February 21: Neutral Particle Power

Every second trillions of neutrinos cross our bodies without ever noticing. Graduate student Jia Liu guided the audience through the mysteries of these tiny particles that have puzzled scientists for decades. Neutrinos were suggested by the famous physicist Wolfgang Pauli to account for the missing energy, when a neutron splits into a proton and an electron (a process known as beta decay).

Neutrinos are abundant in nature and are produced through various processes. They are produced in the core of the stars when light nuclei merge to form heavier elements, in nuclear plants when the opposite process (heavier nuclei are divided into lighter) takes place to provide energy, in supernovae explosions and even when energetic particles from outer space interact with the atmosphere.

Neutrinos come in three varieties, have low mass and interact very weakly with matter, making their detection challenging. Next, Jia showed some of the cutting-edge operating detectors like IceCube in the South pole, ANTARES under the Mediterranean sea and Super-K in Japan, that trace neutrinos from astrophysical sources.

Finally, Jia discussed some intriguing potential (fiction-like) uses of neutrinos in the future, as proposed in serious scientific journals. Some of them included the destruction on nuclear weapons, the communication with extraterrestrial civilizations and equity trading.

After the lecture, the audience had the chance to view 3D movies of the universe on the 13th floor, to participate in roof tours and hear more about neutrino flavors from graduate student Andrew Weis. Later, as the sky cleared out and observing was possible, the few who stayed had the chance to look at Jupiter, the Orion Nebula as well as the new Supernova 2014J in nearby galaxy M82, which is the closest type-Ia supernova discovered in the past 42 years.

We hope to see you in our next event, which will entail an exciting collaboration with the neuroscience outreach group!

--Maria Charisi (graduate student)

November 22: From the Ashes of Cosmic Explosions...

How did we get here?  Jeremiah Murphy, a new faculty member at Florida State University, shared with us the astronomical answer to this age-old question.  Or, rather, he answered the question of how his dog got here.  He traced the history of the elements in his dog's body, starting with the hydrogen and helium that formed in the Big Bang.  Those lighter elements were fused into heavier elements in the cores of massive stars and in supernovae, the explosions of those same stars.  Supernovae occur when iron builds up in the core of a massive star until that iron cannot support its own weight. Jeremiah showed us the results of his simulations showing how the iron core collapses, producing a blast wave and a wave of sub-atomic particles called neutrinos.  Those two waves tear the star apart in under a second.  The energy produced allows the production of all the elements up to uranium.

Although it was cloudy, graduate student volunteers Jeff Andrews and Andrew Emerick gave tours of our rooftop observatory after the lecture.  Other attendees visited the 3D wall, where graduate student Yuan Li showed off 3D movies about the universe.  In the lecture hall, Summer Ash and graduate students Jingjing Chen and myself answered questions and collected survey results about the night's events.  I also gave a short slideshow on supernovae that were seen on Earth and recorded in historical documents.

--Steph Douglas (graduate student)

March 11, 2011: IceCube Astronomy

On March 11, one of our senior undergraduates majoring in astrophysics, David Fierroz, gave a talk about a neutrino telescope that he worked on last summer, IceCube. David talked about how IceCube was built at the South Pole and he described the long trip to get there. About 150 visitors came by to hear how the telescope is opening up a new branch of astronomy, discovering objects in a completely new way. As arguably the largest telescope in the world, IceCube will be able to observe some of the most extreme phenomena in the universe including supernova, and supermassive black holes at the centers of galaxies.


Afterwards, one of our incoming graduate students, Jia Liu, gave a talk about a standard day and night at Kitt Peak National Observatory. Also, one of our graduating students explained how Stellarium works and showed the conjunction of planets over the year. While the weather was not great enough to look at stars through the telescope, we were able to give tours of the telescope roof and dome, and even look at the moon.