A new way to map out dark matter is 10 times more precise than the previous-best method

Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0)

Astronomers have to be extra clever to map out the invisible dark matter in the universe. Recently, a team of researchers have improved an existing technique, making it up to ten times better at seeing in the dark.

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The galaxy with 99.99% dark matter isn’t so mysterious any more

Artist rendering of the dark matter halo surrounding our galaxy. For quasars, the dark matter halos are much more massive. Credit: ESO/L. Calçada
Artist rendering of the dark matter halo surrounding our galaxy. Credit: ESO/L. Calçada

The dwarf galaxy known as Dragonfly 44 caused a stir recently: apparently it had way, way more dark matter than any other galaxy. Since this couldn’t be explained by our models of galaxy formation, it seemed like an oddball. But a new analysis reveals that Dragonfly 44 has much less dark matter than previously thought. In short: it’s totally normal.

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If dark matter is a particle, it should get inside red giant stars and change the way they behave

This artist’s impression shows the red supergiant star. Using ESO’s Very Large Telescope Interferometer, an international team of astronomers have constructed the most detailed image ever of this, or any star other than the Sun. Credit: ESO/M. Kornmesser

Dark matter makes up the vast majority of matter in the universe, but we can’t see it. At least, not directly. Whatever the dark matter is, it must interact with everything else in the universe through gravity, and astronomers have found that if too much dark matter collects inside of red giant stars, it can potentially cut their lifetimes in half.

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Art Installation that Demonstrates How Dark Matter Bends Light with Gravity

Credit: ESA

At the Science Gallery of Trinity College Dublin, a beautiful work of art is capturing the imagination of people all over the world. It’s called “Dark Distortions,” a work of interactive art by Dutch artist Thijs Biersteker of Woven Studio. Inspired by the ESA’s forthcoming Euclid mission, a visible to near-infrared space telescope that will launch sometime in 2022 to study the mysterious nature of Dark Matter.

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A Tabletop-sized Experiment Could Help in the Search for Dark Matter

A computer simulation of the distribution of matter in the universe. Orange regions host galaxies; blue structures are gas and dark matter. Credit: TNG Collaboration

Dark matter is one of the least understood aspects in physics.  The evidence for dark matter is from its gravitational influence on galactic scales which cannot be explained by the presence of conventional matter.  Despite its large gravitational interactions, it is notoriously difficult to learn about dark matter as it does not interact with electromagnetic fields, hence the name of “dark” matter.

But just because it is difficult to get it to interact with anything on the electromagnetic spectrum does not mean it is impossible to detect other feeble interactions it may have.  A team of theoretical physicists from Caltech have recently proposed a novel type of experiment that may just hold the key to understanding dark matter with specific types of interactions.

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There’s no evidence that dark matter interacts with any other force but gravity

HD+ molecular ions (yellow and red pairs of dots: proton and deuteron) suspended in an ultra-high vacuum between atomic ions (blue dots). Credit: HHU / Alighanbari, Hansen, Schiller
HD+ molecular ions (yellow and red pairs of dots: proton and deuteron) suspended in an ultra-high vacuum between atomic ions (blue dots). Credit: HHU / Alighanbari, Hansen, Schiller

Most of the universe is made of one of two kinds of mysterious substances, called dark matter and dark energy. From all the evidence, these two cosmic components only interact with “normal” matter through the gravitational force. And a recent nuclear experiment reveals no presence of any dark contamination in the bonds between atomic nuclei to a level twenty times better than previously recorded.

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Japanese Dark Matter Detector is Seeing a “Surprising Excess of Events”

The top PMT array with all of the electric cables. Credit: XENON Dark Matter Project

Dark matter is notoriously difficult to detect. So difficult that we haven’t detected it yet. Evidence for dark matter can be seen in everything from the warping of light near galaxies to the way galaxies cluster together. We are pretty sure dark matter is real, but we also know it can’t be made of any type of particle we currently know. But a new study has found some interesting data that could be evidence of dark matter, or not.

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A Massive Rotating Disc Discovered in the Early Universe

Artist impression of the Wolfe Disk, a massive rotating disk galaxy in the early, dusty universe. Credit: NRAO/AUI/NSF, S. Dagnello

If we want to understand how the Universe evolves, we have to understand how its large structures form and evolve. That’s why astronomers study galaxy formation. Galaxies are enormous structures of stars, planets, gas, dust, and dark matter, and understanding how they form is critical to understanding the Universe itself.

In 2017, astronomers working with ALMA (Atacama Large Millimeter/sub-millimeter Array) discovered an ancient galaxy. This massive rotating disk galaxy was born when the Universe was only about 1.5 billion years old. According to the most accepted understanding of how galaxies form and evolve, it shouldn’t exist.

But there it is.

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Hundreds of New Gravitational Lenses Discovered to Help Study the Distant Universe

These two columns show side-by-side comparisons of gravitational lens candidates imaged by the ground-based Dark Energy Camera Legacy Survey (color) and the Hubble Space Telescope (black and white). (Credit: Dark Energy Camera Legacy Survey, Hubble Space Telescope)
These two columns show side-by-side comparisons of gravitational lens candidates imaged by the ground-based Dark Energy Camera Legacy Survey (color) and the Hubble Space Telescope (black and white). (Credit: Dark Energy Camera Legacy Survey, Hubble Space Telescope)

General relativity tells us that everything, even light, is affected by the mass of an object. When a beam of light passes near a large mass, its path is deflected. This shift in the direction of light is known as gravitational lensing, and it was one of the first confirmed effects of Einstein’s theory.

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Decaying Dark Matter Should be Visible Here in the Milky Way as a Halo Around the Galaxy

A simulated image of what the X-ray emission from dark matter might be. Image credit: Christopher Dessert, Nicholas L. Rodd, Benjamin R. Safdi, Zosia Rostomian (Berkeley Lab), based on data from the Fermi Large Area Telescope

Astronomers are very sure that dark matter exists, but they’re not sure at all what it’s made of.

The problem is that it isn’t just dark, it’s invisible. As far as we know, dark matter doesn’t emit light, absorb light, reflect light, refract light, scatter light, diffract light, or really have anything to do with light at all. This makes it hard to study. We know that dark matter exists, however, through its gravitational effects. Even though it’s invisible, it still has mass, and so the dark matter in our universe (which, by the way, makes up 85% of all the mass in the cosmos) can affect the motions of normal (or light-interacting) matter, like stars and galaxies.

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