In this image, Planck is superimposed on a false-colour map of the CMB charted by NASA's WMAP satellite in 2003. Planck will improve enormously the sharpness and clarity of all the features in the map.
Credit: ESA (AOES Medialab), NASA/WMAP
It's not exactly Doc Brown's DeLorean from "Back to the Future," but the European Space Agency's (ESA) Planck Observatory will be something of a cosmic time machine after it launches this week.
While Herschel sets its sights on the cold infrared radiation of space, Planck will be looking at the remnants of the first light to shine freely in the universe, effectively allowing astronomers to look back in time.
This relic radiation is called the Cosmic Microwave Background, and was discovered by accident in 1965. The CMB is an "echo" of the Big Bang, the cooled remnant of the first light emitted after the universe had cooled enough to allow it to travel freely.
"The cosmic microwave background shows us the universe directly at age 400,000 years, not the movie, not the historical novel, but the original photons," said Charles Lawrence, NASA project scientist for Planck at JPL.
The CMB can be detected in all directions of the sky at an average temperature of 2.73 degrees Kelvin (-450 degrees Fahrenheit or -270 degrees Celsius). Previous space-based missions have found that the temperature of the CMB varies ever so slightly in different areas.
Planck is built to resolve these variations in greater detail, which could allow scientists to better understand the conditions of the very early universe. In fact, Planck will be bringing temperatures variations into the sharpest focus possible.
The kinks in the early universe are thought to have given rise to the structures we see in space today: galaxies, galaxy clusters and large voids.
The photons in the CMB could also tell astronomers when and how the first stars formed.
Essentially, Planck will help reveal the initial conditions from which the universe we know today evolved.
"Planck will give us the clearest view ever of this baby universe, showing us the results of physical processes in the first brief moments after the Big Bang, and the starting point for the formation of stars and galaxies," Lawrence said.
Question of density
Planck is also planned to determine the density of normal matter in the universe, which will allow astronomers to calculate the total number of atoms present in the universe. Planck will also probe the mysterious dark matter and dark energy though to pervade the universe ? dark matter is though to make up 90 percent of the matter in the universe and dark energy is thought to be the behind the acceleration of the expansion of the universe.
Better understanding the nature of dark energy could help answer a key question about the future of the universe: "Will it keep on expanding for ever or some day collapse back upon itself?" said Simon White of the Max Planck Institute for Astrophysics in Germany, which developed key software for Planck.
Closer to home, Planck will map the cold dust along the Milky Way?s spiral arms for the first time. The telescope will also produce a 3-D map of our galaxy?s magnetic field.
Planck will also do a little observing to overlap with Herschel, looking at distant radio galaxies to shed light on star and galaxy formation.
Planck is slated for a 15-month mission, time enough for two full surveys of the sky. The mission could be extended for another year, but even with the 15 months, "Planck will give an answer to many important questions of cosmology," White said. "The satellite is the most powerful tool ever for studying the Cosmic Microwave Background developed."
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