“Seeing” the Dark Matter Web That Surrounds the Coma Cluster

Artist's impression of Dark matter in the Coma Cluster region. Credit: HyeongHan et al.

According to our predominant cosmological models, Dark Matter makes up the majority of mass in the Universe (roughly 85%). While it is not detectable in visible light, its influence can be seen based on how it causes matter to form large-scale structures in our Universe. Based on ongoing observations, astronomers have determined that Dark Matter structures are filamentary, consisting of long, thin strands. For the first time, using the Subaru Telescope, a team of astronomers directly detected Dark Matter filaments in a massive galaxy cluster, providing new evidence to test theories about the evolution of the Universe.

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There’s Less Dark Matter at the Core of the Milky Way

A study by MIT physicists suggest the Milky Way’s gravitational core may be lighter in mass, and contain less dark matter, than previously thought. Credits:Credit: ESA/Gaia/DPAC, Edited by MIT News

Science really does keep you on your toes. First there was matter and then there were galaxies. Then those galaxies had more stuff in the middle so stars further out were expected to move slowly, then there was dark matter as they actually seemed to move faster but now they seem to be moving slower in our Galaxy so perhaps there is less dark matter than we thought after all! 

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Dark Matter Could Cause Jupiter’s Night Side to Glow

One of the aspects of our study of the universe that fascinates me is the hunt for dark matter. That elusive material that doesn’t interact with much makes it difficult but not impossible to detect.  Gravitational lenses are one such phenomena that point to its existence indeed it allows us to estimate how much there is in galaxy clusters. A paper now suggests that observations of Jupiter by Cassini in 2000 suggest we may be able to detect it using planets too. 

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Will Wide Binaries Be the End of MOND?

Artist view of an orbiting binary star. Credit: ESO/L. Calçada

It’s a fact that many of us have churned out during public engagement events; that at least 50% of all stars are part of binary star systems. Some of them are simply stunning to look at, others present headaches with complex orbits in multiple star systems. Now it seems wide binary stars are starting to shake the foundations of physics as they question the very theory of gravity. 

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Dark Matter Could Help Solve the Final Parsec Problem of Black Holes

This image is from a simulation of two merging black holes. The upcoming Vera Rubin Observatory should be able to detect binary black holes before they merge. But the vexing problem of false positives needs a solution. Image Credit: Simulating eXtreme Spacetimes (SXS) Project

When galaxies collide, their supermassive black holes enter into a gravitational dance, gradually orbiting each other ever closer until eventually…merging. We know they merge because we see the gravitational beasts that result, and we have detected the gravitational waves they emit as they inspiral. But the details of their final consummation remain a mystery. Now a new paper suggests part of that mystery can be solved with a bit of dark matter.

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New Telescopes to Study the Aftermath of the Big Bang

A photograph of a CMB-S4 detector wafer being prepared for testing in a cryostat at Lawrence Berkeley National Laboratory. Credit: Thor Swift/Lawrence Berkeley National Laboratory

Astronomers are currently pushing the frontiers of astronomy. At this very moment, observatories like the James Webb Space Telescope (JWST) are visualizing the earliest stars and galaxies in the Universe, which formed during a period known as the “Cosmic Dark Ages.” This period was previously inaccessible to telescopes because the Universe was permeated by clouds of neutral hydrogen. As a result, the only light is visible today as relic radiation from the Big Bang – the Cosmic Microwave Background (CMB) – or as the 21 cm spectral line created by the reionization of hydrogen (aka. the Hydrogen Line).

Now that the veil of the Dark Ages is being slowly pulled away, scientists are contemplating the next frontier in astronomy and cosmology by observing “primordial gravitational waves” created by the Big Bang. In recent news, it was announced that the National Science Foundation (NSF) had awarded $3.7 million to the University of Chicago, the first part of a grant that could reach up to $21.4 million. The purpose of this grant is to fund the development of next-generation telescopes that will map the CMB and the gravitational waves created in the immediate aftermath of the Big Bang.

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Euclid Recovers From a Navigation Problem and Finds its Guide Stars Again

Artist impression of the Euclid mission in space. Credit: ESA

On July 1st, 2023, the ESA’s Euclid mission headed for space, where it began its mission to observe the Universe and measure its expansion over time. The commissioning process began well as the mission team spent weeks testing and calibrating the observatory, then flew the mission out to Lagrange Point 2 (LP2). The telescope focused its mirrors, collected its “first light,” and the first test images it took were breathtaking! Unfortunately, Euclid hit a snag when its Fine Guidance Sensor (FGS) failed to lock onto its “guide stars.”

According to the latest update from the ESA, Euclid has found its guide stars again, thanks to a software patch. With its navigation woes now solved and its observation schedule updated, the telescope will now undergo its Performance Verification phase (its final phase of testing) in full “science mode.” Once that’s complete, Euclid will commence its nominal six-year mission, providing razor-sharp images and deep spectra of our Universe, looking back 10 billion years. This data will be used to create a grand survey of one-third of the entire sky and measure the influence of Dark Matter and Dark Energy.

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The Milky Way's Mass is Much Lower Than We Thought

The rotation curve of our galaxy compared to the Keplerian rotation curve. Credit: Jiao, Hammer et al. / Observatoire de Paris – PSL / CNRS / ESA / Gaia / ESO / S. Brunier

How massive is the Milky Way? It’s an easy question to ask, but a difficult one to answer. Imagine a single cell in your body trying to determine your total mass, and you get an idea of how difficult it can be. Despite the challenges, a new study has calculated an accurate mass of our galaxy, and it’s smaller than we thought.

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It's Going to Take More Than Early Dark Energy to Resolve the Hubble Tension

Artist impression of a cluster of galaxies in the early Universe. Credit: S. Dagnello; NSF/NRAO/AUI

Our best understanding of the Universe is rooted in a cosmological model known as LCDM. The CDM stands for Cold Dark Matter, where most of the matter in the universe isn’t stars and planets, but a strange form of matter that is dark and nearly invisible. The L, or Lambda, represents dark energy. It is the symbol used in the equations of general relativity to describe the Hubble parameter, or the rate of cosmic expansion. Although the LCDM model matches our observations incredibly well, it isn’t perfect. And the more data we gather on the early Universe, the less perfect it seems to be.

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Dark Matter Experiment Fails to Turn Up the Mysterious Particle, but Narrows its Hiding Places

So much in science is based on constraints. If scientists don’t understand something, they try to constrain it as much as possible so that more precise experiments can finally detect whatever the theorized phenomenon is. Dark matter is notoriously difficult in this regard, as it has evaded detection for over a century at this point, despite even more precise instruments trying to capture a glimpse of it. One of those instruments is the Super Cryogenic Dark Matter Search (SuperCDMS), run by the SLAC National Laboratory and located in northern Minnesota. To help further the cause, researchers looked at the data from the experiment while considering a few new possibilities, and while they didn’t find any evidence of dark matter, they helped tighten the constraints even more.

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