Tuesday, July 16, 2024

In a wild development, physicists have revived an alternative theory of gravity


In the dark depths of space, our models of the universe become chaotic. A new study looking at the super-diffused dwarf galaxy AGC 114905 has revived a controversial theory (or More precisely hypothesis) than gravity, and it gave us more questions than answers about what makes our galaxies tick.

Everything starts with dark matter – Or in this case, there is no dark matter. Although most cosmologists agree that there is something called “dark matter” that causes Spiral galaxies to spin faster than they shouldEven dark matter doesn’t answer all the questions we need.

So, it is not a good idea to look at some alternative options. You know, just in case we can’t find things.

An alternative hypothesis is called dark matter Modified Newton dynamics (MOND) or Milgromian dynamics framework. This hypothesis – first published by physicist Mordihai Milgrom in 1983 – suggests that we do not need dark matter to fill the gravitational gaps in the universe, if we calculate the gravitational forces that stars in the outer galactic regions experience differently from Newton’s laws. Suggest.

To test this idea, which involves working in proportion to a star’s radius or centripetal acceleration, we need to look at the velocities of galaxies – specifically exotic galaxies like Ultra-widespread galaxies.

These dim, ugly ducklings in the galactic realm have a habit of not behaving like a galactic. For example, some super-spreading galaxies seem It consists almost entirely of dark matter, while other materials are almost completely devoid of dark matter.

And that’s where AGC 114905 comes in. This dwarf galaxy is highly diffuse. About 250 million light-years away Recently detailed in Published paper in 2021 Investigate how fast it rotates.

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But this team found that the galaxy’s rotation was too slow — slow enough that they not only need dark matter to confirm the models, but also the galactic rotation curve that casts doubt on the MOND framework. It does not fit either hypothesis.

“The reported extremely low rotational velocity of this galaxy is incompatible with both MOND and the standard dark matter approach,” University of St Andrews physicist and one of the researchers on the new paper, Hong-Sheng Zhao.

“But only Mond is able to get around this apparent contradiction.”

The new paper has revealed the 2021 discovery, which suggests that the problem is not with MOND, but rather with the tilt of the galaxy itself.

When we look at distant galaxies in the depths of space, it can sometimes be difficult to confirm the angle we are seeing. The original team found that AGC 114905 appeared to be elliptical, indicating that we’re looking at the galaxy from an angle.

But using simulations, the researchers now suggest that the galaxy could appear elliptical even when directly facing us. Changing the angle of the galaxy for us will also change the speed of rotation of the galaxy, which makes all the MOND calculations add up after all.

“Our simulations show that the tilt of AGC 114905 may be much lower than what has been reported, which means that the galaxy is in fact rotating much faster than people think, in line with MOND’s predictions,” The lead author of the new paper, physicist Indranil Panek, says:also from the University of St Andrews.

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Now, this question is still open. We don’t know if this new card, or the 2021 card will be crowned victorious – or at least the healthiest.

In the meantime, if this new discovery persists, it looks like the MOND framework could go on for another day. As wild as MOND may be, with dark matter still elusive, and so many other questions still to be answered, we need all the options we can get.

The search was published in Monthly Notices of the Royal Astronomical Society.

Rosario Tejeda
Rosario Tejeda
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