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Universe Evolution

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    Planck is Europe's first mission to study the relic radiation from the Big Bang. Ever since the detection of small fluctuations in the temperature of this radiation, announced in... More »

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Hubble Expansion Last Updated on 2009-11-11 16:13:09 Perhaps the most astonishing and revolutionary discovery in cosmology was Edwin Hubble's observation that galaxies are moving away from us. It provides the underpinning of the big bang picture of creation in which the universe is expanding, and has been for 13.7 billion years. But astronomers in the last century were quick to point out to Hubble, and to the theoreticians like Einstein and Lemaitre who modeled his data, that the observations really only find that galaxies appear red. While relativity does predict that galaxies in an expanding universe will appear red, other causes of redness might be at work -- for example, a radical idea called "tired light" in which light in a static universe just grows redder as it travels over cosmic distances towards us. For over sixty years scientists have tried to determine whether tired light, or perhaps some other effect, might be... More »
Galaxies in the Early Universe Last Updated on 2009-11-11 00:00:00 About ten years ago, astronomers using new submillimeter wavelength facilities discovered the existence of a new class of very distant galaxies. These objects are located so far away that their light has been traveling towards us for over ten billion years - more than 70% of the lifetime of the universe. Although today they are old, we see them as they were only a few billion years after they formed, when they were relatively young. These galaxies were undetected in the visible but emit strongly at submillimeter wavelengths because they have an abundance of warm dust. What heats the dust is still controversial - probably either massive star formation, or an active black hole at the galactic nucleus, or perhaps both. Our Milky Way galaxy, or at least the region where the sun resides, probably formed between seven and ten billion years ago, and so understanding these remote systems... More »
Planck Last Updated on 2009-10-01 15:49:15 Planck is Europe's first mission to study the relic radiation from the Big Bang. Ever since the detection of small fluctuations in the temperature of this radiation, announced in late 1992, astronomers have used the fluctuations to understand both the origin of the Universe and the formation of galaxies. The mission is named after the German physicist Max Planck, whose work on the behaviour of radiation won the Nobel Prize in 1918. The Planck satellite will observe the cosmic microwave background radiation (CMB). This is the radiation released into the Universe by the Big Bang itself, about 14 thousand million years ago. Since that time, what was once a searing fireball has cooled to become a background sea of microwaves. Planck will measure the temperature variations across this microwave background with much better sensitivity, angular resolution and frequency range than any... More »
LIGO Listens for Gravitational Echoes of the Birth of the Universe Last Updated on 2009-08-19 00:00:00 Caltech, Pasadena, CA (Aug. 19. 2009) – An investigation by the LIGO (Laser Interferometer Gravitational-Wave Observatory) Scientific Collaboration and the Virgo Collaboration has significantly advanced our understanding of the early evolution of the universe. Analysis of data taken over a two-year period, from 2005 to 2007, has set the most stringent limits yet on the amount of gravitational waves that could have come from the Big Bang in the gravitational wave frequency band where LIGO can observe. In doing so, the gravitational-wave scientists have put new constraints on the details of how the universe looked in its earliest moments. Much like it produced the cosmic microwave background, the Big Bang is believed to have created a flood of gravitational waves—ripples in the fabric of space and time—that still fill the universe and carry information about the universe as it was... More »
Mysterious Space Blob Discovered at Cosmic Dawn Last Updated on 2009-04-23 00:00:00 Carnegie Institution for Science (Apr. 23, 2009) – Using information from a suite of telescopes, astronomers have discovered a mysterious, giant object that existed at a time when the universe was only about 800 million years old. Objects such as this one are dubbed extended Lyman-Alpha blobs; they are huge bodies of gas that may be precursors to galaxies. This blob was named Himiko for a legendary, mysterious Japanese queen. It stretches for 55 thousand light years, a record for that early point in time. That length is comparable to the radius of the Milky Way’s disk. FIGURE 1 –This image of the Himiko object is a composite and in false color. The thick horizontal bar at the lower right corner presents a size of 10 thousand light year. (Credit: This image is created by M. Ouchi et al., which is the reproduction of Figure 2 in the article of The Astrophysical Journal May 2009 - 10... More »