Chapter 133: More, Bigger

"Then, has anyone considered, is there a possibility?"

"That the universe is actually a sphere, and this sphere has never moved; it just stands quietly in some even larger void."

Hearing this, everyone subconsciously shook their heads.

The universe is a sphere, and it stands in an even larger void?

No matter how one thinks about it, it feels inconceivable.

"We don't live on the inner surface of the universe sphere, but rather in the empty center inside the universe."

"What does that mean? It's like…"

"A person suspended in the space of a vast, transparent spherical ball."

"That person, on a whim, suddenly takes out two flashlights, raises both hands, and fires two beams of light in front of them."

"The two beams are emitted along uniform paths, so naturally, they won't intersect. Converting that to scientists, they would naturally be unable to detect the curvature of the universe, wouldn't they?"

"So some people think the universe is flat, because they haven't detected the curvature of light within the universe."

Hearing this, the physics experts in the lecture hall suddenly brightened up.

"Hiss~ That actually makes some sense."

"Right, this is one of the pieces of evidence that leads some big names to believe the universe is flat."

Professor Hua Yunfeng nodded repeatedly, "Yes, if I take out two flashlights and suspend myself in the center of this huge transparent sphere, as long as I'm not pressed against the surface of the sphere; no matter how I shine them, the light from my two flashlights will hit the inner surface of the sphere directly; and no curvature will be produced."

Hearing this, Old Feng also chimed in, "That's right, exactly; this is also one of the pieces of evidence that some scientists use to believe the universe is flat."

On the big screen.

To consider more ordinary viewers, Jiang Zhe refined the explanation.

"And what about our Earth?"

"In the past, some people believed that the world was round like a dome and square like a base; it wasn't until the great navigator Magellan's voyage that the belief that the Earth was flat ended; later, more and more people knew that the Earth was round."

Next, Jiang Zhe took a palm-sized Earth model from under the table, aimed it at the camera, and explained:

"Just like the model Earth in my hand."

"We live on the surface of the Earth, looking into the distance, we always see the sails appear first on the distant ocean, followed by the ship; simply understood, this phenomenon is the curvature of the Earth."

As his words fell, many viewers suddenly realized.

"Damn, forgive me for only having an elementary school education, I didn't realize this was curvature."

"No wonder some scientists think the universe is a sphere, while others think it's flat; it turns out it's because of detecting or not detecting curvature."

"Thanks, I get it now."

Facing the camera, Jiang Zhe gave a serious instruction:

"Please imagine this!"

"As for the [two flashlights] experiment I just mentioned, you can also discover something."

"A person standing inside a transparent sphere, suspended at the center point of the transparent sphere, fires light into the universe using two flashlights, yet it doesn't exhibit curvature; excluding phenomena like the bending caused when light encounters the Gravity of large celestial bodies within the universe."

"So this result leads some scientists to believe the universe might be flat, after all, no curvature was detected."

"Hmm, those astronomy big shots are right, and they have evidence; the evidence does indeed point to the universe being flat; after all, their conclusions are based on evidence."

"But in reality, is the universe truly flat?"

After saying this, Jiang Zhe blinked gently, grinned, picked up the whiteboard on the table, aimed it at the camera, and tapped on the sphere on the whiteboard.

All the viewers and experts leaned in close to the screen to observe.

The sphere on the paper was about the size of an adult's palm.

The outer circle of the sphere was painted black, the inner circle was blank, and within the blank space, countless simple galaxy clusters were outlined, sitting within it.

Suspended in the very center was the Earth, looking insignificant.

A little person stood on the Earth, holding two flashlights, and turned on the switch facing forward.

Two beams of light were emitted from the Earth, and then those two beams continued to shoot toward the depths of the universe, but they couldn't even approach the inner surface of the universe sphere before being swallowed by the unobservable region of the universe.

In this way, we can discover—

The universe can be a sphere, and it can also be flat.

If it is a sphere, it proves that the Earth is not at the edge of the universe; if there is a planet at the edge of the universe, and you use two beams of light to shoot toward the edge, you would be able to detect curvature.

If the planet is not at the edge of the universe, whether it is suspended in any direction, as long as it is not close to the inner wall of the universe, it is impossible to detect curvature.

After deep thought, the viewers and experts quietly discovered.

The universe can indeed be a sphere, and it can indeed be flat.

Besides these, there is insufficient evidence for any other shape!

As this series of words fell, looking back at the simple and easy-to-understand graphic, the viewers who were originally discussing the shape of the universe suddenly brightened up.

"Holy crap, I understand now."

"So that's it, it really is like this; the Observable Universe plus the unobservable universe can be spherical, and it can also be flat; because there is plenty of evidence to show—if the universe were any other shape, the evidence would simply be insufficient."

"Yes, yes, yes, that's exactly it."

At this time, at Tsinghua University, in room 808 of the teachers' dormitory building.

Professor Zhuang couldn't help but smile upon hearing this.

"A very simple little experiment that let more people know about the shape of the universe."

"Indeed, in the scientific community, there are only 3 main shapes."

"1: Flat universe: The curvature of the universe is zero, similar to a plane in Euclidean geometry."

"In this geometry, two parallel straight lines will never intersect, and the sum of the interior angles of a triangle is 180 degrees."

"Like a membrane, Superstring Theory mentions it; it has many supporters."

"2: Positive curvature spherical universe: The curvature of this universe is positive, similar to spherical geometry."

"In this geometry, two parallel curves will tilt toward a single point, and the sum of the interior angles of a triangle on a sphere is greater than 180 degrees."

"This is the spherical universe that you, Jiang Zhe, recognize. Although the recognition rate is not the highest at present; but your little experiment told others that spherical and flat universe membranes are the highest probability."

"3: Negative curvature saddle-shaped universe, the curvature of the universe is negative, similar to hyperbolic geometry."

"In this geometry, two parallel straight lines will diverge forever, and the sum of the interior angles of a triangle is less than 180 degrees."

Hearing this, the older sister Zhou Qing asked curiously: "Teacher, what shape do you support the universe being?"

"Spherical."

"Ah? Without even thinking about it?"

Professor Zhuang explained without turning his head: "Hmm, because there is the most evidence pointing to a sphere; the spherical shape of celestial bodies in the universe is a direct result of Gravity—from the dust of galaxies to the rocks of planets, Gravity pulls everything into the most stable and balanced shape—a sphere."

"If the Observable Universe plus the unobservable universe = a spherical universe that does not move but only expands in all directions."

"And I also believe that the superluminal movement of the universe's expansion, regardless of whether it expands uniformly, is not pushed by dark energy alone."

This immediately piqued the curiosity of the younger sister Zhou Qingqing, "Is there a possibility that there are other forces pushing the universe's superluminal expansion besides dark energy?"

Professor Zhuang nodded gently, "Yes, assuming this is the universe we live in now, then there is something larger outside our universe in the void in all directions pulling the boundaries of our universe, causing it to expand crazily outward; when our universe expands to a certain extent."

"It will happen… 'Crack'! Rupture."

"It's just that this time is very, very long!"

Zhou Qing frowned, "Teacher, what do you think is outside the universe?"

Suddenly!

Professor Zhuang suddenly turned his head and grinned, "If we refer to the Universe Cyclic Theory proposed by little Jiang, then outside the universe must be—more, larger independent unobservable + Observable Universe!"

As soon as these words came out, the sisters' hearts suddenly trembled, and they were almost frightened by this shocking statement.