Planck Telescope Is Coolest Spacecraft Ever 196
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.'"
Worst metaphor ever? (Score:5, Insightful)
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.
NPOV (Score:4, Insightful)
This is where the so-called "neutral point of view" ceases to be useful.
Why is it so hard for people to understand? (Score:1, Insightful)
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.
Re:Why is it so hard for people to understand? (Score:3, Insightful)
"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?
Re:Why is it so hard for people to understand? (Score:2, Insightful)
Re:Why is it so hard for people to understand? (Score:3, Insightful)
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. :-)
Re:rabit from the moon (Score:5, Insightful)
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
Go north from the North Pole (Score:3, Insightful)
A simpler analogy would be to try to go north from the North Pole.