Spyman

What I said and links I posted represents current accepted consensus in modern cosmology, Wikipedia might not be the best of sources but serves well as an initial read and for a basic understanding. The theory of Relativity has so far passed every test made and is now considered a cornerstone of modern physics. As I and others have said it has no speed limit on how fast space can expand: While special relativity constrains objects in the universe from moving faster than the speed of light with respect to each other, there is no such theoretical constraint when space itself is expanding. It is thus possible for two very distant objects to be expanding away from each other at a speed greater than the speed of light, and this is true for any object that is more than approximately 4.5 gigaparsecs away from us. http://en.wikipedia.org/wiki/Metric_expansion_of_space I never claimed that "space is infinite", what I said was: "We have no idea of how big the whole Universe is" and "there is no knowledge preventing the Universe from having started out infinite big", you and everyone else can scroll up to my post #2 and check it anytime. The Big Bang was not an explosion in space throwing pieces of matter in every direction from a center: The Big Bang is not an explosion of matter moving outward to fill an empty universe. Instead, space itself expands with time everywhere and increases the physical distance between two comoving points. http://en.wikipedia.org/wiki/Big_Bang#FLRW_metric An as long as people cling to this old fashion idea in a Newtonian universe they will have a hard time understanding how an infinite universe is able to expand, but with relativity expansion of space is a scalar between our view and our equipment: This metric contains a scale factor, which describes how the size of the Universe changes with time. http://en.wikipedia.org/wiki/Big_Bang#FLRW_metric Imagine that you are in a universe so huge that you can not see any edges, (it could be infinite), suddenly you and your equipment start to shrink, how do you think that the universe would appear? There is no difference if we shrink or the universe expands, the measurements would be equal and more importantly it doesn't matter if there is an boundary or not, the parts we can see on the inside appears the same whether a boundary exists or not. AFAIK, the Big Bang model does not contain any changes of the laws of physics, and scientist in general assumes that nature doesn't trick them: Underlying assumptions The Big Bang theory depends on two major assumptions: the universality of physical laws and the cosmological principle. The cosmological principle states that on large scales the Universe is homogeneous and isotropic. These ideas were initially taken as postulates, but today there are efforts to test each of them. For example, the first assumption has been tested by observations showing that largest possible deviation of the fine structure constant over much of the age of the universe is of order 10−5. Also, general relativity has passed stringent tests on the scale of the Solar System and binary stars while extrapolation to cosmological scales has been validated by the empirical successes of various aspects of the Big Bang theory. http://en.wikipedia.org/wiki/Big_Bang#Underlying_assumptions

The Michelson-Morley experiment showed that there was no stationary luminiferous aether, an "Etherosphere" rotating with Earth is inconsistent with the phenomenon of stellar aberration and a rotating Earth inside a surrounding "Etherosphere" was ruled out by the Michelson-Gale-Pearson experiment. You did not answer my questions, can you explain how your proposed hypothetical Ether can avoid detection by above measurements and why experiments on a moving vehicle should?

Why would Cederholm J.P.-Townes C.H. Experimental Test of Special Relativity be better than the Michelson-Morley experiment? Why would it make a difference if it is performed on a moving vehicle or fixed on the ground? The Michelson-Morley experiment was performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University in Cleveland, Ohio. It attempted to detect the relative motion of matter through the stationary luminiferous aether ("aether wind"). The negative results are generally considered to be the first strong evidence against the then prevalent aether theory, and initiated a line of research that eventually led to special relativity, in which the stationary aether concept has no role. The experiment has been referred to as "the moving-off point for the theoretical aspects of the Second Scientific Revolution". Michelson-Morley type experiments have been repeated many times with steadily increasing sensitivity. These include experiments from 1902 to 1905, and a series of experiments in the 1920s. In addition, recent resonator experiments have confirmed the absence of any aether wind at the 10−17 level. Together with the Ives-Stilwell and Kennedy-Thorndike experiments, it forms one of the fundamental tests of special relativity theory. http://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment Conclusion: The theory of Relativity has been confirmed in every test and is now considered as a cornerstone of modern physics. The predictions of special relativity have been confirmed in numerous tests since Einstein published his paper in 1905, but three experiments conducted between 1881 and 1938 were critical to its validation. These are the Michelson-Morley experiment, the Kennedy-Thorndike experiment, and the Ives-Stilwell experiment. /snip/ Those classic experiments have been repeated many times with increased precision. Other experiments include, for instance, relativistic energy and momentum increase at high velocities, time dilation of moving particles, and modern searches for Lorentz violations. Also general relativity was confirmed many times, the classic experiments being the perihelion precession of Mercury's orbit, the deflection of light by the Sun, and the gravitational redshift of light. Other tests confirmed the equivalence principle and frame dragging. http://en.wikipedia.org/wiki/Theory_of_relativity#Experimental_evidence

We currently don't know how the Universe started out, the singularity is more an indication of the breakdown of current understanding than a indication of how the Universe started, there is no knowledge preventing the Universe from having started out infinite big. In relativity nothing can travel faster than the speed of light through space but space can expand or contract without speedlimits. We have no idea of how big the whole Universe is, but we can calculate how big the observable universe around us is, that is how far expansion have brought objects that we can see. Time like Space is nothing that moves around inside the Universe but is constantly everywhere and have always been there, from the very start. Here are some links for you to read: The Big Bang theory: http://en.wikipedia.org/wiki/Big_Bang Observable Universe: http://en.wikipedia.org/wiki/Observable_universe Metric expansion of space: http://en.wikipedia.org/wiki/Metric_expansion_of_space

This discovery is not about dark matter and it is not some *new* matter suddenly discovered either, if confirmed they have found ordinary matter that we already knew should be here somewhere but previously couldn't find: NASA's Chandra Shows Milky Way is Surrounded by Halo of Hot Gas If the size and mass of this gas halo is confirmed, it also could be an explanation for what is known as the "missing baryon" problem for the galaxy. Baryons are particles, such as protons and neutrons, that make up more than 99.9 percent of the mass of atoms found in the cosmos. Measurements of extremely distant gas halos and galaxies indicate the baryonic matter present when the universe was only a few billion years old represented about one-sixth the mass and density of the existing unobservable, or dark, matter. In the current epoch, about 10 billion years later, a census of the baryons present in stars and gas in our galaxy and nearby galaxies shows at least half the baryons are unaccounted for. http://www.nasa.gov/mission_pages/chandra/news/H-12-331.html Missing Baryons Astronomers have known for some time that about half of all of the baryonic matter, a.k.a. protons and neutrons, in the recent, nearby Universe is unaccounted for. It's all there in the early Universe, so where did it go? One idea is that these missing baryons became part of an extremely diffuse weblike system of gas clouds from which galaxies and clusters of galaxies formed. One of the best ways to detect these missing baryons is through their faint, but observable, X-ray signatures. http://chandra.si.edu/chronicle/0108/universe/ The Case of the "Missing Baryons The best estimates are that all the stars, gas, and dust within galaxies constitute at most 40% of the baryons predicted by the Big Bang. Where are the rest? The most likely place for the rest of the baryons to be hiding is in diffuse gas between the galaxies: the intergalactic medium. Astronomers can estimate the amount of gas in the intergalactic medium by essentially counting up the number of atoms that absorb the light from distant quasars. This number once again falls well short of that required by the Big Bang theory. If the gas is there, many of the atoms must be ionized, that is stripped of some of their electrons, so that they cannot absorb the radiation. http://praxis.pha.jhu.edu/astro2/astro2_science/starburst.html

But can any relevant absorption still be large enough to make a difference when the blur is too small to be noticeable with our instruments?

Galaxies are grouped into clusters and they are separated by much greater distances, but the large scale structure do look like strings in a web. Simulation of the large-scale structure of the cosmos. The image spans about 400 million light years across. http://en.wikipedia.org/wiki/Galaxy#Larger-scale_structures Large-scale structure Sky surveys and mappings of the various wavelength bands of electromagnetic radiation (in particular 21-cm emission) have yielded much information on the content and character of the universe's structure. The organization of structure appears to follow as a hierarchical model with organization up to the scale of superclusters and filaments. Larger than this, there seems to be no continued structure, a phenomenon which has been referred to as the End of Greatness. Walls, filaments and voids DTFE reconstruction of the inner parts of the 2dF Galaxy Redshift Survey The organization of structure arguably begins at the stellar level, though most cosmologists rarely address astrophysics on that scale. Stars are organized into galaxies, which in turn form clusters of galaxies and superclusters that are separated by immense voids, creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that virialized galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the universe in every direction. However, based on redshift survey data, in 1989 Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light-years long and 200 million wide, but only 15 million light-years thick. The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from redshifts. In April 2003, another large-scale structure was discovered, the Sloan Great Wall. In August 2007, a possible supervoid was detected in the constellation Eridanus. It coincides with the 'WMAP Cold Spot', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This supervoid could cause the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across. Another large-scale structure is the Newfound Blob, a collection of galaxies and enormous gas bubbles which measures about 200 million light years across. In recent studies the universe appears as a collection of giant bubble-like voids separated by sheets and filaments of galaxies, with the superclusters appearing as occasional relatively dense nodes. This network is clearly visible in the 2dF Galaxy Redshift Survey. In the figure, a three dimensional reconstruction of the inner parts of the survey is shown, revealing an impressive view on the cosmic structures in the nearby universe. Several superclusters stand out, such as the Sloan Great Wall, the largest structure in the universe known to date. http://en.wikipedia.org/wiki/Large-scale_structure_of_the_cosmos#Large-scale_structure

I am not an expert either but if our visibility is reduced due to a halo surrounding us then shouldn't scattering of light blur the images?

I think it would be hard to filter out signals from shifts in gravity from natural internal movements of Earth.

Success, you made me smile.

The "Reason for edit" text was put there by a mod when they removed a link to another forum, sunshaker must have made a new edit after.

Depends on how you define vacuum, but in a general sense I agree, we consist mostly of emptiness. List of some densities: 1×10-22 kg/m3 outer space 1×10-18 kg/m3 ultra high vacuum chambers 1×10-3 kg/m3 mechanical vacuum pump 1×10-0 kg/m3 air at sea level 1×103 kg/m3 water at 4° Celsius 1.062×103 kg/m3 average human body 7.874×103 kg/m3 iron metal 2×1017 kg/m3 atom nucleus

If the container is sealed then no air can get inside and nothing from the body can escape outside either, so it would contain exactly the same parts but in a different setup. The overall density of the content inside would be unchanged, however if the components settles on the bottom then it would be almost a vacuum above that layer. This thin layer would be very compact and contain the whole mass of the former body - not very dust like at all.

Air also consists of atoms and atoms in general don't have other atoms freely roaming around inside them, so atoms are mostly empty voids inside. Air is the name given to atmosphere used in breathing and photosynthesis. Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%. http://en.wikipedia.org/wiki/Air

Speed of gravity In the context of classical theories of gravitation, the speed of gravity is the speed at which changes in a gravitational field propagate. This is the speed at which a change in the distribution of energy and momentum of matter results in subsequent alteration, at a distance, of the gravitational field which it produces. In a more physically correct sense, the "speed of gravity" refers to the speed of a gravitational wave. The speed of gravitational waves in the general theory of relativity is equal to the speed of light in vacuum, c. Within the theory of special relativity, the constant c is not exclusively about light; instead it is the highest possible speed for any physical interaction in nature. Formally, c is a conversion factor for changing the unit of time to the unit of space. This makes it the only speed which does not depend either on the motion of an observer or a source of light and/or gravity. Thus, the speed of "light" is also the speed of gravitational waves and any massless particle. Such particles include the gluon (carrier of the strong force), the photons that light waves consist of, and the theoretical gravitons which make up the associated field particles of gravity (a theory of the graviton requires a theory of quantum gravity, however). http://en.wikipedia.org/wiki/Speed_of_gravity

If each LED wants 2.92 V 20 mA and you want to supply 10 LEDs with a 9 volt battery then you can make 5 parallel circuits that each have 2 LEDS and 1 resistor in series. The resistors should have the value of (9-2*2.92)/0.02= 158 ohm to limit LED current to 20 mA.

No, while we can't see light older than the Big Bang there is nothing preventing stars to exist much further away and current expansion of space lets us observe stars in a sphere with a radius of about 46 billion light years. The age of the universe is estimated to be 13.7 billion years. While it is commonly understood that nothing can accelerate to velocities equal to or greater than that of light, it is a common misconception that the radius of the observable universe must therefore amount to only 13.7 billion light-years. This reasoning makes sense only if the universe is the flat, static Minkowski spacetime of special relativity, but in the real universe, spacetime is curved in a way that corresponds to the expansion of space, as evidenced by Hubble's law. Distances obtained as the speed of light multiplied by a cosmological time interval have no direct physical significance. http://en.wikipedia.org/wiki/Observable_universe#Misconceptions The universe is immensely large and possibly infinite in volume. The region visible from Earth (the observable universe) is a sphere with a radius of about 46 billion light years, based on where the expansion of space has taken the most distant objects observed. http://en.wikipedia.org/wiki/Universe#Size.2C_age.2C_contents.2C_structure.2C_and_laws

Well to be honest, I don't think I am able to grasp an infinite universe either, homogenously filled or not. But if you want to advance the thread and discuss this further, then you need to focus on what is troubling you with "an infinite universe filled everywhere with matter", why "expansion of space implies that the universe is closed" and how "models that lead to infinite matter can be ruled out". Can you ask more specific questions or present detailed logic which the discussion can continue around? Because right now, all I can interpret is that you don't understand how an infinite universe can contain an infinite amount of matter, which seems pretty evident to me. Is it the *must* that troubles you, from the cosmological principle? In modern physical cosmology, the cosmological principle is the working assumption that observers on Earth do not occupy an unusual or privileged location within the universe as a whole, judged as observers of the physical phenomena produced by uniform and universal laws of physics. As astronomer William Keel explains: The cosmological principle is usually stated formally as 'Viewed on a sufficiently large scale, the properties of the Universe are the same for all observers.' This amounts to the strongly philosophical statement that the part of the Universe which we can see is a fair sample, and that the same physical laws apply throughout. In essence, this in a sense says that the Universe is knowable and is playing fair with scientists. http://en.wikipedia.org/wiki/Cosmological_principle

We don't understand the initial part of the Big Bang yet, since we don't have a fully working theory of quantum gravity, as such there is no confirmed singularity at the beginning of the Big Bang and the Big Bang theory itself currently starts from an early hot, dense phase shortly after the Bang. The Big Bang theory is not about an explosion sending out matter from a concentrated point into a surrounding empty void. In the Big Bang theory there is no edge of the Universe with a infinite empty void outside, the Universe is everything and not a container inside something larger. We don't know how big the Universe is or how large it was at the initial moment of the Big Bang, all we know is that the part we can observe was much more dense back then and will become much more diluted in the future. The Universe could very well have been infinite already at the initial Bang. Extrapolation of the expansion of the Universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past. This singularity signals the breakdown of general relativity. How closely we can extrapolate towards the singularity is debated-certainly no closer than the end of the Planck epoch. This singularity is sometimes called "the Big Bang", but the term can also refer to the early hot, dense phase itself, which can be considered the "birth" of our Universe. http://en.wikipedia.org/wiki/Big_Bang#Timeline_of_the_Big_Bang However, certain physical phenomena, such as singularities, are "very small" spatially yet are "very large" from a mass or energy perspective; such objects cannot be understood with current theories of quantum mechanics or general relativity, thus motivating the search for a quantum theory of gravity. http://en.wikipedia.org/wiki/Quantum_gravity The Big Bang is not an explosion of matter moving outward to fill an empty universe. Instead, space itself expands with time everywhere and increases the physical distance between two comoving points. Because the FLRW metric assumes a uniform distribution of mass and energy, it applies to our Universe only on large scales-local concentrations of matter such as our galaxy are gravitationally bound and as such do not experience the large-scale expansion of space. http://en.wikipedia.org/wiki/Big_Bang#FLRW_metric The universe is immensely large and possibly infinite in volume. The region visible from Earth (the observable universe) is a sphere with a radius of about 46 billion light years, based on where the expansion of space has taken the most distant objects observed. http://en.wikipedia.org/wiki/Universe#Size.2C_age.2C_contents.2C_structure.2C_and_laws No evidence exists to suggest that the boundary of the observable universe constitutes a boundary on the universe as a whole, nor do any of the mainstream cosmological models propose that the universe has any physical boundary in the first place, though some models propose it could be finite but unbounded, like a higher-dimensional analogue of the 2D surface of a sphere which is finite in area but has no edge. http://en.wikipedia.org/wiki/Observable_universe#The_universe_versus_the_observable_universe

The expansion is scalar. Try to imagine how a flat infinite universe would appear to you, if you and your measuring ruler would be shrinking.

If we live in a artificial universe inside an advanced supercomputer that is simulating our lives, then we would only be computer code in a created world and the likelyhood of Earth duplicates would be rather large. However that don't make the creators more divine than in your other examples. I think it would be very difficult for something to prove its godlike nature without altering our minds and anything powerful enough to fudge with our minds can trick us into whatever it want.

There is no pilot in 'direct' control, the Curiosity rover will have an fully automated landing at Mars on the night of the fifth of August. Huge Mars Rover's Landing Will Be '7 Minutes of Terror' "We've got literally seven minutes to go from the top of the atmosphere to the surface of Mars, going from 13,000 miles per hour to zero in perfect sequence, perfect choreography, perfect timing," Rivellini added. "And the computer has to do it all by itself, with no help from the ground. If any one thing doesn't work just right, it's game over." http://www.space.com/16296-curiosity-mars-rover-landing-terror.html

Cosmic Microwave Background Radiation Raw CMBR data coming down from the space vehicle (i.e., WMAP) contain foreground effects that completely obscure the fine-scale structure of the Cosmic Microwave background. The fine-scale structure is superimposed on the raw CMBR data but is too small to be seen at the scale of the raw data. The most prominent of the foreground effects is the dipole anisotropy caused by the Sun's motion relative to the CMBR background. The dipole anisotropy and others due to Earth's annual motion relative to the Sun and numerous microwave sources in the galactic plane and elsewhere must be subtracted out to reveal the extremely tiny variations characterizing the fine-scale structure of the CMBR background. http://en.wikipedia.org/wiki/Cmbr#Data_reduction_and_analysis From the CMB data it is seen that our local group of galaxies (the galactic cluster that includes the Solar System's Milky Way Galaxy) appears to be moving at 627±22 km/s relative to the reference frame of the CMB (also called the CMB rest frame, or the frame of reference in which there is no motion through the CMB) in the direction of galactic longitude l = 276±3°, b = 30±3°. This motion results in an anisotropy of the data (CMB appearing slightly warmer in the direction of movement than in the opposite direction). The standard interpretation of this temperature variation is a simple velocity redshift and blueshift due to motion relative to the CMB, but alternative cosmological models can explain some fraction of the observed dipole temperature distribution in the CMB. http://en.wikipedia.org/wiki/Cmbr#CMBR_dipole_anisotropy Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at 552 ± 6 km/s with respect to the photons of the CMB, toward 10.5 right ascension, −24° declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction. http://en.wikipedia.org/wiki/Milky_Way#Velocity Hydra (constellation) Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake. It should not be confused with the similarly named constellation of Hydrus. http://en.wikipedia.org/wiki/Hydra_(constellation)

I am sorry but I don't have such technical knowledge of antennas, receivers and amplifiers. But I would guess that the equipment needs to be different if the redshift is very large as from very distant objects and since we are able to view the cosmic microwave background radiation which have a redshift of 1089 compared to the highest observed redshift of an object with 'only' 8.6 for UDFy-38135539, I think the practical challenge lies more in measuring a more faded signal than one with a higher redshift.

Earth has an rotational speed of 0.465 km/s at the equator and an average orbital speed of 29.78 km/s around the Sun which have a velocity of 220 km/s around the center of the Milky Way which is moving with around 552 km/s with respect to the cosmic microwave background radiation. (Data collected from Wikipedia.) Astronomers have all this data and of course their measurements are corrected to account for observatory movement when needed. However the luminosity over time from a type 1a supernova is of brightness and not redshift so it is not affected by observatory movement. The luminosity for type 1a supernovae is another way to measure distance and when compared to redshift they show that the expansion is accelerating. Supernovae are useful for cosmology because they are excellent standard candles across cosmological distances. They allow the expansion history of the Universe to be measured by looking at the relationship between the distance to an object and its redshift, which gives how fast it is receding from us. The relationship is roughly linear, according to Hubble's law. It is relatively easy to measure redshift, but finding the distance to an object is more difficult. Usually, astronomers use standard candles: objects for which the intrinsic brightness, the absolute magnitude, is known. This allows the object's distance to be measured from its actual observed brightness, or apparent magnitude. Type Ia supernovae are the best-known standard candles across cosmological distances because of their extreme, and extremely consistent, brightness. http://en.wikipedia.org/wiki/Dark_energy#Supernovae