Monday, December 9, 2013

December 6: Comet of the Century?

In the year after Comet ISON's detection in September 2012, many predicted that its close encounter with the Sun would produce a show worthy of the title "comet of the century".  However, as graduate student Erika Hamden showed, Comet ISON's passage was less spectacular than predicted, though no less interesting.  The comet's orbit showed that it came from the Oort cloud, a sphere of small icy bodies surrounding the Solar System.  Objects in the Oort cloud probably spend most of their time around 0.75 lightyears from the Sun, but occasionally a nearby star can perturb the cloud and send comets into the inner solar system.  Since Comet ISON came from the Oort cloud, it hadn't interacted with the Sun before and so it could provide information about the composition of Oort cloud bodies.


Erika played movies like the one above from several space-based solar observatories (i.e., NASA's Solar Dynamics Observatory, NASA's Solar and Heliospheric Observatory, and NASA's Solar Terrestrial Relations Observatory) showing Comet ISON as it approached the Sun and after its closest encounter. Astronomers had predicted that, after it passed by the Sun, Comet ISON would be very bright and spectacular to see. However, the comet broke up when it got close to the Sun.  The movies showed that some bright debris reappeared after Comet ISON passed the Sun, but it faded rapidly, indicating that the comet had fallen apart. Comet ISON was probably a loose ball of ice that was destroyed by the Sun's heat, like a poorly-made snowball that falls apart before reaching its target.  Although it was not the "comet of the century", Comet ISON provided astronomers with plenty of information about Oort Cloud comets and provided everyone with a great show.

Clouds and rain prevented any roof activities, but undergraduate Claire Ding showed 3D movies on the 13th floor, and graduate student Andrew Weis gave a slideshow of highlights of the winter sky in the lecture hall.

--Steph Douglas (graduate student)

Thursday, December 5, 2013

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)

Thursday, November 21, 2013

November 8: Astronomer vs Astronomer

Scientists do not always agree with each other, and many times, scientific progress is made through debates. On Friday, November 8th, graduated student Jennifer Weston gave a public lecture about a few of the greatest arguments in astronomy in the past 150 years, and how they were resolved. One of the biggest debates in the history of astronomy and astrophysics, the 'Great Debate', was about whether the Milky Way, our own galaxy, was the entire universe, or there were other galaxies out there, seen as the "spiral nebulae". The debate was eventually resolved by the work of Edwin Hubble, which shows that the spiral nebulae are not only galaxies outside of our own, but they are also moving away from us at high speeds. 

After the lecture, many people went to the roof where graduate student Adrian Price-Whelan showed off the Moon and Albiero along with Andrew Emerick, Susan Clark, Aleksey Generozov, and David Jaimes. On the 13th floor, visitors enjoyed 3D astronomy movies with Barnard student Gladys Velez-Caicedo. In the lecture hall, graduate student Yuan Li presented a slide show on planets outside the solar system found by NASA's Kepler telescope

Join us on November 22 for a lecture by Jeremiah Murphy on supernova explosions.

-- Yuan Li (graduate student)

Thursday, November 7, 2013

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)

Monday, October 28, 2013

September 27: Voyager's Venture

The Voyager satellites are currently the furthest man-made objects from Earth.  Launched in 1977, these satellites are now at the edge of our solar system.  In his lecture, PhD student David Hendel took the audience through the story of this highly successful mission, from the initial design of the satellites to their current status past Pluto.  Taking advantage of a unique planetary alignment, David explained how the NASA scientists were able to set the instruments on a Grand Tour, flying by all of the planets on their way out of the solar system.  This tour has produced some of the highest quality images of the planets to date.

After the lecture, bad weather prevented observing.  Yet those who stayed were able to enjoy roof tours, to view our 3D wall or to listen to a description of the moons of our solar system and their naming history.  

-- Lauren Corlies (graduate student)

Tuesday, September 17, 2013

September 13: Fossils of Formation

On Friday, September 13th, we launched our 2013 Fall Public Lecture & Stargazing series with a talk on the Milky Way. Post-doctoral researcher, Allyson Sheffield, presented what we currently know about the formation of our galaxy. It turns out that galaxies formed in a hierarchical manner after the Big Bang, with small clumps of gas and dust forming stars, then clusters of stars, and eventually protogalaxies and galaxies. In essence, all galaxies form by accreting other galaxies in a process called galactic cannibalism. Allyson's work deals with observing tidal streams surrounding our galaxy and tracing them back in time and space to determine what structures they originally came from. She is currently focusing her efforts on the Triangulum-Andromeda over-density.

After the lecture, many visitors headed to the roof for some clear sky observing of the Moon, Mizar and Alcor, Alberio, and the Ring Nebula while others remained in the lecture hall to hear about the recent news of the Voyager 1 probe entering interstellar space.

Friday's volunteers included graduate students Jinjing Chen in the lecture hall, Adrian Price-Whelen, Susan Clark, Steven Mohammed, Doug Thornhill, and Yuan Li on the roof, and undergraduates Gladys Velez-Caicedo and Varad Srinivasan on the 3D Wall.

Join us for our next event on Friday, Sept. 27th to hear more on Voyager 1!

--Summer Ash, Director of Outreach

Wednesday, June 19, 2013

June 14: Cowboys & Aliens

Last Friday, June 14, we screened the joint Western+SciFi action film "Cowboys & Aliens" for an audience of enthusiastic movie-goers. We started the night with a short film, "The Shot", a 5-minute piece about a magical camera lens that works as a teleportation device. The short portrays a man who finds and then uses the lens to travel the world, but trouble arises when he accidentally takes a photo that has him travel out of this world!

The feature, "Cowboys & Aliens", is a genre-mashup that asks "how would a pre-1900, small western town handle an alien invasion?" The answer is: Daniel Craig, the film's leading actor. The film combines references to classic western films like "A Fistful of Dollars" alongside clear homage to sci-fi movies such as "Alien" and "Close Encounters of the Third Kind" (up next in our summer film series). Though there is not much science to discuss in the movie, we did estimate that the height of the alien rocket is about ~3 times the size of a Saturn V at about ~10 times the width. One wonders how the aliens use gold as a power source for such a large vessel...

Join us next time on July 12th for our next Summer Film & Stargazing Event!

--Adrian Price-Whelen (graduate student)

Monday, May 13, 2013

May 3: Why Dark Matter Matters

On Friday night, Kerstin Perez, a post-doc here at Columbia, told us that we can only see about 20% of the mass in the universe. The matter in the universe is mostly stuff that we can't see. The way that stars move in galaxies tells us that there's a lot more mass in those structures than we thought. But this extra mass doesn't emit light or interact with magnetic fields - we only see its gravitational effect. Because the matter doesn't emit or absorb light, astronomers have named it 'dark matter'. The current theory posits that dark matter is a fundamental particle that rarely interacts with normal matter, and then only via the weak nuclear force.

Kerstin also told us about the different ways scientists are looking for dark matter particles, including her own research. She built an instrument that flew on a balloon over Antarctica and attempted to detect the particles that form when two dark matter particles run into each other and annihilate. Other astrophysicists at Columbia are involved in a part of the ATLAS project at CERN that could detect dark matter particles from high energy collisions that simulate the early universe. Still others work at big underground detectors where they try to detect dark matter particles passing through Earth.

After Kerstin's talk, most of our audience members headed up to the roof of Pupin where Saturn and Arcturus were on display through our telescopes. The sky was clear and people were especially excited to check out Saturn's rings. A few folks chose to delay their observing to listen to a short presentation on the Herschel Space Observatory, the European Space Agency's infrared telescope which ran out of coolant last week and is no longer in operation. Others watched films about the universe on our 3D wall. 

--Steph Douglas (graduate student)

Monday, April 29, 2013

April 19: Extragalactic FM

On Friday, April 19th, Ph.D. candidate Destry Saul shared with us the wonders of the Universe as seen  in the radio portion of the electromagnetic spectrum. He introduced the audience to some of his favorite radio images taken with his favorite radio telescopes. Radio telescopes can either be single dish (like Arecibo or Parkes) or arrays (like the VLA or the VLBA). Objects that emit in the radio include galaxies, supernova remnants, and pulsars. Destry's favorite objects include the closest and most powerful radio source, Cygnus A, and the brightest radio supernova remnant, Casseopeia A.

Unfortunately, the skies were quite cloudy, so observing was replaced by tours of our rooftop observatory given by graduate students Adrian Price-Whelan and Steph Douglas. Audience members were also treated to a guided viewing of our 3D Wall by undergraduate Gladys Velez-Caicedo, and a discussion of the other end of the electromagnetic spectrum, X-ray astronomy, by graduate student Yuan Li.

We hope to see you at our next event on May 3rd.

--Summer Ash (Director of Outreach)

Friday, April 12, 2013

April 5: Eyes in the Sky

On a beautifully clear (almost) spring night, PhD student Ximena Fernandez gave a talk entitled "Eyes in the Sky" to a packed room of over 200 people. Ximena's talk focused on how the combination of space telescopes that operate at a variety of wavelengths have been invaluable in revealing the secrets of our Universe. Starting with our galactic center, she showed how only through the use of infrared and X-ray data have we begun to understand the nature of our galaxy's supermassive black hole. Moving to nearby galaxies, GALEX images revealed the largest known spiral galaxy, which has extended spiral arms thanks to an ongoing interaction with another galaxy. At the end, Ximena presented the newly released Hubble Extreme Deep Field, the single longest exposure in all of astronomy. The image contains over 5 billion galaxies, including the oldest known galaxy to date. The talk ended with a video that zoomed through the image to show the distribution of the galaxies in the picture. You can watch the video here!

After seeing so many wonderful images, the good weather gave everyone the opportunity to see amazing objects with their own eyes.  Most popular were the Orion Nebula and Jupiter.  Some chose to remain in the lecture hall where there was a presentation on the Cosmic Microwave Background and the new results just released by the Planck Telescope.  Finally, there was also the possibility of experiencing our 3D wall. Everyone had a great time and we're looking forward to our next event.

--Lauren Corlies (graduate student)

March 21-23: Stargazing with BAM

In partnership with the Brooklyn Academy of Music (BAM), Columbia Astronomy Public Outreach put on a trio of stargazing sessions in Brooklyn over spring break. These "star parties" were a complement to another event at BAM on those same nights entitled Planetarium - a musical collaboration between Bryce Dessner, Nico Muhly, and Sufjan Stevens. The three musicians produced an collection of songs by the same name inspired by the Solar System. 

We transported four telescopes (three Dobsonians, and a Celestron) from the Upper West Side of Manhattan to the Boerum Hill neighborhood of Brooklyn and set them up on the roof of the new Fisher Building. Even though it was quite cold and windy, the skies were extremely cooperative, allowing for a full hour of observing on all three nights. Our celestial targets included the Moon, Jupiter, the Orion Nebula, and the Mizar-Alcor star system

Huge thanks to BAM for reaching out to us and to all who attended. Special thanks to all our volunteers - undergraduate: Doug Thornhill; graduate students: Lia Corrales, Ximena Fernandez, Erika Hamden, David Hendel, Duane Lee, Jenna Lemonais, Steven Mohammed, Dan D'Orazio, Adrian Price-Whelan, and Munier Salem; and post-docs: Josh Peek and Matt Turk. 

--Summer Ash (Director of Outreach)

(Photo credit: Ed Lefkowicz)

Friday, March 29, 2013

March 20: School Visit

Over spring break, Professor Kathryn Johnston hosted a group of 30 high-school students from the New York Harbor School. Prof. Johnston discussed her research on "galatic cannibalism" which focuses on how the Milky Way has evolved over time by gravitational interactions with other galaxies, i.e., capturing and accreting them. Prof. Johnston also spoke with the students about various career paths into science. Following the talk, the students toured the Rutherfurd Observatory with undergraduate Doug Thornhill.

Tuesday, March 26, 2013

March 15: Cosmic Candles

Last week, Ashley Pagnotta, a post-doc at the American Museum of Natural History, gave a talk entitled, "Supernovae: Cosmic Candles of the Universe." Ashely's research focuses on stellar explosions known as supernovae which occur toward the end of a star's life. Different phenomena give rise to different types of supernovae and by understanding the nature of these explosions, astronomers can better constrain the parameters that help us describe the behavior of our Universe. 

It was less than a hundred years ago that astronomers even discovered that the Universe wasn't static, i.e., "standing still". Using the doppler effect to measure the speed at which galaxies were moving away from Earth and cepheid variable stars to measure distance, Edwin Hubble made a plot of of these two variables and discovered that the farther a galaxy was from Earth, the faster it was moving a way from us. Today, we call this plot the Hubble Diagram in his honor and continue to update it as we make better and better measurements. You can make you own Hubble Diagram using data from the Sloan Digital Sky Survey here

While Hubble's work showed that Universe is expanding, it said nothing about the future of this expansion. To investigate this, two teams of astronomers proposed using Type 1a supernovae to probe the Universe out to greater distances, and therefore farther back in time. They used Type 1a supernovae instead of cepheid variables as these supernovae have a characteristic explosion that allows astronomers to use them as a standard candle of sorts; astronomers know how bright they are at a given distance so they can observe them at various distances and extrapolate their true distance based on their observed brightness. Both teams ended up discovering that the expansion of the Universe was *accelerating*, giving rise to the theory of dark energy, and as a result we awarded the Nobel Prize for Physics in 2011

Ashely went on to explain how studying how Type 1a supernovae form in more detail can help astronomers minimize errors associated with their distance measurements and thereby improve our understanding of dark energy. You can view the slides from Ashely's talk here

Unfortunately, the skies were cloudy again so after the lecture, the 120+ audience members toured the roof with the help of graduate student Adrian Price-Whelan, viewed 3D movies with undergraduate Jose Montelongo, and learned about Comet PANSTARRS with Director of Outreach, Summer Ash, and graduate student Yong Zheng. 

Please come see us on April 5th when graduate student, Ximena Fernandez, will present highlights from lesser known space telescopes that are providing astronomers with great glimpses of the Universe. 

--Summer Ash (Director of Outreach)

Monday, March 11, 2013

March 1: Martian Summer

We hosted author, Andrew Kessler, and approximately 80 members of the general public on Friday, March 1st to hear all about the people and the science behind NASA's Phoenix Mars mission. Kessler spent a year with the engineers and scientists who worked on Phoenix to learn what it takes to launch a spacecraft from Earth and safely place it on the surface of another planet. Phoenix landed near the north pole on Mars, the first craft to ever land in the polar regions of the red planet. It's mission was to study the history of water in the ice-rich boundary of the Martian arctic. To do this, the Phoenix lander was equipped with a robot arm that could scoop up soil samples for analysis by an array of instruments including a mass spectrometer, a wet chemistry lab, and a high resolution imager. Not only did Phoenix discover subsurface water ice, but it also found that Martian soil contained high concentrations of chloride which converts to perchlorate in the presence of sunlight. You can read all about the Phoenix mission and Kessler's experience in mission control in his book, "Martian Summer: Robot Arms, Cowboy Spacemen, and My 90 Days with the Phoenix Mars Mission" and you can follow him on Twitter here.

After the talk, audience members toured our rooftop observatory (with the help of graduate students Jennifer Weston and Yong Zheng and undergraduate Jose Montelongo), viewed 3D movies (with undergraduate Bryan Terrazas), and listened to graduate student Steph Douglas explain the myriad of motions experienced by the Earth from our rotation around the Sun all the way out to the expansion of the Universe.

Join us for our next event on Friday, March 15th when post-doc Ashely Pagnotta explains how supernovae are used to understand the mysterious force known as dark energy.

--Summer Ash (Director of Outreach)

Sunday, March 3, 2013

March 2: Grumpy Bert

On Saturday night, graduate student Munier Salem and Director of Outreach Summer Ash helped kick off the opening of a spectacular photography exhibit at Grumpy Bert in Brooklyn. The exhibition entitled "The Universe in Color" runs through the end of the month and features 22 large format images of the Universe taken by astrophotographer (and physician) Robert Gendler.

Munier opened the evening with an informal talk on light and how astronomers make use of the entire electromagnetic spectrum in order to learn as much as possible about the Universe. Then the 40+ audience members asked some very astute questions ranging from the expansion of the Universe to extraterrestrial life. The event culminated in a lively reception which allowed everyone to examine Gendler's amazing works up close and personal.

Additional photos from the event can be found here.

Tuesday, February 26, 2013

February 15: My Life as a Higgs Boson

Friday, February 15th, Gladys Velez Caicedo had the very difficult task of explaining what exactly the Higgs Boson is and how its existence is necessitated by the Standard Model of Physics. The Standard Model explains all the particles we know, such as protons, neutrons, and electrons, along with their interactions. Gladys is a second year undergraduate at Barnard College studying Astrophysics and Literature and is a researcher at Nevis Laboratories working with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) and the Fermi Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope. If you missed the talk or if you just want to immerse yourself in some hard-core physics, you can view the slides from Gladys's talk here.

Over 175 people came out for the event, and we were lucky to have the roof available for star-gazing for an hour after the lecture despite the encroaching cloud cover. The 3D wall was manned by Bryan Terrazas.

After the lecture, I led a small discussion in which we talked about the recent meteorite impact in Russia, along with the near-Earth asteroid that came within 17,200 miles of us, closer than orbiting equatorial geosynchronous satellites! In comparison, the moon is between 220,000 to 250,000 miles away. The discussion was slightly free-form due to the recent nature of the event, and it included us watching some internet videos from Russia. The discussion also focused on efforts humans are undertaking to detect future near-Earth asteroids and possible collisions. Thanks to all who came and participated in this Friday’s outreach program!

Meteor and asteroid videos:
Russia Meteorite Compilation
Another Meteorite Video
Asteroid 2012 DA14 Close Approach
Asteroid Discoveries

--Emir Karamehmetoglu (undergraduate student)

Tuesday, February 5, 2013

February 1: Saving Hubble

On Friday, February 1st, we kicked off our spring Public Lecture & Stargazing series with not a lecture, but a film. Saving Hubble is a documentary that chronicles NASA's decision to cancel the Hubble Space Telescope in 2004 and the subsequent public outcry. Filmmaker David Gaynes interviewed people far and wide on their thoughts about the pioneering space telescope that became a household name, from scientists and engineers who worked on Hubble to amateur astronomers, cabdrivers, and kids who are self-proclaimed "Hubble Huggers." After the screening, Summer Ash led Q&A with David and Ph.D. candidate, Christine Simpson.

If you missed the film, you can see a clip of it here and find out about upcoming screenings here.

The event attracted a sizable audiences of over 200 people who got to see some great sights from the rooftop telescopes after the film, thanks to the clouds that decided to clear out. Graduate students Jeff Andrews, Lauren Corlies, Ximena Fernandez, and David Hendel had telescopes trained on Jupiter and the Orion Nebula, both wonderful offerings of the winter sky. We also had the 3D wall up and running.

Join us on Feb. 15th for our next event: My Life as a Higgs Boson.

 --Summer Ash (Director of Outreach)