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.

Space is mind-bogglingly big
avatar

Writer Douglas Adams says space is mind-bogglingly big. Here is perhaps an interesting facet for thinking on this topic. Imagine sitting at one end of a room in which at an appointed time a friend enters from the far side. Now imagine that you look and look but cannot see this friend when they first enter, no matter how hard you squint your eyes. After a while, the person does appear to walk into the room, but the information is delayed from the time at which it actually happened. We are not familiar with such experiences. It does not happen to us on Earth only because of the small size of our planet, but it does happen in outer space. The reason for this ‘optical illusion’ has to do with the properties of light. Our eyes know that a friend is present only when light from a light bulb, or sunlight coming in through a window, bounces off of that … Continue reading

To a Big Telescope Luminary
avatar

Many years ago I was lucky enough to conduct student research at the Keck Observatories, atop the 14,000 foot peak of Mauna Kea, Hawaii. This is the site of the largest optical telescope in the world. On one of my return flights, coincidentally I found myself sitting next to Professor Jerry Nelson, whose work was largely responsible for existence of this spectacular observatory! I asked many questions which he was willing to entertain without hesitation. If the accomplishments of this person stopped with the design of a big telescope then that would already be commendable. In this case, though, he also managed to overcome an obstacle blocking progress to building big telescopes. The story goes something like this. One can build larger and larger solid telescope structures only up to a certain size. Beyond a diameter of around 5 meters (or about 16 feet), the mirror approaches such a weight that it starts to sag until eventually the the ability … Continue reading

Hopscotching with Aliens?
avatar

There is a new initiative in the area of the Search for Extra-Terrestrial Intelligence (SETI). Although the SETI program has history of listening for deliberate (or accidental) messages from any potential advanced civilizations dating back more than 50 years now, we knowingly transmit messages less than 1% of that time. Indeed some long wavelength transmissions such as TV programs do manage to leak into space, but they are too faint to decipher across interstellar distances. In all that time we have never received a message from aliens. There is also no evidence at all that aliens have ever visited us. Space appears to be empty. Does this mean other intelligent creatures do not exist at all? The struggle to answer that question has motivated a new initiative called the Messaging Extra Terrestrial Intelligence (METI). The aim is to take action to send messages in the direction of known planetary systems. Most people at this point ask, “Is this exciting?, or … Continue reading

The Dark Energy Spectroscopic Instrument (DESI)
avatar

This week there is a large gathering of extragalactic astronomers here at at Lawrence Berkeley National Lab (LBNL) to attend a conference on the Dark Energy Spectroscopic Instrument (DESI), a new experiment that will be commissioned on a large telescope on Kitt Peak National Observatory (KPNO) in Arizona. With a team now 500 people strong, the focussed goal is to measure the relative positions and orientations of millions of galaxies in order to study properties of the early universe. One can get at a straightforward understanding of this project by considering galaxy shapes. Galaxies are complicated objects with billions of stars. Even so, from a distance galaxies mostly take on oval shapes. These oval-shaped galaxies that we see on a typical pictures can face any which way. This turns out to be the case when one views galaxies within regions of space in which one can see only hundreds of examples at a time, but not millions. On such scales … Continue reading

How Galaxies Are Like Apricots
avatar

The common lore has it that in addition to hosting 10-100 billion stars, all galaxies are also covered in a massive invisible layer of dark matter. One cannot see this dark matter, nor is its composition known. Nevertheless, one can see the effects of the dark matter indirectly by the way they alter the motions of those myriad stars. If one imagines each galaxy to be an apricot pit, then the dark matter is the orange fruit surrounding the pit. The stars in this analogy would all be situated inside the pit. If one find a way to separate the pit from the fruit by just a little bit then one could get important information concerning the properties of this mysterious dark matter. There are no giant humans in space to bite into the fruit. Second best, if we could ram together two massive galaxies then we just might be able to see some of the fruit separated away from … Continue reading

Discovery of Ice Crystals on Earth
avatar

When we send astronomical satellites out to explore the solar system, we also take the opportunity to set them to look back on Earth. This tradition dates back to the time of the late 1970s when astronomer Carl Sagan requested a view of Earth from the Voyager 1 satellite from vantage point of Saturn. In that famous photo, the entire Earth occupies a scant couple of pixels on the image. Since that time, many pictures of Earth have ben taken at still higher spatial resolution. As the level of our ability to see fine details grew, we started noticed something curious about the images. In addition to seeing the beauty of our tiny marble-colored planet, we also saw brief surges of light appear on the surface. The source of such “twinkles” went undiscovered from their first occurrence in 1993 until 2016. At first planetary scientists attributed these mysterious twinkles to reflections off of the water, except that the twinkling took … Continue reading

Digging up Astronomical Fossils
avatar

Imagine looking up at the night sky. With our own eyes we can see at most a few thousand of the nearest stars to us. Now consider looking through a large telescope with a very large field of view. Through such an instrument millions of objects come into view, with most of these objects being galaxies, not stars. Interestingly, galaxies are not scattered randomly about the sky, as one might expect. Rather, they trace out a structure that looks a bit like a 3D spider web, called by astronomers the “cosmic web.” Fair enough. The story gets more interesting though when we find out that the mean separation between galaxies, equating roughly to the mean separation between the threads of a spider web, was set early on in the universe’s history. When the universe was only about 370,000 years old, various sound waves that traversed its extent were frozen into place by changing physical conditions. Astronomers maintain that events that … Continue reading

The Disappearing Star
avatar

And now for the next trick, we will make a star disappear! Astronomers have just discovered a star in the Galaxy that is losing brightness fast. Although generally stable, a star can and does vary in brightness every so slightly during the adult phase of its lifetime. A star can slowly increase in brightness as it builds up more nuclear fusion products in its stellar center. This happens to all stars. For the Sun this amounts to a 30 percent increase in brightness since it formed 4.5 billion years ago. Eventually, in another 1 billion years, the Sun will be so hot that it will boil away the oceans (but let us not digress). Secondly, many stars brighten and fade on regular timescales of hours to years. These are wee brightness changes amounting to about 0.1 – 1 percent of the total flux on average, with some more extreme cases known especially for the smallest stars. There is one attribute … Continue reading

Connecting Religion and Intelligence over 230,000 years
avatar

An archaeological discovery was announced from South Africa this week of new skeletal remains of Homo Naledi. Multiple age-dating techniques indicate that these early hominids lived an estimated 230,000 years ago. It was expected that they would have used their arms and legs much like humans do today, except that these beings would have had a brain only one-third that of modern humans. We refer to the blog from last week to learn how astronomy plays a role in such age measurements. Even so, there is new evidence that these hominids buried their dead deliberately in cave structures. From this behavior, archaeologists infer some level of religious ritual to have been present in their community. One wonders if this might be the first example of religious rituals. Expanding on this idea, one can wonder also by which process did these beings decide to build religious rituals into their lives? Finally one can take a step back and ask if religious … Continue reading

How Astronomy Helps Us Learn about the Mastodons
avatar

An exciting discovery was made just this past week in the well-known Cerutti Mastadon site near San Diego, CA. Near to one of the mastodon skeletons was found also large stones that showed tell-tale signs to use as tools by early hominid visitors. What is interesting is not that people lived near San Diego before we called it by that name, but rather that hominids arrived there a full 115,000 years earlier than archaeologists had ever expected. Meanwhile the mastadons, a slightly smaller version of the mammoth, were commonly found in the Americas 130,000 years ago. A natural question to ask is how do we know that this particular mastodon site really is that old? Archaeologists determine ages by measuring the radioactive decay of certain elements like carbon or in this case uranium. Okay, fine, so where does the astronomy part fit in? Well in addition to the sunlight we appreciate so much in springtime, the sun also makes cosmic … Continue reading

Why the Upturn in UFO Sightings?
avatar

A new book serves to document sightings of Unidentified Flying Objects (UFOs) in the past decade. The punch line is that UFO sightings are on the rise. When I discuss UFOs in my class I feel it is important to point out from the start that we have never found compelling evidence for life outside of Earth in any form. In fact, the term UFO refers simply to an object in the sky for which we do not know what it is. One can imagine that many of us do see UFOs by that description. The curious part is that when we see one, we do not stop there, but rather tend to jump suddenly to a conclusion such as to say “Oh, I don’t know what that is – that it must be a space ship from another planet that has come to Earth.” Why is that? Dr. Neil deGrasse Tyson remind us that there is a human tendency … Continue reading

Getting Baby Stars to “Dohsey-doh” Well with Others
avatar

One hundred billion stars whirl about each other and, collectively, around the Galaxy, yet rarely do they ever collide. This is because stars are much more likely to interact with each other the way people do in a square dance: namely, by approaching one’s partner, linking arms while skipping in a full circle ’dosey-doh,’ and then making a retreat. One tries to avoid the full-on collision to preserve the health of one’s partners. Stars interact similarly to well-trained square dancers, by exchanging momentum with the partner star. The two stars approach, describe a circular ‘dosey-doh,’ and then move away. Having said that, every so often two stars find themselves on a path to a direct collision. This event is so unlikely, and so short-lived, that astronomers do not often get the opportunity to see it. One of the best chances to look for such an unfortunate activity is in stellar nurseries called molecular clouds. This is because stars are born … Continue reading