Cosmic rays from Voyager 2

New results from an old spacecraft, revealing fascinating complexities at the boundary between the heliosphere and interstellar space. This is work from my PhD advisor and colleagues. These boundaries between our local space environment and the larger Galaxy have always interested me.

Presolar Grain Workshop

We’ve just returned from the Presolar Grain Workshop, held at U. Chicago this year. It was a fantastic weekend — I learned a lot, developed some exciting new ideas for research projects, and made new friends. A highlight was our dinner *inside* the Field Museum, a tour of the U Chicago CHILI lab, and seeing some great meteorites up close (including a ~200 kg pallasite and a beautiful lunar meteorite).

Rocks from Space: summary

Rocks from Space by O. Richard Norton is one of my favorite books, a well-written introduction to meteorites. Nate Conway wrote a very nice summary which I have posted here.

Cumberland Falls

These might be the most beautiful rock samples I’ve had the pleasure of studying: Cumberland Falls (aubrite), expertly prepared in thick section by Laurence Garvie at Arizona State University.

MetSoc – Return from Japan!

Six members of our lab presented work at the 82nd Annual Meeting of the Meteoritical Society in Sapporo, Japan. It was a most fantastic conference. Our St. Louis group presented some very exciting results. Now it’s back to work for the rest of the summer!

Brendan: Ph.D.!

Yesterday Brendan successfully defended his Ph.D. The title of his dissertation was “Correlated SEM, FIB, and TEM studies of Material Collected by the NASA Stardust Spacecraft”. He talked about all the cool science he’s done while studying some of the most challenging and important extraterrestrial materials in our collection. Congratulations Brendan!

Presolar Grain Database

We’ve moved the presolar grain database to a group-editable Google Sheets format in an effort to keep it up-to-date and error free. My summer student last year Drew did a great job fixing a lot of errors in the database. If any of my esteemed colleagues would like to help maintain the database please let me know!

Presolar Grain Searching

This is the type of data we look at to identify isotopically anomalous presolar grains (micrometer sized dust that formed around other stars before the Solar System’s formation).

The left image shows the ratio of oxygen-17 to oxygen-16 in a 10×10 micron region of a primitive meteorite. You can see one small grain on the left is enriched in oxygen-17 by ~2000 per mil, which means it has twice as much oxygen-17 as terrestrial matter. On the right is the plot on the left divided by the statistical uncertainty of each pixel. This shows that the oxygen-17 anomaly is indeed statistically significant, close to 20-sigma.