Month: February 2017

Enlarge / Labeled 3D model. The little arrows are galaxies, and the lines coming from them depicts their velocities (with the influence of the Universe's expansion on their velocities removed). Our galaxy, the Milky Way, is located in the Local Group, near the center of the image. The motions of all the galaxies seen here are dominated by the Shapley Attractor and the Dipole Repeller. (credit: Hebrew University of Jerusalem)

You may not notice it, but our Milky Way galaxy is cruising along at 630 kilometers (~391 miles) per second. That speed is often attributed to the influence of a single gravitational source. But in a new study, a group of researchers has found that the motions of the Local Group—the cluster of galaxies that includes the Milky Way—are being driven by two primary sources: the previously known and incredibly massive Shapley Supercluster and a newly discovered repeller, which the researchers dub the Dipole Repeller.

Shapley’s contribution was already known, but the Dipole Repeller’s hadn't been recognized prior to this study.

The researchers plotted the motions of many galaxies in the nearby Universe in a 3D model, using data from the Cosmicflows-2 database. Since the Universe is expanding, most galaxies are moving away from ours, creating a red-shift in the light they emit. But since the researchers were more interested in the other influences on a galaxy’s motion, they simply subtracted the expansion’s contribution. The resulting plot shows what the motions of galaxies would look like if space wasn’t expanding.

Enlarge (credit: Getty Images/Visual China Group)

Uber chief Travis Kalanick has resigned from US president Donald Trump's business advisory council after a bruising few days in which it was reported that hundreds of thousands of customers had deleted their accounts in protest at the firm's apparent cosiness with the US government.

In an e-mail to Uber employees on Thursday, Kalanick admitted that he was stepping back from the president's strategic and policy forum because the company was being widely perceived as "somehow endorsing the administration’s agenda"—a situation which appears to be bad for business.

The perception arose last weekend, in the chaotic wake of Trump's heavily criticised executive order to prevent the citizens of seven Muslim-majority countries from entering the US. As sudden protests broke out in light of the travel ban, the New York Taxi Workers' Alliance—many of whose members are working class immigrants and Muslims—announced it would cease pickups at the city's main airport hub, JFK.

(credit: Ken Lund / flickr)

The Walt Disney Company, including Pixar, Lucasfilm, and Two Pic MC, have agreed to pay $100 million to settle (PDF) claims that they conspired to lower the wages of animators and visual effects employees.

The agreement between the "Disney Defendants" and former workers could be the final settlement for a series of legal claims against entertainment and high-tech companies that were accused of having "no poach" agreements that limited how much they recruited each others' workers.

Combined with earlier settlements with Sony, DreamWorks, and Blue Sky Studios, the class of animator plaintiffs will get about $160 million, assuming US District Judge Lucy Koh approves the settlements currently on the table.

Enlarge / Martian Marine Bobby Draper and her team get ready for action. (credit: Rafy/Syfy)

The Expanse—whether we're talking about the books or the SyFy series that's just starting its second season—is some of the best science fiction we've seen in years. Originally conceived as an MMO at the turn of the century, it finally appeared as a novel in 2011, written by Dan Abraham and Ty Franck (under the James SA Corey nom de plume). In December, the sixth book in the series was released, and last year it also hit our TV screens thanks to SyFy.

In fact, we're such big fans of the space opera that we've chosen is as the next subject to cover in Decrypted, our culture podcast. Season 2 of The Expanse premiered this week, and to mark the occasion we lined up an interview with Messrs Abraham and Franck to dig a little deeper into the solar system they've created for us.

One particularly interesting aspect of the show is that the authors have a massive amount of input into the TV show. That means the story is likely headed to the same destination, but the journey doesn't mirror the books perfectly. This was something that initially unsettled me until I learned to deal with "canon shock."

Enlarge / The Bullet Cluster, which has been viewed as a demonstration of dark matter. (credit: APOD)

Across decades, the hunt for a dark matter particle has looked at many possible solutions—but so far, humanity hasn’t produced a clear answer. Is dark matter a neutrino? An axion? A figment of our imagination? Scientists don’t agree, though experiments from XENON to ADMX continue to strive towards giving us an answer.

“We have to be extremely open-minded about what it might be,” James Bullock, a professor of physics and astronomy at UC Irvine, told Ars. “Dark matter could be even more interesting than we were thinking it was going to be 20 or 30 years ago.”

The built-up confusion surrounding dark matter today can be extremely hard to parse. Recent headlines declared dark matter may not even exist, and even dedicated followers could be forgiven for asking how scientists came up with the idea in the first place. So to better understand dark matter’s place in the Universe, it may be helpful to take a look back at how our ideas about this mysterious material started and evolved over time—it's time to traverse a condensed history of dark matter.