Sample Pieces

Here are a few excerpts from some pieces that I’m particularly proud of from 2015. I’ll update this soon with my many, many more (and better) articles and news stories from 2016. To see a more complete list with links, take a look at the Articles & Writings page.

 

President Obama—take nukes off hair-trigger alert
San Francisco Chronicle, 15 September 2015

Following weeks of intense debate in the United States, the international agreement to prevent Iran from developing nuclear weapons is moving forward. It is a historic arrangement that demonstrates the world’s resolve to prevent the spread of nuclear weapons. It will not end, however, all the nuclear threats that face the world.

A decommissioned Titan II missile in an Arizona silo. (Credit: Sam Howzit, Union of Concerned Scientists)

A decommissioned Titan II missile in an Arizona silo. (Credit: Sam Howzit, Union of Concerned Scientists)

So it is important to ask what other steps can be taken to reduce the still- considerable risks posed by nuclear weapons as the Iran agreement enters its implementation phase. The place to start is with countries already possessing nuclear weapons. Persuading them to take their nuclear weapons off “hair-trigger alert” would be an important first step.

As commander in chief, President Obama can end the U.S. hair-trigger alert policy without approval by Congress. In fact, both he and former President George W. Bush pledged to do so during their presidential campaigns, but neither did. Now is the time to do so.

[For the rest of the article, see the San Francisco Chronicle website or view it in this PDF.]

 

Hubble’s Long Look at Distant Galaxies
Sky & Telescope, 19 January 2015

Hubble Space Telescope observations are enlightening astronomers about the evolution of galaxies in the distant universe.

Astronomers are studying growing galaxies in the early years of the universe using a unique Hubble Space Telescope survey, and they presented a host of results at the winter meeting of the American Astronomical Society.

The survey, known as 3D-HST and led by Pieter van Dokkum (Yale University), fleshes out an existing set of Hubble images with spectroscopy, adding a third dimension to a previously two-dimensional view.

3D-HST adds spectroscopy, and hence the third dimension, to this stunning two-dimensional image from the CANDELS Ultra Deep Survey. (Image credit: NASA / ESA / A. van der Wel / H. Ferguson / A. Koekemoer / the CANDELS team)

3D-HST adds spectroscopy, and hence the third dimension, to this stunning two-dimensional image from the CANDELS Ultra Deep Survey. (Image credit: NASA / ESA / A. van der Wel / H. Ferguson / A. Koekemoer / the CANDELS team)

Hubble spent about a month collecting near-infrared spectra of galaxies living in a universe less than half its current age. The short observing time netted an incredible amount of data: “The unique ‘slitless’ nature of the 3D-HST observations provides simultaneous high-quality spectra of everything in the HST field-of-view,” says Gabriel Brammer of the Space Telescope Science Institute.

The precise distance measurements add a third dimension to tens of thousands of galaxies detected in CANDELS, Hubble’s single largest observing program.

[For the rest of the article, see the Sky & Telescope website or view it in this PDF.]

 

Struggling Against Gender Bias in STEM Fields
Status newsletter for the Committee on the Status of Women in Astronomy

Suppose that two astrophysicists with similar education, experience, and accomplishments—let’s call them Dr. X and Dr. Y—apply for a tenure-track faculty position. If Dr. X is female and Dr. Y is male, and if the selection committee members have conscious or unconscious gender bias, then, unfortunately, one might expect it to be more likely that Dr. Y would be offered the position.

But a controversial and influential new paper argues the opposite. In the title of their April 2015 article in the Proceedings of the National Academy of Sciences, Wendy M. Williams and Stephen J. Ceci, both psychologists and full professors at Cornell University, claim, “National hiring experiments reveal 2:1 faculty preference for women on STEM tenure track.”

The authors base their conclusions on five randomized, controlled experiments at 371 U.S. colleges and universities in biology, engineering, economics, and psychology. In these experiments, tenure-track faculty members evaluated the biographical summaries or the curricula vitae of fictitious faculty candidates—including one “foil” candidate—mostly with impressive qualifications but with different genders and different life situations, such as being a single parent or having taken parental leave.

Their analysis reveals an unexpected result: faculty reviewers strongly preferred female candidates to male ones by a highly significant 2:1 advantage. Williams and Ceci conclude, “Efforts to combat formerly wide-spread sexism in hiring appear to have succeeded. After decades of overt and covert discrimination against women in academic hiring, our results indicate a surprisingly welcoming atmosphere today for female job candidates in STEM disciplines, by faculty of both genders.”

[For the rest of the article, see the Status website or view it in this PDF.]

 

Scientists Map the Dark Matter Around Millions of Galaxies
Universe Today, 17 April 2015

This week, scientists with the Dark Energy Survey collaboration released the first in a series of detailed maps charting the distribution of dark matter inferred from its gravitational effects. The new maps confirm current theories that suggest galaxies will form where large concentrations of dark matter exist. The new data show large filaments of dark matter where visible galaxies and galaxy clusters lie and cosmic voids where very few galaxies reside.

The first Dark Energy Survey map to trace the dark matter distribution across a large area of sky. The colors indicate projected mass density. (Image: Dark Energy Survey)

The first Dark Energy Survey map to trace the dark matter distribution across a large area of sky. The colors indicate projected mass density. (Image: Dark Energy Survey)

“Our analysis so far is in line with what the current picture of the universe predicts,” said Chihway Chang from the Swiss Federal Institute of Technology in Zurich, a co-leader of the analysis. “Zooming into the maps, we have measured how dark matter envelops galaxies of different types and how together they evolve over cosmic time.”

The research and maps, which span a large area of the sky, are the product of a massive effort of an international team from the US, UK, Spain, Germany, Switzerland, and Brazil. They announced their new results at the American Physical Society meeting in Baltimore, Maryland.

According to cosmologists, dark matter particles stream and clump together over time in particular regions of the cosmos, often in the same places where galaxies form and cluster. Over time, a “cosmic web” develops across the universe. Though dark matter is invisible, it expands with the universe and feels the pull of gravity. Astrophysicists then can reconstruct maps of it by surveying millions of galaxies, much like one might infer the shifting orientation of a flock of birds from its shadow moving along the ground.

[For the rest of the article, see the Universe Today website or view it in this PDF.]