Mysterious magnetic fields lit up the universe

You are surrounded by magnetic fields. It comes, among other things, from the cable to the lighted table lamp, your mobile phone battery and the ground under your feet.

Magnetic fields are formed by moving electric charges. It arises in cables and mobile phones from electron migrations, and in the core of the planet is the rotation in liquid iron lumps and in stars like our sun, it is the motions in the plasma of the elementary particles that tear them apart, in isolation.

Magnetic fields reach far into space. Field lines jump from star to star throughout our galaxy and even larger magnetic fields extend between galaxies in giant galaxy clusters.

In 2019, observations showed that magnetic fields also occur on the widest scale, in the so-called cosmic spider web, where filaments of thin gases connect galaxy clusters.

An international group of astronomers Discover 50 million light-years of magnetic field lines run along one of these filaments of gas. It raises a fundamental question: Are the vast voids in the universe between filaments of gas also entangled with magnetic fields?

If yes, then magnetism must have already been born Big Bangs And it played an important role in the distribution of matter in the universe.

Other than gravity, magnetism is the only known natural force with a sufficiently long range to shape the universe as a whole.

If astronomers can show that it also occurs in large voids, we can get answers to many big mysteries, for example about how the first stars in the universe were illuminated.

Childbirth help for the stars

All stars today are formed in galaxies, and it is there that magnetism plays an important role. In galactic nebulae, gravitational magnetic fields help hold matter together so that stars can form.

If the magnetic field lines lead directly into the nebula, the field can create rivers of gas, which are directed toward a specific area in the nebula.

Gravity speeds up the process, so that the density of the gas increases and the temperature and pressure rise. Eventually it gets so hot in the cloud that mergers begin and stars light up.

But how did the first stars form in the oldest dwarf galaxies? Either it happened without the help of magnetic fields, although astronomers don’t know how, or the answer is primordial magnetism from the big bangs.

We have seen the primordial domain indirectly

Astronomers believe primordial magnetism either originated in the first microsecond after the Big Bang or over the next 380,000 years, when all matter was a turbulent plasma of shredded protons and electrons.

Today, primordial magnetism may be so weak that there is only one place we can detect it: in the great voids of the universe, where it is undisturbed and engulfed by stronger fields that arose in galaxy clusters later in the history of the universe.

To this end, astronomers have created an indirect intelligent method, which has already shown signs of the existence of the primordial sphere. The method involves measuring gamma radiation from extremely powerful light sources around supermassive black holes in distant galaxies.

On the way through the vacuum of the universe, bits of the powerful radiation are converted into charged particles, which in turn turn into gamma radiation, albeit with much less energy.

If there is no magnetism in the vacuum, the radiation will reach our telescopes, but if the vacuum is magnetized, the magnetic field must sweep the charged particles aside, so that the radiation from them does not reach.

Astronomers used the Fermi Space Telescope to make the measurements. So far, no weak radiation has been recorded, indicating the existence of the primordial sphere.

The field affects the expansion of the universe

According to the researchers’ calculations, the primordial magnetism is so weak that the field strength corresponds to only a billionth of the strength of an ordinary refrigerator magnet.

This particular force is intriguing in connection with another of the great mysteries of cosmology, which is how fast the universe is actually expanding. Today, using different methods, researchers have come up with two answers to this question.

One method is based on the cosmic background radiation, which provides a snapshot of the universe 380,000 years after the Big Bang. From there, astronomers are prepared for today’s world.

In the second method, scientists start from the present and measure the distance to near and far supernovae, which represent different epochs in the history of the universe.

The problem is that the latter method results in ten percent faster expansion than the first method. However, new computer simulations incorporating primordial magnetism in the first method lead to the same speed as supernovae. Thus, the problem appears to have been resolved.

A new telescope will decide

Before scientists can allow a champagne cork to fly, they need to find concrete evidence of primordial magnetism. They will be able to do this using the SKA radio telescope, which is being built in South Africa and Australia and is expected to be completed in 2028.

With thousands of antennas spread over two continents, SKA will be able to detect the primordial field by recording radio flashes from distant galaxy clusters.

Radio waves from these flashes always oscillate in a certain plane, such as vertically, but if the waves encounter magnetic fields as they travel through a vacuum, the plane is twisted, so it might oscillate horizontally instead. After a number of years, SKA will be able to gather enough data to prove or disprove the existence of primordial magnetism.

At this point, we will finally have an answer as to whether the magnetism we experience around us has roots going back to the birth of the universe and the big bang.