Professor Jim Peebles is the 2019 Nobel Laureate of Physics. I have had the pleasure to meet him and hear him give talks in the field of Cosmology, or the study of the shape, history, and future of the universe. In a recent talk Professor Peebles made an interesting comment about the study of science in general. He asserted that “nature operates by rules we can discover.” He went on to say that there was never a guarantee that it would have turned out to be that way. Scientists do seem to work with a kind of blind faith that the universe is knowable, and without necessarily realizing how exciting it is that so much of science is that way. After all, we know enough physics now to launch rockets that explore space. At the same time, there is a lot of physics that we still do not fully understand, such as how gravity works. When I give a talk … Continue reading →
About Dr. Brenda Frye
Brenda L. Frye is an observational cosmologist with research interests in the area of the formation and evolution of galaxies. 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 physical properties of faint and distant galaxies which are boosted artificially in brightness by natural telescopes in space, an approach that enabled her to study galaxies when the universe was less than one billion years old.
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 Physics Nobel Prize winner Professor Saul Perlmutter. She then crossed the country to hold two consecutive postdoctoral fellowship positions at Princeton University.
She has taught physics and astronomy at the undergraduate and graduate levels at Dublin City University in Ireland, the University of San Francisco, and the University of Arizona where she is currently Associate Professor of Astronomy.
This year the Ligo Interferomenter Gravitational-wave Observatory (LIGO) Scientific Collaboration announced the discovery of a potentially new type of object that fell into a black hole, of course never to be seen or heard from again! Black holes are always interesting, but in this case it is not the black hole that is in the spotlight. Instead, it is that ill-fated infalling object that grabbed all the attention. This is because information was obtained that points to the discovery of the heaviest known neutron star. Neutron stars should not be confused with ordinary stars we see in the sky. Stars are made of hydrogen and tend to shine in colors which our eyes can see. On the other hand, neutron stars are formed from the centers of massive stars. They are made of neutrons, and are very dark against the night sky. These dim neutron stars are also densely-packed: so much so that a single teaspoon would weigh as much … Continue reading →
Is there a black hole in our backyard? In Part One we discussed a proposed space mission called “Breakthrough Starshot,” whose objective is to send a spacecraft the size of a grain of rice to the nearest star system, Alpha Centauri. All of us will be keen to get the first “up-close” photos of planets around a new star system. One would like to add that the journey may prove to be just as interesting as the destination. This is because there is a growing consensus the nanocraft will pass by an object en route that is 5-10 times more massive than the Earth called “Planet 9.” This enigmatic object was discovered by its pull on nearby metal-rich icy bodies (aka “dirty snowballs”) in its immediate vicinity. Planet 9 is larger than expected for its placement in the outskirts of the Solar System, and on top of that has not yet been directly imaged. Because it may be dark and … Continue reading →
Welcome ! For a little escape from the Solar System, let us take a look at the “Breakthrough Starshot” mission. The plan is to send a spacecraft to the nearest star apart from the Sun, Alpha Centauri, and to make that journey in only 20 years. This should impress you because the only objects deliberately launched from Earth that have left the Solar System, the Voyagers 1 and 2 satellites, require 200,000 years to achieve the distance of this nearest stellar neighbor, Alpha Centauri. The actual spacecraft must be a very light one gram, or the weight of a single raisin. This feather-light construction already sounds like a tall order, but, recall that the processor of a cell phone has significant computing power yet is not much more than a factor of ten times more massive than what is required. Moving along, this “nanocraft” must also be able to travel at breakneck speeds of about one-tenth the speed of light, … Continue reading →
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 →
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 →
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 →
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 →
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 →
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 →
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 →
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 →