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Structure:
Stars vary considerably in size: Nebula - an interstellar cloud of dust, hydrogen, helium and other ionized gases. Most nebulae are large, reaching sizes of even hundreds of light years in diameter.
The Milky Way galaxy contains about 300-500 billion (5x1011) stars.
Clusters of Galaxies - Galaxies are not uniformly distributed. They are grouped in clusters of up to 50 galaxies which in turn are part of larger groups. Laniakea Supercluster Complex Virgo Supercluster Local group: Andromeda, Milky Way and 50+ dwarf galaxies.Superclusters - The Milky Way is part of the virgo supercluster. Super Cluster Complexes: - large structures of galaxies, called "filaments", "walls" or "sheets", that may span between several hundred million light-years to one billion light-years. The Laniakea Supercluster is the supercluster that contains the Virgo Cluster, Local Group, and by extension our galaxy, the Milky Way. Filaments, thread-like structures, are the largest known structures in the universe, that form the boundaries between large voids in the universe. See: Plasma Kosmology Supercluster - Wikipedia The Universe within 100 million Light Years - The Virgo Supercluster
Universe - The diameter of the observable universe a sphere around 92 billion light-years.
The Flatness Problem :
Expansion Speeds up: It is speculated that this shift from slowing expansion to accelerated expansion occurred about 5 billion years ago. See The Expanding Universe: From Slowdown to Speed Up: Scientific American.
Current estimates are that Dark Energy makes up 73% of the universe, Dark Matter makes up 23% of the universe. The visible matter that we are familiar with, only makes up 4% of the universe.
A 2008 study using Wilkinson Microwave Anisotropy Probe (WMAP) data found that distant galaxy clusters appear to be zooming through space at phenomenal speeds that surpass 1 million mph. The clusters were tracked to 2.5 billion light-years away - twice as far as earlier measurements, along a path roughly centered on the southern constellations Centaurus and Hydra . At a 2002 NASA press release the Hubble team announced they had computed the age of white dwarfs in globular cluster M4 in the Milky Way to be 12-13 billion years old. These extremely old, dim stars provide a completely independent reading of the universe's age without relying on measurements of the universe's expansion, which came up with estimates of 14 Billion years. Because the first stars formed less than 1 billion years after the universe's birth in the big bang these findings are consistent.
Astronomers say that in around 100 trillion years (1014) all stars will decay into white dwarfs or explode in supernovas leaving behind a neutron star or black hole. So the universe will be very dim. Most of the radiation a neutron star is X-rays with little in the visible spectrum.
There are at least one hundred billion (1011) galaxies in our Universe. There are 70 sextillion (7x1022)stars in the visible universe
Mostly H with some He -> Hyper Novi Creats 1 Billion Yrs Stars (Initially H fused to create He) As a star starts to use up He it starts to shrink and gets hotter so it can burn He. 3 He -> C Creates more elements up to Fe (Iron) Creats super Nova which creates heavier elementsSee: Timeline of the Big Bang - Wikipedia, the free encyclopedia and http://www.pbs.org/wgbh/nova/origins/univ-nf.html 4.5 Billion - Our Sun
Terms - Glossary: CMB - Cosmic microwave background ESA - European Space Agency GUT - Grand unification Theory Hypernova - Supernova of a hypergiant star. Nebula - Interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases. Quasar - A compact region in the center of a massive galaxy surrounding its central supermassive black hole. They are sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars. Supernova - A stellar explosion of a dying massive star. ULASJ1234+0907 - 10,000 times the mass of the super-massive black hole in our own Milky Way WMAP - Wilkinson Microwave Anisotropy ProbeBibliography: Cosmology: A Short Bibilography. at NCSA U. Ill Urbana-Champaign Our Cosmic Habitat, Martin Rees (1) Until the mid-1990s the data on the rate cosmic expansion were so uncertain that the best estimates of the age the universe stood at between 10 and 20 billion years. New calculations have zeroed in on 13.7 B years.
In 2004 Astronomers announced that "The Universe is is at least 156 Billion light years across."
History > Universe
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