Science Alumni Spotlight: Michael Weisberg

November 1, 2021

Dr. Michael Weisberg at the electron microscope at Kingsborough Community College.
Dr. Michael Weisberg at the electron microscope at Kingsborough Community College.

I am both alumni and faculty of the CUNY Graduate Center. I received my Ph.D. from the Earth and Environmental Sciences Program in 1991. I think I was among  the first several students to receive a Ph.D. from that Program since its inception in 1983. My thesis research was in Meteoritics, the study of meteorites. I worked under co-advisors Dr. Martin Prinz from the American Museum of Natural History (AMNH) and Prof. Cherukupalli E. Nehru from Brooklyn College. Dr. Prinz was Curator of Meteorites in the Museum’s Earth and Planetary Science Department (formerly Department of Mineral Sciences). I did much of my thesis research using samples from the meteorite collection and using the research facilities at the AMNH. I think of myself as a product of the close relationship between the AMNH and CUNY. After receiving my degree I continued to work at the AMNH with Dr. Prinz, as a Postdoctoral Fellow. In 1999, I filled a faculty line at Kingsborough Community College, became part of the faculty at the Graduate Center and continued my relationship with the AMNH as a Research Associate, all positions that I hold to this day. I was also the Deputy Executive officer of the Earth and Environmental Sciences Program at the Graduate Center from 2018-2020.

My Ph.D. thesis work was focused on primitive meteorites called carbonaceous chondrites. These meteorites are among the oldest materials that formed in our Solar System and are interpreted to have formed before the Earth and other terrestrial planets. Chondrites have changed little since they formed over 4.5 billion years ago, hence the term “primitive”. My research was specifically on exploration of carbonaceous chondrites that had not been previously studied in detail and I discovered and classified new kinds of chondrites, including unusual metal (iron-nickel)—rich chondrites. The origin of these metal-rich chondrites and their unusual characteristics is still being studied today and has led the Planetary Science Community toward exploring the role of large, asteroid-scale collisions as an important process in the early Solar system.  I recently discovered that metal-rich chondrites formed both in the inner and outer Solar System, so the process responsible for their formation, possibly large scale collisions between Solar system bodies, was Solar System wide. In my thesis I also used oxygen and nitrogen stable isotopes measurements as a tool to identify genetic relationships between different kinds of meteorites and I studied the water-rock reactions that altered meteorites while they resided on their parent asteroids.

see caption for description
NWA 8785 (ELS, AMNH PTS) map 14-Nov-2018 MKW/DE 15kV 40nA 12 ms/pxl
AI|BSE|Ca|Cr|Fe|Mg|Ni|P|Si|TiWDS 7 mu/pxl (1054x1054 pxls = 7.378 x 7.378 mm) Mg,Ca,AI

Magnesium - calcium- aluminum (red - green - blue, respectively) composite element map the of the Northwest Africa 8785 enstatite chondrite. The image shows the distribution of magnesium in red, calcium in green and aluminum in blue. The map was collected using the electron microprobe at the American Museum of Natural History. This is a powerful tool for studying the distribution of elements in rocks at the micrometer scale.

My research continues to include exploration of new types of Solar System materials to understand their origins and how they fit into to current ideas about the evolution of our Solar System and what we know about asteroids and comets. I am also interested in the geologic processes that have altered meteorites while they resided on their parent asteroids.  My most recent research is focused on a group of meteorites called the enstatite chondrites. What distinguishes these primitive meteorites from others is that they are the only chondrites that have isotope chemistry identical to the Earth and Moon. This potentially links them to the inner Solar System and makes them good candidates to be among the building blocks for the Earth and other terrestrial (Earth-like) planets. I am currently studying the small particles and inclusions that constitute these meteorites and I am documenting the range of their chemical and physical properties. My goals are to look for clues about processes and conditions that resulted in development of the inner Solar System where the Earth formed, unravel the collisional evolution of the asteroids that these meteorites are derived from and understand the origin of water on Earth.

In addition to meteorites, I am also interested in other extraterrestrial materials including the comet particles that were brought back to Earth by the Stardust Space Sample Return NASA Mission in 2006. I served on the Stardust Preliminary Examination Team when the samples were first returned to Earth. By studying comet grains I found similarities between comets and chondrites (derived from asteroids), suggesting that some asteroids may have originally formed as comets in the outer Solar System but where later transported to the asteroid belt. My work has been funded through NASA Research Programs that included Cosmochemistry, Stardust Participating Scientist, Discovery Data Analysis and Emerging Worlds. This has allowed me to support my research endeavors, as well as support graduate students and build a Scanning Electron Microscope Laboratory at Kingsborough Community College in 2006.

One of the best aspects of being on CUNY faculty is the excellent students I have had the honor to work with, both graduate and undergraduate. Serving on advisory committees for PhD students and serving as their advisor has been a rewarding experience. I have always strived to include undergraduate students in my research through independent study courses, programs like the Louis Stokes Alliance for Minority Participation (LSAMP) and the NSF funded, AMNH-CUNY Research Experience for Undergraduates (REU) Program. I recently (in 2021) co-authored a scientific paper with one of my REU students. We reported possible first evidence of extensive fluid-reaction alteration on the asteroid parent asteroid from which the enstatite chondrites are derived. I also co-authored a paper (currently in press, 2021) with a recent LSAMP student on deformation of an enstatite chondrites, leading us to the conclusion that frequent impacts (collisions) of weak magnitude, possibly during formation of asteroidal bodies, may have been the process that compacted chondrites into rock. I am currently advising Mabel Gray, an Earth and Environmental Sciences Doctoral Program student studying volatile elements and organic materials in enstatite chondrites to understand the building blocks that came together in the early Solar System to form the Earth, provide Earth with water and possibly life. I am also helping advise CUNY grad student Sam Alpert in his study of metals and oxides in meteorites to understand the separation of metal from stony material in the early Solar System, a process which may have influenced some the chemical differences observed among the terrestrial planets.