But even this idea has a problem. Its predictions deviate by four percent from the data of ESA’s Planck observatory, which precisely mapped the cosmic background radiation. However, these measurements fit the previous theory exactly. Now the researchers want to expand their model in such a way that this difference will disappear. Then the new theory might not necessarily reflect truth, but—as it best explains all observations—it would be the most likely explanation so far for the origin of the universe. Physicists don’t demand more than that from a good theory.
Spanish researchers described another exciting scenario. Their model started out shortly after the Big Bang. Back then, irregularities in the distribution of matter must have existed. These could have grown into bubbles. Earlier, we already identified them as the cores of primordial black holes. After the inflation phase, the following scenarios are possible:
•The bubble forms a primordial black hole.
•The bubble forms a black hole containing a baby universe connected to the outside world via a wormhole.
•Over time, the bubble becomes a supermassive black hole.
A baby universe would have the interesting feature of continually expanding—just like our own universe! In addition, new bubbles would repeatedly form inside it, for which the scenarios mentioned above are possible. These in turn could generate baby universes. The result would be a multiverse of universes connected by wormholes. It would be relatively easy to find out whether we are living in such a universe—the black holes would have a specific, characteristic energy distribution. So if we ever measure that at a black hole, it would be proof for the existence of a multiverse.
Are there also Naked Singularities?
There are increasing clues that the universe might be harboring naked singularities, in addition to black holes. These ‘white holes,’ which lack event horizons, would allow a direct view of the singularities in their centers—a view which physicists currently dread, rather than desire.
Right now, cosmologists share a problem some people know from visiting nude beaches. Under certain circumstances, it might be better if some things remain hidden. This also applies to the phenomenon of a black hole. Because this cosmic monster is surrounded by an event horizon, science does not have to show any interest in what really happens inside this radius. Since nothing ever escapes from a black hole, we can develop conjectures, but never support these with observations. This is practical, because we currently lack the physics to understand the events in the singularity floating in the center of the black hole. The physical laws we know would be pulverized by the gravitation trending towards the infinite, just like anything else that crosses the event horizon boundary.
Unfortunately, physicists are increasingly troubled by a phenomenon whose existence has not been proven by observations, the ‘naked singularity.’ Up to now they attempted to get rid of the problem by formulating a theorem. In 1969 the physicist Roger Penrose postulated that singularities would probably always have to be surrounded by an event horizon. The universe itself, acting as a ‘cosmic censor,’ prevents the ugliness of a singularity from being seen. There are even some indications Penrose might be right. Among other things, a white hole could violate causality. What happens in the vicinity of a naked singularity could not be theoretically predicted, at least with the means at our disposal—one might as well consider the events there as pure magic.
On the other hand, white holes would allow another cosmic phenomenon often used by science fiction writers—the wormhole, also called the ‘Einstein-Rosen bridge’ by physicists. Wormholes could make direct connections through the space-time-continuum possible, perhaps even into different universes. At one end would be a matter-absorbing black hole, and there would be a matter-ejecting white hole at the other. It has been mathematically demonstrated that humans could pass through a variant of these connections. To open the door you would only need a tiny amount of ‘exotic matter,’ exotic in the sense that it has to exhibit a negative energy density.
Only a few physicists go that far, though, and it must be clearly said that these are purely mathematical games, for now. On the other hand, researchers have not yet been able to prove the theory of the cosmic censor either. Very recently, simulations of the collision of two black holes proved that a naked singularity could not be formed this way. Yet there are still many open questions.
If you simulate the collapse of a massive star, the formation of a white hole seems definitely possible. Physicists are faced with two problems here. On the one hand, it is hardly possible, so far, to simulate a nova in the computer with all necessary variables. Stars are not homogenous, nor are they 100 percent spherical—assumptions required, in many simulations, for black holes to form. On the other hand, models show that even slight changes of the initial conditions can lead to completely different results. Sometimes the computer briefly shows a naked singularity, which soon is covered by an event horizon, sometimes there is a black hole from the very beginning, and now and then the outcome is a stable white hole.
The preconditions for its existence are not as exotic as one might think. Let’s take a giant star collapsing under the force of gravity, whose density decreases towards the outside, like an onion. Because the gravitational force depends on the density of the individual layers of our illustrative onion, it is stronger in the interior than on the outside. Therefore, the inner sections of the star collapse more rapidly into a singularity than do the outer ones. If the star is sufficiently homogenous, it could happen that the individual layers do not have enough mass to absorb the light like a black hole does, and the singularity would remain naked.
And why shouldn’t we look inside? Naked singularities, if they exist, would grant us a direct view of the effects of quantum gravity, the force that is supposed to someday unite the general theory of relativity with quantum theory. So far, physics has attempted to gain clues from the early phase of the universe, when conditions were so extreme that they cannot be described using the general theory of relativity.
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Excerpt: Silent Sun
October 15, 2071, 1866 Sisyphus
“Stop squirming around!”
Sobachka hung her head in acknowledgment of the reproach. Finally her muscles relaxed, allowing him to slide the suit over her front paws. It was a familiar procedure, yet the anticipation of an upcoming excursion inevitably got the better of her.
“Good girl!” said Artem encouragingly, stroking her head softly. The suit’s soft material hardly restricted her movements. Just the diaper at her rear end bulged outward. He wore one, too. The excursion would only last a short time, but in space one never knew, and as always, ‘better safe than sorry.’
“Hold still, now!” Here was the tricky part. Sobachka never liked him closing her helmet. She couldn’t understand, of course, that vacuum was lethal.
He would probably react the same if someone was to interfere with his primary senses in the same way. With the helmet closed, the dog could only smell herself. He stabilized the back of her head with his right hand and shoved the helmet over her head with his left, until the helmet snapped into place at the middle of her neck. Then Artem activated the comms. “Great job!” he told her.
Sobachka shook her head and tried to lick his hand, but the helmet cut the effort short. She yapped in a sound kind of like growling and howling all mixed up.
“Sure, sure. I don’t like that myself.” Artem had tried to leave her on board during a spacewalk but the dog liked that even less. Besides, he needed her to do her thing later on.
He put on his own helmet, leaving the visor open.
He queried the helmet radio: “Current position?”
A small, transparent heads-up panel moved before his left eye. He focused on it and recognized their destination: Asteroid 1866 S
isyphus. Stats on the side indicated 1,500 meters distance from his ship. The object, the term ‘egg-shaped’ probably coming closest to an accurate description, wasn’t more than a grain of sand in the sea of the universe. From this close, however, its eight-kilometer length was pretty impressive.
“Exit in ten minutes,” the system intoned in a monotone voice. He had intentionally opted out of an AI-sounding voice. While he considered the decision somewhat silly, he hadn’t wanted the ship to sound more intelligent than himself. After all, he had Sobachka, who was brushing around his legs right now, for company during the months of solitude in space. Sometimes he couldn’t help thinking she’d have preferred to be a cat. The dog, a mongrel, had gotten used to space nearly as quickly as a cat, and to the lack of up and down in space, too.
“Come along then,” he said. Artem opened the inside hatch of the airlock. Sobachka knew what he expected and followed by his side as he entered the chamber. He broke a smile despite himself as he saw her giving just the tiniest push with her rear paws to sail in alongside.
He closed the inside hatch and locked it with the rotary wheel.
“Hatch closed,” he said aloud. Then he flipped his helmet shut. Beside the hatch there was a panel with several buttons. He pressed the blue one.
The system confirmed: “Evacuating airlock.” It was heavenly. A lovely silence built during the evacuation. He lifted his feet to cut that last path of transmission and relished the brief moment of complete silence.
“Three minutes.”
Things were getting serious. Artem checked whether Sobachka was breathing regularly. He bent down, made eye contact, and stroked her back. She was doing well. She had been a professional cosmonaut for a long time now.
“Shall we, Sobachka?”
She tried to bark upon hearing her name, which didn’t work well inside her helmet. Artem held her with one arm and attached the short lifeline between his spacesuit and the hook at the back of her suit. Then he clipped his own lifeline to the hook next to the outside hatch. This line was quite long, being his means of returning to the ship with Sobachka. His right hand grabbed the rotary wheel and he opened the hatch.
The moment had come. He couldn’t help his heart beating faster just before launching himself downward. He pressed the hatch out, aided by the last remnants of air.
Far below he saw brightly-lit rocks with hard-cut edges and deep black shadows. Now that he viewed the asteroid first-hand, rather than on a display, it felt like the gateway to hell—and fearfully far at the same time.
But the display claimed only 300 meters to go. Artem jumped with the dog in his arms. A brief moment of panic, then experience kicked in and let him reorient his senses. The destination was ahead, not below. With his ship in orbit, he slowly drifted toward the asteroid. Every meter yielded more detail.
A tourist would not notice, but the expert quickly noted that Sisyphus had been being mined for a long time already. The visible lines were too straight to be natural. And the residual waste filling craters was out of place, too. But that was what Artem was here for. His money came from being quicker than the rightful owner. Others would call him a thief.
Early on he had aspired higher, maybe a kind of Robin Hood, but more recently he had admitted to himself that it was all about the money. Sisyphus was going to reach its closest orbital point from Earth in about a month, the perfect opportunity for its owner, the Russian conglomerate, RB, to send specialized transport ships to pick up the results of two-and-a-half years of mining.
He was going to be quicker. He didn’t need special transport since he was only here for the rare earths that the machines of the RB Group had extracted from the rock of the asteroid. A ton and a half of his bounty would pay for the next three years—plus add a sweet little sum to his bank account. The risk was minimal, the core operation was would take about half an hour, and his small ship could accelerate faster than those plump transporters.
Only 50 meters to go. The distance indicator started blinking on the display. He needed to concentrate. The asteroid rotated by in slow motion. At the moment, the dome where the two guards spent their time was passing under him. They posed no threat since their pay was terrible. The RB Group only employed them to meet legal requirements to keep the mining license on Sisyphus. At one point, trade unions had been able to ban staff-free mining. Even if these guys tried to interfere, he’d have his weapon to keep them in check. And before that, one of them would have to look up into the sky and notice his ship. Normally they would rely on their radar to detect visitors more reliably than any video cam. But his ship was protected against radar by expensive meta-materials. So far he’d had eight successful raids and everything had gone well.
At ten meters he ignited the braking jets. There was a big rock between himself and the dome so that his activity would go unnoticed. The dome was of no interest to him. It housed the guards and he’d avoid them anyway. The resources he was after were stocked about 500 meters away from the dome.
Artem checked directions on the eye display and carefully released Sobachka. The dog noticed at once that she was free. At first she struggled with her legs, but then she remembered how things worked in space. Her suit had its own jets that she controlled by pressing her front paws to her body. The harder she pressed, the more she would accelerate. Sobachka was perfectly in control. She showed him artistic pirouettes. Artem smiled and was deeply pleased to see her enjoying the performance. He’d have loved to be able to sit on a rock and keep watching, but they had work to do.
He pointed in the direction of the stockpile with his right arm, and the dog followed along obediently. Halfway there the sun rose; a cold, white fireball. It appeared over the near horizon, with the rapid rotation of the asteroid speeding the process along. Rocks glistened where they were flooded with light while hard-edged, pitch-black shadows spread behind objects. Then the stockpile came into sight. It was easy to spot by the rectangular shapes of the containers. They stood out like paper cutouts.
He had worked on an asteroid as a contractor before going independent, so he knew the processes here quite well. The containers were hard steel all around. Opening them in space was not part of the procedure. To fill them, they had docking ports on all sides for tubes with a diameter of half a meter. Flat robots that looked like many-legged cockroaches transported the resources that had been previously mined and separated into specific raw materials. Extending the length of the tubes was all that was required as the mining process moved along.
To avoid inefficiencies due to long distances, the guards had to add a new ‘roach’ to the system every three or four weeks. That was where the maintenance hatches in the tubing came in. Artem was heading there.
“Come!” he called out to Sobachka. The dog responded immediately. Ahead of them a tube snaked across the scraggy surface. Artem pointed forward with his headlamp. He only needed to move ten meters toward the container to find an entry. He was able to remove the flap, secured by eight large screws, with the toolkit he had brought. He set the screws aside. He’d put them back in place later. The guards wouldn’t even guess that he’d moved through. Later, back on Earth, some manager would notice an unusually low yield of rare earths.
Now it was his companion’s turn. He knelt before the dark opening, stroked her, and removed the safety line. Sobachka didn’t flinch. She knew what he expected of her. On his first trip he had tried a drone but it proved impossible to maneuver through the dark tubes. Artem lit up the helmet lamp for the dog, put his hand in the tube, and knocked on the floor there. That was her signal. The dog had an infallible instinct for her surroundings. He wouldn’t need to guide her around obstacles. If he spotted anything on her camera he’d let her know via helmet radio.
“Search!” he commanded. Sobachka turned toward him for a last look and disappeared into the dark. Artem followed her progress on the display. Where each raw material was stored was different from asteroid to asteroid. The dog entered the first container. It was nearly fu
ll, so it couldn’t be anything valuable. Artem activated the gamma spectrometer on Sobachka’s back anyway. It detected some iron mineral, complete junk. No need to say anything, the dog was already looking for the next tube onward. The containers were interconnected so the roaches could store any raw material as needed.
Half an hour later they finally came across something. The gamma spectrometer indicated the stuff he was looking for, starting phase two. He encouraged Sobachka via radio, prompting her to remember the container. Then he called her back. He was glad to see her crawl out of the hole after another five minutes. Unimaginable, if something were to happen to her!
He loaded her with a bundle weighing about a kilogram on Earth. Training her with this pack bag had been the most difficult part. Sobachka carried the bundle straight to the right container, unrolled it, and spread it roughly over the desired material. Then Artem activated the fibers at the edge of the textile. They dug into the pile and enclosed part of it in the pack bag. That was the first load of bounty. He praised the dog again, and she started the return journey carrying the full but nearly weightless bag. Artem checked the clock: 47 minutes for the first bag.
To meet his expenses, Sobachka needed to fill eight bags. His goal was twenty. Thirty would be a personal record. The longer they took, the higher the risk that one of the guards would see the bright speck that didn’t belong up there in the sky, and wasn’t detected by radar.
He heard a noise on the helmet radio. That can only be Sobachka, he thought. Artem quickly knelt before the tube entrance. But the camera in her suit showed no image. Had something happened to her? His heart raced. He tried to peer into the tube in the direction from which she would be coming. Right then something knocked into his visor. She was back. Phew, first transport done. Artem stood up. Even as he rose he noticed a shadow next to him that hadn’t been there before. He pulled the weapon from his suit pocket, blinked while working out where the origin of the shadow would be, and shot. The recoil made him feel the projectile leaving the barrel, vacuum preventing the sound from reaching his ears. There was a dull groan on the helmet radio. Hit! Artem lifted his head and saw a person holding the side of his spacesuit.
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