Planck Telescope

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==BBC: Planck achieves ultra-cold state==
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"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 prepares to go super-cold
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Page last updated at 17:31 GMT, Friday, 3 July 2009 18:31 UK
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Europe's Planck observatory has reached its operating temperature, making it the coldest object in space.
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The observatory's detectors have been chilled to a staggering minus 273.05C - just a tenth of a degree above what scientists term "absolute zero."
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Launched in May, Planck will survey the "oldest light" in the Universe.
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Its detectors, or bolometers, should see detail in this radiation that offers new insights into the age, contents and evolution of the cosmos.
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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.
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This frigidity should ensure the bolometers will be at their most sensitive as they scan the sky for the target light.
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The remarkable conditions are maintained, in part, by always pointing Planck away from the heat of the Sun. Shields and baffling get the telescope down to about -220C.
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Three active refrigeration systems then lower the onboard environment at the heart of the observatory extremely close to the state of zero heat energy - when, theoretically, atoms would stop moving.
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Planck has been sent to an observation position some 1.5 million km from Earth. Its first data release is expected next year.
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The European Space Agency mission was launched along with another telescope called Herschel. This second observatory is sensitive to shorter wavelength radiation than Planck and will be studying the birth of stars and the evolution of galaxies.
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It, too, carries bolometer technology, but operates at a slightly warmer temperature - just 0.3 of a degree above absolute zero.
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==ScienceDaily: Coolest Spacecraft Ever In Orbit Around L2 (-273 Degrees Celsius)==
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ScienceDaily (July 4, 2009) — On July 2 the detectors of Planck's High Frequency Instrument reached their amazingly low operational temperature of -273°C, making them the coldest known objects in space. The spacecraft has also just entered its final orbit around the second Lagrange point of the Sun-Earth system, L2. Planck is equipped with a passive cooling system that brings its temperature down to about -230°C by radiating heat into space. Three active coolers take over from there, and bring the temperature down further to an amazing low of -273.05°C, only 0.1°C above absolute zero - the coldest temperature theoretically possible in our Universe.
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Such low temperatures are necessary for Planck’s detectors to study the Cosmic Microwave Background (CMB), the first light released by the universe only 380 000 yrs after the Big Bang, by measuring its temperature across the sky.
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Like measuring the heat of a rabbit on the Moon
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The detectors will look for variations in the temperature of the CMB that are about a million times smaller than one degree – this is comparable to measuring from Earth the heat produced by a rabbit sitting on the Moon. This is why the detectors must be cooled to temperatures close to absolute zero (–273.15°C, or zero Kelvin, 0K).
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Details on the different stages of the cool-down process are available via the 'Planck in depth' link at right.
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Arriving at L2
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Starting at 13:15 CEST July 2, the Planck Mission Control Team conducted a crucial orbit insertion manoeuvre designed to place the satellite into its final orbit about L2.
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Once commanded, the burn was auto-controlled by Planck, with the thrusters operating for between 12 and 24 hours. The manoeuvre directed the satellite into its final operational orbit around the second Lagrange point of the Sun-Earth system, L2.
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The thruster burn was planned to deliberately under-perform by a small margin, necessitating a small 'touch up' manoeuvre in the coming days to bring the satellite fully onto its planned trajectory.
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"While this manoeuvre itself is routine, it represents the final major step in the long voyage to L2, and everyone here is quite happy to see Planck getting into its operational orbit," said Chris Watson, Spacecraft Operations Manager, speaking in the mission's Dedicated Control Room at ESA’s European Space Operations Centre, Darmstadt, Germany.
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The manoeuvre was planned to change the satellite’s speed by 211.6 km/hour, ending with a final speed of 1010 Km/hour with respect to the ground. Together with Earth and the virtual point L2, Planck will then be orbiting the Sun at a speed of 106 254 km/hour (29.5 km/second).
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At the start of yesterday’s manoeuvre, Planck was located 1.43 million km from Earth.
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Science operations to begin soon
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All commissioning activities are on schedule, and this phase of the mission is practically complete. Over the next few weeks, the operation of the instruments will be fine-tuned for best performance.
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Planck will begin to survey the sky in mid-August.
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Adapted from materials provided by European Space Agency.
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==From ESA: Objectives==
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Planck will provide a map of the Cosmic Microwave Background (CMB) field at high angular resolution, covering at least 95% of the sky over a wide frequency range. Planck has been designed to have ten times better sensitivity to temperature variations of the CMB and more than fifty times the angular resolution of the Cosmic Background Explorer (COBE) spacecraft.
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The simultaneous mapping of the sky over a wide frequency range will permit the separation of Galactic and extragalactic foreground radiation from the primordial cosmological background signal. Planck will offer vastly improved performance compared to balloon-borne and ground-based experiments and will exceed the performance of other space-based instruments. The spacecraft revolves about its Sun-pointing axis once per minute to gyroscopically stabilise its attitude. Planck will use this stabilisation spin to operate in a sky scanning survey mode, observing at least 95% of the sky on two separate occasions within twelve months.
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The key objectives of PLANCK are as follows:
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* Measurement of CMB anisotropies with a temperature resolution (ΔT/T) of the order of 10-6 (astrophysical limit set by small scale fluctuations in foreground emission) at all angular resolutions greater than 10 arcminutes - this will allow a determination of fundamental parameters such as the spatial curvature of the Universe, the Hubble constant H0 and the baryon density to a precision of a few percent
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* Tests of inflationary models of the early universe - specifically the determination of the spectral index of the primordial fluctuation spectrum to high precision and the possible detection of a component of the CMB anisotropies induced by primordial gravitational waves, which would show conclusively that the Universe passed through an inflationary phase
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* Detection of characteristic signatures in the CMB created by topological defects, such as cosmic strings and textures, generated at a phase transition in the early Universe
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* Measurement, with greatly improved accuracy, of the amplitudes of structures in the CMB with physical scales between 100 and 1000 h-1Mpc, that have sizes comparable to the voids and filaments observed in the galaxy distribution today - by comparing these Planck measurements with new redshift surveys of around 106 galaxies it will be possible to establish a consistent theory of the formation of cosmic structure and shed light on the nature of the dark matter that dominates the present Universe
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* Measurements of the Sunyaev-Zeldovich effect - temperature anisotropies that are due to the frequency change of microwave background photons undergoing inverse Compton scattering by hot electrons in the gaseous atmospheres of rich clusters of galaxies - Planck will detect this effect in many thousands of rich clusters, providing information on the physical state of the intracluster gas and on the evolution of rich clusters - these measurements can also be combined with spatially resolved X-ray observations to estimate the Hubble constant H0
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* Using the high sensitivity of Planck's sub-millimetre bolometer channels, it will be possible to disentangle the frequency dependent Sunyaev-Zeldovich effect in rich clusters of galaxies from temperature differences caused by their peculiar motions - it should be possible to measure peculiar velocities for more than 1000 clusters to an accuracy of around 250 kms-1, providing powerful tests of theories of structure formation and information on the mean mass density of the Universe
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Last Update: 23 Feb 2004
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==BBC: Lift-off for European telescopes==
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By Jonathan Amos
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Science reporter, BBC News
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The Ariane 5 lifts off from the Kourou spaceport in French Guiana
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Europe's Herschel and Planck telescopes have blasted into space on an Ariane 5 rocket from Kourou in French Guiana.
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The satellites are being sent into orbit to gather fundamental new insights into the nature of the cosmos.
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The Ariane thundered clear of the launch pad at 1312 GMT (1412 BST) - its flight lasting just under half an hour.
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Mission controllers in Germany made contact with the telescopes over the Indian Ocean once they had separated from the rocket's upper-stage.
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The acquisition of the signals, relayed through ground stations in Australia, will have been a moment of huge relief for everyone connected with the two observatory projects.
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Their combined programme cost is 1.9bn euros (£1.7bn; $2.5bn), which made Herschel and Planck the highest value payload the European Space Agency's (Esa) science division had ever put on a single rocket.
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"The launch today is just one step in a long chain of decisions and a fantastic amount of work by thousands of scientists and engineers," said agency director-general Jean-Jacques Dordain.
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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
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Prof George Efstathiou, Cambridge University
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"All these scientists and engineers have worked together with just one objective, which is to discover the unknown and to make the technologies that are necessary to make this scientific progress."
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The ascent through the Earth's atmosphere was just the first stage in what will be a long journey for the astronomical satellites.
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They will spend the next two-to-three months making their way out to observation positions some 1.5 million km from Earth on its "night side".
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The long cruise will allow engineers to check out sub-systems and commission the telescopes' instruments. One of the first things controllers have to do is to get a precise description of the telescopes' orbits.
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The Ariane is an excellent rocket but the satellites will almost certainly need some correction to their flight paths to be sure of making the proper transition to deep space. To save fuel, the controllers would like to make these correction manoeuvres as early as possible, perhaps on Friday.
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Birth of stars
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Herschel is the largest telescope anyone has put in space.
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Its 3.5m-diameter primary mirror is one-and-a-half-times the size of Hubble's main reflector.
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Such size would ordinarily incur a huge weight penalty but the Herschel mirror has been kept to just 350kg by constructing it from silicon carbide, a novel ceramic material.
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HERSCHEL SPACE TELESCOPE
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Herschel (Esa)
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Herschel was released first from the Ariane rocket's upper-stage
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The observatory is tuned to see the Universe in the far-infrared
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Its 3.5m diameter mirror will be the largest ever flown in space
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Herschel can probe clouds of gas and dust to see stars being born
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It will investigate how galaxies have evolved through time
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The mission will end when all the superfluid helium boils off
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Telescope seeks cold cosmos
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The telescope will be sensitive to far-infrared and sub-millimetre (radio) wavelengths of light, allowing it to peer through clouds of dust and gas to see stars at the moment they are born.
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This infrared capability will also enable Herschel to look deep into space, to gaze at those galaxies that thrived when the Universe was roughly a half to a fifth of its present age. It is a period in cosmic history when it is thought star formation was at its most prolific.
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"Herschel is going to help us understand much, much better how stars form right now and how they have been forming throughout billions of years of cosmic history; and therefore, indirectly, it's going to help us understand how our own Sun and our own Solar System formed," Dr Göran Pilbratt, Esa's Herschel project scientist, told BBC News.
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The spacecraft carries an enormous flask of "superfluid" helium to chill its instruments and detectors close to minus 273C (or "absolute zero", the point beyond which no further cooling is possible).
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"We are observing at long wavelengths where all warm objects glow, so we need to cool the telescope and the instruments as much as possible, otherwise the weak signals we are trying to detect from the sky will be totally swamped by radiation emitted by the telescope itself," said Professor Matt Griffin from Herschel's Spire instrument team.
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'Uncertain' physics
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Planck is a survey telescope. It will spin to map the sky at even longer wavelengths of light - in the microwave portion of the electromagnetic spectrum.
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It will make the finest ever measurements of what has become known as the Cosmic Microwave Background (CMB).
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The CMB is the "oldest light" in the Universe. It is all around us and comes from a time 380,000 years after the Big Bang.
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PLANCK SPACE TELESCOPE
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Planck (Esa)
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Planck spins to make its sky maps
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Planck will survey the famous Cosmic Microwave Background
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This ancient light's origins date to 380,000 years after the Big Bang
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It informs scientists about the age, contents and shape of the cosmos
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Planck's measurements will be finer than any previous satellite
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The extra detail may confirm inflation, even find new physics
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Planck prepares to go super-cold
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Scientists say there are temperature variations in this ancient heat energy that can give them insights into the early structure of the Universe. Planck will be the third spacecraft to investigate the CMB, after Nasa's COBE and WMAP satellites.
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"Planck has the sharpest sight so far; it has the most sensitive instruments and the widest frequency range; and it will therefore make that next big step," explained Esa's project scientist on the mission, Dr Jan Tauber.
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"It will allow us to pin down all the basic characteristics of the Universe with very high accuracy - its age, its contents, how it evolved, its geometry, etc."
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One key question facing Planck concerns "inflation". This is the faster than light expansion that cosmologists believe the Universe experienced in its first, fleeting moments.
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Theory predicts this event ought to be "imprinted" in the CMB and the detail should be retrievable with sufficiently sensitive instruments. Planck is designed to have that capability.
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Planck investigator Professor George Efstathiou from Cambridge University, UK, thinks the telescope could throw up fundamentally new discoveries.
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"We will be probing regimes that have never been studied before where the physics is very, very uncertain," he said.
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"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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Latest revision as of 12:11, 5 July 2009

"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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