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The concept of gravity without mass offers a novel explanation for the inability to detect dark matter





A novel hypothesis posits that the nonexistence of dark matter is the reason behind our inability to detect it. Contrarily, the author believes that our comprehension of gravity has been flawed. While others have previously proposed similar ideas, the latest suggestion of gravity without mass, generated by topological imperfections in space-time, is notably innovative.

The concept of dark matter was initially introduced in 1932, following the observation that the movement of galaxies aligns with the presence of additional mass beyond what can be accounted for by stars and gas alone. What began as a small number of unexpected measurements has developed and grown significantly. Concise explanations, such as the underestimation of star populations, have unequivocally proven to be unsuccessful.

Various hypotheses have been put up regarding the composition of dark matter, ranging from primordial black holes to subatomic particles. Thus far, our search has yielded no discoveries, except for rogue planets and star mass black holes, which alone can only explain a small portion, less than one percent, of the missing matter.

This has prompted certain physicists to question whether our understanding is fundamentally flawed. It is possible that dark matter does not exist, and instead, gravity operates in a manner that differs from our current understanding on bigger sizes. One variant of this concept, referred to as Modified Newtonian Dynamics (MOND), has garnered much interest. However, it has found greater favor among online commentators than among physicists, who typically view it as highly unlikely.

Professor Richard Lieu from the University of Alabama at Huntsville has entered this issue with his unique interpretation of gravity, suggesting that it can exist independently of mass. If his assertion is accurate, it would significantly challenge the current understanding of cosmology and render the pursuit of dark matter a misguided distraction in the scientific progress, akin to the historical concept of phlogiston. Nevertheless, there is still a considerable distance to be covered before it is widely seen as credible, much alone probable.

Lieu suggests that space-time experienced the formation of topological faults shortly after the occurrence of the Big Bang.

“Topological effects refer to highly condensed areas in space that contain a significant amount of matter. These regions are typically in the form of linear structures called cosmic strings, although spherical shells are also a possible configuration,” stated Lieu.

The paper shells I have contain a thin inner layer with positive mass and a thin outer layer with negative mass. The combined mass of both layers, which is the only measurable mass, is precisely zero. However, when a star is positioned on this shell, it encounters a significant gravitational force that pulls it towards the center of the shell.

The force in this scenario would have a magnitude proportional to the reciprocal of the distance, rather than the reciprocal of the square of the distance as described by Newton’s equation of gravity. The practical feasibility of this concept remains unverified, however, Lieu asserts that it is mathematically sound.

Lieu suggests that as light traverses a gravitational lens, such as a galaxy, it is deflected inward because to its interaction with these shells. The degree of bending would be indiscernible from that which would result from increased gravitational force. Similarly, this applies to the orbital motions of a star around the central mass of a galaxy.

According to Lieu, if an alternate process is found for both of these phenomena, it would make dark matter redundant, as they form the foundation of our belief in its existence.

Conversely, the concept of shells with positive and negative mass on opposite sides is equally unverified, and it is even more challenging to rationalize their existence.

Lieu suggests that the emergence of these imperfections was linked to a “cosmological phase transition” during the early stages of the universe, where matter experienced a state change throughout the entire cosmos.

“I was inspired by my personal quest to find an alternative solution to the gravitational field equations of general relativity,” Lieu stated. This phenomenon can provide a gravitational pull that is finite even when there is no visible mass present.

Lieu’s proposition necessitates multiple elements for which we lack explicit substantiation, in contrast to the singular requirement associated with dark matter. The researcher acknowledges that the specific type of phase transition in the cosmos that could lead to these types of topological flaws is still uncertain.

He has proposed other potential actions, such as the hypothesis that the shells were formerly planes or straight strings that subsequently became coiled. However, at now, the situation appears to be very improvised, resembling the ad hoc nature of the epicycles employed by Ptolemaic astronomers to elucidate the planetary orbits.

However, in support of his argument, Lieu could argue that the concept is so novel that no one has yet been actively seeking appropriate proof. However, a significant amount of money and the most brilliant intellects of our time have been dedicated to the fruitless quest for dark matter.

“I am motivated by my frustration with the current situation, specifically the belief in the existence of dark matter without any direct evidence for the past hundred years,” Lieu stated.

“While the presence of a second solution, although highly suggestive, is not enough to disprove the dark matter hypothesis, it may only serve as an intriguing mathematical exercise,” Lieu said. “However, this is the initial evidence that gravity can exist in the absence of mass.”

The idea has been published in the scientific journal Monthly Notices of the Royal Astronomical Society.

As Editor here at GeekReply, I'm a big fan of all things Geeky. Most of my contributions to the site are technology related, but I'm also a big fan of video games. My genres of choice include RPGs, MMOs, Grand Strategy, and Simulation. If I'm not chasing after the latest gear on my MMO of choice, I'm here at GeekReply reporting on the latest in Geek culture.


Light is the fastest thing that can “move” across a surface





Einstein’s theory of special relativity says that it is impossible to move faster than light in a vacuum.

Things that don’t have mass have to move at the speed of light. But things that do have mass can’t get close to 299,792,458 meters per second (983,571,056 feet per second) without using up all of their energy. Physicists and sci-fi authors have tried to get around this by using concepts like the warp drive. But it’s likely that these will be illegal because of those pesky physics laws. Traveling faster than light can cause paradoxes that break the rules of the universe.

You are not in a dark room, though, because there is something in this room right now that can slow down or stop light. It is possible for shadows to go faster than light, and they can even smash through it.

You might ask things like, “What the hell are you talking about?” Imagine that you have a flashlight that is strong enough to light up some of the moon. If you quickly move your finger across the front of the flashlight, the shadow it casts can move across the moon’s surface at speeds much faster than light.

If you wave a laser across the night sky, you can get the same kind of effect. Think of a huge dome that is, say, 100 light-years across and surrounds you. When this laser hits that dome 100 years from now, the points will fly across it at speeds much faster than light.

But these two examples are just tricks.

Astrophysicist Michio Kaku told Big Think, “There is no message, no net information, and no physical object that actually moves along this image. There is only the image of the beam as it races across the night sky.”

No, the laser point isn’t really moving. What you’re seeing are photons hitting the dome and then different photons hitting a different part of the dome 100 years later after you moved your laser.










The universe and physics stayed the same because nothing really moved faster than light, and no information was sent.

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Space Exploration

Someone in high school builds a model rocket that can land vertically, like a Falcon 9 Booster





After three years of hard work, a high school student has finished a big project: making a model rocket that lands vertically.

It’s really rocket science to say that landing a rocket vertically is not easy. And SpaceX will tell you that they have blown up many a rocket stage while trying to land rocket boosters. But sometimes they do land before they blow up.

A student named Aryan Kapoor started building his own vertical lander in August 2021. At the end of May 2024, he finally hit the ground.

In a video for his YouTube channel JRD Propulsion, Kapoor said, “This rocket works differently than other model rockets of its kind.” “My rockets don’t have fins to keep them stable; instead, they use thrust vector control.” Thrust vector control lets the rocket’s engine move like a gimbal, giving the pilot control over the rocket’s path in space.

Even more impressive is the fact that software controls the rocket’s flight on its own.

“To guide the rocket, a flight computer makes all inflight decisions, such as steering the rocket and deciding when to ignite the landing motor.”

The onboard barometer gave the wrong reading of the rocket’s altitude during its first test flight in 2023. Kapoor wrote on his JRD Propulsion website, “The rocket did well in all other ways and collected useful data.” “Future flights will use only the accelerometer to measure altitude, providing much higher accuracy and precision.”

On his fifth attempt, Kapoor has landed successfully once more.

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Space Exploration

The Moon’s first cave has been found – Is it ready to be lived in?





Atunnel has been found for the first time under the moon’s surface, right where people first set foot on the Sea of Tranquility. Although this isn’t the most likely place to build a colony, there are probably more caves in the area, which makes it more likely that people will move there in the future.

Even though the cost of launch is going down, it will still be very expensive to send heavy things to the moon for a while. Being able to get as much as possible on site is important for even a short-term base, let alone something permanent. A lot of attention has been paid to finding water sources lately, but shelter is also very important.

If future astronauts want to stay on the Moon for a long time, they will need to be well protected from space radiation and the huge changes in temperature that happen there. Also, we want something that is strong enough to survive a small asteroid strike, which happens a lot when there is no atmosphere to protect it. It would be much better if this was found naturally instead of having to build or dig our own.

In a statement, Professor Lorenzo Bruzzone stated that the Miniature Radio-Frequency (Mini-RF) instrument discovered a pit in Mare Tranquilitatis in 2010 as part of the ongoing Luna Reconnaissance Orbiter (LRO) NASA mission. After a while, we looked at these data once more using sophisticated signal processing techniques and discovered radar reflections from the pit area that are only consistent with an underground cave conduit. This finding is the first direct proof of a lava tube that can be reached below the moon’s surface.


























There have been more than 200 observations of pits like the one Bruzzone and his colleagues looked at. It is called the Mare Tranquillitatis pit. Some or all of these look like they were made when the ceiling of a lava tube caved in. But the fact that there is a pit like this doesn’t mean there is a cave below that is big enough to be useful.

That’s why the Mare Tranquillitatis pit looked like a good place to begin. It’s about 100 meters (328 feet) across, and the walls are so steep that they might hang over. For that reason, it’s one of the few big enough for the LRO’s radar to be able to pick up on internal features.

Orbital synthetic aperture radar images taken from the side by the LRO show a bright spot on the west side of the pit. Based on simulations, it looks like a pipe that is 30 to 80 meters (98 to 262 feet) long and 45 to 148 meters wide. It might not be big enough for a city, but it would be a good place for a lunar village. It is thought that the cave’s floor is flat enough to be useful. There are more than 100 meters (328 feet) between the cave entrance and the surface, but since the moon has low gravity, that might not be a big problem.

The authors made two models of the pit and cave that were based on different assumptions about their sizes. The main difference was the height of the rock pile that formed when the pit’s ceiling collapsed, which affected how steep the floor was.

gif of entering a lava tube on the Moon

The Sea of Tranquility is like New York: it’s a great place to visit, but we wouldn’t want to live there. That’s because it doesn’t have ice, which is another important thing about living on the moon. There is probably frozen water at the poles of the moon, especially at the south pole, which is what started the race to land there.

Mare Tranquilitatis is a flat equatorial plane. Any ice that was close to the surface of this plane would have melted in the hot lunar days. Being about 7 degrees north of where Armstrong took “one small step” won’t make up for not having anything to drink.

However, the work makes it more likely that these kinds of lava tubes could exist at the poles. What’s more, it may be more important that we can find them in space with a little better detail. “People have thought about these caves for more than 50 years, but this is the first time we have proven they exist,” Bruzzone said.

The study was written up in Nature Astronomy.

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