Jan 29 - BLAST!

Our first event of the year didn't exactly go as planned as our scheduled screening of BLAST! was plagued by technical difficulties. On the other hand, a thoroughly overcast day miraculous cleared up right as our stargazing began so what might have otherwise been a disappointing night turned into one of the better observing sessions we've had this winter! Led by graduate student Yong Zheng, astronomers on the roof had telescopes pointed at the Orion Nebula, Jupiter and the Galilean moons, and the Pleiades star cluster. On the indoor side, undergraduate Gladys Velez-Caicedo, ran our 3D Wall for a packed house.

For those interested in seeing what actually happened with the BLAST experiment, we hope you'll give us another chance and come see us over the summer for our Film & Stargazing series. We will reschedule our screening of the film then (and will bring every back-up system ever invented).

Thanks to everyone who came out for their incredible patience throughout the evening.

-- Summer (Director of Outreach)

Dec 4 - On the Care and Feeding of Black Holes

Aleksey Generozov, a 4th year PhD student in the astronomy department, introduced us to the majesty of black holes. Black holes are regions in space-time, where gravity is so strong that nothing (particles or even light) can escape from inside; we could make a black hole if we squeezed the entire earth into the size of our fingernails.

Aleksey next described the discovery of a supermassive black hole at the center of our galaxy, the Milky Way. Observing the orbits of stars very close to the galactic center, with very high precision, astronomers concluded that an object very massive (with mass a few million times the mass of the sun) and very compact (that would fit in a sphere with radius smaller than the radius of our solar system) must be hidden in the galactic center. The only feasible explanation was a huge black hole. These days, we are actually on the verge of seeing the radius of the black hole (the event horizon), with a network of radio telescopes positioned around the globe.

And although the black hole at the center of our galaxy is relatively quiet, this is not the case for every galaxy. In the '60s, astronomers discovered some very bright radio sources, equally bright as some nearby stars, which they named quasars (quasi-stars). Later, when the size and distance of these objects were measured, it was realized that the enormous amount of energy is produced when gas falls onto a supermassive black holes at the center of a very distant galaxy. The gas is brought to the central black holes, when two galaxies collide. This also explains why our own supermassive black hole is quiet; It's starving! However, there is some evidence from observations of very high energy photons, that our own black hole had a more spectacular past. The talk concluded with Aleksey and the audience singing along "twinkle-twinkle quasi-star".

After the lecture, the audience had the chance to hear about the K2 mission, which is the second phase of NASA's Kepler space telescope, lead by graduate student Stephanie Douglas. Moreover, they had a chance to further explore galaxies and black holes by watching 3D movies, guided by undergraduate Briley Lewis. The clear sky and the mild temperature gave us a wonderful opportunity for stargazing on Pupin's roof with the help of Adrian Price-Whelan, Emily Stanford, Daniel De Felippis, Rasmi Elasmar, and Richard H Nederlander. Attendees were treated to views of the Andromeda Galaxy, the Pleiades star cluster, and the Red Giant Betelgeuse.

-- Maria Charisi (graduate student)

Feb 13: New Developments in Gravity

It was a pleasure to have Dr. Rachel Rosen, Assistant Professor of Theoretical Physics at Columbia University, give a lecture on the New Developments in Gravity. Dr. Rosen is an expert in areas of research pertaining to field theory, cosmology, and particle physics. She is recognized for her contributions to the theory of massive gravity, a modified theory of gravity. In the lecture, she explained to us that the currently accepted standard theory of gravity is Albert Einstein’s general relativity. In this theory, the graviton (the particle responsible for the force of gravity) is a massless particle. However, Dr. Rosen stated that people have been interested in whether or not it's possible to modify this theory of gravity, particularly at large distances. One way to do this is to give the graviton a mass and make it a massive particle. Recently, it has been shown that it is possible to have theoretically consistent theories in which the graviton has a mass. The recent discovery of dark energy and the associated cosmological constant problem has prompted investigations for long distance modifications of general relativity. Dr. Rosen believes that making the graviton a massive particle may lead us to understand natural phenomena like the observed expansion of the universe.

After the main lecture, graduate student, Stephanie Douglas, gave a brief talk on star-forming regions in open clusters.  She showed images of open clusters such as Trumpler 16, Pleiades, Hyades, Alpha Persei, all ranging in age between 500,000 and 680 million years. Stephanie explained how some of the open clusters have regions that glow differently in different parts of the light spectrum (i.e., visible versus infrared).  She explained that when look at regions obscured by gas and dust in at different wavelengths we can pick out areas where stars are being formed.

After the lecture, audience members headed up to the roof to see the Moon, Jupiter, and the Orion Nebula. Graduate student, Adrian Price-Whelan, set up a digital SLR camera in the Big Dome to demonstrate how it's still possible to see faint sky objects, even from the heart of New York City. The image below was taken through our 14" Meade telescope.

-- David Jaimes (post-back student)