Monday, October 22, 2018

October 19th - Vacation guide to the Solar System

Have you planned your next vacation yet? For those of you interested in winter sports, the onset of November means you can finally start hitting the slopes at the variety of ski resorts within the US! But, why not kick things up a notch? Want to get bigger air so you can practice back-to-back frontside 1080s and rival the likes of Chloe Kim? Then head on out to Pluto!

If you're not a big fan of snow, fear not! Jana Grcevich, our speaker on Friday, stepped us through the top 10 vacation spots within the Solar System. From taking in the breathtaking views of Saturn's haxagonal cloud pattern around its north pole to taking a leisurely blimp ride through the upper atmosphere of Venus; there is bound to be something everyone would enjoy! As Jana explained, we are at the dawn of a space tourism revolution, and although there are plenty of hurdles to overcome (such as how to protect ourselves from the lethal radiation doses we would be exposed to on such trips), it's fun to daydream about touring the Solar System one day.

"But I want to go right now!" Yeah, I hear ya! Fortunately Jana gave a couple of options we could all pursue starting now! The Intergalactic Travel Bureau, a group that Jana is a part of, has put out a virtual reality app that allows smartphone users to embark on "space vacations". So go get yourself a cardboard VR viewer, download the app, and start exploring! Alternatively, Jana briefly talked about a book she and Olivia Koski co-authored: "Vacation Guide to the Solar System", a fun book for readers of all ages.

After the talk, Jana answered many fun questions from the audience and had awesome Solar System post cards to pass out. The audience then headed up to the roof for some star gazing but were instead greeted with mostly cloudy skies. Nevertheless, views from atop the roof are always a nice treat!

-- Jorge Cortes (graduate student)

Saturday, October 6, 2018

October 5th - Slooh your way to the stars

What's in an acronym? Paige Godfrey, Slooh's research director, gave us an overview of the services offered by this online observatory. As of today, Slooh provides access to six telescopes. The majority, 5, are located in the Canary Islands. These include their largest instrument with an aperture of 0.5 meters (20 inch). Another telescope in Chile gives access to the many interesting objects located in the southern sky, and a solar scope equipped with a narrow band H-alpha filter allows observations of the solar chromosphere. By locating their observatories under some of the darkest skies, they facilitate access to high quality observations to individuals who would live in areas that suffer from light pollution (all cities).

Individuals can access the data obtained by the cameras attached to Slooh's telescopes. Paige showed some examples of work done by members of their community, from processed images, mosaics and gifs, to discoveries of new comets. Since the processing of astronomical data can have a rather steep learning curve, they're developing materials to make it easy for anyone to get started.

Paige explained how these resources allow schools to incorporate observational astronomy into their curriculum, and they're launching a specific program, AstroLab, with the support of the National Science Foundation.

As an illustrative example of how Astronomy can help answer some of the most fundamental questions we've asked ourselves through history, Paige introduced the use of Drake's equation, a way to quantify the number of communicating civilizations in a given volume, and applied it to the set of stars visible in a typical image taken with one of Slooh's telescopes. Turns out vulcanians may be out there for real!

-- Jose Zorrilla (graduate student)

Monday, September 24, 2018

September 21 - Clocks of the Universe

Imagine that half of your wedding guests show up at the venue a month before the event because the government’s decision to add a month to this year’s calendar did not reach them. Turns out that such a scenario could not be completely ruled out in ancient Rome. Mihir Kulkarni, our speaker on Friday, opened our eyes to how the way we measure and keep track of time has evolved through history and how different cultures use different systems.

Until recently, no man-made device could match the regularity of celestial movements. As a result, we used the Earth’s spin, its rotation around the Sun and the Moon’s movements to measure time. These measurements became encoded in the calendars that helped regulate human activity, from seeding to religious festivities. Small differences between the actual movement of celestial bodies and that captured by calendars add to the point where they become noticeable and sometimes, disruptive. Such disagreements were often dealt with through ad-hoc adjustments, but ultimately they inspired calendar refinements based on more accurate astronomical models. This way, we learned about hard-to-measure phenomena such as the precession of the Earth’s rotation axis. As the axis wobbles not unlike that of a spinning top, the closest star to the north pole -called the North Star-, changes. This shift occurs on timescales of thousands of years, long compared with a person’s lifespan but measurable through history.

Finally, minute perturbations and secular changes to the Earth’s movement relative to the rest of the universe pose a fundamental limit to the precision with which we can measure time. To beat these limitations, our current time standards do not rely on astronomical calculations anymore, but that has not removed all implementation challenges, as the “Unix 2038 year” problem illustrates.

After the talk, Mihir answered many insightful questions from the audience. You can also find a detailed summary of the talk by Steven Fertig, of the Amateur Astronomers Association of New York, here.

Clouds prevented us from star gazing, but we had the opportunity of touring the Rutherfurd’s observatory facilities lead by Daniel and Matthew while Douglas discussed some counter-intuitive properties of black holes with the support of animations in our 3D wall.

-- Jose Zorrilla (graduate student)

Monday, April 16, 2018

April 6 - Signal to Noise

We have a special joint event with the Wallach Art Gallery on May 6th. The event, titled “Signal to Noise”, is an interdisciplinary salon that discuss and exhibit the significance and nuisance of sounds and noise in our daily lives.

Andrea Derdzinski, a fourth-year NSF graduate fellow, gives her lecture on gravitational waves. She first introduces the electromagnetic spectra and explains how astronomers use them to study various celestials objects in the universe. Then she focuses on the recently discovered gravitational-wave events, including the first finding of the 30-solar-mass black hole mergers and the recently discovered neutron-star merger.

After Andrea’s lecture, Ariana van Gelder, who is a Ph.D. candidate at CUNY and an experimental musician, make her performance by improvising experimental rhythm as inspired by the random sounds in the lecture hall. Then, Ariana together with her artistic fellows, Emmy Cathedral, Constance DeJong, Ray Ferreira, Dominika Ksel, and Sarada Rauch, exhibit a light and sound salon in the library and stairwell on the 14th floor of Pupin. The salon features how signals (i.e., light and sound) intervene and enhance our daily experiences with the nature and society.

-- Yong Zheng (graduate student)

Friday, March 16, 2018

March 9 - Alien Weather

Our speaker this week was Statia Cook, a Columbia Teaching Fellow and a Research Associate at the American Museum of Natural History. She is an observational astrophysicist whose research focuses on studies of the weather and climate of other planets, especially the giant planets in the outer Solar System.

Statia started by orienting us to some of the key differences between weather on the Earth and on the "gas giants" (Jupiter and Saturn) and "ice giants" (Uranus and Neptune). On the Earth, the atmosphere is very thin compared the diameter of the planet -- similar to a few layers of cling wrap on a basketball. The giant planets, by contrast, are mostly (or entirely) atmosphere, although their density and temperatures vary with depth to such a degree that the same gasses may behave differently at different layers. In addition, the Earth's weather is driven almost entirely by energy from the Sun, whereas the giant planets still retain a large amount of heat from their formation. The release of that energy can be as important as the Sun to their climate. Finally, on Earth almost all clouds are water vapor, while the various colors seen in the giant planets trace clouds with different compositions including methane and ammonia.

Next, we heard about perhaps the best know extraterrestrial weather pattern: Jupiter' Great Red Spot, a persistent storm larger than the Earth that has existed for at least 180 and possibly more than 350 years. This vortex is accompanied by many other short-lived systems in Jupiter's atmosphere, with colors varying from white to pink to red. Neptune also had a giant storm, dubbed the Great Dark Spot, although it vanished in the five years between its discovery by the Voyager 2 spacecraft and observations by the Hubble Space Telescope five years later.

Finally, Statia told us about some of her own research which include detailed maps of Neptune using submillimeter radio interferometry, a pair of storms near Neptune's south pole that seemed to circle and merge together, amateur-inspired observations of a new Dark Spot on Neptune, and seasonal climate variation of the Ice Giants.

After the talk, Statia fielded questions, followed by a presentation by yours truly on the history of evidence for dark matter.

-- David Hendel (graduate student)

Sunday, February 25, 2018

February 23 - The LSST Revolution

Our speaker this week was Federica Bianco, a research scientist at both New York University's Center for Urban Science and Progress and their Center for Cosmology and Particle Physics. Her work focuses on transients - temporary changes in the sky. She is also the chair of the Large Synoptic Survey Telescope (LSST)'s Transients and Variable Stars Collaboration.

Federica's talk revolved around how the survey program of LSST will revolutionize our understanding of the changing universe, also known as time-domain astronomy. In particular, current studies tend to be at most two of wide (covering a large area of the sky), deep (observing faint objects) and fast (repeatedly observing the same place in quick succession). LSST is the first survey to attempt all three of these simultaneously by observing the entire Southern sky from its mountaintop in Chile, cataloging objects about 100 times fainter than current surveys with such a wide area, and imaging each patch of sky about once every three days -- with five different color filters.

LSST can achieve this due to its unique optical design that gives it an enormous field of view -- equal to the size of about 40 full moons -- and a 3,200 megapixel camera. This giant sensor will generate 15-20 terabytes of data a night, which will be immediately piped up to University of Illinois National Center for Supercomputing Applications in Urbana-Champaign, Illinois. There, the goal is to process each image and release in less than 60 seconds, including comparisons to previous data and generating an estimated 10 million science alerts per night. Just storing the 50-100 petabytes of data generated during its 10-year survey will be an immense challenge! Another amazing property of the LSST data is that it will be public immediately to all people in the US, so anyone interested can see what's happening in the sky almost in real time.

Federica also described the diverse science goals of LSST, which include understanding the nature of dark matter and characterization of dark energy; mapping the Milky Way; cataloging the Solar System; and exploring the changing sky. Many more details about LSST and its goals are available on its website.

After her talk, Federica answered questions in the lecture hall. Later, American Museum of Natural History fellow Betsy Hernandez gave a presentation on Active Galactic Nuclei while Columbia undergraduate Richard showed presentations on the 3D Wall and graduate students Daniel, Aleksey, and Adam gave tours of the observatory.

- David Hendel (graduate student)

Tuesday, February 20, 2018

Feb 9th - The Zoomable Universe

Our speaker this week was Caleb Sharf, a research scientist at Columbia University and Director of its Astrobiology Center. Caleb is a prolific writer with contributions in publications such as The New Yorker, The New York Times, The Atlantic, Wired, and Scientific American in addition to highly regarded scientific journals. He has also written a textbook on exoplanets and three popular science books on various astronomical topics.

In his talk Caleb gave an overview of his latest book, The Zoomable Universe. In it, he explores phenomena that cross the vast range of physical scales, from the very largest we can observe (the entire diameter of the observable Universe, about 10^27 meters) to the smallest (the Planck scale, 10^-35 meters, where the fabric of spacetime stops obeying known laws of physics).

Caleb uses this vast range - a factor of one hundred trillion trillion trillion trillion trillion, of which the human scale is conveniently close to the middle - to illustrate the incredible diversity of phenomenon in the Universe. Starting with the mysterious dark energy and the large scale structure of dark matter that makes up the skeleton of galaxy formation, we zoomed in repeatedly to examine the Local Group of galaxies, the birth of a solar system, the surface of a planet, and continued down to our own DNA and eventually the structure of spacetime. An illustrated version of this journey can be found here.

After his talk, Caleb fielded questions in the lecture hall while Columbia undergraduate Richard showed presentations on the 3D Wall while graduate students Steven and Aaron gave tours of the observatory. 

- David Hendel (graduate student)