Unlike flat-earth promoters, flat-universe
proponents use scientific evidence rather than Biblical literalism to support
their views. But, how can a 3D universe with gravity wells wherever there is mass be flat?
Earth actually serves as a good analogy.
In the old days, the limited amount of earth a person could see was not really flat.
There were mountains and valleys. Even the ocean had waves. But, to early
humans, it seemed that things always dropped in the same direction – down - and
that earth’s surface everywhere spread perpendicular to down.
It wasn’t until some half-dozen centuries
BC that people began suspecting earth was spherical but how could that be
proven? Along came Aristarchus in the 3rd century BC and, by observing
the angles cast by shadows of the sun at two different latitudes hundreds of
miles apart, he was able to use simple geometry to estimate the average
curvature of Earth’s surface.
Another geometric trick would be to
draw a huge triangle on the earth’s surface using low-frequency radio waves
that travel over the horizon (beyond line of sight) and then use radio
direction finding to see whether the sum of the angles is more than 180 degrees.
If so, the earth’s surface is convex.
Like Earth, the universe is not
smooth. It has gravity wells wherever matter is concentrated. But what is its overall
shape? By analyzing the Cosmic Background Radiation and using a method analogous
to the triangle measurement, physicists have learned that the overall curvature
of the cosmos must be at least very close to “flatness” as it applies to 3D
space.
Unfortunately, because science cannot get an exact measurement, they still
cannot rule out the possibilities that the universe could be hyperspherical or saddle-shaped
rather than flat but there is pervasive prejudice toward flatness (curvature variable Ω0=1).
The universe is somewhat like a spherical balloon that is inflated so big that an ant on its surface can’t see that it is anything but flat. Even if physicists had perfectly precise measurements, since much of the universe has expanded beyond that which is theoretically observable from Earth, we can never know the shape of the entire universe. Nevertheless, biased by myriad other finely tuned aspects of creation, many physicists suspect the universe of being precisely flat but measurement limitations will likely prevent science from ever reaching a consensus.
The universe is somewhat like a spherical balloon that is inflated so big that an ant on its surface can’t see that it is anything but flat. Even if physicists had perfectly precise measurements, since much of the universe has expanded beyond that which is theoretically observable from Earth, we can never know the shape of the entire universe. Nevertheless, biased by myriad other finely tuned aspects of creation, many physicists suspect the universe of being precisely flat but measurement limitations will likely prevent science from ever reaching a consensus.