Current Events

Addressing Equity in Astronomy 101, Part 1:

Over the past few years, major events have brought into the spotlight the injustices some face in their everyday lives. Unfortunately, the world of academia offers no exemptions. Every student differs when it comes to factors like race, age, gender and gender expression, socio-economic status, technology access, and food security. In the introductory astronomy classroom, our challenge is to reach every student, regardless of their background.

In this four-part series, Dr. Stacy Palen will discuss her own journey toward recognizing and addressing issues of equity in the Astro 101 classroom. We encourage this to be an open communication and discussion through the comment section below.


Before I really dive in, let me first say that the issue of equity is complex, fast-moving and developing. Equity is an issue of fairness and justice in the way people are treated.  But we can’t always identify these issues without help from others.  In the words of Maya Angelou, “Do the best you can until you know better. Then when you know better, do better.”  Be a little kind to yourself as you learn all the ways that we, both individually and as a society, fail to live up to our stated goal of “justice for all”.

There are many axes along which people may lack equity or fair treatment.  An incomplete list might include socio-economic status, sex, race, age, marital status, and disabilities of all kinds. My goal is to make every bit of astronomy as approachable as possible for every student in my classroom.  This is hard to do, frankly. It has meant learning to see the pursuit of equity as a challenge, a puzzle, or a chance to sharpen my problem-solving skills. Like most faculty, I am often overwhelmed by my To-Do list which literally never gets shorter, and it can sometimes be hard to summon enthusiasm for creating yet another way to explain a concept or teach a skill.  Usually, I can find the grit to take a deep breath and then dive in.

I should say a few words about where I teach, to clarify my background.  I am not an expert in educational equity, race or gender relations, or any kind of sociology.  Instead, I am a person who has spent a long time in the trenches of teaching and learning, trying to adapt to the environments in which I work. I have been 20 years now at Weber State University in Ogden, UT. We are a “regional, open-enrollment, dual-mission University”. To translate:

Regional: we primarily draw students from the surrounding area who are non-traditional. Students may be older, married, have children, full-time jobs or be full-time caretakers for parents or other relatives.  A very small fraction of students look like the “typical” college student.  On the plus side, nearly every student lives off campus and commutes, so we don’t have any party-school problems!  On the minus side, that means they don’t really form study groups or stick around on campus to find out what a college education is really all about (I would argue: NOT job-training).

Open-enrollment: we have no admissions standards; we take everyone. I say we are a “second chance” institution, not a “second-rate” institution. I would put my best students at Weber into competition with my best students at the University of Washington (where I used to work) any day of the week.  The proportion of those top students is much smaller, however, because of the competing responsibilities in student’s lives.  Very few of my students can focus the majority of their effort or time on their education, and a very large fraction of them are first generation college students. First-gen students have special challenges simply (sometimes literally) navigating the campus.

Dual-mission: we co-locate a community college onto the university campus.  At registration, no distinction is made among those students.  This means a typical Astro101 course will have students from high school through the end of college and beyond. We have a significant fraction of “community” students; retired aerospace engineers, teachers working professional development, etc.

We also have a significant focus on supporting Hill Air Force Base, which means we have a significant population of current military personnel and veterans. Deployment creates a unique set of problems to solve!

Also in my background is my undergraduate education, which occurred at Rutgers University in Camden, NJ, across the river from Philadelphia. Camden is a famously dangerous place to live, even now. It was there that I really learned what “disadvantaged” and “underserved” meant.  My eyes were opened by that experience, and I try hard to keep them that way.

This practical background has led to a teaching approach that has equity at its heart, because it led me to experiment so widely with approaches that could reach students who were facing enormous challenges in their pursuit of their education.  I’m not always successful, but I’m always learning.  And when I know better, I can do better.

Next time: The framework I have developed for myself for addressing equity in my classroom.

Current Events: Moon Formation around Exoplanets

By Stacy Palen

ALMA continues to delight us with its unsurpassed and exquisite resolution and sensitivity. In this case, we have the first clear detection of a moon-forming disc around a planet orbiting a very, very young star.

Below are some questions to ask your students based on this article.

1). What is extraordinary about this observation?

Answer: For the first time, astronomers clearly identified a disc around a planet and estimated its size.

2). What sort of planet is PDS 70b at the center of this disc?

Answer: A gas giant, like Jupiter.

3). How large (in AU) is the moon-forming disc, and how much mass does it have?

Answer: The disc is about 1 AU in diameter, and it has the mass of about 3 of Earth’s moons.

4). Why is such a disc not detected around PDS 70b?

Answer: That planet did not have enough dust around it, because its dust was “stolen” by PDS 70c.

5). Does this observation support or refute the basic theory of star and planet formation that you learned about in the text?

Answer: This observation supports that theory and is basically exactly what we would predict we should find!

Current Events: Astronomers Discover Record-Breaking Star As Small As the Moon but with More Mass Than the Sun

By Stacy Palen

Astronomers set a new record for the densest known white dwarf.

Below are some questions to ask your students about this article.

1). How is a white dwarf typically formed?

Answer: A star less than about 8 times the mass of the Sun loses its outer layers, leaving behind a dense carbon core. (Note: This is NOT in the article, but they should know it from class.)

2). How might a system of two white dwarfs form?

Answer: If a binary star system consists of two stars less than 8 times the mass of the Sun, and both stars evolve, the system will become a binary white dwarf system.

3). The lead author states, “Smaller white dwarfs are more massive.” Is this how normal matter (like cows and people) behaves? What is the name for matter that behaves this way?

Answer: No; degenerate matter.

4). How massive is the combined star?

Answer: 1.35 times the mass of the Sun.

5). Why did this pair of white dwarfs not become a supernova when they merged?

Answer: Because this combined mass is under the Chandrasekhar limit.

6). What comes next for this white dwarf?

Answer: It may become a neutron star, as it is dense enough for charge destruction to take place.

7). How often does a merger like this happen?

Answer: We don’t know, but they are probably common, if there is one nearby.

8). This white dwarf has an extreme magnetic field. How did it develop such a strong magnetic field?

Answer: Nobody knows!

Current Events: "There May Not Be Conflict After All" in Expanding Universe Debate

By Stacy Palen

The two main ways to measure the expansion of the universe have turned in different answers. For the last several years, astronomers have been arguing about whether this disagreement is unimportant (a result of measurement errors) or important (a result of new, unknown physics). This is a terrific example of the process of science. In June 2021, Wendy Freedman published a new review paper arguing that there is not a conflict after all.

Below are some questions to ask your students based on this article.

1). What is the Hubble constant?

Answer: The Hubble constant measures the rate at which the universe is expanding.

2). What are the two ways to measure the Hubble constant?

Answer: The first way is to look at the cosmic microwave background. The second is to measure the velocities and distances of galaxies to make the Hubble law graph.

3). What are the two values of the Hubble constant derived from these two methods?

Answer: 67.4 km/s/Mpc and 72 km/s/Mpc.

4). Historically, the distance to nearby galaxies was determined using Cepheid variables. What is the problem with these measurements?

Answer: They are noisy and more complicated, and the observations may be contaminated.

5). What other objects are now being used to measure the distance to nearby galaxies?

Answer: Freedman is using red giant stars, which always reach the same peak brightness before fading. These observations are less noisy.

6). What does this new method of measuring distances give for the value of the Hubble constant?

Answer: 69.8 km/s/Mpc.

7). Is this new method in better or worse agreement with the method that uses the cosmic microwave background?

Answer: This new method gives a value that is much closer—it cuts the disagreement in half.

8). Review the Scientific Method flowchart in Chapter 1 of the textbook. What part of the flowchart describes the science that’s described in this article?

Answer: The science in the article is on the loop on the left. Previous tests did not agree, so a new hypothesis was suggested (that Cepheid variables are subject to too much noise), and a new experiment (measuring red giants) was devised and performed. Further tests will be in the loop on the right.

Current Events: The Milky Way's Shredded Companion Provides Clues about Dark Matter

By Stacy Palen

The Milky Way is tearing apart the Sagittarius dwarf galaxy. Gaia observations of the resulting tidal streams permit sufficient accuracy to detect the influence of the Large Magellanic Cloud on the interaction. Simulations show that the Milky Way’s dark matter halo is complex.

Below are some questions to ask your students based on this article.

1). Prior to this study, what was known about the shape of the dark matter halo?

Answer: Not much. Different simulations found various shapes, some more symmetric than others.

2). In this study, what is new that allows astronomers to build a more detailed picture?

Answer: The Gaia satellite pinpoints the location of stars with truly unprecedented accuracy.

3). The following questions cannot be answered directly from the article but can be answered with a Google search. The paper discussed in this article was posted to the preprint server arXiv. What is a preprint?

Answer: It is a full draft that has not been peer reviewed.

4). In the process of scientific publication, what comes after the preprint stage?

Answer: The article undergoes formal peer review, and then it might be published.

5). What is the advantage of preprints?

Answer: They give access to the most up-to-date research.

6). Should you treat the results discussed here with more or less skepticism than the results published in a peer-reviewed journal?

Answer: You should treat them with more skepticism.

7). How could you know if the results held up to peer review?

Answer: You could search for the authors’ names or the topic in a database of journal articles.

Current Events: First Results from Mars InSight

By Stacy Palen

The Mars InSight lander is using marsquakes to probe the interior of Mars. In July 2021, the first clutch of papers on the results were published.

Below are some questions to ask your students based on this article.

1). What is a marsquake?

Answer: It’s like an earthquake, but on Mars. While on Earth, quakes are caused by the movement of tectonic plates, on Mars, quakes are caused by stresses as the planet cools.

2). How many marsquakes had InSight observed as of the date of this article?

Answer: 733, but only 35 of them provided data for the papers discussed here.

3). How many interior layers was Mars predicted to have?

Answer: Mars was predicted to have three layers: a crust, a mantle, and a core.

4). How many layers were found by Mars InSight? Were they as predicted?

Answer: Three layers were observed. The core was the size that was predicted, but the crust was thinner than expected. Logically, we conclude that the mantle would be thicker than expected.

5). Were there any other surprises in the observations?

Answer: Yes. The biggest quakes come from one area: Cerberus Fossae, which has “recently” been volcanically active. But no quakes have been observed from the giant Tharsis region, which might be a result of Mars InSight’s location in the “shadow” of the core.

6). Is the mission still ongoing, or has Mars InSight finished its work?

Answer: The mission is still ongoing.

Current Events: Venus Lacks Plate Tectonics, But It Has Something Much More Quirky

By Stacy Palen

A reanalysis of Magellan images has led to the hypothesis that Venus has “campi,” or blocks of rock that float on the mantle, shimmying and bumping into each other like packs of ice.

Below are some questions to ask your students based on this article.

1). Describe plate tectonics on Earth.

Answer: On Earth, a small number of very large plates float on top of the mantle, bumping into each other, sliding under or along each other’s boundaries, and creating geological features.

2). Why is liquid water required for plate tectonics?

Answer: Water lubricates the plates, permitting them to break bend and flow.

3). What happened to Venus’ liquid water?

Answer: It was lost during some kind of apocalyptic event that heated Venus to temperatures too high for liquid water to persist. This event happened about a billion years ago.

4). How is the process with campi, described in the article, different from that of plate tectonics?

Answer: Campi don’t flow past, rise over, or slide under each other. The campi are much smaller than the tectonic plates on Earth.

5). What is the evidence that this process might still be ongoing?

Answer: The observed campi are in the lava-covered lowlands, which are geologically young.

6). How will scientists explore whether this process is still actually occurring?

Answer: Several spacecraft are heading to Venus over the next few years. These spacecraft have higher-resolution radars than Magellan's and will compare the current positions of the campi with the positions observed by Magellan.

Current Events: The Tides of the Moon and the Suez Canal

By Stacy Palen

How delightful! The phases of the Moon were in the news in late March, giving all of us an opportunity to teach students about the practical applications of astronomy in the modern world. You will likely recall the giant container ship that was stuck in the Suez Canal for almost a week, disrupting supply chains around the world. The arrival of spring tide helped float the ship off the bank where it was wedged, setting it free.

CNN reported about this news, although there are other outlets as well. 

I have included some snippets about this news with some questions on my final exam, asking students to sketch the relative positions of the Earth, Moon, and Sun during spring tide, and to make a sketch that demonstrates why so-called “supermoons” result in extra-high spring tides. Sketches like these are very quick to grade, so I like to use them during any times of the semester when I have a large grading load.

I can also code these questions as addressing the “Science and Society” general-education learning outcome, so that the crowd that does our general-education assessment will be able to check the box on their report.

I have in mind that I could build an entire assignment around this event, for future semesters, but I haven’t done it yet. Like you, I am just trying to put one foot in front of the other to get to the end of this semester!

Current Events: NASA Releases Stunning Hi-Res Photos of Jupiter's Swirling Atmosphere

By Stacy Palen

Sometimes, you just want to look at a lot of pretty pictures. Juno’s got ‘em. This is a nice intersection of science and society because there are issues of intellectual property rights here that can prompt students to think a little more deeply about who owns science and scientific data.

Below are some questions to ask your students based on this article.

1). What is a “citizen scientist?”

Answer: A citizen scientist helps scientists analyze raw data or produce images from raw data.

2). The images shown in the article have been processed to create “visually pleasing work for the public.” Click through to the dedicated Juno website to look at a few raw images. How do these processed images differ from the raw images?

Answer: The processed images have much greater contrast and are more colorful. The colors are often changed.

3). What information is lost when the images are processed in this way, and what information is made more available? 

Answer: Information about composition is lost, especially if the color is changed, but information about wind patterns is enhanced and made more visible.

4). Is it “honest” to process images in this way and present them as images of Jupiter?

Answer: Answers vary.

5). Are these images art, science, or something in between? Support your answer with an argument about the purpose of art and/or science.

Answer: Answers vary, but something in between is most likely.

6). What is the benefit of making “visually pleasing work for the public?”

Answer: Answers vary, but I expect to see something about public support for science.

7). You may have heard the term “intellectual property”; this is the concept that gives rise to copyright law, for example, where artists and writers own their work. Historically, images from NASA spacecraft have been part of the public domain—because the public paid for the spacecraft, they own its products, and anyone could use them to make posters or T-shirts. These images, though, have a more complicated origin. The raw data comes from the spacecraft, but the processing has been done by an unpaid graphic artist who has done something absolutely unique with each image. Who do YOU think “owns” these images: the public or the artist?  Explain and support your viewpoint.

Answer: Answers vary, but I’m looking for something “well-reasoned and insightful.”

Current Events: Hubble Uncovers Concentration of Small Black Holes

By Stacy Palen

Astronomers have long been on the hunt for “intermediate-mass” black holes. These are black holes with masses between a few hundred and a few ten-thousands of solar masses. It was thought that these should exist in globular clusters. While looking for these, astronomers have instead found a swarm of smaller black holes, forming a mini-cluster in the center of a globular cluster!

Below are some questions to ask your students based on this article.

1). What is the approximate range of masses for an intermediate-mass black hole?

Answer: Tens to hundreds of thousands of solar masses.

2). How old is this globular cluster? 

Answer: This globular cluster is almost as old as the universe itself, so nearly 13.7 billion years old.

3). How do astronomers find the age of a globular cluster?

Answer: They make an H-R diagram and find the main-sequence turnoff.

4). How does the team of astronomers from the IAP know that there is not one single black hole at the center, but rather a swarm of black holes?

Answer: The shape of the orbits of nearby stars shows that the mass at the center is extended in size, rather than point-like.

5). How do they know that those masses in the core are black holes and not stars?

Answer: They used the theory of stellar evolution, combined with the fact that the mass is invisible.

6). Why are all the black holes in the cluster found near the core?

Answer: Because of dynamical friction, where they lose momentum to other less-massive stars.

7). How might astronomers further test this idea about the core of this globular cluster?

Answer: Mergers of these black holes might be detected by LIGO/VIRGO.