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Planck Telescope Is Coolest Spacecraft Ever
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.'"
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!
Rhymes that keep their secrets will unfold behind the clouds.There upon the rainbow is the answer to a neverending story
Uh, yea. Atmopheric distrotion is bad enough for visible radiation...thermal would basically be a second level of distortion.
That's a pretty small telescope you have there, and it doesn't last very long either ; ).
"Kill 'em all and let Root sort 'em out"
"Sorry for the Inconvenience"
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?
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
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.
Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
Space rabbits are a minimal threat. The space vixens keep their population in check.
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.
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.
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!
According to Japanese and Aztek folklore, a rabbit has been there for a long time. I could never really make out the face or the rabbit in the moon's craters when I look.
Ryan Fenton
This is where the so-called "neutral point of view" ceases to be useful.
I'm just disappointed they couldn't find a way to turn it into a car analogy instead of rabbits.
L2 is behind the earth, as seen from the sun. And the distance given is correct.
that's colder than a witch's titty (-273.04C).
Wikipedia has an excellent article describing each of the Legrangian points and why each of them is pseudo-stable.
Don't Bogart the fish sticks
You did a lot of typing in your post. I think perhaps you could have saved a lot of it in your quest to enlightenment if you'd have chosen a text field on a different web page. May I suggest http://google.com/ and the phrase "earth sun l2"? The first link even has a very descriptive map. http://en.wikipedia.org/wiki/Lagrangian_point
Behind what?
Nerd rage is the funniest rage.
while (measured_age_of_the_universe != 6000)
launch a better satellite;
Why is it so hard for people to understand that there is no "before the big bang"? Time was created at the big bang. There is no "before time began". Before time, there is no before. A bit like there was no spelling bee champion 65 million years ago. Maybe very little like that. Or maybe a bit like asking what is west of the moon. Hmmm... ok, very little like that, too. How about like asking at what date 13 became a prime number? Yes, more like that. You get the gist. Time is part of our universe. The big bang created the universe, space and time together.
If there was no big bang, then maybe there was something before whatever was then. But if there was a big bang, there was nothing before that.
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?
20 rabbits = 5 hares
MUAD'DIB: the adapted kangaroo mouse of Arrakis, a creature associated in the Fremen earth-spirit mythology with a design visible on the planet's second moon. This creature is admired by Fremen for its ability to survive in the open desert. [1]
[1] Herbert, Frank. Dune. 1965.
I dunno. What's the temperature of the library of congress? How long can it maintain that temperature if we put it on the moon, and for how long has it been on the moon?
Conscience is the inner voice which warns us that someone may be looking.
Easy. Has slightly less temperature than a truck full of tapes on the highway, simple really.
In soviet russia, moon rabbit measures you!
Seven puppies were harmed during the making of this post.
Volkswagen makes a model of car called the Rabbit.... what makes you so sure it isn't a car analogy?
If you believe everything you read, you'd better not read. - Japanese proverb
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
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.
A simpler analogy would be to try to go north from the North Pole.
Oliver.
How would a Volkswagon Rabbit get to the moon, some German hippies taking acid back in the 70's teleported themselves there?
An Education is the Font of All Liberty
Hmm, so we're measuring telescope resolution and fidelity by the ease at which we can look at rabbits on the moon? How many libraries of congress worth of data can these 1-rabbit-resolution telescopes transmit back to earth per hogshead?
Depends on the rabbit. some of them yield 14kg of meat each.
An Education is the Font of All Liberty
Now that we know of their retreat to the moon, make no mistake, they are building their numbers rapidly. The space rabbit invasion will come.
Sorry but the man in the moon eat the first bunny and none have been seen since.
How would scientist tell exactly or even generally what was making the Cosmic Microwave Background. If anyone on slashdot knows (and yes I am insulting your ego to get more answers).
Aztek folklore? That must be some prety brutally ugly stuff right there.
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!
I have nothing to add, save the fact your slashid's are exactly 200,000 apart. Neat.
/wrists
Don't worry if you're a kleptomaniac, you can always take something for it.
we must be prepared to take account of the fact that our location in the universe is necessarily privileged to the extent of being compatible with our existence as observers
http://en.wikipedia.org/wiki/Anthropic_principle
If you ever see a hot moon rabbit just don't look her in the eye for your sanity's sake.
But... the future refused to change.
If the rabbits don't have the Holy Hand Grenade in their arsenal..... :-)))
Step away from the hand grenade and the drum. -- Its a Plan Nine reset server.
So is moon-rabbits the new metric standard unit for measuring instrument sensitivity?
"Destroy science and religion. Science would re-emerge exactly the same; but not religion." - Penn Jillette, paraphrased
"Its too late, the invasion has begun!"
That was '72, the goodies came to our rescue and defeated big bunny's transistorized carrots in '73.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Libraries of Congress is a measure of amount of information. The more information is contained, the less the entropy.
Heat difference provides also is quantified by entropy. So obviously the heat produced by the rabbit can be converted into libraries of congress. ....
The applicable equation is the first one in http://www.scholarpedia.org/article/Bekenstein-Hawking_entropy which relates entropy to the planck length (to bring it back on topic of TFA). The actual conversion factor is left as an exercise to the reader
Yes, of course informational entropy vs thermodynamic entropy as in http://en.wikipedia.org/wiki/Introduction_to_entropy, but the one is a function of the other per black hole theory. (http://www.scholarpedia.org/article/Bekenstein-Hawking_entropy) .... http://www.mediamarksurveys.com/playboy/
This is also clearly the reason why we perceive intelligence as hot
So .... how hot is the Library of Congress anyway ?
Dude! Same thing! http://www.vw.com/rabbit/en/us/ ^^
Any sufficiently advanced intelligence is indistinguishable from stupidity.
For more information you can catch up with Planck on the mission blog on Planck's twitter, and on the Planck outreach website.
I help maintain the blog and work on both the Planck and Herschel missions.
What he really wanted to say was; When will the space vixens invade earth? And will they make us their sex slaves.
- These characters were randomly selected.
Same way as a Desoto, just drive there!
Justice is the sheep getting arrested while an impartial judge declares the vote void.
How many station wagons do you get per truck ?
Squirrel!
And you can see now why they gave you old-fashioned rabbit instead of uniformly accepted units - 71pLoC/s does not sound too sexy.
I'm a haiku hunter. Trophies are displayed here.
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.
Squirrel!
Just a little nitpicking. Noise randomness doesn't mean that you'll get a good estimation of the signal by averaging.
The mean estimator works all right (it's the MVU, IIRC) when you're getting zero-mean noise, or noise whose PDF is symmetrically distributed around its expected value (in this case, you could correct the bias by extracting the mean of the noise).
But I just flunked an exam on this very topic, so to hell with me :D
My 0.02 cents
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?
And what prevents you from inventing this capability for all of us, so that we are no longer disappointed? Just like the way you solved the streaming problem in the first place? Oh wait...
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!
Yikes, it's fucking huge.
http://en.wikipedia.org/wiki/Absolute_zero Absolute zero is -273.15. Therefore -273.05 - (-273.15) is a tenth.
i wish i could mod everyone offtopic! less rabbit, more Planck telescope!
Just a little nitpicking. Noise randomness doesn't mean that you'll get a good estimation of the signal by averaging.
The mean estimator works all right (it's the MVU, IIRC) when you're getting zero-mean noise, or noise whose PDF is symmetrically distributed around its expected value (in this case, you could correct the bias by extracting the mean of the noise).
But I just flunked an exam on this very topic, so to hell with me :D
You're quite right. I should have been more precise when I said "random". What I meant was zero-mean random so that by repeated averaging (done intelligently), the signal survives while the noise averages out to give a large signal-to-noise. Thanks :)