The entrance to our hotel in Washington is in sight of the Capitol Dome. Something is universal about the spherical shape. Domes have been part of human architecture for thousands of years. The architecture of our bodies is full spherical cells. Moons, planets, stars and even raindrops form spherical shapes. Many great thinkers have thought that the Universe itself is spherical.
Blaise Pascal, one of the great mathematicians of all time, thought the Universe was spherical. "Nature is an infinite sphere of which the center is everywhere and the circumference nowhere," wrote Pascal. Edgar Allen Poe, who lived near here in Baltimore, also thought the Universe was spherical. The spherical Universe was subject of Poe's EUREKA, a prose about cosmology. Among all his great works of poetry and fiction, Poe was most proud of the little-known EUREKA.
Most prescient, Poe suggested that this spherical universe expanded from a tiny point! "From the one particld. as a center, let us suppose to be irradiated spherically--in all directions--to immeasurable but still to definite distances in the previously vacant space." 75 years later Alexander Friedmann, who was a big Poe fan, also predicted an expanding Universe.
Einstein realized that if the Universe contained enough mass, gravity would bend it into a sphere of four dimensions. He also realized that gravity would also cause the sphere to collapse, unless it were already expanding. Einstein then added a repulsive "cosmological constant" to prevent collapse. Later, when Edwin Hubble's observations showed that the Universe was expanding, Einstein considered the CC his greatest blunder.
Today it is fashionable for cosmologists to say that our Universe is flat, like the Earth. If you question cosmologists, they will first ignore you but then admit that on the large scale it must be spherical. If the Universe expanded from a tiny point, it is topologically impossible for it to be flat. The exponential expansion called inflation would have expanded the sphere so much that it would appear flat to our observations. On the largest scales, the Universe must still be spherical.
The beauty of the Capitol dome reminds us that the spherical shape is universal. Applied to the Universe, great thinkers like Pascal, Einstein and Poe considered our Space/Time to be spherical. Edgar Allen Poe made amazing predictions like an expanding universe. Einstein first proposed a cosmological constant, then considered it a great blunder. Though it is fashionable to say the universe is flat, fashions change with time.
We finish the meeting with a banquet at the Rayburn Senate Office building, close to the Capitol. As the spherical Sun disappears behind the curve of a spherical Earth, we are reminded how universal the sphere is.
