It would be very optimistic to suggest that we have a good handle on dark matter. But even the slightest understanding we have can lead to the loss of something important.
New observations from the Hubble Space Telescope have found much higher concentrations of dark matter in the order of magnitude than expected in some galaxies.
These concentrations are inconsistent with theoretical models, suggesting that there is a large gap in our understanding – the simulations may be incorrect, or there may be a property of dark matter that we do not understand, according to the research team.
“We have done a very careful test in comparing the simulations and data of this study, and we do not match,” said Massimo Menegetti, an astrophysicist at the National Institute for Astrophysics in Italy.
“One possible root for this discrepancy is that we may lose some key physics in simulations.”
Dark matter is the biggest thorn in our understanding of the universe. Simply put, that’s not what we know. It does not absorb, reflect or emit any electromagnetic radiation, which makes it completely undetectable directly. However, it interacts with the visible matter of the universe by gravity.
This means that we can study how to distribute and move objects like galaxies and stars around the universe, calculate the gravity needed to produce those distributions and movements, and study how to calculate and subtract the gravity produced by a visible object. Can.
The gravity left shows how much dark matter there is in the universe – and, what we can say is a lot. About 85 percent of the matter in the universe can be dark matter.
One way we can indirectly detect dark matter is through gravitational lensing. Really large-scale objects, such as clusters of galaxies, create such intense gravitational fields that space-time only rotates – meaning that space travels on any light-curved path passing through time.
Therefore, objects on the far side of that gravitational field, such as distant galaxies, appear to us to be large, smelly, mimicked, and distorted.
Gravity lensing (NASA, ESA and L. Calda)
By studying these distortions and putting the galaxies together, we can learn how light is distorted, which means that we can map the gravitational field – the larger the distortion, the stronger the gravitational field. Once again, subtract the visible matter, and that – a map of the black matter inside that lensing cluster. He is clever in mind.
Managetti and his team were doing this by observing observations of 11 galaxy clusters in Chile using the Hubble Space Telescope and a very large telescope from the European Southern Observatory.
“Galaxy clusters are ideal laboratories for understanding whether computer simulations of the universe reliably reproduce what we can think of about the interaction of dark matter and its luminous matter.”
When the team sat down to analyze the data, they found massive lensing effects as expected to be produced entirely by the galaxy. But they also found tiny lensing effects inside. These small lenses, produced by individual galaxies in clusters, did not appear in the simulations of the clusters, indicating more of a dark object.
To test their findings, the team performed spectroscopic observations of galaxies, using light shifts to calculate the motion of moving stars – an excellent tool for measuring dark matter.
And they double-checked their distance calculations, as they could make a definite difference in the calculation of dark matter.
Researchers have found that the concentration of dark matter in individual galaxies is much higher than the simulations for the concentration of dark matter. But the simulations were based on our best understanding of dark matter – so where does the extra mass come from?
Well, we don’t know. But it will be an exciting journey of discovery.
“Personally, for me, the factor of 10 differences between an observation and a theoretical prediction is to find the sinking distance,” said Yale University astrophysicist Priyamvad Natarajan.
“The main goal of my research is to test theoretical models with the quality of data correction to find these gaps. There are such gaps and inconsistencies that often reveal that we are either missing something in current theory, or that it points the way. On a brand-new model, with more clarity. “
Either way, finding out what is the cause of the discrepancy between simulation and observation leads us to a better understanding of the dark subject.
Research has been published in Science.
Full cover image credit: NASA, ESA, G. Kamina (University of Groningen), m. Menegatti (Observation of Rope Strophysics and Space Science of Bologna), p. Natarajan (Yale University), Clash Team, and m. Cornmeaser (ESA / Hubble)
.
