Why do scientists get things wrong?

By Dr. Christina Smith

It occurred to me over the last couple of weeks that lots of people have found the changing information and guidelines, recommendations, and findings on COVID-19 to be surprising, sometimes frustrating, and perhaps don’t understand why things can change so rapidly. I’ve heard things like “why should I trust this information if its different to last week’s?” I’m not an epidemiologist or any kind of bio-anything scientist so that’s the only thing I’ll be saying about COVID-19. But, it dawned on me that perhaps it isn’t completely clear that people at the forefront of any field in science are really piecing together bits of information and evidence the best way they can to try and figure out what is happening. With time and enough information the explanations (often – not always) become more and more in agreement but with newer problems and smaller amounts of information, the findings that people come up with can vary wildly.

Intro to Infection Modelling

Like everyone else, the COVID-19 pandemic has drastically changed how our group operates and interacts. However, we've been luckier than others in our operations since relatively few projects that are currently active require access to the university experimental facilities which are now closed. 

Everyone has a different way of coping with the anxiety and stress that an unprecedented event like this one produces. For many scientists, there is a certain comfort in information. Sometimes the act of defining, modeling, classifying can make you feel as if you have more control over an uncontrollable situation and, at least, you might gain insight that might be actionable. 

The next two articles on this blog, submitted by the Postdocs, discuss the pandemic. The first, below, tries to consider the modeling of these systems. The second tries to grapple with the things that scientists get "wrong," by laying bare how piecing together a real-world puzzle from incomplete information can sometimes lead to dramatic shifts in our understanding of how these systems operate. In times like these, the public often turns to scientists for advice and it's important to remember that none of us has a crystal ball.

Wherever you are, I hope you are as safe and secure as you can be and are managing the physical and mental toll. No matter your circumstances you aren't alone in this.

by Dr. Paul Godin

With the COVID-19 pandemic drastically impacting our day-to-day lives, I thought it worth examining how epidemiologist model infections and how social distancing can “flatten the curve”.  (Note, this idea was inspired by Peter Taylor, who provided the initial matlab code to run the simulations)

Characterizing the atmosphere of exoplanet K2-141b

 

The image above (Credit: ESO/L. Calçada) shows CoRoT-7b, an exoplanet located so close to its parent star that the input of radiation causes the surface to melt. It is for this reason that these strange worlds are called "Lava Planets" and they have unique atmospheres that are made up of rocky vapours. PVL PhD student Giang Nguyen has been working on understanding how a similar world, K2-141b, operates in collaboration with Prof. Nick Cowan at McGill University. There will be a paper out soon, but Giang provides a preview of the work below.

by Giang Nguyen

K2-141b belongs to a subset of rocky planets that orbit very closely to their star and are tidally locked. The dayside of the planet is hot enough to not only melt rocks (about half the planet is one giant magma ocean, hence the name lava planet) but to vapourize them as well. This vapourization process ultimately creates a thin atmosphere that may be detectable from hundreds of light year away with the right space telescopes.

For my work, I have been using computer models to simulate the atmosphere of K2-141b. I considered two cases: a sodium atmosphere and a silica atmosphere. Sodium is chosen as it is the most volatile component in minerals while silica is chosen as it is expected to be the most abundant for rocky planets. The atmospheric model is based on the shallow-wave equations with steady-state flow driven mainly by the temperature contrast between the planet’s permanent dayside and nightside hemispheres. As expected, since sodium is much more volatile, the pressure of the sodium atmosphere is more than 50 times that of the silica atmosphere. This also allows the sodium atmosphere to exist beyond the day-night terminator while the silica atmosphere collapses just before this point. However, as sodium has a lower heat capacity than silica, the sodium atmosphere cools off much faster which has implications for observations. In either case, the wind exceeds 1.5 km/s which is useful for high-dispersion spectroscopy.

The Worst Thing on Mars is Powdered Milk

Hemani Kalucha (bottom of image above) recently became the second member of our group to put in a tour of service at the Mars Desert Research Station in Utah, USA (the other being former PVL MSc Eric Shear). She shares her experience and some great photos below.

by Hemani Kalucha

Sitting on top of the North Ridge at 3 pm on a Saturday, I experienced, for the first time, a real “deafening silence”. I was 200 metres above the Utah desert, and I could see nothing but miles of reddish sand until the horizon in every direction. It was a peaceful moment that marked the end of our two week rotation at the Mars Desert Research Station (MDRS), an analogue facility in the middle of the Utah desert. Our crew was made up of six members – Maria Grulich (Commander), Luis Monge (Engineer), Jess Todd (Greenhab Officer), Me (Journalist), Rawan Alshammari (Doctor), and Ghanim Aloitabi (Astronomer). Together, it was our job to live and work as astronauts on Mars. 

Putting That Space Engineering Degree To Use

Many of our projects are muti-faceted. The MAPLE project, being led by PDF Christina Smith, is no exception. Primarily tasked to couple a CW laser with an all-sky camera, this work also includes side investigations, such as the exploration of HDR imaging led by PVL MSc Trainee Alex Innanen.

by Alex Innanen

For the past… perhaps longer than I would like to admit, I have been working on building a setup for an HDR imaging system using a DMD. That’s a lot of acronyms right off the bat so let’s break that down.

HDR stands for High Dynamic Range – that is, in imaging, achieving a greater range of luminosity values. Have you ever tried to take a picture with a mix of bright light and shade? The light tends to overpower the shaded regions, and you can’t see details within them. Take this picture of my office I took with my phone: you can’t see anything inside the office because of the sheer brightness of the window. Conversely, if I try to resolve the inside of the office, the scene through the window gets washed out. HDR imaging (HDRI) techniques can help us see both!

The strength of Ancient Mars’ Greenhouse Effect

Over the past couple of years, Paul Godin has been leading an effort in my group to understand the warming potential of the ancient martian atmosphere, above he shows experimentally-derived values for CO2-CH4 CIA as measured using the Canadian Light Source. He just submitted a paper on this topic which is now under review.
 

By Dr. Paul Godin

We’ve discussed in previous blogposts about our group’s effort to better constrain the early Mars atmosphere by taking measurements at the Canadian Light Source (http://york-pvl.blogspot.com/2018/11/searching-for-liquid-water-on-mars-at.html and http://york-pvl.blogspot.com/2019/04/the-continuing-adventures-at-canadian.html). As a quick summary, geological features on the surface of present-day Mars imply that there was once liquid water on the surface. To have liquid water on the surface, a sufficiently strongly absorbing atmosphere is required to produce enough of a greenhouse effect to warm the surface above freezing temperatures. Since most ancient Mars modeling suggest that Mars did not have a dense atmosphere, the remaining possibility is that the gas composition of an ancient Mars atmosphere could be strongly absorbing. One idea was collision induced absorption (CIA) between CO2 and H2 molecules, and CO2 and CH4 molecules, could provide enough absorption to warm ancient Mars. The goal of the CLS trips was to experimentally measure this CIA effect to determine if it was as strong as predicted.

Question Time (Part 2)

Something us scientists love to do is to take questions from the public about the work that we do and the topics that we study. I know that when I give a public talk, the Q&A is almost always my favorite part. This week, Christina holds another such session after the success of her previous post on this topic.

by Dr. Christina Smith

A few months ago (or maybe longer than a few…) I did a post called “Answer me these questions… five?” where I answered questions that people had asked me on social media. Its my turn again to do a post and I thought why not reprise this topic as it was quite fun the first time!

So, without further ado…