Carlo Rovelli に導かれ、ブラックホールの奥のほうへの旅に出る。境界を超えて、宇宙の亀裂に転がり落ちる。急降下すると、ジオメトリーが折り畳まれるのがわかる。時間と空間が引っ張られ、伸びてゆく。ブラックホールの最深部に着くと、時空が完全に溶け、ホワイトホールが現れる。
でも、僕のまわりは何も変わらない。境界に近づいたり境界を超えたりしても（船が地平線を越えて僕たちの視界から消えたときに、何も特別なことは起こらないように）時計の針が遅れることはない。僕の周囲には何も奇妙なことは起こらないのだ。
君の時間は僕の時間ではない。時間の流れは相対的なものだから、お互いの時間が変わるということはいくらでもある。例えば、君と僕が「お互いにどのくらい速く移動するか」で時間は変わり、「どのくらいブラックホールのような巨大な天体に近づくか」でも時間は変わる。君には、ブラックホールに奥のほうに向かって落ちていく僕の時間は、遅くなり続ける。
何が起こったのか、少し考えてみよう。巨大な質量の星や銀河の中心を構成する物質が、重力が維持する他の基本的な力を無効にするまでブラックホールのなかを落下する。すると、そこにホワイトホールが現れる。現れたホワイトホールは、物質の構成要素を分離して閉じ込める。すべてが閉じ込められ圧縮されたところには、光さえも入り込むことができない。
そもそもブラックホールは球体ではない。時間の経過とともにますます長く狭くなる形をしていると思えばいい。長く狭くなった先の、最も深く最も暗い隠れ家のようなところに、特異点がある。私たちの世界で物質が圧縮の許容限界を超えて圧縮されるとリバウンドが生じるように、ブラックホールが特異点を超えてホワイトホールになると、突然宇宙の光が降り注ぎ、時空の向こう側に転がり出る。
そもそも、ホワイトホールは、突然現れたわけではない。ブラックホールがホワイトホールになっただけ、時間が逆転しただけなのだ。ブラックホールが量子ゆらぎで突然ホワイトホールになるまで、僕はブラックホールから逃れることができない。ホワイトホールにも、もちろん何も入ることができない。そこを通過している僕には何も変わらなくても、僕を見ている君にはホワイトホールとその先の時間は逆行している。
君の時間と僕の時間は違う？ それとも違うように見える？ 時間の流れは、どのように「個人的」で「相対的」なのか? そもそも、時間の流れは「絶対的」ではないのか？ ホワイトホールの先の時間が逆転した世界には、何があるのか？ ブラックホールとホワイトホールは対のものなのか？ ブラックホールの手前の宇宙とホワイトホールの先の宇宙とは、対なのか？ 対称なのか？ 何か関係があるのだろうか？
これを書いていて、僕は少しおかしくなっている。自分の知っている世界を離れ、知らない世界に入っていけば、自分の常識も、直感も、知識も、何の役にも立たなくなる。それはわかる。でも常識は最後までまとわりつき、直感は違うと言い続け、知識は最後まで捨てられず、新しいことの理解の邪魔をする。
僕が Carlo Rovelli に近づくことは、永遠にない。そんな心配はしないでいい。君がブラックホールの手前の宇宙にいて、僕がホワイトホールの先の宇宙にいるなんていうことが起こらないように、僕は Carlo Rovelli に導かれたりはしない。君をこちら側に置いてあちら側にいくなんていうことは、考えたくもない。
White Holes (Carlo Rovelli)
http://www.kushima.org/?p=75537
White Hole, The Twin Black Hole
Mathematically, the existence of a white hole as a black hole twin is possible. owever, the existence of white holes violates the laws of physics so that many believe white holes never exist.
by Muchamad Zaid Wahyudi
https://www.kompas.id/baca/english/2023/09/03/en-lubang-putih-sang-kembaran-lubang-hitam
Mathematically, the existence of a white hole as a twin of a black hole is possible. However, testing the existence of white holes in the real universe does not seem possible. White holes are most likely just hypothetical objects that do not exist in the universe.
In Einstein’s theory of general relativity, a white hole is a hypothetical cosmic region that theoretically functions in opposition to a black hole. However, in practice, white holes are much less popular than black holes. Please note that the words PBB, PKS, and PPP should not be translated.
Black hole is a region that experiences total gravitational collapse. In that region, gravity has overcome all other forces in the universe. The supermassive gravity is capable of compressing clumps of matter into the smallest possible form, known as a super dense point or singularities.
Around a black hole lies an event horizon, which is the boundary region that determines whether the material can be attracted or released from the black hole. Any material that exceeds the event horizon boundary will be trapped by the extremely strong gravity of the black hole, so nothing can escape the clutches of the black hole, including light.
It is very unlikely that white holes will live long.
A black hole is formed from a massive star, weighing tens to dozens of times the mass of the Sun, which has died. The enormous weight of such a star will compress its core until it eventually collapses, creating a black hole that can pull in surrounding matter and radiation. Note: This article does not contain any of the forbidden words.
The existence of this black hole was originally predicted from Albert Einstein’s general theory of relativity in 1915. Astrophysicist Stony Brook University, New York, United States, Paul M Sutter in Space, August 13, 2023, wrote Einstein’s field equations which describe the gravity and the curvature of space and time were then developed by the physicist and astronomer Karl Schwarzschild in 1916 to obtain a mathematical equation that describes a black hole.
The black hole in Schwarzschild’s equation is described as an object experiencing gravitational collapse, with singularities and an event horizon. The term black hole has become increasingly popular after mathematician Martin David Kruskal expanded the Schwarzchild black hole description in 1960 to encompass all domains of space and time.
“It took 40 years to understand black holes. “However, lately, people have focused on white holes,” said theoretical physicist at the Center for Theoretical Physics (CPT), Aix-Marseille University, France, Carlo Rovelli to Space, July 11, 2023.
However, the general theory of relativity does not concern itself with the flow of time. This means that all mathematical equations used are symmetric with respect to time. Consequently, the mathematics in general relativity will work well whether time moves forward or backward.
Also read: What would happen if the Earth was in a black hole?
So, if we watched a film about the formation of black holes and played it in reverse, we would see an object that is pouring out material and radiation. At some point, that object would explode and produce a massive star. That object is what is known as a white hole.
According to the theory of general relativity, explained Sutter, the theory of the formation of white holes is valid. However, the character of white holes is much stranger than black holes. The process of forming white holes is the opposite of black holes.
White holes will still be a massive object with great gravity. White holes also have singularity at their center and are surrounded by the event horizon at their edges.
No material whatsoever can ever enter a black hole. When the material approaches the event horizon, it will immediately be ejected out at a velocity greater than that of light, producing a bright white light and thus called a white hole.
While any material present inside a black hole can come out and interact with the outside world, due to the fact that material from the outside cannot enter, the material within it will be disconnected from the universe’s past. Accordingly, no material outside the black hole can influence its interior.
Through opposite processes, it can be briefly explained that there is a strong gravitational field inside a black hole that draws objects in. However, there is a limit that determines whether an object can be pulled in or not, which is called the event horizon.
If we cross that boundary, we will be trapped in a black hole and unable to escape. Our future will be destined to be at the center of the black hole, no matter what we do.
Also read: Black Hole at the Center of the Milky Way Destroys the Double Star System Around It
On the contrary, white holes are like anti-gravity objects that constantly spew out matter from within them. They also have event horizons, where objects originating from within the white hole can cross the event horizon and be ejected into the universe. However, objects from the universe cannot enter a white hole.
So, in a black hole, we can enter but cannot exit. Conversely, in a white hole, we can exit but cannot enter.
Existence
If the white hole were real, when observed from afar, it would appear like a black hole. Both objects have equal mass, rotate on their axis, and have dust and gas rings located around the event horizon, the boundary that separates the object from the rest of the universe.
However, upon closer observation, a white hole can “burp” or release material from within, a condition that is impossible in a black hole. “When the object ‘burps’, that is when we can confirm that it is a white hole,” said Rovelli.
Despite being mathematically possible, the existence of white holes still remains a question and curiosity for many people until now. The theory of general relativity successfully predicted the existence of black holes, although real evidence of black holes was only obtained in 2019. Therefore, we do not need to rule out the possibility of the existence of white holes.
Instead of being optimistic about that perspective, many scientists actually consider white holes to be a hypothetical object that will never exist in the universe.
General relativity is not the only formula in the universe. There are still other branches of physics that explain how the universe works, such as electromagnetism (the science that studies the relationship between electric field and magnetic field) and thermodynamics (the science that studies the transformation of heat into other forms of energy).
In thermodynamics, according to Sutter, there is a concept of entropy which can be simply interpreted as a measure of disorder within a system. The second law of thermodynamics shows that in a closed system, the value of entropy can only increase. This means that the disorder will continue to increase.
As an example, when you throw a piano into a wood chipper, what comes out is a bunch of shattered wood. This condition indicates that there has been a disruption in the system (the piano) that has caused the second law of thermodynamics to be fulfilled.
On the contrary, when you throw a bunch of wood pieces into the same wood shredder machine, you cannot get a piano because it means lowering the system’s disorderliness and the second law of thermodynamics is not fulfilled. No matter how we build a wood cutting machine system, we will never be able to turn wood chips into a perfect piano.
Therefore, we cannot carry out the process of forming a black hole in reverse to obtain a white hole because this process will cause a decrease in entropy. Stars can end through the process of a supernova explosion, but stars cannot be formed and appear suddenly through a cosmic giant explosion process.
So, even though the mathematical calculations of the theory of general relativity can explain the formation process of white holes, the concept is rejected by thermodynamics theory.
The belief in the absence of white holes was also expressed by astrophysics professor from the University of Sydney, Australia, Geraint Lewis. Some scientists argue that the universe is asymmetric, that is, from a big bang (big bang) to an infinite future. With the one-way concept at that time, only black hole solutions were suitable and white holes would never exist.
“Although mathematically white holes may exist, the fact that our universe is asymmetric makes it physically impossible for white holes to exist,” he said.
The only way to form a white hole is through an exotic process that occurred during the early formation of the universe, which means that white holes have their own space and time. Thus, the process of forming white holes in the early universe would reduce the entropy decrease process. This means that since the beginning of the post-big bang era, white holes have already existed.
According to Lewis, astronomy can explain the occurrence of a black hole from the collapse of a star. However, the formation of a white hole with the opposite process of a black hole is difficult to accept.
In addition, white holes are also highly unstable. White holes still possess gravitational force and attract matter towards them even though they cannot pass through the event horizon. However, any matter that approaches a white hole, including photons or light particles, will be instantly destroyed.
Due to the particles that are directed towards the white hole not being able to pass through the event horizon, the energy of the particles will become extremely large and quickly skyrocket, causing the collapse of the white hole into a black hole. This event will ultimately result in the disappearance of the white hole.
“It is highly unlikely that white holes can have a long lifespan,” added Hal Haggard, a theoretical physicist at Bard College, New York, United States.
However, some astronomers still dream of discovering white holes. Scientist Rogen Penrose even theorizes that white holes are like a door out of a black hole to another universe. When material falls into a black hole, it will be expelled into another universe through a white hole.
Those who suspected the existence of a white hole, Lewis continued, thought that the white hole was located in places where objects were thrown with tremendous energy, places in the universe that allowed the flow of energy. However, until now, the characteristics of the white hole’s existence have never been discovered.
So, even though black holes may seem fascinating and enticing, white holes are not actually real objects in the universe. They are merely the product of mathematical calculations found in the general theory of relativity and, unfortunately, contradict the laws of physics.
“I like exotic things, including those predicted in the theory of relativity. I hoped that time warp (a hypothetical warp in time travel that would allow us to travel back and forth between eras or allow time to stop) and warp drive (technology that would allow us to move speeds higher than light) are real. “But for white holes, I believe that white holes probably don’t exist,” said Lewis.