On most weekends, you can find Indiana University graduate student Sam Cohen at Bloomington Animal Care and Control, a local animal shelter where she has volunteered for two years as a pet adoption counselor. She gets to know the dogs, talks with visitors, and helps them identify which dogs they might want to adopt. But, according to Sam, people have minds of their own when it comes to choosing their pets, and their logic is not always easy to follow. (more…)
For many of us who have been switching between different schools, even different cities for most of our life, it can be hard to visualise doing one thing for 20 years. Many undergraduates have not yet celebrated their 20th birthday. But for the past twenty years, the Cassini mission has been traveling through space with one goal: to study the world of Saturn.
It all started on October 15, 1997 when the Cassini-Huygens probe was launched from Cape Canaveral, Florida. The next seven years were spent traveling through space and using the gravity from Venus, Earth, and Jupiter to propel the probe all the way to Saturn’s orbit.
Shortly after it arrived, the Huygens probe separated from Cassini and dropped though the atmosphere of Saturn’s largest moon, Titan, and became the first probe to land on a moon other than our own. From this probe, we have learned that Titan has rain, lakes, and oceans beneath a thick Nitrogen-rich atmosphere. It’s not liquid water, but liquid ethane and methane are similarly awesome finds.
Whether it’s the “alternative facts” from politicians or the “fake news” from the media, facts are at the fore. While they can’t agree on much else, politicians, pundits, and the public do agree (mostly) about facts: facts are separate from fictions, they are reliable and authoritative, and, most importantly, they have something to do with (good) science. But, what exactly is a scientific fact?
Let’s a take a contemporary example: it is a scientific fact that the earth’s atmosphere has warmed in an unequivocal, unprecedented manner. This is the first conclusion from the most recent assessment report (AR5) from the Intergovernmental Panel on Climate Change (IPCC) (for one representation of this fact, see figure 1). You should note that this fact describes a temperature trend around the planet. It is not an explanation for the trend, such as, that humans are responsible for releasing heat-trapping emissions. (The IPCC AR5 states this as a fact as well, but we’ll start with the basics.) (more…)
What is “change”? This might at first seem like an oddly philosophical question to encounter in a science blog. The Greek philosopher Heraclitus once described change as the idea that “One cannot step into the same river twice” (paraphrased; Graham 2015). However, this more existential definition for change differs in important ways from the one that scientists use in their research into physical and biological properties of the natural world. Given that the ideas, devices, and data generated by the science and technology industries is enormous, it is critical that we understand these subtle differences in the definitions for change.
But before we can define change, we first need to take a step back. To understand how some measurement (or “variable”) of interest might change over space and time, or relative to a central value, we also need to understand change’s paired half, and that is “variability”. You may be familiar with the concept of an average: average grade in a class, average height of human beings, average daily temperature, etc. An average, or mean, is a single number that we can use to summarize and describe an entire population of individual measurements: multiple test grades, multiple people, multiple days, etc. Yet the individual values within the population can deviate from the mean (Fig. 1). The degree to which individual values differ from the population mean is a measure of variability. Statisticians and scientists need to understand how much variability there is in a population in order to understand differences between groups or how population means might change (Fig. 1). (more…)
Six months ago, my credit union sent me a new Visa card. It’s bold and dynamic, featuring a white space shuttle lifting off at dawn as flames and smoke billow from the rocket boosters. Overlying this image are four letters that catch the cashier’s eye: NASA. (more…)
Have you ever heard of genetic testing? Ever had a family member who sent a sample to companies like ancestry.com? With the rise in popularity of sites like ancestry.com, it’s becoming increasingly tempting to trace your roots through genetic testing. But, how do these genetic tests work? In this post, I will explain the science these companies use to break down your ancestry.
Genetic testing uses our DNA to identify our ancestral connections. DNA is made up of 4 different molecules: Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). A gene, the functional unit of DNA, contains stretches of A’s, T’s, G’s, and C’s. Genes are clustered together on chromosomes, and we have 23 pairs of chromosomes in each cell of our body. Because we inherit one-half of our chromosomes from each of our parents, DNA serves as a molecular tool to trace our ancestors. (more…)
When Carl Sagan said that we are made of star stuff, he wasn’t just using flowery language to appeal to your imagination; we really are made from metals formed in stars. Keeping track of these metals is not only important to our understanding of where we come from, but it is also vital to understanding the history of the stars.
But before we can dive into the role of metals in the history of stars and ourselves, we need to know what astronomers mean when they use the term metals. We aren’t referring to the conductive elements on the left of the periodic table. We mean any element that is not hydrogen or helium. The amount of these other elements determines a star’s metallicity.
The first stars formed in the Milky Way consisted mostly of hydrogen and helium. As the stars’ central temperatures and pressures rise, nuclear fusion begins in the center of the star. (more…)
When I am on Twitter, every now and then a witty or funny tweet catches my attention. I laugh, and sometimes re-tweet. More often, however, I read tweets that cause anxiety and make me frown at my computer screen with the countenance of a distraught fish. I am talking about tweets like this one (Fig. 1):
Here is what Mr. Allen most likely imagines when he thinks about evolution: At some point in the past, this monkey-like creature with long limbs that you can see at the zoo – what Mr. Allen calls an “ape” – had a baby that looked less “ape-ish” and more “human-ish”. Over many generations, this process culminated in us (Fig. 2). The small-scale equivalent (if you “zoomed in”) would be the linear genealogical chain from grandparent to grandchild.
Mr. Allen’s question could be a publicity stunt, or maybe he is just a provocateur, but many of the 50,000 “likes” his tweet has at the moment are probably genuine. This gives me cold sweats. Why? (more…)
Imagine your friend, Alex, has bipolar disorder. Alex feels like the medication he has been taking gives him headaches and that getting high on pills works better, and he chooses to stop taking it as a result. Very soon, Alex’s symptoms begin to come back. To you he seems anxious and maybe even impulsive, but maybe that is just the spontaneous Alex you’ve always known. One night, after a lot of push from his friends, he decides to get high and go out with them to blow off some steam from the stressful week he has had. Alex gets into a fight, and is arrested and charged with aggravated assault after the fight ended with the other person going to the hospital.
This is where criminal justice diversion programs, like problem-solving courts, can come into play. Problem-solving courts are becoming more and more prevalent, with almost 4,000 courts  dedicated to deferring specific populations of offenders with mental illness or substance abuse problems, veterans, those with domestic abuse charges, prostitutes, and many more. While there are many types of problem-solving courts, they share one overarching goal, to treat the underlying causes of criminal behavior and foster desistance from crime. Mental illness itself doesn’t cause crime, but untreated symptoms such as anger and impulsivity can exhibit themselves as criminal behavior, resulting in involvement with law enforcement or even conviction and incarceration . The structure of problem-solving courts allow time for defendants to talk directly with their judge on a weekly basis, live in the community, have a job, and receive treatment. (more…)
Imagine you’re out around town and see a protest down the street. Within the first two seconds, you’re making judgments about the crowd of people you see. You may evaluate the crowd and their cause as being justified and join their protest. Or you may evaluate them as being unjustified and stop to argue with the protesters or join a counter-protest to make sure your views are heard, too. When people view protests, however, they do more than just evaluate how much they agree or disagree with the opinions being raised: they may also evaluate the emotions they see among the protesters. This may be especially important to observers as it helps them figure out if a protest may become violent or dangerous, in which case they may choose to leave the area. Even the police may not be immune to these rapid perceptual judgments, which could then influence when and how much force they choose to use against those protesters.