Check out my latest articles and writings this past month, for Undark, Nature, New Scientist, and Now.Space. As always, thanks go to my editors. If you read just one, I recommend the Undark piece, which I’m particularly proud of and took a lot of work to write and report on.

 

Bite Marks and Bullet Holes

The Attorney General ended the National Commission on Forensic Science, suppressing an opportunity for reducing convictions based on faulty evidence.

Keith Harward spent more than three decades in prison on the presumed strength of forensic dentistry. No fewer than six forensic dentists testified that his teeth matched a bite mark on a 1982 victim of rape and murder. But in April of last year, after serving more than 33 years in a Virginia penitentiary, new DNA evidence prompted the state Supreme Court to make official what Harward knew all along: He was innocent, and the teeth mark analysis was unequivocally, tragically wrong.

“Bite mark evidence is what the whole case hinged on and ultimately had me convicted,” Harward said. “But,” he added, “this stuff is just guesswork.”

Today, many forensic scientists would agree — and they’d say the same, or nearly so, about a menagerie of other techniques that are used to convict people of crimes, from handwriting analysis to tire track comparisons. And while some techniques fare better than others, everything short of DNA analysis has been shown to be widely variable in reliability, with much hinging on forensic practitioners with widely varying approaches and expertise.

[Read the entire story in Undark, published on 2 June.]

 

Fleeting phase of planet formation discovered

These celestial bodies coalesce into objects shaped like giant red blood cells.

Rocky planets, including Earth, endure violent beginnings. Giant impacts vaporize enormous chunks of protoplanets, surrounding them in a flattened halo of debris. Scientists believe that these disks eventually condense to form planets. Now, improved computer simulations of planet formation suggest that many of these embryonic objects pass through a phase late in their adolescence in which they assume the shape of enormous red blood cells called synestia.

Researchers led by planetary scientist Sarah Stewart at the University of California, Davis, published their description of these huge, spinning clouds of vaporized rock on 22 May in the Journal of Geophysical Research: Planets. The finding could help scientists to improve their understanding of planet formation, and lead to better explanations of how Earth’s Moon formed.

“We discovered that there’s a different class of objects where the system is rotating so quickly, and it’s so hot, that there’s no actual boundary between what we used to call the planet and the disk,” Stewart says…

[Read the entire story in Nature, published on 24 May.]

 

Nowcasting may help forecast big earthquakes in 53 major cities

The ground can start shaking under your feet with almost no warning. Earthquakes have proven nearly impossible to forecast so far, but a technique borrowed from economics and finance can now help us estimate how high the risk is.

Seismic nowcasting, as it is called, assesses the current risk of a major earthquake in a given area based on the smaller tremors the area has experienced in the past. Nowcasting gives a snapshot in time, whereas forecasting looks into the future. It’s akin to metrics that incorporate the latest fluctuating data to evaluate whether there’s a looming downturn in an economy or industry.

John Rundle at the University of California, Davis, and colleagues have used the technique on data from the US Geological Survey’s earthquake catalogue to calculate the “earthquake score” of 53 major cities around the world.

“If you have a high earthquake score, and then you start seeing more small earthquakes, I’d get worried. You’re accumulating hazard, so to speak,” says Rundle, who presented the team’s results at an earth science conference in Chiba, Japan, on 22 May…

[Read the entire story in New Scientist, published on 26 May.]

 

New Study Shows How Even Small Asteroids Can Make a Big Impact

A giant asteroid careening toward Earth threatens to wipe out human civilization as we know it, and it’s up to scientists with nukes or Bruce Willis to save the day and prevent us from going the way of the dinosaurs. We see this in the movies, but such asteroids are extremely rare. More than 90% of them have been tracked with telescopes, and they’re not on a path to Earth, at least in our lifetimes.

But impacts from asteroids between the size of a house and a city block are much more common and could pose a greater threat, according to a new study published this month in Icarus. An asteroid with a diameter of just 65 meters could do a lot of damage, from driving tsunamis to decimating a highly populated region. Moreover, asteroids between 100 and 130 meters in diameter pose an even bigger threat due to their thermal radiation, according to Donovan Mathias of NASA Ames Research Center in Mountain View, California, lead author of the study.

Mathias and his team used computer simulations of hypothetical asteroids to model impact scenarios of varying sizes, density, entry angle, impact speed, and impact location. The team simulated an asteroid’s trajectory towards the Earth’s surface and then calculated the spread of the impact’s energy to determine local hazards, such as blast effects and the potential to create a tsunami. The team also mapped out the asteroid’s damage zone and estimated the number of people that would be affected by the impact…

[Read the entire story in Now.Space, published on 10 May.]