What was the basis for the present calculated mass of the Universe?
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What is the mass of the Universe? Also how can you prove that this is the true mass of the Universe?\n\nAs nobody knows the size of the universe, one cannot really talk about the mass of the universe, though one can talk about the mass of the observable universe. What is normally sought after is the density of matter in the universe (which is the mass per unit volume). This is what is important in determining the fate of the universe: whether it will collapse one day or whether it will continue expanding forever.\n\nThe density of matter in the universe can be measured by various means, which are too technical to go into at this point: people measure the density by studying the fluctuations in the Cosmic Microwave Background, superclusters, Big Bang nucleosynthesis, etc.\n\nAccording to these studies, the density of matter in the universe is about 3 x 10-30 g/cm3, which means that it is 300 billion billion billion times less dense than water. Note that this includes the contribution of dark matter and so the density of luminous matter (that we see as stars and galaxies) is only about one-tenth of the figure given above.\n\nNow, the size of the observable universe is about 14 billion light years, and using the above value of density gives you a mass (dark and luminous matter) of about 3 x 10^55 g, which is roughly 25 billion galaxies the size of the Milky Way.
895733
Energy=Mass * (speed of light)^2
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E=m c^2\nEnergy=Mass &#92;times (speed of light)^2
51809
The correct answer is that no one knows.  We don't even know what most of the universe is made of (right now it's being called dark matter, because all we know about it is that we can't see it).\n\nIf I had to make a bet, I would go with total energy equals zero.  \n\nThere is a lot of matter in the universe, as everyone is saying, and that makes for a lot of mass energy.  But, the flip side is that there is a lot of mass in the universe, and that makes for a lot of negative gravitational potential energy.  It is possible they cancel.
1096987
The scientific theory is that the Universe started as a fluctuation of the vacuum. Such vacuum fluctuations make appear a small amount of energy, for a small time. This phenomenon is responsible for the existence of forces, that hold the Universe and matter together.\n\nNormally the bigger the energy fluctuation, the smaller the time it is in existence.\n\nNot so the Big Bang. That was a HUGE fluctuation. So big that a lot of energy came to appearance in the form of mass, elementary particles. These particles started expanding, before the vacuum could reclaim the energy.\n\nAnd it is still expanding today. 14 billion years later.
626622
The universe is an indefinite entity.It is bounded by 'nothing' even in the strict sense of modern physics.
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The Universe stretches out like a tent.Note a tent has rims.that means there is a limit to the strech.\nA tent curves at the rim . The curvature of the Universe is based on the area and the volume its containment has.\nA very long shot calculation would be 2.112676056/10^26\nThe overall gravity power stored in the volume of the Universe would be proportional to this curvature.\nNote The observation of Hubell based on the doppler red shif is not a conclusive proof of the expansion.\nThe wave dispersion effect  is just as valid an  assumption ,and it disproves Hubble's Redshift. Therefore I would be skeptical about those who believe that the Universe is expanding. The initial cosmological Constant of Einstein may have been the correct assumption.For all those who feel they know the answer saying they have proof should not talk out of the top of their hat!\nAs far as I am concerned it can be  postulated  that in order for  the Universe to function as it does , it must maintain rotational equilibriun.\nAnd on that note ,its constrol system can always be expressed as a second order differential equation no matter how many variable are involved and it will  maintain a steady state equilibrium.This would involved system that gain mas and sytem that loose mass.Rotational equilibrium is maintained by the revolving mass increasing its radius or decreasing it. It Has nothing to do will the Universe changing it radius.Nor is the Universe a ballon that is being blown until it explodes.\n\nI wonder how Stephen Hawkins would view this explanation.?
67071
In Newtonian space, F = ma or m = F / a (mass is equal to the force it has divided by the acceleration applied to it).\nIn an space-time continuum (relativity aspects as per Einstein) the mass is relative to its location and velocity with respect to the observer.
548934
No! Even without virtual particles, most of which self-annihilate almost immediately, the overall density of 'empty space' in the universe has been calculated to be about 2.11^ minus 29 kg/cubic meter.
40749
Sorry, as Braxton points out, the size to the edge of the observable universe is 78 billion light years due to the expansion of the universe (same source as the other guy used, Wikipedia) There is much debate as to whether or not the universe is infinite, but many scientists believe that the universe is indeed finite in size.\n\nBY THE WAY: I find it comically amusing how two people can cite the same source, yet somehow I'm the wrong one.  Oh well ;)
342592
The physics behind the beginning of the universe  was probably different than it is today.  For instance the period of inflation was not something that is happening now  Unless the current expansion of the universe is the same thing just slowed down.  But I would say the chances are that even a TOE won't help us understand where the universe came from.
310924
Emerging scientific basis\nSee also: Timeline of cosmology and Timeline of the Big Bang \nThe theoretical scientific exploration of the ultimate fate of the universe became possible with Albert Einstein's 1915 theory of general relativity. General relativity can be employed to describe the universe on the largest possible scale. There are many possible solutions to the equations of general relativity, and each solution implies a possible ultimate fate of the universe. Alexander Friedmann proposed one such solution in 1921. This solution implies that the universe has been expanding from an initial singularity; this is, essentially, the Big Bang.\n\nAn important parameter in fate of the universe theory is the density parameter, Omega (Ω), defined as the average matter density of the universe divided by a critical value of that density. This creates three possible ultimate fates of the universe, depending on whether Ω is equal to, less than, or greater than 1. These are called, respectively, the Flat, Open and Closed universes. These three adjectives refer to the overall geometry of the universe, and not to the local curving of spacetime caused by smaller clumps of mass (for example, galaxies and stars).\n\nObservational evidence was not long in coming. In 1929, Edwin Hubble published his conclusion, based on his observations of Cepheid variable stars in distant galaxies, that the universe was expanding. From then on, the beginning of the universe and its possible end have been the subjects of serious scientific investigation. In 1933, Georges-Henri Lemaître set out a theory that has since come to be called the Big Bang theory of the origin of the universe. In 1948, Fred Hoyle set out his opposing theory of a static universe, called the Steady state theory. These two theories were active contenders until the 1965 discovery, by Arno Penzias and Robert Wilson, of the cosmic microwave background radiation, a fact that is a straightforward prediction of the Big Bang theory, and one that the Steady State theory cannot account for. The Big Bang theory immediately became the most widely held view of the origin of the universe.\n\nWhen Einstein formulated general relativity, he and his contemporaries believed in a static universe. When Einstein found that his equations could easily be solved in such a way as to allow the universe to be expanding now, and to contract in the far future, he added to those equations what he called a cosmological constant whose role was to offset the effect of gravity on the universe as a whole in such a way that the universe would remain static. After Hubble announced his conclusion that the universe was expanding, Einstein wrote that his cosmological constant was his "greatest blunder."\n\nStarting in 1998, observations of supernovae in distant galaxies have been interpreted as consistent with a universe whose rate of expansion is accelerating. Subsequent cosmological theorizing has been designed so as to allow for this possible acceleration, nearly always by invoking dark energy and dark matter. Hence recent theorizing about the ultimate fate of the universe allows for a nonzero cosmological constant.\n\n[edit]\nRole of the shape of the universe\nSee also: Shape of the universe \nThe ultimate fate of the universe depends on its overall shape, and on how much dark energy it contains.\n\n \nThe overall geometry of the universe is determined by whether Ω is less than, equal to, or greater than 1.[edit]\nClosed universe\nIf Ω>1, then the geometry of space is closed like the surface of a sphere. The sum of the angles of a triangle exceeds 180 degrees and there are no parallel lines; all lines eventually meet. The geometry of the universe is, at least on a very large scale, elliptic.\n\nIn a closed universe lacking the repulsive effect of dark energy, gravity eventually stops the expansion of the universe, after which it starts to contract until all matter in the universe collapses to a poi
101436
The mass of the Earth is roughly 5.9742 E24 kilograms.\n\nWhy the need for such an accurate number?
925552
What is " a bunch of m's"?\nThe 6.67 refers to the Gravitational constant: 6.67x10-8 dyne cm2 g-2.  \nAccording to the law of universal gravitation, the attractive force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them.\nThe formula is F=G (m1m2)/r2, where F is the force, G is the 6.67 business above, m1 and m2 are their masses (in grams) and r2 is the distance between them squared (in cms).
1023214
The age of the universe from the time of the Big Bang, was estimated to be about 13.7 billion (13.7 × 109) years, with a margin of error of about 1 % (± 200 million years), according to NASA's WMAP (Wilkinson Microwave Anisotropy Probe)
1020559
The toatal quantity of energy-mass in the universe is always the same. However, mass is not getting scarces, just less 'concentrated'. The current overall density of the universe is about the equivalent of 5.9 hydrigen atoms per 1 cubic meter.
965826
L = 8pi G rho/c^4 is the definition of the cosmo constant L (1/m^2); where c = light speed and rho is the energy density of the known universe in a vacuum.\n\nF = GmM/r^2 is the equation for the attraction force F between two masses m and M, r distance apart.\n\nL was created by Einstein to make his equations come out right.  By that, he meant the universe should be spherical (not flat or saddle shaped).  His original results showed a flat universe, and he just "knew" that was wrong; so on came L to fix the shape problem.\n\nF was the result of experiments by Newton.  Through observation, he found that the attractive force between two bodies was proportional to the inverse square of the distance between them and to the product of the magnitudes of the two masses.  That is, F varies as (~) (mV/r^2).  \n\nWhenever there is a proportionality, as in F ~ mM/r^2, there has to be a constant of proportionality.  In this case Newton called it G; so that F ~ mM/r^2 becomes F = GmM/r^2 when the constant is inserted.\n\nThe G in both equations is the same constant.  But Sir Newton came upon it long before Einstein found it could be used in his equations and the calculation of L.  So there is no way that Newton (1642-1727) could know about Einstein's (1879-1955) use of it much later.