Nov 21: Constellations R Us

This week, Irene Pease guided the audience through the constellations on the sky. Irene Pease has works as an astrophysics educator and leads astronomy classes as a Brooklyn’s Friendly Neighborhood Astronomer. During the lecture, Irene Pease showed us the distributions of constellations on the dark night sky in well-populated cities (e.g., New York) where city light has been a plague. Ancient sky across different cultures, such as Egyptian, European and Chinese, were compared, which amazingly showed great similarities in the definitions of constellations. She then introduced the modern constellations which were defined by Interactional Astronomical Union (IAU). The celestial sphere are divided into 88 official constellations, most of which inherit their names from their Graeco-Roman predecessors (e.g., Orion, Leo), while those in Southern sky have more modernized names (e.g., Microscopium). By using a ball and a cartoon paper to mimic the earth and horizon, Irene also explained the rotation of the celestial sky relative to the earth and the different paths of stars across the sky as viewed by observers at different latitudes. 

After the lecture, a video “The First Earth-sized World of Alpha Centrauri” was shown to the audience. This 7-minute long video introduced the first earth-sized planet orbiting around the star Alpha Centauri. On the roof, observations of double-star Alberio, open cluster Pleiades were led by graduate student, Jose Zorrilla. 

-- Yong Zheng (graduate student)

Sept 26: The Inconstant Moon

This week Columbia Astronomy's own outreach director, Summer Ash, discussed the many ways in which the Moon, frequently taken for granted in our night sky, can exhibit surprising and complex dynamics due to its complicated relationship with the Earth. After reminding us of the most well-known variation, lunar phase, she described the months - all six types!

Moving on from illumination effects, Summer described the many ways the orbit of the Moon around the Earth affects how we see it. Since its distance varies, sometimes it seems larger and brighter in the sky that others; this is the origin of the "Super Moon." Additionally, its orbit makes a small angle with the plane of the Earth-Sun orbit, which is why we don't experience eclipses at every new moon. Speaking of eclipses, she reminded us that total eclipses, where the moon completely enters the shadow of the Earth, are the ones you really want to get out of bed and check out. The Moon's red color during such an eclipse is due to the Sun's light being scattered by the Earth's atmosphere, the same reason the Sun looks red-orange at sunset: only red light can make it straight through!

If you were unable to attend the talk, or would like to read more, Summer wrote a blog piece on this same topic which you can read on Starts With a Bang.

After the lecture, graduate student Yong Zheng lead a lively discussion of the Milky Way's gas dynamics while Pratishta Yerakala demonstrated a variety of astronomical phenomena at the 3D wall and Adrian Price-Whelan, Jose Zorrilla, Emily Sandford, Maria Charisi, and Aleksey Generozov ran stargazing from Rutherfurd Observatory atop Pupin Hall. Objects targeted included the Ring Nebula, the Andromeda Galaxy, the Double Cluster and the beautiful visual binary star Albiero. 

-- David Hendel (graduate student)

October 25: The Sounds of the Stars

In the lecture on Friday, October 25th, the magic of sound was unveiled by Jeff Oishi, a research scientist in AMNH, who vividly showed that sound waves could be decomposed into simple sinusoidal plane waves. With the help of specific frequency-analyzing software, the differences among various types of sounds, such as whistles, noises, singing were visualized based on their amplitudes and frequencies (pitch). Jeff also introduced an application of sound waves in asteroseismology, by which means the internal structures of stars wound be known since sound waves wound present different oscillation modes when propagating through different depths. 

After the lecture, discussions on topics such as interpretations of sound waves’ propagation and the earth tides took place between the speaker and the audience. In addition, the weather was so amazingly good that a lot of visitors went up to the roof to enjoy the observations of Altair, Albireo, Vega, and the Owl Cluster. 

Volunteers on Friday night included graduate students Jingjing Chen in the lecture hall and Susan Clark, Steph Douglas, Ron Tso, Tze Gho and David Jaimes on the roof.

— Yong Zheng (graduate student)

Yeshiva University Outreach

On October 7 at 7:30 pm, about 30 students from the Chemistry Clubs at Yeshiva University visited the Astronomy Department to get a tour of the heavens. Graduate student, Jana Grcevic gave a presentation on color and chemistry of the heavens as well as a view of our 3D movie theater. Then, we proceeded up to the roof to get views of Jupiter, Alberio, and the Ring Nebula.