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 [1] 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 [3][4]. 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.
Many of us probably remember learning about greenhouse gases in middle school. The one that first comes to mind is likely carbon dioxide. But it is only one of several primary greenhouse gases. Water vapor, methane, nitrous oxide, and ozone are all on the list as well.
But what is the determining factor of whether a gas is a greenhouse gas? A greenhouse gas is a gas in the atmosphere that absorbs and emits radiation within the thermal infrared range. In other words, first it must be able to absorb radiation. Traditionally, to absorb radiation a molecule must have a dipole moment; this means that the positive and negative charges are not equally balanced in the molecule. For example, water consists of a negatively charged oxygen and two positively charged hydrogens, and like a magnet, it has a negative end and a positive end. As a counter example, hydrogen gas, H2, has no dipole moment because the charge distribution is symmetric, with an equal number of positive and negative charges between the two identical atoms. (more…)
Although only our neighboring galaxy, Andromeda, is visible with the unaided eye in the Northern hemisphere, there is a wide variety of galaxies in our universe. Grand spirals dominate the covers of many textbooks and irregular galaxies are the subject of many motivational posters, but the universe is dominated by small dwarf galaxies.
To study dwarf galaxies, astronomers first had to develop telescopes that could detect them. Unlike the Milky Way’s 200-400 billion stars, a typical dwarf galaxy only contains about 100 million stars, meaning it is much more dim in the night sky. Most telescopes rely on the visible matter–mainly stars–in a galaxy and the light it emits to detect the presence of a galaxy. This means that the bigger and brighter an object appears, the easier it is to detect; a dwarf galaxy is neither of these. We knew these small galaxies existed, but their abundance wasn’t known until modern powerful telescopes were built. (more…)
There is a dizzying array of things to think about when signing up for classes and again later when you’re thinking about what to keep the first week of classes. You may have to consider requirements for your major or for the Common Ground and Shared Goals curricula at IU. You may try to sign up for classes that your friends are taking, especially if there might be group projects. And you may even look for which classes or instructors have given out the best grades in the past.
One thing you might not have thought much about yet is how your instructors view their students: specifically, their lay theories of intelligence. Lay theories of intelligence refer to how instructors (and even students themselves) think about the nature of intelligence. There are two lay theories of intelligence: entity and incremental. The entity theory of intelligence means you think that intellectual abilities are set and cannot be changed, or in other words, thinking that you either have the innate intellectual abilities for a certain topic or you don’t. For example, some people may think they are innately talented in business and marketing but believe they just don’t have it for physics. (more…)
Are you one of the lucky ones who has seen a total solar eclipse in person? Whether you are a solar eclipse veteran or have yet to see your first one, the Great American Eclipse is coming Monday, August 21, 2017! All of North America will be able to see the Moon cover at least part of the Sun for 2-3 hours. But, the best part of the show will occur for only a couple minutes, reserved for viewers in the narrow path between Oregon and South Carolina, when the Moon will completely cover the Sun’s face! The skies will darken to twilight levels with sunset colors on the horizon, and Sun’s magnificent corona will be visible. For many Americans, this will be a once in a lifetime opportunity to see a total solar eclipse from just a day’s drive away. If you live here in Bloomington, Indiana, you’ll have to drive to either Kentucky or Illinois to be within the path of totality (the links here show the major cities in each state that are in this path).
To be able to view a total solar eclipse, when the Sun is fully blocked out, you have to be at the location within the darkest part of the moon’s shadow, the “umbra.” The map below shows the path of the total solar eclipse, which is only roughly 70 miles wide, and also shows at what local times totality will occur. The moon’s shadow will hit the United States on the West Coast in Oregon at about 10:15 am Pacific Time, and make its way across the United States, passing over Carbondale, Illinois at 1:21 pm Central Time, and then Hopkinsville, Kentucky at 1:25 pm Central Time, reaching South Carolina at 2:45 pm Eastern Time. At each location the total solar eclipse will last for just a little more than two minutes, so don’t be late! (more…)