February 2019 Letter from the Director

DTM Director Rick Carlson shows the geochemistry team's new mass spectrometer to a high school student visiting BBR on February 14 as part of the American Junior Academy of Science conference. Photo: Roberto Molar Candanosa.
Thursday, February 28, 2019 

January and February have been busy months at DTM in the midst of the typically chilly and grey Washington winter. Not long after the end-of-the-year break, the DTM geochemistry group received its new mass spectrometer, a Thermo-Electron Triton Thermal Ionization Mass Spectrometer (TIMS), shown being off-loaded from the delivery truck in the picture below. The instrument is now mostly assembled and ready to make the diverse isotopic measurements needed by the projects currently on-going within the geochemistry group.

The new thermal ionization mass spectrometer arrived on January 15, 2019. Photo: Roberto Molar Candanosa, DTM.

The arrival of this instrument frees up our existing 2004-vintage Triton for installation of a new type of ion source, a cavity ion source that offers the potential of a factor of ten or more improvement in sensitivity compared to the traditional flat-filament thermal ionization source. Once the performance of the DTM designed and built cavity ion source is verified, the source will be transferred to the old Triton to enable extremely high precision isotope measurements to further unlock the secrets of early Solar System and Earth differentiation that were recorded in the variety of short-lived (half-lives of 0.7-100 million years) radioactive elements that were present when the Solar System formed.

Development of the cavity source for the 2004-vintage Triton is currently being done by DTM postdoc Jesse Reimink and myself on the reassembled, DTM designed and built, 15-inch radius TIMS, where we achieved "first light" with the new ion source just last week. Photo: Jesse Reimink, DTM.

Nature Geoscience published a News and Views article by DTM Staff Scientist Peter Driscoll near the end of January. Driscoll's article commented on the report of paleomagnetic measurements that support his previous prediction of a declining, and perhaps multi-polar, magnetic field on Earth near the end of the Precambrian period about 560 million years ago. His previous theoretical study of the generation of Earth's magnetic field by convection in Earth's core noted the possibility that declining heat flux into the mantle over time would cause a decline in field strength and cause the field to become disorganized, losing its dipolar character. Nucleation and the beginning of crystallization of the solid inner core would provide a new energy source to kickstart the field again, causing it to strengthen and return to the dipole we are familiar with today. Whether or not the timing of this period of weak, unorganized, magnetic field is at all connected with the explosion in the diversity of terrestrial life at this time period is not yet known. If further measurements provide a clearer view of the nature of the magnetic field during this era, investigations into the consequences of such a marked transition in magnetic field strength for the evolution of life on Earth, particularly at its surface, could help determine whether the temporal similarity of these two events is more than just coincidence.

January and February saw a number of outreach activities by DTM scientists. DTM Staff Scientist Alan Boss' general interest book Universal Life: An inside look behind the race to discover life beyond Earth was published. The book received a very complimentary review in the Washington Post. Alan also presented the opening address to the meeting of the American Junior Academy of Sciences (AJAS). The AJAS assembles top high-school students interested in STEM careers from around the country to attend the American Association for Advancement of Science annual meeting that this year was held in Washington. Fifty of the AJAS students and chaperones were given a tour of the various laboratories on the BBR campus followed the next day by a breakfast generously hosted by P-Street for the full attendance of 200 students and senior scientists participating in the AJAS meeting. In addition, DTM Staff Scientist Alycia Weinberger helped staff the Carnegie booth at the AAAS Family Science Day during the AAAS meeting, teaching the participants how to build their own spectrographs.

Scott took a full auditorium on a journey through the largest, deepest survey ever attempted of our Solar System's fringes. Photo: Roberto Molar Candanosa, DTM.

Late in February, Scott Sheppard set a new preregistration record for a Capital Science Lecture with 1300 Washingtonians signing up for his lecture on the search for Planet X. Even though the lecture had to be postponed for a day due to snow, the Elihu Root auditorium at P-Street was filled to overflowing to the point that the lecture had to start ten minutes late to accommodate the throng of people still entering the building. At the end of his lecture, Scott announced a public naming contest for five of the moons of Jupiter that he discovered. The rules for Jupiter moon naming require a pretty in-depth knowledge of Roman or Greek mythology as the names must be of either descendants or lovers of the god known as Jupiter or Zeus. Given the large number of moons now known to be orbiting Jupiter, one hopes that Zeus or Jupiter were sufficiently, um....connected to provide enough candidates for these names. The end date for the naming contest is April 15, 2019.

Finally, we note with pride that DTM Postdoctoral Fellow Jaehan Bae was awarded the Ralph B. Baldwin Prize in Astrophysics and Space Sciences from the University of Michigan. The Baldwin Prize is given to recent Michigan PhD students on the basis of the excellence of their research activities as revealed in the student's thesis and publications. In addition to the honor of the Baldwin Prize, Jaehan also was just awarded a NASA Hubble Fellowship as a Sagan Fellow. To our delight, he has chosen to remain at DTM to pursue the research supported by this prestigious award.

Richard Carlson, Director, DTM
Carnegie Institution for Science

February 2018 Newsletter