The dinosaur-killing dark matter of DOOM!

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A few weeks ago, several news outlets ran stories based on a press release, in which a researcher claimed that dense clumps of dark matter could be responsible for the extinction of dinosaurs. I found this claim dubious, based on what we know about dark matter. Here’s my response.

Did Dark Matter Doom the Dinosaurs?

From Slate:

he history of life on Earth is marked by occasional mass extinctions, events wiping out huge numbers of species. The most famous of these killed off all the dinosaurs (or at least those that hadn’t evolved into birds) 65 million years ago. But the mass extinction that ended the Permian period 250 million years ago was even more dramatic, killing off 90 percent of all species in an astonishingly short amount of time. As yet, the cause of this devastation is unexplained.

Mass extinctions have happened at least five times. (A sixth great extinction currently in progress, but that’s an anomaly because humans are responsible.) Some researchers have tried to figure out whether they’re periodic, recurring after specific time intervals. If they truly do repeat regularly, maybe there’s a common cause for them. [read more on Slate.com]

Slowing light to measure the creep of glaciers

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My most recent article is an interesting combination of fundamental quantum physics research — the slowing of light inside specially-designed materials — with the study of the impacts of climate change on Greenland glaciers.

How to clock a glacier

From Nautilus:

low-flying airplane buzzes along the coast of Greenland, hovering over a glacier. The belly of the plane holds a laser that bounces light off the glacier’s face. As the light beam returns to the plane, it enters a black box that slows it to a crawl, turning it into a moment-by-moment report on the glacier’s speed. Each flight, each glacier measured, allows researchers to map the diminishment of the Greenland ice cap. Similar planes skirt Antarctica and the coast of Alaska, charting the damage to the ice cover.

These airplanes and their experimental equipment don’t exist yet. But the need to measure glacier flow in real time does exist. The latest report by Intergovernmental Panel on Climate Change (IPCC) projected that melting ice may result in as much as one meter of sea-level rise by the year 2100, threatening millions of people in low-lying nations and coastal cities. Knowing how glaciers melt can help researchers predict the future. But glaciers are, well, glacial. Most of them creep roughly two to three kilometers each year, covering less distance than most of us can walk in an hour. The fastest ice flow in Greenland is the glacier Jakobshavn, which moves at the blazingly slow speed of about 16 kilometers in a year—about 180 centimeters per hour. [Read the rest at Nautilus]

A space robot arrives at a new world: Dawn at Ceres

The asteroid dwarf planet Ceres, in a view showing the intriguing two bright spots. [Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA ]

The asteroid dwarf planet Ceres, in a view showing the intriguing two bright spots. [Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA ]

Sunday is my birthday, and NASA kindly decided to give me a whole asteroid. I got to write about it for The Daily Beast.

NASA’s Dawn Spacecraft Made It to Dwarf Planet Ceres

From The Daily Beast:

When I was young, I obsessively read through a National Geographic science book called Our Universe, a good overview of current astronomy and especially the Solar System. Voyager 2 was cutting edge at the time, which gives you a hint of when this was. One chapter was devoted to asteroids, the small rocky bodies scattered throughout the inner Solar System and especially the region between Mars and Jupiter. At that time, we didn’t have clear photos of any of them, so the book had paintings of Ceres, Vesta, Pallas, and several asteroids. My mental image of Ceres for more than 30 years has been that artist’s impression: a perfectly spherical, heavily cratered object, colored a light gray.

I mention this because for the first time in history, we now have real photos of Ceres, thanks to NASA’s Dawn spacecraft. Dawn entered orbit around Ceres today, providing us with our first close-up views during its approach. [Read more at The Daily Beast…]