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Everything posted by Arch2008

  1. Ummm…no. The observable universe is neither 9 billion light years nor 18 billion light years in radius. The correct figure is over 90 billion light years. So, still no “one eighth rule”. The conjecture about particles having different ages due to their spin number is quite frankly ludicrous. The hadrons and leptons were made over 13 billion years ago and that is what they have been ever since. You might try some really basic sites about cosmology and quantum theory.
  2. WMAP confirmed predicted effects of DM for the entire universe. McGaugh has a few observations that he “contends” cannot be equally well explained with DM. Both of these links explain that MOND is not well accepted.
  3. Janus already mentioned that the only way DM can interact with light is through gravity. To elaborate, everything with mass bends space-time. As the article points out, the enormous DM mass around the center of this galaxy has bent space-time so much that light passing through is “focused” similar to the effect of a lens. However, the enormous mass is still spread out over a similarly enormous volume, certainly trillions of cubic light years. So its density is still really low as Janus described.
  4. From your link: "Fusion of elements with mass numbers (the number of protons and neutrons) greater than 26 uses up more energy than is produced by the reaction. Thus, elements heavier than iron cannot be fuel sources in stars. And, likewise, elements heavier than iron are not produced in stars, so what is their origin?" (my italics) Then it explains the method by which neutron capture works to make elements like bismuth by the s process. IIRC fusion in the star creates nickel and cobalt isotopes that are unstable and decay into iron. However, that is as high on the periodic table that star fusion goes. However, this states that low mass stars (red dwarf?) use the s-process as you say. However, they would not go supernova ever and the elements in them would stay in them forever. http://www.optcorp.com/edu/articleDetailEDU.aspx?aid=1671
  5. Well no one has discovered it yet. The energy of a supernova by far outstrips that of any man-made device, so most certainly natural plutonium is possible. As our ability to image individual photons from ever smaller parts of the supernova ejecta increases, it may eventually be possible to find evidence of this.
  6. Gravity alone affects DM normally, not weakly. One might say that particles affected by the mechanics of all four fundamental forces strongly clump together forming the objects we know, however DM is only affected by gravity and weakly clumps together, forming diffuse clouds. http://www.physorg.com/news176457990.html http://arxiv.org/pdf/0903.0101.pdf These links describe how in the early universe the density of DM was perhaps enough that “Dark Stars” (stellar objects) did form and that Weakly Interactive Massive Particles (a candidate for DM) can collide and annihilate creating energy that would produce light and heat like more common stars. So the reason DM does not form stellar objects from gravity alone is due to its density at present.
  7. Most of the elements up to and including iron are created by normal fusion in massive stars. When these stars go nova the other elements are created. Each supernova does this from the early universe to the present. Super heavy elements have a very short half-life and are difficult to observe in the spectra of supernovae, so its anyone’s guess. So that would be yes, no, yes and maybe. P.S. 26 elements are considered "man-made" because they have only been observed in accelerators. As I mentioned above, this is because of the difficulty in observing their presence during a supernova.
  8. Yes! The hydrogen bomb would be utterly destroyed. The comet or asteroid on the other hand would most likely become several (radioactive) asteroids or comets.
  9. Dark Energy makes up 72% of the universe, while Dark Matter makes up 23% and the more familiar matter is 4.6%. So DM is 83% of all matter and the DM to matter ratio is 5/6, not 7/8. “All normal exoplanets follow the one eighth rule.” The press release is about 19 exoplanets that have been confirmed from Kepler’s observations. The number of exoplanets confirmed from other sources numbers in the hundreds. So “all normal exoplanets” is a little bigger set than you seem to think. No “one eighth rule” exists. The effect of DM has been confirmed by the WMAP.
  10. Four fundamental forces are present in the universe, gravity, electromagnetism and the strong and weak nuclear forces. Traditional matter is governed by all of these forces. The strong force binds quarks into atoms. The weak force causes certain atoms to decay. The electromagnetic force binds atoms into molecules. Gravity causes atoms and molecules to form larger structures like pebbles and super galaxy clusters. Dark matter particles are not bound by the strong force into atoms, do not decay radioactively by the weak force and do not have an electromagnetic charge. These particles only clump together weakly through gravity.
  11. Uh…no. Two galaxies separated by a distance of one megaparsec are not moving at a velocity away from each other (i.e. the cars aren’t moving). The space itself (the distance between them) is inflating. A distance of one mps becomes one mps + 70 km after one second. It inflates to one mps + 140 km after two seconds and so on. A third galaxy that is at a distance of two mps from the first will be two mps + 140km distant after one second. Accordingly, the distance will inflate to two mps + 280km after 2 seconds. Another galaxy separated by a distance of 1000 mps will be 1000 mps + 140,000km distant after one second, etc. Let’s say that I have a file system with two files called A and Z. Tomorrow I add file B and the next day I add file C. File A and file Z are not moving. The files between them are increasing at a rate of one file per day. Similarly, two galaxies are not moving due to inflation. The space between them is inflating. (The galaxies still move due to gravity.) You don’t need an expert. It’s really that simple.
  12. Nonetheless, the distance between the galaxies in the example starts at one mps. After one second the new distance is one mps + 70 km. After two seconds it would be one mps + 140km. The distance increases by the Hubble constant. Also, your confusion may be over what a velocity is. Velocity is distance over time (miles per hour). The Hubble constant is a rate of change in distance, 70 km per second per mps. The distance increases at the rate of change equal to the Hubble constant.
  13. If the distance between hypothetical galaxies G were v=one megaparsec, then: G1 v G2 v G3 v G4 would change over time to: G1 v+h G2 v+h G3 v+h G4 Where h is the Hubble constant, 70 km per second per mps. The galaxies themselves are not responsible for this. The expansion is related to a property of space itself between the galaxies, called Dark Energy. So, as already stated, the moving car analogy is incorrect. http://xxx.lanl.gov/PS_cache/astro-ph/pdf/9812/9812133v1.pdf http://en.wikipedia.org/wiki/Virgo_Supercluster Also, the hubble constant is the rate at which the velocity of recession of the galaxies increases with distance; the value is about 70 kilometers per second per megaparsec with a relative uncertainty of about ± 10%. Since the Virgo Super Galaxy Cluster is 33 mps in diameter, the space between the galaxies is inflating, not just the space between SGC's. Also, Purlmutter’s paper was based on SN observations from galaxies inside the Virgo SGC.
  14. Galaxies move according to the laws of gravity. So galaxies in our Virgo Super Galaxy Cluster orbit around a common center of gravity. Thus, the Milky Way and Andromeda are moving toward each other, while others are moving away from us. However, the space itself between every galaxy is inflating. This is caused by Dark Energy. A given megaparsec (mps) of so-called empty space inflates according to Hubble’s constant. The more megaparsec’s you have between any two galaxies, the greater the effect of inflation. So two galaxies separated by a thousand mps will have the distance between them increase faster than two galaxies separated by only one mps by a factor of a thousand. An observer on any particular galaxy will see the distance between their galaxy and all others increase and conclude that the galaxy they are on is “at the center”, which is a misconception. The actual space between is inflating. Dark Energy (DE) may be the energy of space itself. At current levels, gravity is stronger than DE. This is why the effect is not noticed inside galaxies. However, the more space inflates the more DE you get. If the rate continues, then in about fifty billion years, DE will overcome the Strong nuclear force and all of the hadrons will fly apart.
  15. Maybe not... http://www.dailygalaxy.com/my_weblog/2011/12/time-machine-shows-how-black-holes-became-supermassive-after-big-bang.html http://www.astronomy.com/en/News-Observing/News/2011/12/Early%20black%20holes%20grew%20big%20by%20eating%20cold%20fast%20food.aspx?utm_source=SilverpopMailing&utm_medium=email&utm_campaign=ASY_Sub_news_111216_final&utm_content= http://www.sciencedaily.com/releases/2011/12/111212124557.htm I haven't found the paper in Arxiv...yet. Here you go: http://arxiv.org/abs/1107.1253
  16. You also have a problem of semantics. Jupiter’s surface area is about one percent that of the Sun. By definition, brightness is determined by luminosity divided by surface area. So if the present surface area of Jupiter magically “was shining just as bright as our Sun”, then only one percent of the energy the Sun uses would be needed to accomplish this. Energy propagates through space according to the inverse square law. If the Sun were five times as far away as it is now, we would only get one twenty-fifth as much energy from it. Thus, keeping the Jupiter at 5.2 AU from Earth value and factoring in an energy output for a Jupiter “as bright as our Sun”, then we would get one twenty-fifth of one percent as much energy from this Bright Jupiter, as we get from the Sun. This would approximately be about half a watt per affected square meter of the Earth’s surface.
  17. Baric, if you had actually read the previous 5 pages or knew of Kardeshev or Freeman Dyson’s work, or even got the part where the orbital solar collectors are integral to the Bernal sphere and don’t need to “laser” their energy to an Earthbound user, then it might be a lot easier for you to understand statements that have been substantiated over the past few decades. http://en.wikipedia.org/wiki/Bernal_sphere http://en.wikipedia.org/wiki/Kardashev_scale http://en.wikipedia.org/wiki/Space_colonization http://en.wikipedia.org/wiki/Beam-powered_propulsion As you hopefully can see, this is not Gene Roddenberry stuff. Actual scientists have crunched the numbers and this is what our future holds. However, space is the final frontier and these are the best solutions to over-crowding and survival, so not just our species would figure this out.
  18. The Sun produces a million times humanity’s annual energy needs every second. A ten-mile diameter asteroid would have more ore on it than humanity has mined on Earth in all of history. Orbital solar-powered lasers can energize the hull of a spherical shuttle on the ground so that the atmosphere under it explodes and drives the ship to orbit. Dyson calculated that an orbital colony in Bernal spheres would grow exponentially and produce enough living space in new space habitats to house the population of the Earth in less than 60 years. We have the technology to do all of these things right now. A star, and whatever orbits it, would provide all the energy and resources a civilization would need to continue exponential colonization. Even a white dwarf star would radiate heat energy from convection that could be used by a colony. So an entire galaxy would eventually be colonized by any space-faring species. I can’t tell you how a civilization with technology a million years more advance than we have would travel from star to star or galaxy to galaxy. I can only tell you that no scientific reason exists that they couldn’t. This is the “they” that Fermi is talking about when he asked, “Where are they?”
  19. Here’s a program that calculates DM: http://users.telenet.be/nicvroom/program2.htm When scientists observed a galaxy rotate and then added up an approximation of the mass of the visible matter they were surprised. According to general relativity, the galaxy should have spun itself apart. The galaxy would need an additional 5 times the observed mass for it to match the observations. This has since been proved with the WMAP: http://map.gsfc.nasa.gov/ So, the mass of the universe is 4.6% baryonic matter, 23.3% non-baryonic (dark) matter and 72.1% dark energy. However, the matter in the universe is one sixth baryonic and five sixths dark matter. In the ‘90’s, two ideas competed for the dark matter crown. Weakly Interactive Massive ParticleS (WIMPS) and MAssive Compact Halo ObjectS (MACHOS). It seems that WIMPS more closely match the observations. So uncounted black holes with five sixths of all the matter in the universe aren’t as feasible as a cloud of sub-atomic particles that clump together by gravity but don’t form visible matter.
  20. Arch2008


    Scientists at CERN discovered that 15000 neutrinos were found to travel faster than light. A webcast is planned today about the findings: http://webcast.cern.ch/ Woo hoo!
  21. A star spins, giving it a property known as angular momentum. When a super-massive star collapses into a singularity, it continues to spin. Angular momentum cannot be destroyed, so the singularity must also spin. A point cannot exhibit spin. A disk is unstable, because the interior would be attracted to the edge by the centrifugal force of the spin. So a ring singularity is stable and exhibits angular momentum. Its also totally flat, so its volume is zero (width times length times zero), making its density infinite (mass divided by zero). This is what Kerr figured out.
  22. The article explains how you can log in to Zooniverse and assist in the hunt for exoplanets by sifting through the data from Kepler. Good luck! http://www.universetoday.com/81734/become-an-exoplanet-hunter-with-newest-zooniverse-citizen-science-project/ http://www.zooniverse.org/home
  23. http://en.wikipedia.org/wiki/Fine-structure_constant http://www.technologyreview.com/blog/arxiv/25673/ But get this. While data from the Keck telescope indicate the fine structure constant was once smaller, the data from the Very Large Telescope indicates the opposite, that the fine structure constant was once larger. That's significant because Keck looks out into the northern hemsiphere, while the VLT looks south This means that in one direction, the fine structure constant was once smaller and in exactly the opposite direction, it was once bigger. And here we are in the middle, where the constant as it is (about 1/137.03599...) That's a mind blowing result. One of the biggest conundrums that cosmologists face is explaining why the fundamental constants of nature seem fine tuned for life. If the fine structure constant were very different, stars and atoms wouldn't form and the universe as we know it couldn't exist. No theory explains why it takes the value it does which leaves scientists at a loss. The implication from Webb and co's data is that the fine structure constant is continuously varying throughout space and is merely fine-tuned for life in this corner of the cosmos: the universe's habitable zone. Elsewhere, presumably well beyond the universe we can see, this constant is entirely different. (Dear moderators, the above passage is a quote, not plagiarism. That is why they are called quotation marks.) If the constant is less by a small percent, then there is no nuclear fusion, no stars and no life. If it is too large, then no carbon gets fused and again no life like us. Are we in the Goldilocks Zone of the universe?
  24. If there were some place for the EM to radiate away from the universe, then the primordial universe that was extremely hot would have rapidly radiated away to nothing. The universe is a closed system. Space is expanding and the further you go from any given point the greater the rate of expansion. At a certain point, the space in between is expanding faster than the speed of light. So EM radiation from the Sun will never escape the universe, because it only travels at the speed of light. This same situation exists for every other star and every other point in the universe.
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