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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.

No Wine Before Its Time

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You may have heard the news from NASA that the James Webb Space Telescope (JWST) will suffer a delay in its launch date to March 30, 2021? In short, the sophisticated spacecraft plus solar shields were not quite up to specifications, requiring additional time for testing. The JWST is the most celebrated telescope in the making. It is the much-touted “replacement” for the aging (26 year old) Hubble Space Telescope, yet this is hardly a fair comparison. The JWST will have seven times the collecting area of its predecessor and more sophisticated instruments which will enable us to see 13 billion years into the past. This is remarkable as the universe is only 13.7 billion years old. A significant challenge arises because unlike the Hubble Space Telescope, the JWST will not be serviceable. It has to survive the agitation of liftoff in a rocket, operate in the bitter cold of space, protect the sensitive astronomical instruments from damaging sunlight, and … Continue reading →

Counting Exercise

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We learn that there are four fundamental forces in nature: gravity, electromagnetism, and the strong and weak nuclear forces. One research group led by Dr. Lijing Shao from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has recently set out to test the possibility of a fifth force of nature. We already know that gravity acts on matter. For example, gravity reliably pulls us to the Earth, keeps the Earth orbiting the Sun, and causes the Sun to orbit the center of the Milky Way. The proposed new force would act preferentially on the dark matter. Dark matter is a component of the universe which dominates the mass of the universe, meaning that there is more dark matter than the protons, neutrons and electrons that we are made of, yet we cannot see it. This “fifth” force would pull ordinary matter towards the dark matter, or the other way around. To search for evidence of a fifth force, … Continue reading →

Black Hole Chomps Up Part of a Star?

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Astronomers recently witnessed yet another ho-hum explosion of a star, or so they had thought.. Stars are fairly common near the centers of pairs of colliding galaxies, as are supermassive black holes. What happens when the two objects approach each other? The story begins when the star that is central to this week’s story appeared to fall right on top of a black hole, at which point it released large amounts of X-rays. This signature is typical of an exploding star, which is also a relatively common phenomenon in the centers of galaxies. On tracking this supernova over a ten-year period, however, the star did not show the attributes typical of others. It did not fade away over time as its energy dissipated, but instead formed into a long radio jet similar in appearance to a jet trail of an airplane passing overhead. According to the results of a long-term study led by Seppo Mattila of the University of Turku … Continue reading →

The Perfect Storm

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Do you ever wonder how the “bumps” in the path of the Sun affect our weather? Probably not, and it certainly is not the leading story in the evening weather report. To the credit of meteorologists, this is because the Sun rarely does come across any “bumps,” or side effects of near collisions with other stars. . From time to time the Sun will approach very closely to other stars in its orbit around the Milky Way. By “close” we mean that another star will pass within about three light-years of the Sun, which for reference is less than the distance between the Sun and the nearest star. . For example, a close passage of the Sun with another star 65 million years ago may have shaken loose several of the trillions of comets surrounding our solar system. Some of these “freed” comets would be sent hurtling into the inner solar system, where one of them could strike the Earth. … Continue reading →

Our Interacting Neighbors

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Two of the nearest galaxies to the Milky Way, the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), are easily spotted by eye in the southern hemisphere. Sometimes shortened as “The Clouds,” these much smaller and irregular-shaped “dwarf” galaxies orbit about the Milky Way, and will eventually be assimilated by it. . We have known for a while now of a column of hydrogen gas and stars that connects these two dwarf galaxies. But therein also lies the mystery: where did this stream of material come from? The two close contenders are: close fly-bys of the Clouds with the Milky Way, or close fly-bys of the LMC with the SMC. . Clues to solve this mystery come from studying the stars near the outer edges of The Clouds, which are held more tentatively as a result of the weaker gravitational pull. . Astronomer Dougal Mackey and collaborators (Australian National University) have undertaken a census of stars in the … Continue reading →

The Gluttonous Consumer

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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

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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?

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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

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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?

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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

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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

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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 →