Post by Andrei Tchentchik on Apr 30, 2020 11:43:45 GMT 2
(.#449).- Dark matter could be older than the Big Bang.
Dark matter could be older than the Big Bang.
By: Brice Louvet, science editor
August 9, 2019, 10 h 52 min
Dark matter simulation.
Credits: Tom Abel and Ralf Kaehler / KIPAC / SLAC / AMNH)
Where does dark matter come from? What is it made of? For the moment, the mystery remains unresolved. But a new theory could change everything. According to a physicist at Johns Hopkins University (United States), matter could have been created before the Big Bang.
Summary :
Strange dark matter
Before the Big Bang
Early material
Strange dark matter
We know it's there, that it exists. We cannot detect it directly, but there is plenty of indirect evidence of its existence. The movement of stars and galaxies, for example, cannot in fact be explained by the mere presence of normal matter. There is something else". A more powerful invisible matter, in larger proportions, that shapes the large-scale structure of the Universe. Researchers today estimate that it contains around 26.8% dark matter, compared to just 4.9% ordinary matter (which makes up us). That is to say. As for the rest, it's dark energy.
Several theories have attempted to explain dark matter. One of them suggests that it would be composed of a very light and electrically neutral particle called "axion". Researchers have developed an experiment - the Axion Dark Matter eXperiment (ADMX) - but the results have so far been unsuccessful. What if we finally got it wrong? What if we look at the problem from another angle? At least, Tommi Tenkanen of John Hopkins University has suggested that dark matter may have originated before the Big Bang.
Credits: iStock
Before the Big Bang
We know today that the Universe is expanding. And let everything go away at an accelerated pace. Starting from this principle, if we go back “the machine” backwards, all the matter of the Universe is found compacted into a singularity of infinite density. About 13.8 billion years ago, this singularity “exploded”, creating space (and therefore time). It’s the Big Bang. All the ordinary matter that exists today comes from this cataclysmic event. And so far, we thought that was also the case for dark matter.
But for the researcher, it doesn't stick. "If dark matter was really a vestige of the Big Bang, in many cases we should already have seen a direct signal of its presence in different particle physics experiments," says Tommi Tenkanen.
In our mind, we believe that the Big Bang is the start of everything. But ultimately we have no concrete evidence. It may indeed be that this event is ultimately only a horizon line. To take a very simple example: when we look out to sea, we are looking at the horizon. You can't see anything beyond it, but that doesn't mean there's nothing behind it.
Credits: Wikimedia Commons
Early material
This is where the principle of cosmic inflation (presented above) comes into play. This is a period in which the Universe has grown exponentially. Like a balloon. It is generally believed that this period occurred between about 10-36 and 10-32 seconds after the Big Bang. But some believe it happened just before the Big Bang. And for Tommi Tenkanen, it was at this precise moment that dark matter came into being.
He thus proposes that during this period, the Universe would have produced a type of particle called “scalar” (like the Higgs boson), whose spin number was equal to zero. The advantage of this new theory, he says, is that it works to explain the interactions between dark matter and normal matter, which we have already measured. In other words, this explanation fits perfectly into the current dynamics of the Universe.
Starting from this principle could also allow us to identify this strange matter once and for all. "If dark matter is made up of new particles born before the Big Bang, they uniquely affect the way galaxies are distributed in the sky," explains the researcher. This connection can be used to reveal their identity and draw conclusions about the times leading up to the Big Bang too. ”
According to Tenkanen, the instruments and experiments in progress cannot currently allow this type of discovery, but he believes in the satellites to come. Like Euclid, from the European Space Agency (ESA). A new space telescope scheduled to launch in 2022.
F I N .
Dark matter could be older than the Big Bang.
By: Brice Louvet, science editor
August 9, 2019, 10 h 52 min
Dark matter simulation.
Credits: Tom Abel and Ralf Kaehler / KIPAC / SLAC / AMNH)
Where does dark matter come from? What is it made of? For the moment, the mystery remains unresolved. But a new theory could change everything. According to a physicist at Johns Hopkins University (United States), matter could have been created before the Big Bang.
Summary :
Strange dark matter
Before the Big Bang
Early material
Strange dark matter
We know it's there, that it exists. We cannot detect it directly, but there is plenty of indirect evidence of its existence. The movement of stars and galaxies, for example, cannot in fact be explained by the mere presence of normal matter. There is something else". A more powerful invisible matter, in larger proportions, that shapes the large-scale structure of the Universe. Researchers today estimate that it contains around 26.8% dark matter, compared to just 4.9% ordinary matter (which makes up us). That is to say. As for the rest, it's dark energy.
Several theories have attempted to explain dark matter. One of them suggests that it would be composed of a very light and electrically neutral particle called "axion". Researchers have developed an experiment - the Axion Dark Matter eXperiment (ADMX) - but the results have so far been unsuccessful. What if we finally got it wrong? What if we look at the problem from another angle? At least, Tommi Tenkanen of John Hopkins University has suggested that dark matter may have originated before the Big Bang.
Credits: iStock
Before the Big Bang
We know today that the Universe is expanding. And let everything go away at an accelerated pace. Starting from this principle, if we go back “the machine” backwards, all the matter of the Universe is found compacted into a singularity of infinite density. About 13.8 billion years ago, this singularity “exploded”, creating space (and therefore time). It’s the Big Bang. All the ordinary matter that exists today comes from this cataclysmic event. And so far, we thought that was also the case for dark matter.
But for the researcher, it doesn't stick. "If dark matter was really a vestige of the Big Bang, in many cases we should already have seen a direct signal of its presence in different particle physics experiments," says Tommi Tenkanen.
In our mind, we believe that the Big Bang is the start of everything. But ultimately we have no concrete evidence. It may indeed be that this event is ultimately only a horizon line. To take a very simple example: when we look out to sea, we are looking at the horizon. You can't see anything beyond it, but that doesn't mean there's nothing behind it.
Credits: Wikimedia Commons
Early material
This is where the principle of cosmic inflation (presented above) comes into play. This is a period in which the Universe has grown exponentially. Like a balloon. It is generally believed that this period occurred between about 10-36 and 10-32 seconds after the Big Bang. But some believe it happened just before the Big Bang. And for Tommi Tenkanen, it was at this precise moment that dark matter came into being.
He thus proposes that during this period, the Universe would have produced a type of particle called “scalar” (like the Higgs boson), whose spin number was equal to zero. The advantage of this new theory, he says, is that it works to explain the interactions between dark matter and normal matter, which we have already measured. In other words, this explanation fits perfectly into the current dynamics of the Universe.
Starting from this principle could also allow us to identify this strange matter once and for all. "If dark matter is made up of new particles born before the Big Bang, they uniquely affect the way galaxies are distributed in the sky," explains the researcher. This connection can be used to reveal their identity and draw conclusions about the times leading up to the Big Bang too. ”
According to Tenkanen, the instruments and experiments in progress cannot currently allow this type of discovery, but he believes in the satellites to come. Like Euclid, from the European Space Agency (ESA). A new space telescope scheduled to launch in 2022.
F I N .
