The universe
is flat, according to scientists. But to say our universe is flat and leave it
there would be irresponsible – it’s not quite that simple. So, we must first
delve into what scientist mean by “flat” and how they came to such a
conclusion. The Baryon Oscillation Spectroscopic Survey (BOSS) telescope gave astrophysicists a new view of the universe, and a pretty accurate one, too.
The telescope down in New Mexico mapped out 1.2 million galaxies in the universe, plotting their locations to an accuracy of one percent. This map represents a tiny sliver of the universe and it was still able to tell us a lot about how it functions on a large scale. With this accurate measurement, cosmologists were able to determine the universe is “extraordinarily flat” and infinite, extending forever throughout space and time.
The telescope down in New Mexico mapped out 1.2 million galaxies in the universe, plotting their locations to an accuracy of one percent. This map represents a tiny sliver of the universe and it was still able to tell us a lot about how it functions on a large scale. With this accurate measurement, cosmologists were able to determine the universe is “extraordinarily flat” and infinite, extending forever throughout space and time.
What does a
“flat” universe mean?
When
scientists say the universe is flat, they are speaking in geometric terms. At
this point, I’m going to ask you to go back to math class, when you learned
about parallel lines. So, let's scale down how cosmologists might rule out that
the universe is round, by asking how do we know the Earth is not flat?
Well, one
way would be to draw two lines from the equator, going directly north. These
lines may start out parallel, but eventually they will intersect. The distance
between them does not remain constant.
Diagrams of
three possible geometries of the universe: closed, open and flat from top to
bottom. The closed universe is of finite size and, due to its curvature,
traveling far enough in one direction will lead back to one's starting point.
The open and flat universes are infinite and traveling in a constant direction
will never lead to the same point. Image and caption text permission of NASA
Official: Gary Hinshaw
By using this
as the basis for our knowledge, we then must observe how light from a few of
these 1.2 million observable galaxies behaves. Scientists noted the light from
several galaxies from the observable universe remained parallel to one another;
these two lines will stay parallel forever.
“One of the
reasons we care is that a flat universe has implications for whether the
universe is infinite,” said David Schlegel, a member of the Physics Division of
the U.S. Department of Energy’s Lawrence Berkeley National Laboratory. “That
means – while we can’t say with certainty that it will never come to an end –
it’s likely the universe extends forever in space and will go on forever in
time. Our results are consistent with an infinite universe.”
Geometry vs.
Topology
Geometrically,
the universe is flat. Parallel lines stay parallel, but it doesn’t tell us
about the topology of the universe. Scientists believe the universe could have
one of 18 different shapes. It could be a Möbius strip for all we know—a shape
where space bends and distorts, but lines stay parallel, ultimately connecting
one end of space to another. That is to say, you could start from one point in
the universe and drive in a straight line; you would end up back where you
came.
But we cannot yet determine what shape the universe has taken because of our small view.
