Jun 13, 2017

Scientists can "see" dark matter with a new, massive simulation

Joachim Stadel / UZH

Astrophysicists from the University of Zurich in Switzerland have built the largest simulation of the universe yet. The simulation, which was described in Computational Astrophysics and Cosmology, enables scientists to see how dark matter interacts with the universe. The photo above is part of the simulation, which highlights the dark matter halos in yellow — the dark matter that hypothetically surrounds galaxies.

How big? The simulation models more than 25 billion virtual galaxies.

Why it matters: The simulation will serve as a calibrator to help the Euclid satellite gather information from the universe. The simulation with help frame what Euclid will look for in its investigation into dark matter and dark energy. The satellite is set to launch in 2020.

How to see dark matter: Scientists believe dark matter and dark energy constitute 95% of our universe — the other 5% is what we can see, but this dark matter has remained mostly a mystery. Euclid won't be able to literally see the dark matter, but it will be looking for changes in the light as it travels the Universe. The astrophysicists' simulation predicts how dark matter and dark energy operate, which helps frame the kind of dark matter effects Euclid should be looking for and measuring.

Go deeper: Read the press release with details on how the simulation was built and Euclid's goals, here.

Go deeper

Trump hits back at Mattis: "I gave him a new life"

President Trump speaks at the White House. Photo: Doug Mills - Pool/Getty Images

President Trump unloaded on his former defense secretary via Twitter on Wednesday, hours after James Mattis condemned him for making a "mockery of our Constitution" in his response to mass protests in the wake of George Floyd's killing.

What he's saying: "Probably the only thing Barack Obama & I have in common is that we both had the honor of firing Jim Mattis, the world’s most overrated General. I asked for his letter of resignation, & felt great about it. His nickname was 'Chaos', which I didn’t like, & changed it to 'Mad Dog'"

Obama praises young protesters, urges mayors to pursue police reforms

Former President Barack Obama called on all mayors to review their use-of-force policies and commit to policing reform in a virtual town hall Wednesday hosted by the Obama Foundation's My Brothers Keepers Alliance.

Why it matters: Obama has addressed the killing of George Floyd and the nationwide protests that followed on social media and in a Medium post, but this was his first time speaking about the past week's events on camera. His voice will add weight to the growing pressure on local, state and federal officials to pursue policing reforms.

James Mattis condemns Trump as a threat to the Constitution

Mattis on Fox in Septemnber 2019 in New York City. Photo: Steven Ferdman/Getty Images

Former Secretary of Defense James Mattis condemned President Trump for making a "mockery of our Constitution" in a statement to The Atlantic on Wednesday, saying he was "appalled" at the president's response to mass protests in the wake of George Floyd's killing.

Why it matters: Trump’s former defense secretary had refrained from publicly criticizing his former boss since resigning in 2018.