- 3062 - DARK MATER - is it real? We have known about Dark Matter for a long time Back in the 1930’s, a Swiss astronomer named Fritz Zwicky noticed that galaxies in a distant cluster were orbiting one another much faster than they should have been given the amount of visible mass they had. He proposed than an unseen substance, which he called “dark matter“, might be tugging gravitationally on these galaxies.
----------------------- 3062 - DARK MATER - is it real?
- Astronomers have confirmed that this mysterious dark matter material can be found throughout the cosmos, and that it is six times more abundant than the normal matter that makes up ordinary things like stars and people.
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- Despite seeing dark matter throughout the universe, scientists still do not know what it is? Or is it even real?
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- Originally, some scientists conjectured that the missing mass in the universe was made up of small faint stars and black holes, though detailed observations have not turned up nearly enough such objects to account for dark matter's influence. The laws of gravity tell us this.
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- The current leading contender for dark matter's mantle is a hypothetical particle called a “Weakly Interacting Massive Particle“, or WIMP, which would behave like a neutron except would be between 10 and 100 times heavier than a proton.
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- If dark matter is made from WIMPs, they should be all around us, invisible and barely detectable. So why haven't we found any yet? While they wouldn't interact with ordinary matter very much, there is always some slight chance that a dark matter particle could hit a normal particle like a proton or electron as it travels through space.
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- Researchers have built experiment after experiment to study huge numbers of ordinary particles deep underground, where they are shielded from interfering radiation that could mimic a dark-matter-particle collision.
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- After decades of searching, not one of these detectors has made a credible discovery.
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- Ordinary matter is made up of particles like protons and electrons, as well as a whole zoo of more exotic particles like neutrinos, muons and pions. So, some researchers have wondered if dark matter, which makes up 85 percent of the matter in the universe, might also be just as complicated. Only 15% is “ordinary matter”
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- There is no good reason to assume that all the dark matter in the universe is built out of one type of particle. Dark protons could combine with dark electrons to form dark atoms, producing configurations as diverse and interesting as those found in the visible world of “ordinary matter”
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- Along with additional particles of dark matter, there is the possibility that dark matter experiences forces analogous to those felt by regular matter. Some researchers have searched for "dark photons," which would be like the photons exchanged between normal particles that give rise to the electromagnetic force, except they would be felt only by dark matter particles.
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- Physicists in Italy are gearing up to smash a beam of electrons and their antiparticles, known as “positrons“, into a diamond. If dark photons do exist, the electron-positron pairs could annihilate and produce one of the strange force-carrying particles, potentially opening a brand-new sector of the universe. A positron is a mimic of an electron except it has the opposite electrical charge.
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- One of the leading alternatives to WIMPS is a hypothetical particle known as an “axion“, which would be extremely light, perhaps as little as 10 raised to the 31st power less massive than a proton.
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- Axions are now being searched for in a few experiments. Recent computer simulations have raised the possibility that these axions could form star-like objects, which might produce detectable radiation that would be quite similar to mysterious phenomena known as “fast-radio bursts“.
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- Astronomers originally discovered dark matter through its gravitational interactions with ordinary matter. Dark Matter particles should be their own antiparticles, meaning that two dark-matter particles would annihilate with one another when they meet.
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- The “Alpha Magnetic Spectrometer” (AMS) experiment on the International Space Station has been searching for the telltale signs of this annihilation since 2011 and has already detected hundreds of thousands of events. Scientists still aren't sure if these are coming from dark matter, and the signal has yet to help them pin down exactly what dark matter is.
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- Because it so massively outweighs ordinary matter, dark matter is often said to be the controlling force that organizes large structures such as galaxies and galactic clusters.
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- A long-standing mystery in particle physics are the puzzling results of a European experiment known as DAMA/LIBRA. This detector, located in an underground mine below the Gran Sasso mountain in Italy, has been searching for a periodic oscillation in dark matter particles.
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- This oscillation should arise as the Earth moves in its orbit around the sun while flying through the galactic stream of dark matter surrounding our solar system, called the “dark matter wind“. Since 1997, DAMA/LIBRA has claimed to see exactly this signal, though no other experiment has seen anything like this.
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- A signal from the beginning of time has led some physicists to suggest that dark matter might have an electrical charge. Radiation with a wavelength of 21 centimeters was emitted by stars in the universe's infancy, just 180 million years after the Big Bang.
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- It was then absorbed by cold hydrogen that was around at the same time. When this radiation was detected in February, 2021, its signature suggested that the hydrogen was much colder than scientists had predicted.
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- Astrophysicist hypothesized that dark matter with an electrical charge could have drawn heat away from the all-pervasive hydrogen. But this conjecture has yet to be confirmed.
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- Can ordinary particles decay into dark matter? Neutrons are regular matter particles with a limited lifetime. After around 14.5 minutes, a lone neutron unmoored from an atom will decay into a proton, an electron and a neutrino.
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- Two different experimental setups give slightly different lifetimes for this decay, with the discrepancy between them about 9 seconds . In 2021 physicists suggested that if 1 percent of the time, some neutrons were decaying into dark-matter particles, it could account for this anomaly. These physicists monitored neutrons for a signal that could be dark matter but were unable to detect anything so far.
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- Given the difficulties that scientists have faced trying to detect and explain dark matter, one might wonder if we are going about it all wrong. For many years, a vocal minority of physicists have pushed the idea that perhaps our theories of gravity are simply incorrect, and that this fundamental force works differently on large scales than we expect.
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- Often known as "modified Newtonian dynamics," or MOND models, these suggestions posit that there is no dark matter and the ultrafast speeds at which stars and galaxies are seen to rotate around one another is a consequence of gravity behaving in surprising ways defying the math that we are familiar with.
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- "Dark matter is still an unconfirmed model," yet the latest evidence suggests that dark matter is real. We still have more to learn, stay tuned. Here are other review:
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- 3049 - DARK MATTER - is real but what is it? Dark matter is still an unconfirmed model, yet , the detractors have yet to convince the larger field of their ideas. And the latest evidence? It also suggests that dark matter is real. But what is it?
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- 2931 - DARK MATTER - explorations? - Researchers remain unsure about what exactly dark matter is. Originally, some scientists conjectured that the missing mass in the universe was made up of small faint stars and black holes, though detailed observations have not turned up nearly enough such objects to account for the significant amount of dark matter's influence.
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- 2897 - DARK MATTER - produces many new theories? When something seems a little mysterious or we just don’t understand what is going on we like to describe it with the adjective ‘dark’. This is one of the reasons why the term ‘dark’ matter got coined which was first proposed to explain the anomaly observed in the rotational velocities of galaxies.
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- 2886 - DARK MATTER - mysteries? When something seems a little mysterious or we just don’t understand what is going on we like to describe it with the adjective ‘dark’. We do not understand 95% of the universe we live in. The 5% that is left is everything we know about and are still learning about.
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- 2861 - DARK MATTER - how we know it is there? - The big idea of dark matter is that there’s something other than these known particles contributing in a significant way to the total amounts of matter in the Universe. We look at the motions of these objects, we look at the gravitational rules that govern orbiting bodies, whether something is bound or not, how it rotates, how structure forms, and we get a number for how much matter there has to be in there.
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- 2823 - DARK MATTER - needs to be a new 2020 discovery? Researchers remain unsure about what exactly dark matter is. Originally, some conjectured that the missing mass in the universe was made up of small faint stars and black holes, though detailed observations have not turned up nearly enough such objects to account for dark matter's influence.
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- 2790 - DARK MATTER - to discover what it is? - There is a race to discover “dark matter“. Dark matter is that elusive substance that has mystified science since the 1930s, when astronomers first realized galaxies needed some kind of invisible gravitational glue to hold them together. No one knew what it was, so it was named “dark matter“.
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- 2768 - DARK MATTER - What is the Universe Made of? Since 1970 astronomers have believed Dark Matter existed because studying the orbits of galaxies and stars around galaxies could not be calculated based on the stars and matter they could see. Either Kepler’s and Newton’s formulas for the laws of gravity and motion were incorrect, or there was matter there that they could not find.
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February 25, 2021 DARK MATER - is it real? 3062
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