Author Archives:

Dr. Brenda Frye

About Dr. Brenda Frye

Brenda L. Frye is an observational cosmologist at the Department of Astronomy/Steward Observatory, University of Arizona. She earned her Ph. D. in Astrophysics from the University of California at Berkeley, assisted by a National Science Foundation Graduate Research Fellowship. Her thesis work involved measuring the concentration of the total mass of visible plus dark matter in the fields of massive galaxy clusters, a program requiring the use of some of the largest telescopes in the world. Moving a mile from her Ph. D. institution, she assumed a postdoctoral position with the Supernova Cosmology Project at Lawrence Berkeley National Laboratory under the direction of Professor Saul Permutter. She then treked across the country to take a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship and a Princeton Council on Sciences and Technology Fellowship both at Princeton University. Moving further east, she became a Lecturer in Physics at Dublin City University in Dublin, Ireland, where a number of European collaborations were formed. From there she crossed back across the pond to the west coast of the U. S. to become a tenure-track Assistant Professor of Physics at the University of San Francisco. Her travels have now landed her at her Alma Mater in Tucson, where she teaches and does research. The aims of her research continue to be to use gravitational telescopes in space as 'lenses' to study the properties of dark matter and those of distant galaxies back to when the universe was <900 million years old.

The Gluttonous Consumer

The Catholic Astronomer avatarPosted on by

In a study led by Dr. Christian Wolf and reported in the Publications of the Astronomical Society of Australia, a black hole was just discovered that is consuming material at a record-breaking rate of one star every 2-3 days. Dr. Wolf and his team found this black hole by searching for objects in the sky that do not move. Hyper-achieving black holes are very small and point-like, so can often be initially confused with stars. Side-by-side, the distinguishing feature is that only the stars are near to us. The implication is that over a period of years or decades only the stars will move across the sky. But, once a distant object with an “active” black hole is found, what is going on there? Why is it shining so brightly? One can imagine an assembly line that carries stars along it one-by-one. Each time a star drops off of the conveyer belt “at the end of the line,” the star … Continue reading →

Hawking’s Last Article

The Catholic Astronomer avatarPosted on by

Professor Stephen Hawking wrote one final paper which is published posthumously. In this new paper, Hawking and collaborator Professor Thomas Hertog conclude that our Universe sprung from a larger state or “multiverse” that is not infinite. Let us understand what this is all about by stepping back about 13.7 billion years in time. In these early days there is various evidence that our young Universe experienced a rapid period of growth called “inflation.” A very short time later, the inflation stopped and calmed down into the more gentle mode of expansion plus acceleration we see in our Universe today. But what is the situation beyond our Universe, in the multiverse, and how does it behave? The prevailing idea is that inflation is a normal attribute in the multiverse, such that the multiverse is expanding all the time at exponential rates in state called “eternal” inflation. From time to time, a universe such as our own emerges, and potentially even an … Continue reading →

Monsters in the Closet?

The Catholic Astronomer avatarPosted on by

Black holes are hard to point to because they are…black. Nevertheless, we did find out that there is a supermassive black hole at the Milky Way’s center. It has a mass that is greater than that of the Sun by factors of tens of millions. We arrived at this conclusion by watching what individual stars do that are very near to the Galactic center. These ill-fated stars describe oval-shaped orbits as if they are waltzing about some invisible central object. Recent studies using sophisticated computer simulations are showing that about ten supermassive black holes should be lurking somewhere in galaxies the size of the Milky Way. Only one of these monsters would be situated at the very center (the one we found), while the others would orbit the galaxy at distances that are large compared to the Sun’s distance from the Galactic center (whew), and far above or below the Galactic plane. Fortunately, we are situated exactly in the plane … Continue reading →

GAIA Opens Our Eyes to the Galaxy

The Catholic Astronomer avatarPosted on by

There is a release of new astronomical data by the European Space Agency satellite called “Gaia.” The main purpose of GAIA is to report accurate distances to stars in the Milky Way. GAIA does this by measuring parallaxes. This method relies on measuring what we might colloquially call “perspective.” The idea is that a high precision snapshot of a nearby star will make a pattern on the sky with respect to its fixed stellar neighbors. If you then wait for six months and take another snapshot image of that same nearby star, you will see a slightly different pattern. The Difference between the two images is called parallax. Physically, what happens is that view of a nearby star against the background of fixed stars change when the Earth is one one side of its orbit compared to when the Earth is on the other side of its orbit. Similar an artist will paint a completely different picture of the same … Continue reading →

What’s in a Galaxy?

The Catholic Astronomer avatarPosted on by

The working definition of a galaxy is a huge collection of stars whose motions we do not understand. It was therefore a surprise when a galaxy was recently discovered whose motions we do understand. This new type of galaxy is called an Ultra Diffuse Galaxy (UDG). Astronomers usually ascertain the mass of a galaxy by observing the speeds of the stars and star clusters that orbit it. There is a straightforward formula which relates the speed of the stars with the mass of the galaxy. The Sun and the Earth, for example, move at a speed of 475,000 miles per hour about the center of the Milky Way. From this fact we work out that the mass of the Galaxy is about 300 billion times the mass of the Sun. But what is this mass anyway? Well, embarrassingly we cannot even see the majority of the mass in the Milky Way. Put another way, there is some form of material, … Continue reading →

The Company of Black Holes

The Catholic Astronomer avatarPosted on by

A result was announced last week that the supermassive black hole at the center of our Galaxy has company in the form of 10,000 much smaller stellar mass black holes. We think that supermassive black holes are situated in the centers of most galaxies. The one in Milky Way has a mass of about 3-4 million times the mass of the Sun. This “invisible” astronomical body assimilates any object that hits its surface or “event horizon,” with the result being to grow its size. This is similar to how a fan of hamburgers and french fries “assimilates” that tasty fare in the form of a big tummy. It is thought that there are a great many examples of the much smaller stellar mass black hole varieties, which are the ones formed by the explosions of massive stars. Or, at least it is thought that there _were_ many examples of this stellar black hole variety. That is before these unsuspecting small … Continue reading →

The Hawking Radiation Cartoon

The Catholic Astronomer avatarPosted on by

There is interest on behalf of our readers to know more on the discovery by Professor Stephen Hawking that black holes radiate away, or equivalently, lose mass over time. Black holes are, well, black. They are hard to find and even harder to study. A black hole does have a surface which is called an event horizon. Unlike a surface of any planet, however, the event horizon is a point of no return. Any object that falls inside of this surface is lost forever. The popular version of the story of Hawking radiation starts by reminding us that particles are created and destroyed in pairs constantly all over space. The plot takes shape when one of these particle-antiparticle pairs appears very very near the event horizon. The fate of such an unlucky couple is that if one particle wanders out of the event horizon then it will escape, leaving the other one imprisoned behind the event horizon. The plot is … Continue reading →

Understanding Each Other through Science

The Catholic Astronomer avatarPosted on by

It happened – the world’s largest telescope to be in space has been delayed by another year. This refers to the James Webb Space Telescope or “JWST,” the successor to the famous Hubble Space Telescope or “HST.” I first started working on the JWST as a Lecturer in Dublin, Ireland in 2006. The task was to test one of the four JWST instruments called the Mid InfraRed Instrument (MIRI). We worked hard to make the components “space ready” by simulating their performance in a cryogenic facility under vacuum at Rutherford Appleton Laboratory in England. No one got to go inside the vacuum, as it has no air (among other things), but we did get to run the simulations by sending software commands from a climate-controlled room adjacent to the chamber. Meanwhile, the other three instruments were tested at other cryogenic facilities in different countries. By 2018 all instruments had been individually tested, assembled, and tested again, then moved to Northrop … Continue reading →

An Alternative to Black Holes?

The Catholic Astronomer avatarPosted on by

The great physicist Stephen Hawking helped us to appreciate that black holes really exist. In this week’s article in Sky and Telescope there is discussion on yet another new type of ultra-compressed object called a “semiclassical relativistic star.” Although not nearly as catchy as “black hole,” the semiclassical relativistic star has the advantage of being made out of real matter. After all, stars are made out of real matter. The standard lore has it that a massive star unlucky enough to run out of hydrogen fuel will explode as a supernova, leaving behind a neutron star or a black hole. This week we ask the relatively new question: what if there is also a third choice? In this article physicist Carballo-Rubio considers what happens if we introduce additional quantum mechanics considerations on top of what we already know about black holes. In particular, he wanted to find out how that ill-fated massive star responds to the effects of quantum fluctuations. … Continue reading →

Stephen Hawking: do what you do best

The Catholic Astronomer avatarPosted on by

The world has lost a great luminary of science. Brother Guy Consolmagno called Hawking a “scientist of admirable intuition, who knew even more extraordinarily to give a human face to cosmology and to astronomy.” Professor Hawking had a significant public following. I recall learning this lesson first-hand when he gave a public talk while I was a graduate student at the University of California at Berkeley. There was so much interest that we had to book a venue to hold the hundreds of ticket-holders. I recall volunteering to serve as an usher. Later I would find out just how very much ushers were needed at this popular event. This is because dozens of disabled individuals found their way to this auditorium. I recall that Professor Hawking offered advice. He said not for everyone to see him as a role model and study mathematics, but rather for each person to find out what one does best and then do that one … Continue reading →

The Countdown for launch of the successor to the Hubble Space Telescope

The Catholic Astronomer avatarPosted on by

The James Webb Space Telescope (JWST), the most anticipated telescope to follow the wildly successful Hubble Space Telescope, is now safely ensconced in Los Angeles, California, where it will get fully outfitted with four giant solar shields and endure some final pre-launch tests. Following this last bit of human interaction, the telescope will get folded, placed into a European Ariane 5 rocket, and then pushed along to its launch site. Stepping back a few years, I was lucky enough to get to be an instrument tester for two of the instruments on this grand telescope, the European-built Mid-Infrared Instrument (MIRI), and the U. S.-built Near-Infrared Camera (NIRCam). The procedure is to place the instruments into a vacuum to simulate the environment in outer space. We then would turn on the instruments and make sure they worked according to specs. The testing duties involved writing computer algorithms, performing quality checks on the incoming data, and carefully saving all the technical information. … Continue reading →

Low-fat Dark Matter

The Catholic Astronomer avatarPosted on by

When did the first stars turn on in the universe? This grand question motivates new observations that may change the way we think about the first stars and, in a surprising turn of events, also about the mysterious dark matter in which the stars are embedded. The discovery is reported in the most recent issue of Nature magazine by Principal Investigator Dr. Judd Bowman. Dr. Bowman and his team of astronomers used a radio telescope for this experiment which operates at frequencies close to your those of your favorite radio stations on the FM dial! The idea is that if there were stars existing when the universe was a mere 180 million years old, then the starlight would change the absorbing properties of the abundant neutral hydrogen atoms surrounding the stars. This change would allow an absorption to be detected by the hydrogen as it interacts with the all-pervasive cosmic microwave background radiation. Astronomers expected that there would eventually be … Continue reading →