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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
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.
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
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.
I read TFA and all I got was this lousy cookie
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.
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
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?
"Why is it so hard for people to understand that there is no "before the big bang"? Time was created at the big bang."
That's certainly an interesting hypothesis. In what way do you propose we test it out?
Unless our universe exists within something larger, with its own time. If there were universes prior to this one in that larger space then there would have been something before the big bang, regardless of our universes local time. You might not think so, but really, nobody knows.
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.
So basically what you're saying is that in the beginning, there was nothing, which exploded.
And you wonder why people have a hard time grasping current big bang theory. :-)
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.
Easy. Has slightly less temperature than a truck full of tapes on the highway, simple really.
I'm pretty sure what happened before the big bang is similar to what will happen after eternity.
Opus: the Swiss army knife of audio codec
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
A simpler analogy would be to try to go north from the North Pole.
Oliver.
For your statement to make sense, you assumed the same property "time" exists within and outside the universe, and that it made sense to connect the two. It is like saying since Earth existed within something larger, there might be something due North of Earth's North Pole.
Unfortunately, North/South is a local property of Earth, while there is plenty space above the North Pole, you cannot go more north from the North Pole. Similarly, spacetime is a property of our observable universe, and that property breaks down at Big Bang. Trying to simply extrapolating spacetime from the universe to beyond is like trying to reach space by just keep going North on the Earth.
Oliver.
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!
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.
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!
The big bang is not a definition. It, and the details of what got created how/when and what happened shortly after and whether it's meaningful to talk about "before" are all hypotheses and theories, not definitions.