  • Really, it doesn't have a reason to go on the moon.... if they would give the mouse for example, i'm sure that little critter would love to be on the moon much more than a rabbit, so that it can eat all the cheeze there is there!
  • NPOV (Score:4, Insightful)

    by michaelmalak (91262) <michael@michaelmalak.com> on Saturday July 04, 2009 @06:16PM (#28582925) Homepage

    just a tenth of a degree above what scientists term "absolute zero."

    This is where the so-called "neutral point of view" ceases to be useful.

    • I scratched my head over this, too.

      Why is "absolute zero" in quotes? And what do "people" who aren't "scientists" call "0" on the "temperature scale" that "scientists" term "Kelvin"?

      • Re: (Score:3, Interesting)

        by michaelmalak (91262)
        The idea of absolute morality is so forbidden in mainstream media that anytime anyone uses the word "absolute", it has to be portrayed in a relativistc sense. So in this case, scientists believe in some sort of "absolute zero", but that doesn't mean everyone does, and thus the myth that there are no absolutes is preserved.
      • by muridae (966931)

        I think it was a wikipedia meets special relativity pun. Since there can be no absolute reference frame, how can there be an "absolute zero". Maybe, somewhere outside our 4 dimensional reference, an object we think is at complete rest is vibrating and contains energy. Then you match that with Wiki's intended neutral point of view . . .

        And if it wasn't a really horrible pun, then maybe the GP was trolling

      • by Lehk228 (705449)
        summary reads like it was meant for CNN.com not slashdot.org. I am certain that nobody with a slashdot account would be both ignorant of what absolute zero is and incapable of JFGI
    • by pjt33 (739471)

      I'm not sure that's even the worst infelicity of the summary. The start, "Launched in May, BBC" establishes that BBC (perhaps "the BBC") was launched in May.

  • that's colder than a witch's titty (-273.04C).

  • So is moon-rabbits the new metric standard unit for measuring instrument sensitivity?
  • by davecl (233127) on Sunday July 05, 2009 @04:13AM (#28585093)

    For more information you can catch up with Planck on the mission blog [wordpress.com] on Planck's twitter [twitter.com], and on the Planck outreach [cf.ac.uk] website.

    I help maintain the blog and work on both the Planck and Herschel [wordpress.com] missions.

  • Stupid units (Score:4, Informative)

    by the_other_chewey (1119125) on Sunday July 05, 2009 @08:47AM (#28585887)
    Just to clarify: -273.05C equals 0.1 Kelvin. That looks much more impressive, as it
    indicates how close to absolute zero it is - and even is easier to grasp in my opinion.
    Come on, we're on Slashdot, dammit!

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