Stars Travel More Slowly at Milky Way’s Edge

Physicists discovered stars near the edge of the Milky Way travel more slowly than those closer to its center — a surprise suggesting our galaxy’s gravitational core may have less dark matter than previously thought.

By clocking the speed of stars throughout the Milky Way galaxy, MIT physicists have found that stars further out in the galactic disk are traveling more slowly than expected compared to stars that are closer to the galaxy’s center. The findings raise a surprising possibility: The Milky Way’s gravitational core may be lighter in mass, and contain less dark matter, than previously thought.

The new results are based on the team’s analysis of data taken by the Gaia and APOGEE instruments...

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Astrophysical Jet caught in a ‘Speed Trap’

Violett leuchtende und wabernde Gasblase in Cocoon-Form vor schwarzem Hintergrund mit blauen Lichtstrahlen entlang einer Linie im Inneren
Artist’s impression of the SS 433 system, depicting the large-scale jets (blue) and the surrounding Manatee Nebula (red). The jets are initially observable only for a short dis-tance from the microquasar after launch — too small to be visible in this picture. The jets then travel undetected for a distance of approximately 80 light-years (25 parsecs) before un-dergoing a transformation, abruptly reappearing as bright sources of non-thermal emission (X-ray and gamma-ray). Particles are efficiently accelerated at this location, likely indicating the presence of a strong shock: a discontinuity in the medium capable of accelerating particles.
© Science Communication Lab for MPIK/H.E.S.S.

The science fiction author Arthur C...

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When Lab-Trained AI Meets the Real World, ‘Mistakes can Happen’

AI and pathology
When humans examine tissue on slides, they can only look at a limited field within the microscope, then move to a new field and so on.

Tissue contamination distracts AI models from making accurate real-world diagnoses. Human pathologists are extensively trained to detect when tissue samples from one patient mistakenly end up on another patient’s microscope slides (a problem known as tissue contamination). But such contamination can easily confuse artificial intelligence (AI) models, which are often trained in pristine, simulated environments, reports a new Northwestern Medicine study.

“We train AIs to tell ‘A’ versus ‘B’ in a very clean, artificial environment, but, in real life, the AI will see a variety of materials that it hasn’t trained on...

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What Coffee with Cream can Teach us about Quantum Physics

What coffee with cream can teach us about quantum physics | CU Boulder  Today | University of Colorado Boulder

A new advancement in theoretical physics could, one day, help engineers develop new kinds of computer chips that might store information for longer in very small objects.

Add a dash of creamer to your morning coffee, and clouds of white liquid will swirl around your cup. But give it a few seconds, and those swirls will disappear, leaving you with an ordinary mug of brown liquid.

Something similar happens in quantum computer chips — devices that tap into the strange properties of the universe at its smallest scales — where information can quickly jumble up, limiting the memory capabilities of these tools.

That doesn’t have to be the case, said Rahul Nandkishore, associate professor of physics at the University of Colorado Boulder.

In a new coup for theoretical physics, he a...

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