A New Cosmology
September 2, 2010 |11:54 | Cosmogony By : Team X
A new one? What s the old one? Cosmology, from the Greek, cosmologia-order and logos (word, reason, plan) is study of the Universe in its totality! So we think as though we know it all? By extension then the conclusions are humanity's place in it. Though the word cosmology is recent (first used in 1730 by Christian Wolff), the study of the Universe has a long history involving science, philosophy, esotericism, and religion. So, we're talking something BIG here!
Let's begin by saying the cosmos is what the cosmos is, but we the inhabitants of it are changing greatly! The consciousness of humanity is a story of an ever increasing, and probably greatly interrupted, advances in our ability to udnerstand the world we live in. we're going to need to employ all of the philosophical disciplines, get beyond the creation myths, or at least understand them. As had as it will be for the scientific community we must realize that the cosmos, as Gill Edwards put it, "is based on unconditional love, which we are inseparable. Love is what we are. What is more, we are not victims of fate or chance or karma, but divine co-creators of everything (without exception) that happens to us.
Clearly imagination must be the source from which astronomy•cal theories are developed about the cosmos that surround us. But according to Sagan, skepticism is the very tool to keep things in check, helping to filter out the fantasy from reality.
The Cosmic Dawn began as galaxies began to form out of the debris of massive stars which died explosively shortly after the beginning of the Universe. The Durham calculation predicts where these galaxies appear and how they evolve to the present day, over 13 billion years later.
A dusty stellar nursery shines brightly in a new image from NASA’s Spitzer Space Telescope formally known as the Space Infrared Telescope Facility. Spitzer’s heat sensing “infrared Eyes” have pierced the veiled core of the Tarantula Nebula to provide an unprecedented peek at massive new born stars. "We can now see the details of what's going on inside this active star-forming region," said Dr. Bernhard Brandl, principal investigator for the latest observations and an astronomer at both Cornell University, Ithaca, N.Y., and the University of Leiden, the Netherlands. Launched from Cape Canaveral Air Force Station, Florida, the Spitzer Space Telescope is the fourth of NASA's Great Observatories, a program that also includes Compton Gamma Ray Observatory, the Chandra X-ray Observatory and the Hubble Space Telescope. Spitzer's state-of-the-art infrared detectors can sense the infrared radiation, or heat, from the farthest, coldest and dustiest objects in the universe. One such dusty object is the Tarantula Nebula. Located in the southern constellation of Dorado, in a nearby galaxy called the Large Magellanic Cloud, this glowing cloud of gas and dust is one of the most dynamic star-forming regions in our local group of galaxies. It harbors some of the most massive stars in the universe, up to 100 times more massive than our own Sun, and is the only nebula outside our galaxy visible to the naked eye. While other telescopes have highlighted the nebula's spidery filaments and its star-studded core, none was capable of fully penetrating its dust-enshrouded pockets of younger stars. The new Spitzer image shows, for the first time, a more complete picture of this huge stellar nursery, including previously hidden stars. The image also captures in stunning detail a hollow cavity around the stars, where intense radiation has blown away cosmic dust. "You can see a hole in the cloud as if a giant hair dryer blew away all the gas and dust," said Brandl. By studying this portrait of a family of stars, astronomers can piece together how stars in general, including those like our Sun, form.
Using ESO’s very large telescope Interferometer, astronomers have probed the inner parts of the disc of material surrounding a young stellar object, witnessing how it gains its mass before becoming an adult. The astronomers had a close look at the object known as MWC 147, lying about 2,600 light years away towards the constellation of Monoceros ('the Unicorn'). MWC 147 belongs to the family of Herbig Ae/Be objects. These have a few times the mass of our Sun and are still forming, increasing in mass by swallowing material present in a surrounding disc. MWC 147 is less than half a million years old. If one associated the middle-aged, 4.6 billion year old Sun with a person in his early forties, MWC 147 would be a 1-day-old baby. Being 6.6 times more massive than the Sun, however, MWC 147 will only live for about 35 million years, or to draw again the comparison with a person, about 100 days, instead of the 80 year equivalent of our Sun. The morphology of the inner environment of these young stars is however a matter of debate and knowledge of it is important to better understand how stars and their cortège of planets form.The astronomers Stefan Kraus, Thomas Preibisch, and Keiichi Ohnaka have used the four 8.2-m Unit Telescopes of ESO's Very Large Telescope to this purpose, combining the light from two or three telescopes with the MIDI and AMBER instruments. "With our VLTI/MIDI and VLTI/AMBER observations of MWC147, we combine, for the first time, near- and mid-infrared interferometric observations of a Herbig Ae/Be star, providing a measurement of the disc size over a wide wavelength range*," said Stefan Kraus, lead-author of the paper reporting the results. "Different wavelength regimes trace different temperatures, allowing us to probe the disc's geometry on the smaller scale, but also to constrain how the temperature changes with the distance from the star." The near-infrared observations probe hot material with temperatures of up to a few thousand degrees in the innermost disc regions, while the mid-infrared observations trace cooler dust further out in the disc. The observations show that the temperature changes with radius are much steeper than predicted by the currently favoured models, indicating that most of the near-infrared emission emerges from hot material located very close to the star, that is, within one or two times the Earth-Sun distance (1-2 AU). This also implies that dust cannot exist so close to the star, since the strong energy radiated by the star heats and ultimately destroys the dust grains. "We have performed detailed numerical simulations to understand these observations and reached the conclusion that we observe not only the outer dust disc, but also measure strong emission from a hot inner gaseous disc. This suggests that the disc is not a passive one, simply reprocessing the light from the star," explained Kraus. "Instead, the disc is active, and we see the material, which is just transported from the outer disc parts towards the forming star." The best-fit model is that of a disc extending out to 100 AU, with the star increasing in mass at a rate of seven millionths of a solar mass per year. "Our study demonstrates the power of ESO's VLTI to probe the inner structure of discs around young stars and to reveal how stars reach their final mass," said Stefan Kraus. The authors report their results in a paper in the Astrophysical Journal ("Detection of an inner gaseous component in a Herbig Be star accretion disk: Near- and mid-infrared spectro-interferometry and radiative transfer modeling of MWC 147", by Stefan Kraus, Thomas Preibisch, Keichii Ohnaka"). *MIDI is the mid-infrared instrument of the VLT interferometer. It operates between 8 and 13 microns. AMBER observes in the near-infrared, from 1 to 2.4 microns.
