My name is Ben. I'm a PhD student in theoretical astrophysics and astrobiology at the Origins Institute at McMaster University in Canada. I build numerical models based on chemical, geophysical, biological, and astrophysical data to try to understand one of the most fundamental mysteries in the cosmos: how did life begin?
My career path was far from a straight line. My first BSc was in software engineering, after which I did software development and testing in Calgary and Germany for a few years in my mid-20's. Ultimately, I couldn't escape the feeling that I could be making a more meaningful contribution to the world. So I went back to school to get a BSc and Msc in astrophysics, and now I have the best job in the world!
Our Paper Recently Won the Cozzarelli Prize!
One of the deepest questions intelligent beings can ponder is, where did we come from? Evolution by natural selection explains how simple cellular life progressed into the diverse set of species we observe on Earth today, but it is still unclear how non-living, organic molecules converted into to something that can reproduce and evolve. Evidence is growing for the idea that if the right ingredients are settled in the right environment, life will arise naturally. My research focuses on the early stages of this hypothesis, beginning on the surface of our early habitable planet with only the basic starting materials delivered by asteroids and comets, or those readily available from simple terrestrial processes. For details, see my scientific articles at the bottom of this page!
I was recently interviewed on CBC Quirks and Quarks. Check it out below!
My research was also recently featured on SciShow. Check it out here:
Overview of Scientific Articles
Life's emergence on Earth Was likely between 4.5 and 3.7 billion years ago
There are two types of evidence that can be used to constrain when life arose on Earth. First, astrophysical and
geophysical studies provide a timescale for the formation of Earth and the Moon, for large impact events on early
Earth, and for the cooling of the early magma ocean. From this evidence, we can determine a habitability boundary,
which is the earliest point at which Earth became habitable. Second, biosignatures in geological samples, including
microfossils, stromatolites, and chemical isotope ratios, provide evidence for when life was actually present. From
these observations we can determine a biosignature boundary, which is the earliest point at which there is clear
evidence that life existed. From these two types of evidence, we can constrain the emergence of life to 4.5–3.7 billion years ago.
RNA Likely Emerged in Warm Little Ponds fed by Meteorites
There are two competing hypotheses for the site of the origin of life: hydrothermal vents and warm little ponds. Warm little ponds have seasonal wet and dry cycles, which have been shown to promote the chaining up of nucleotides into long genetic (RNA) molecules. Genetic molecules cannot form in environments constantly surrounded by liquid water, as is the case with hydrothermal vents on the deep ocean floor, thus warm little ponds appear to have the edge. We show, by building a comprehensive numerical model of warm little pond environments, that meteorites provided high concentrations of nucleobases to thousands of warm little ponds on the early Earth, 4.5–3.7 billion years ago. These nucleobases would then quickly react to form the first RNA molecules, setting the stage for first life on Earth.
3 of the 4 Nucleobases in RNA Were Delivered to the Early Earth by Meteorites
The first forms of life on Earth are thought to have been long chains of RNA (ribonucleic acid). These molecules are capable of making imperfect copies of themselves, and thus satisfy the simplest definition of life. There are 4 different building blocks of RNA, characterized by their nucleobase. Only 3 of the 4 nucleobases can survive in the early liquid-water interiors of asteroids and rocky comets, and be delivered to the early Earth by the fragments of these bodies. The origin of the other nucleobase remains elusive.
Amino Acids in Meteorites Formed via Strecker Synthesis
Asteroids and comets formed in a disk containing basic molecules which froze onto grains. These grains contained Aluminum-26, which upon decay, releases heat. Thus the asteroids and rocky comets formed out of these grains were able to host liquid-water interiors for millions of years. These aqueous environments were ideal for forming amino acids via a well-known reaction pathway called Strecker Synthesis. Once delivered to the early Earth, meteoritic amino acids can act as catalysts for organic chemical reactions, and eventually be incorporated into the first proteins.
Carbon-rich Meteorites Contain Life's Building Blocks
Amino acids, the building blocks of proteins, and nucleobases, the building blocks of DNA/RNA have been detected in various carbon-rich meteorites. This provides evidence that these biomolecules can form chemically in some asteroids and comets (i.e. the parent bodies of meteorites), and therefore were a source of such ingredients to the early Earth.