Hi, all!  There will be NO Physics Table this week.

In its place, the whole IDEA team will meet (visit our web pages to find out who we are) during common time, 12:25 pm on Tuesday (tomorrow).  Join us for the last meeting of the term (if you’re already on the team) or to find out more about us (if you’re interested in joining!)

Freja Olsen                                                                                                                                                            Wednesday, March 3rd 2021                                                                                                                                          4:20 pm on Zoom

The Tunguska Event

Early on the 30th of June 1908 in the middle of the Siberian forest near the Tunguska river, the peace of the morning was disturbed by the explosion of a meteor in the atmosphere. This explosion released the same amount of energy as 13 Megatons of TNT and destroyed the meteor. For the past 113 years, scientists have been investigating the Tunguska Event to better understand the nature of large meteors. In this talk, I will explore how scientists determined the parameters of the explosion using eyewitness observations and seismic data recorded from the event. I will also investigate the origin of the Tunguska Meteor using mathematical models and meteoric remnants found at the explosion site, which suggest that the meteor was cometary in origin rather than from an asteroid. Finally, I will look at the possibility that the Tunguska Meteor was part of Comet Encke and the implications for the frequency of large meteors entering the earth’s atmosphere.

Jack Heinzel                                                                                                                                                                 Friday, March 5th 2021                                                                                                                                                   4:20 pm on Zoom

Cosmic Inflation 

In this talk, we will overview cosmic inflation, a theory which proposes the universe expanded by over 30 orders of magnitude when it was very young. This is theoretically accomplished by introducing a new quantum field called the inflaton field. To motivate cosmic inflation, we will quickly overview the standard picture of the Hot Big Bang in conventional cosmology, and then see that this leads to several deep problems which require an extraordinary degree of fine-tuning to explain. Using The mathematics that we’ve developed, we’ll see how these problems can be avoided by introducing a brief period of exponential expansion (called cosmic inflation) in the very early history of the universe, which could be generated by an undiscovered and highly extreme scalar quantum field. We will introduce the inflaton field and the chaotic inflation model, and slowly walk through the timeline of inflation. We Will start with the inflationary epoch when the universe expands at least 30 orders of magnitude, then enter the brief period of preheating, when oscillations in the inflaton field drive enormous particle production in a coupled field. Finally, inflation ends with reheating, when the inflaton field decays completely into other more ordinary quantum fields (quark fields, photons, Z bosons etc). At the end of the talk, we will see how this picture tells us we live in but one bubble universe of infinite different bubble universes.

Evan David                                                                                                                                                               Monday, March 8th 2021                                                                                                                                                    8:30 am on Zoom

Dark Matter

Astronomers can measure the mass of galaxies by directly counting a galaxy’s visible matter or by measuring the gravitational effects of the galaxy’s mass.  These two measurements differ from each other by roughly a factor of 5, suggesting that the majority of the universe’s matter is made up of transparent and non-luminous dark matter.  The composition of this dark matter remains one of the largest open questions in astronomy.  Over the last century, two competing theories of dark matter have emerged: celestial bodies known as MaCHOs that do not produce light but are otherwise made of ordinary baryons and exotic particles, which as of yet have remained undetected, known as WIMPs.  This talk will review the methods behind two of these mass measurements and compare the theories of MaCHOs and WIMPs.