is the universe flat or or a circle?

Question

i was watching a program saying if the universe was flat or a circle and they sed it was both

Answer 1

It is mapped out by the hubble space telescope as oblong ..

The shape of the universe is determined by a struggle between the momentum of expansion and the pull of gravity. The rate of expansion is expressed by the Hubble Constant, Ho, while the strength of gravity depends on the density and pressure of the matter in the universe. If the pressure of the matter is low, as is the case with most forms of matter we know of, then the fate of the universe is governed by the density. If the density of the universe is less than the "critical density" which is proportional to the square of the Hubble constant, then the universe will expand forever. If the density of the universe is greater than the "critical density", then gravity will eventually win and the universe will collapse back on itself, the so called "Big Crunch". However, the results of the WMAP mission and observations of distant supernova have suggested that the expansion of the universe is actually accelerating which implies the existence of a form of matter with a strong negative pressure, such as the cosmological constant. This strange form of matter is also sometimes referred to as the "dark energy". If dark energy in fact plays a significant role in the evolution of the universe, then in all likelihood the universe will continue to expand forever.

Answer 2

An important open question of cosmology is the shape of the universe. Mathematically, which 3-manifold represents best the spatial part of the universe?

Firstly, whether the universe is spatially flat, i.e. whether the rules of Euclidean geometry are valid on the largest scales, is unknown. Currently, most cosmologists believe that the observable universe is very nearly spatially flat, with local wrinkles where massive objects distort spacetime, just as the surface of a lake is (nearly) flat. This opinion was strengthened by the latest data from WMAP, looking at "acoustic oscillations" in the cosmic microwave background radiation temperature variations.

Secondly, whether the universe is multiply connected, is unknown. The universe has no spatial boundary according to the standard Big Bang model, but nevertheless may be spatially finite (compact). This can be understood using a two-dimensional analogy: the surface of a sphere has no edge, but nonetheless has a finite area. It is a two-dimensional surface with constant curvature in a third dimension. The 3-sphere is a three-dimensional equivalent in which all three dimensions are constantly curved in a fourth.

If the universe is indeed spatially finite, as described, then traveling in a "straight" line, in any given direction, would theoretically cause one to eventually arrive back at the starting point.

Strictly speaking, we should call the stars and galaxies "views" of stars and galaxies, since it is possible that the universe is multiply-connected and sufficiently s mall (and of an appropriate, perhaps complex, shape) that we can see once or several times around it in various, and perhaps all, directions. (Think of a house of mirrors.) If so, the actual number of physically distinct stars and galaxies would be smaller than currently accounted. Although this possibility has not been ruled out, the results of the latest cosmic microwave background research make this appear very unlikely.

Answer 3

Circles are 2D--just as things which are considered 100% flat in physics. So... it's very simple to understand how both the shape of a circle and flatness in general can be used to describe our universe.

I don't agree with this, however.

I do know that if you and another observer stood back to back and had the ability to see so far into space that you'd observe the light from the most distant object possible, you'd both be looking at the same object.

Knowing this, the geometry of the universe as a whole is much more complex than what we understand on Earth.

Answer 4

A circle is flat, i.e. it is a 2-D figure. A sphere is a 3-D version of the circle. Maybe that is what you mean. Your question does not make sense as stated. Probably, the show dealt with non-Euclidean geometry in theories of cosmology.

Answer 5

The universe is infinite, therefore everything *must* happen, including flatness, circleness and the detection of something vaguely resembling intelligenge in George dubya Bush. (but don't hold your breath on that last one)

Answer 6

I'm not a physicist or astronomer but if it is infinite as it is usually described then it is both flat and a circle as infinity would by definition include both. Therefore it is also wavy, jagged, square, spherical, etc etc.

Answer 7

It's not really either since we can't tell, but if you had to do direct comparison it's 3D for all the parts that we know so it's a circle. Saying it's flat would imply that it's 2D which it certainly isn't.

Answer 8

It`s neither. When things explode, as in the big bang theory, there is a spherical expansion of energy so it`s like a big ball that is getting bigger

Answer 9

A slightly flattened circle I would say, a circular ellipse.

Answer 10

These are human concepts the universe is neither or both ,it depends how we interpret it.If we were bulhs we would ask if it was hulop or velglog.