What Have We Learned About Mars?

Where Are The Black Physicists?

Black scientists make up less than one percent of physics PhDs in the U.S. And since 1999, most physics departments in the country have failed to graduate more than one or two Black undergraduates. Furthermore, the share of Black students in physics is declining: If the number receiving a bachelor’s degree in physics had kept pace with the rising popularity of the major, there would be 350 Black physicists graduating every year. Instead, in 2020, that number was 262.

But why is this number so small? A comprehensive investigative series in Science Magazine this week examines those statistics, the academic climate of physics departments, and how academia may be limiting the achievement of Black students. The series also highlights some success stories about proposed solutions, with mixed results.

But why is physics a uniquely white, male discipline—and how can institutions make the climate more friendly to students from marginalized backgrounds? Ira talks to Apriel Hodari, one of 150 Black women to receive a PhD in physics in the U.S., who now researches the culture of higher education in STEM fields.

 

Why The Equinox Can Make Your Credit Card Fail

Twice a year, people listening to signals from satellites in geostationary orbit face a problem known as a solar outage, a solar transit, or sun fade. Around the spring equinox, the Sun approaches the equator from the south, as the north gets ready for spring. In the fall, near the autumnal equinox, the Sun appears to move back below the equator. During these times, it comes into the view of Earthbound satellite dishes directed at geostationary satellites positioned some 22,000 miles above the equator.

When a ground receiver, the satellite it’s looking at, and the Sun all line up, the radiation from the Sun can temporarily overwhelm the satellite receiver. Think of it like when you’re driving on a westbound road close to sunset, and you’re staring straight into the setting sun—it gets hard to read the road signs.

The effect is temporary: a maximum of 12 minutes at any given location for several days in a row. But it can affect everything from a satellite TV dish to credit card processing at your local gas station—even public radio stations receiving live programming over the satellite network.

SciFri’s Charles Bergquist talks with Chris DeBoy, who teaches a course in satellite communications at the Johns Hopkins University (and is also the RF communications lead for the New Horizons Mission to Pluto, and the Space Engineering Branch Manager at the Johns Hopkins Applied Physics Laboratory), about the advantages and disadvantages of geostationary satellites, and what can be done to minimize the impact of solar outages. They are joined by MaryJane Peters, technical operations chief at KAZU in Monterey, California, who describes the effect the seasonal outages have on station operations.

Can Meteorites On Earth Point To Ancient Life On Mars?

In 1996, the late astrobiologist David McKay and his team published a paper arguing that a four-pound rock from Mars, called Allan Hills 84001 (found in Antarctica), showed evidence of ancient microbial life on the planet Mars. The team pointed to several mineral structures, including tiny beads of magnetite, as well as shapes that might be fossilized bacteria.

This hypothesis ignited a storm of controversy and a flurry of research that contradicted the team’s theory. But decades later, ALH 84001, like the other meteorites that have been linked to the Red Planet, remains an important insight into Martian geology and the formation of organic molecules in the absence of biological processes.

Producer Christie Taylor talks to astrobiologist Andrew Steele, who has been studying ALH 84001 and other meteorites for decades. He discusses the process of probing meteorites for data, the difficulty of studying rocks without their original contexts, and how new samples from the Perseverance rover could change everything. Plus, how the original controversy over ALH 84001 changed the trajectory of planetary science.

 

From Zero To 100 Butts: The Wild World Of Invertebrate Behinds

Recently, the staff of Science Friday came across a tweet that caught our attention, sent out by researcher Dr. Maureen Berg.

 

Turns out, it was a call to source comic ideas for Invertebrate Butt Week, a celebration of—you guessed it—the butts of invertebrates. “Invertebrates really get the short end of the stick,” says Rosemary Mosco, the creator of the comic series Bird And Moon and #InverteButtWeek organizer. “People are not as excited about them as, say, a majestic whale or a beautiful bird. And I love my birds, but [invertebrates have] such an incredible diversity. So, butts are sort of a cheeky way to access some of that amazing diversity and celebrate it.”

 

Rosemary and other scientists and illustrators teamed up to create #InverteButtWeek, a celebration of the behinds of the backbone-less. “It’s a chance for some people who do science communication to do the silliest thing that they can possibly think of,” says Dr. Ainsley Seago, curator of invertebrate zoology at the Carnegie Museum of Natural History.

 

Science Friday’s Daniel Peterschmidt talks to the organizers of #InverteButtWeek about how it came together, their favorite invertebrate butt facts (like how sea cucumbers have anal teeth), and how you can participate in the celebration.

 

Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.