The universe is everything that physically exists. It is a vast expanse of mainly empty space, in which exist galaxies made of swirling patterns of stars, dust, hydrogen and other elements. One such galaxy is our own Milky Way. It is not known how big the universe is, but even if its limit could be fathomed, it would not be possible to travel even a tiny fraction of the distance between Earth and the edge of space's vast abyss.
A couple of recent creationist models are based on a universe bounded by an edge, meaning that there is a limit to the matter of the universe and therefore a centre to the matter of the universe. This contrasts with the standard assumption of cosmology that the universe is unbounded. In theory, space could be positively curved, negatively curved, or flat. A positively curved space would resemble the surface of a sphere. A negatively curved space would resemble a saddle shape. Flat space would not curve, so would be, in principle, infinite, although it does not follow that matter fills that infinite space, as opposed to being concentrated in one part of it (such as, for example, the observable universe). Data from the WMAP telescope show a a flat space (to 0.4% accuracy, so it's still theoretically possible that it's saddle-shaped or spherical, but on a scale too large for us to measure the curvature). Versions of the Big Bang model that include inflation predict the flatness to be very nearly perfect.
Some theorists have suggested that there may be more spatial dimensions than the three we perceive. They would be invisible to us either because they are "rolled up" to a very small size, or because there is some effect that constrains us to reside in a "brane" of only three dimensions however these theories only exist mathematically and cannot be considered 'theories' in the scientific sense at this time.
Others have postulated that there may be more than one universe, or even an infinite number of universes (a "multiverse"); this would appear contrary to the very definition of a universe, but it may be that other universes exist in places, dimensions or planes entirely removed from our own, with which we cannot interact. Such postulations are speculative and not based on actual evidence, although a few scientists claim that recent data from the Planck Telescope hint at a gravitational signature which could be from a universe outside of our own. This is not generally accepted, however.
We cannot determine the size of the universe with a single method but must use a "distance ladder". The lower rungs, providing a correspondence between laboratory standards of length and stars in our galaxy, are based on triangulation. The upper rungs, connecting stars to distant galaxies, are usually based on the apparent brightness of objects with known brightness. Finally, even larger distances can be estimated by assuming that Hubble's Law continues beyond the range where it has been directly verified. The most distant object yet observed, according to this methodology, is a gamma ray burst 13 billion light years away. Applying the Big Bang model to this data suggest that the visible part of the universe is approximately 93 billion light years in diameter. How large the universe is beyond the visible part is unknown.
The exact time of the Creation of the universe is unknown, but calculations based upon Biblical chronology place it at approximately 6000 Earth years ago. The best-known date is 4004BC, based on the work of 17th century scholar James Ussher.
This compares to a date of around 14 billion years, about 2 million times older, as determined by various scientific methods based on assumptions that ignore the biblical evidence.
Recent attempts to resolve the starlight problem propose that time runs (or once ran) more slowly for the Earth than for the rest of the universe. In that case, the universe could be billions of years old, even if everything was created, as seen from the Earth, only 6000 years ago.
One straightforward method to calculate an age for the universe based on secular science uses redshift, the shift in the spectrum of light from distant galaxies towards the red end of the spectrum, given by the Hubble constant, measured to be H0 = 70.6 ± 3.1 (km/sec)/Mpc. If the galaxies have always been moving at their current speeds, and the tangential components of the velocities are negligible (as they must be if the Earth does not have a special position in the universe), then all galaxies must have been very close to that common point 13.8 billion years ago. More detailed models do not significantly change this estimate.
Another approach scientists use is to date not the whole universe, but the oldest things they can find in the universe. This, of course, cannot provide an exact age of the universe, but at best a lower limit to the age, since the universe must be at least as old as the things in it. These might be
- groups of stars (The lack of high mass stars, which burn out more quickly than those of lower mass, in the globular cluster known as Messier 92 has been used to estimate the age of the cluster as 12-14 billion years.),
- individual stars (It is estimated that the white dwarf known as WD 0346+246 has needed at least 8 billion years to cool down to its current temperature.), or
- rocks (Multiple radiometric dating techniques applied to several meteorites and moon rocks have yielded an age of 4.5 billion years, while the age of a rock outcrop in Canada known as Acasta Gneiss has been reported to be 4.0 billion years.).
Bounded or unbounded?
A 'bounded' universe is one that has an edge, and therefore a centre. An 'unbounded' universe has no edge, and therefore no centre. Such an unbounded universe could either be infinite in size, or it could be due to space being sufficiently curved in a fourth spacial dimension to become a closed "loop". In the second case, the universe would be the surface of a four-dimensional object, similar to the two-dimensional surface of a three-dimensional sphere: while the sphere has a centre, its surface (analogous to our universe) does not.
Because we see approximately the same amount of matter in all directions when looking into space, it appears as though Earth is at the centre of the universe. However, if the universe is unbounded, this appearance would be an illusion; every other location would also see approximately the same amount of matter in all directions. The Earth being at the centre of the universe would, given the size of the universe, be either an extraordinary co-incidence or it would be by design, and thus be evidence for the existence of God. It being at the centre due to a co-incidence is extremely unlikely (the odds are less than one in one trillion), and Edwin Hubble along with other astronomers and cosmologists concluded that the universe must be unbounded, without addressing the possibility that the Earth is at the centre of the universe by design. 
A few scientific studies, however, have pointed to the Earth (or more accurately, the Milky Way) truly being somewhere near the centre (in comparison to the size of the universe). These studies have suggested that redshifts are "quantized", which would imply that the universe has a center, and that we are located somewhere near that centre. The first of these studies was published in 1973, with others following up to 1997 . After these studies were performed, tremendous advances were made in redshift cataloging, so that there are several orders of magnitudes more data available today that can be used to look for such effects. Several groups[Who?] examining the new data have concluded that the quantization previously reported was not real, but the result of noise or statistical effects[Citation Needed].
- Hartnett, John, Cosmologists Can’t Agree and Are Still In Doubt!, Journal of Creation 16(3):21–26, December 2002.
- Hartnett, John, New evidence: we really are at the centre of the universe, Journal of Creation 18(1), 2004, p.9
- Humphreys, Russell D., Our galaxy is the centre of the universe, ‘quantized’ redshifts show, Journal of Creation 16(2):95–104, 2002.
- ↑ Will the Universe expand forever?, NASA.
- ↑ Timur Moon, Planck Space Data Yields Evidence of Universes Beyond Our Own, International Business Times, Sun. 19th May, 2013Sun. May 19th, 2013.
- ↑ Richard Harris, Astronomers Detect Most Distant Object Ever Seen, National Public Radio, October 29, 2009
- ↑ S. H. Suyu, P. J. Marshall, M. W. Auger, S. Hilbert, R. D. Blandford, L. V. E. Koopmans, C. D. Fassnacht and T. Treu. Dissecting the Gravitational Lens B1608+656. II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State. The Astrophysical Journal, 2010; 711 (1): 201 DOI: 10.1088/0004-637X/711/1/201
- ↑ P. Bergeron, The Halo White Dwarf WD 0346+246 Revisited, The Astrophysical Journal, 558:369-376, 2001 September 1
- ↑ N.C. Hambly, S.J. Smartt, and S.T. Hodgkin, WD 0346+246: A Very Low Luminosity, Cool Degenerate in Taurus, The Astrophysical Journal, 489:L157–L160, 1997 November 10
- ↑ Patterson, Claire, Age of meteorites and the earth, Geochimica et Cosmochimica Acta vol. 10 No. 4, 1956, p.230-237 (accessed 7 July 2009) doi=10.1016/0016-7037(56)90036-9 bibcode=1956GeCoA..10..230P
- ↑ S.A. Bowring and I.S. Williams, Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada, Contributions to Mineralogy and Petrology, Volume 134, Number 1, 3-16, DOI:10.1007/s004100050465
- ↑ http://map.gsfc.nasa.gov/universe/uni_age.html
- ↑ http://www.wired.com/wiredscience/2010/02/nasa-wmap-universe-age/
- ↑ Humphreys, 2002
- ↑ Hartnett, 2002
- ↑ Humphreys, 2002
- ↑ Hartnett, 2004
- ↑ Tifft, W. G., "Fine Structure Within the Redshift-Magnitude Correlation for Galaxies", The Formation and Dynamics of Galaxies: Proceedings from IAU Symposium no. 58 held in Canberra, Australia, August 12-15, 1973. Edited by John R. Shakeshaft. International Astronomical Union. Symposium no. 58, Dordrecht; Boston: Reidel, p.243
- ↑ Napier, W.M. and Guthrie, B.N.G., Quantized redshifts: a status report, Journal of Astrophysics and Astronomy 18(4), 1997, pp 455–463