An alternative theory of gravity – a new understanding of the main force of the Universe

Scientists have been trying to unravel the mystery of dark matter for nearly a century, a hypothetical form of matter believed to be responsible for certain gravitational effects unexplained by general relativity (GR). Fortunately, a new hypothesis may change the course of events. A paper recently published in the journal Monthly Notices of the Royal Astronomical Society demonstrated the possible existence of the most powerful force in the Universe – gravity – without the presence of mass. Such an unusual approach, according to the authors of the study, may cast doubt on the very existence of dark matter. The new theory is based on the idea that the gravity needed to hold galaxies and galaxy clusters together may be due to special topological structures formed in the early Universe. It sounds complicated, so let's figure it out!

An alternative theory of gravity is a new understanding of the main force of the Universe. Gravity rules the Universe. But what does dark matter have to do with it? Image: www.techexplorist.com. Photo.

Gravity rules the Universe. But what does dark matter have to do with it? Image: www.techexplorist.com

Gravityis one of the four fundamental forces in physics, along with the electromagnetic force, the strong and weak nuclear forces.

Contents

  • 1 Her Highness Gravity
    • 1.1 General Relativity
  • 2 Gravity and dark matter
  • 3 Topological defects
  • 4 Cosmic strings

Her Highness gravity

Before diving into the tangled jungle of the new theory, let's define gravity and why it plays a key role in the formation and structure of the Universe. This fundamental force of nature, which attracts objects to each other, is literally inseparable from the mass of objects – the greater their mass, the stronger their gravitational pull.

Remember Isaac Newton's famous apple? It was he who, in the 17th century, noticed that apples fall from a tree to the ground and suggested that this was due to the force that acts between the apple and the Earth. Newton developed the law of universal gravitation, which states that the force of gravity between two objects is proportional to the product of their masses and inversely proportional to the square of the distance between them.

Her Highness Gravity. Newton's classical theory of gravity is a law that describes gravitational interaction within the framework of classical mechanics. Image: static.techno-science.net. Photo.

Newton's classical theory of gravity is a law that describes gravitational interaction within the framework of classical mechanics. Image: static.techno-science.net

More on the topic: Can gravity be a source of light?

On Earth, gravity acts in such a way that all objects fall to the surface with an acceleration of approximately 9.8 m/s². This means that when an object is in free fall, the speed of an object increases by 9.8 meters per second every second. In space, gravity behaves differently, keeping planets in orbit around stars. Gravity is also responsible for the formation of stars, planets and galaxies – clouds of gas and dust in space are compressed by gravity, forming stars and planetary systems.

General relativity

Newton's theory of universal gravitation dominated science until the beginning of the twentieth century, when Albert Einstein proposed a new theory of gravity – the general theory of relativity (GR), which describes gravity not as a force, but as a curvature of space and time caused by mass objects. The greater the mass of an object, the more it bends the space-time around it. General Relativity is amazing because it explains why objects move along certain trajectories in a gravitational field.

General Theory of Relativity. General Theory of Relativity is the currently accepted theory of gravity, describing gravity as a manifestation of the geometry of space-time. Image: static.dw.com. Photo.

The general theory of relativity is the currently generally accepted theory of gravity, which describes gravity as a manifestation of the geometry of space-time. Image: static.dw.com

Moreover, over the past century we have learned that gravity has several effects, such as the feeling of heaviness (which we experience on Earth), the tidal forces of the Moon (the gravity of the satellite is the cause of the ebb and flow of tides on Earth). The most interesting things, however, occur outside the Earth and relate to black holes – objects whose gravitational force is so strong that not even light can escape their confines.

Don't miss: What is Einstein's General Theory of Relativity?< /p>

So, to put it very simply, gravity is an integral part of our life and the Universe. It controls the movement of planets, the formation of stars and galaxies, and even influences our daily actions. Understanding this fundamental force of nature helps us study the structure of the world around us.

Gravity and dark matter

Despite its apparent simplicity, gravity is one of the greatest mysteries of modern science. Thus, researchers still put forward a variety of theories about it – from acceleration as a leading force to gravitons – hypothetical massless elementary particles. This is because the two leading physical theories – general relativity and quantum mechanics – work ideally separately, but together they contradict each other.

In other words, scientists are still in search of a «theory of everything» , capable of explaining the structure of our world on both macro and micro scales, and gravity is one of the stumbling blocks. First, most of the time gravity was thought to be purely matter-related, but what if that wasn't actually the case? What if this amazing force of nature could exist without mass?

Gravity and dark matter. It seems it's time to look at gravity from a completely different angle. Image: images.newscientist.com. Photo.

It seems that the time has come to look at gravity from a completely different angle. Image: images.newscientist.com

It sounds as unusual as possible, but it was this idea that attracted the attention of the authors of a recently published study. The fact is that if gravity can exist without mass, then the need for dark matter – hypothetical matter that does not enter into electromagnetic interaction and makes up up to 85% of the total volume of the Universe – completely disappears.

You want to always be in up to date with the latest news from the world of science and high technology? Subscribe to our channel on Telegram – so you definitely won’t miss anything interesting!

Let us recall that the existence of dark matter has not been proven, and its concept was first developed to explain why galaxies are held together by high-speed rotation. The introduction of this hypothetical and invisible matter allowed physicists to put forward all sorts of ideas and avoid inconsistencies in existing theories.

Topological defects

The lead author of the new study, astrophysicist Richard Liu of the University of Alabama in Huntsville, suggested that instead of dark matter binding galaxies and other celestial bodies, the Universe may contain thin, shell-like layers of “topological defects” that generate gravity. without any underlying mass.

Topological defectsare macroscopic structures that have macroscopic properties. The spatial scale of the influence of topological defects can be compared with the size of the observable Universe.

Liu began by trying to find another solution to Einstein's field equations, which relate the curvature of space-time to the presence of matter in it. As Einstein described in General Relativity, spacetime curves around clumps of matter and radiation flows in the Universe depending on their energy and momentum. This energy, of course, is related to mass in the scientist's famous equation: E=mc2.

Topological defects. Einstein's theory is an order of magnitude more complex than Newton's theory of universal gravity, and the new theory goes even further by removing mass from the equation. Image: thedebrief.b-cdn.net. Photo.

Einstein's theory is an order of magnitude more complex than Newton's theory of universal gravitation, and the new theory goes even further, removing it from the equation mass. Image: thedebrief.b-cdn.net

Thus, the mass of an object is related to its energy, which bends space-time – this curvature of space-time is what Einstein called gravity. In other words, general relativity says that gravity is inextricably linked with mass, but Lew argues that this is not so.

This is interesting: Does dark matter exist? And why were the opinions of scientists divided?

Cosmic strings

As the work progressed, the astrophysicist began solving a simplified version of Einstein's field equations, which allow for a finite force of gravity in the absence of any detectable mass. Liu says his efforts were “driven by frustration with the status quo, namely the idea that dark matter exists despite the absence of any direct evidence for a century.”

The solution proposed by the author of the work is to identify topological defects in the form of shells, which can arise in very compact regions of space with a very high density of matter. These sets of concentric shells contain a thin layer of positive mass hidden within an outer layer of negative mass.

These two masses cancel each other out, so the total mass of the two layers is zero. But when the star is on this shell, it experiences a strong gravitational force that attracts it to the center, the article says.

Cosmic strings. Gravity without mass can really exist. However, at the moment there is only mathematical evidence. Image: muyinteresante.com. Photo.

Gravity without mass can actually exist. True, at the moment there is only mathematical evidence. Image: muyinteresante.com

Recall that topological defects– These are very compact regions of space with a very high density of matter, which are usually represented in the form of linear structures known as cosmic strings. However, two-dimensional structures such as spherical shells are also possible.

Some scientists disagree with Liu's conclusions and believe that dark matter is the key to the theory of gravity. Details here, don't miss it!

Moreover, scientists have long known that the force of gravity allows all objects, both massless and otherwise, to interact with each other, since this, in essence, entails the curvature of space-time itself. For example, it was previously established that celestial bodies exert a gravitational attraction on massless photons.

Of course, all the assumptions I made in the article are controversial, but if they are confirmed in the future, then the need to continue to search for dark matter will completely disappear. So the next question is whether my assumptions can be confirmed or refuted through observation, Liu says.

Cosmic strings. The universe is full of mysteries. Image: i0.wp.com. Photo.

The Universe is full of mysteries. Image: i0.wp.com

And although the astrophysicist admits that his proposed solution is «suggestive» While this in itself cannot discredit the dark matter hypothesis, his work can be an interesting mathematical exercise, as it allows us to look at the Universe and the forces that control it from a different angle. Nevertheless, the findings published in the article arethe first mathematical proof that gravity can exist without mass. And this is not enough, don’t you agree?


Date:

by