Probe gets clearest glimpse yet of cosmic dawn
The Planck spacecraft has obtained its first peek at the afterglow of the big bang, revealing it in unprecedented detail. Its first map of the entire sky is set to be complete in about six months.
The European Space Agency spacecraft was launched into space on 14 May. It is observing the glow of hot gas from just 380,000 years after the big bang – about 13.73 billion years ago – called the cosmic microwave background.
The detailed properties of this background may contain hints of hidden extra dimensions or multiple universes, as well as providing clues to what caused a brief, early period of incredibly rapid cosmic expansion.
Planck began surveying the microwave background on 13 August, a few weeks after reaching its planned perch 1.5 million kilometres from Earth at a point called L2 and cooling its detectors to within 0.1 °C above absolute zero.
Now, the Planck team has released the probe's first image, an observational strip covering about 5 per cent of the sky.
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Slight variations in temperature from place to place in the early universe give the image its mottled appearance. "With a few per cent of the data in, you can see it's working well and delivering good stuff," says team member George Efstathiou of the University of Cambridge.
Planck is expected to provide the most detailed all-sky map of the cosmic microwave background yet, improving on the best current map, obtained by NASA's Wilkinson Microwave Anisotropy Probe (WMAP), which launched in 2001.
Planck's detectors have more than 10 times the sensitivity of WMAP's, and about 2.5 times the angular resolution. "Every strip that Planck scans, we're getting data that is many, many times more sensitive than WMAP," Efstathiou told New Scientist.
Although Planck was only designed to observe the sky for 15 months, the team believes it could last for more than 30 months, based on new estimates of how long its coolant will last. The extra time will allow Planck to measure the radiation with even greater precision, since it will scan the entire sky four times – two more than originally planned.
Hopefully, I'm very excited about what we stand to learn.
