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)

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)

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)

Nov 10 - Going out in style: Nebulae at the end of a sun-like star’s life

Our speaker this week was Rudy Montez, an astrophysicist at the Chandra X-ray Center of the Smithsonian Astrophysical Observatory in Cambridge, MA. Rudy studies "planetary nebulae," the ghostly shells sloughed off by dying stars.

Rudy began by showing a gallery of beautiful Hubble Space Telescope photographs of planetary nebulae, explaining how the various colors tell us about the composition of the layers of each nebula. He noted that astronomers always expected planetary nebulae to be spherical, because they're believed to form as the outermost layers of a giant star expand away in all directions from the hot core.

But that's not what we see! Real-life nebulae display amazing, complex structure, including dumbbell-shaped bi-polar lobes. Rudy explained that the leading hypothesis to explain the formation of these lobes is that a donut-shaped ring of dust surrounding the dying star blocks the star's outer layers from expanding in certain directions, forcing them out at the opposite openings of the donut hole. The origins of this ring of dust are not quite clear, but they may be leftover debris from a pair of binary stars orbiting each other at the center of what will eventually be the nebula.

Rudy then discussed his area of particular expertise: X-ray observations of planetary nebulae from the Chandra space telescope, which give us a window onto the hottest, densest central regions. He showed beautiful composite images of Chandra, Hubble, and Spitzer data, which illuminate, respectively, the innermost, middle, and outermost regions of planetary nebulae. Three windows onto these extraordinary objects.

Nov 7: Juggling with Black Holes

This week, Hubble Postdoctoral Fellow Andreas Kupper described the dynamics of multiple massive objects in the same system.  When two massive objects are near each other, they exert gravitational forces on each other and their motions can be described analytically - that is, the motions at all times can be calculated by hand from basic theories.  When three or more massive objects interact gravitationally, the interactions become complicated and can only be modeled using computer simulations. Andreas showed the results of a few of his simulations - after the objects orbit chaotically around each other for a while, one object (usually the one with the lowest mass) is thrown out of the system with a very high velocity.  The remaining objects end up closer together, and this process, called scattering, is thought to be responsible for bringing massive objects like black holes and neutron stars close enough together that they can merge into an even more massive object. 

After the lecture, audiences were treated to a showing of LIGO: A Passion for Understanding, a 20 minute film about a project to detect gravitational waves coming from closely interacting massive objects.  After the film, graduate student Aleksey Generozov and I answered questions about gravitational waves and LIGO.   Graduate student Yong Zheng was the roof captain, sharing glimpses of the Moon, Albireo and the Ring Nebula while undergraduate Pratishta Yerakala took attendees on a 3D tour of the Universe with the 3D wall.

-- Steph Douglas (graduate student)

Oct 10: Explosive Lighthouses

This week, Columbia Astronomy's 4th year graduate student, Maria Charisi, gave a talk on gamma-ray bursts, or GRB for short. Gamma-rays are a kind of electromagnetic wave, like optical light, but with very short wavelengths, even shorter that of X-rays.

Maria started by telling us the history of how GRBs were discovered. The first GRBs were found by detectors which were built to detect nuclear explosion on the Earth during the Cold War. However, scientists found no correlation between these events and any nuclear explosions on the Earth. So this problem was passed assigned to astronomers to find out if they were related to any astronomical events. At first theorists proposed many mechanisms for GRBs, from neutron star collisions to alien space wars. Astronomers also argued about the location of these events. Some believed they were galactic; others believed they were cosmological. The varieties of theories and beliefs were due to the fact that the location distribution and distance of the GRB events were still unknown. With the launch of the Compton Gamma-Ray Observatory in the mid 90's and the Swift Gamma-Ray Burst Mission in the early 21st century, and with the red-shifts measured from spectra, astronomers finally concluded that GRBs are extremely luminous events that happen all over the Universe. 

Maria then described findings from more recent studies on GRBs. GRBs only last for a short time in the gamma-ray band, but astronomers believed there should be afterglows in other wavelengths, just like charcoals will glow as a fire burns out. They did follow-up observations of GRBs in the optical and infrared bands and found evidence of these afterglows. From the duration distribution of the bursts, astronomers split the GRBs into two different categories: short bursts which lasts less than 100 seconds, and long bursts which last a few hundreds seconds. 

The physical image of GRBs is still not clear today. One of the most widely believed theories is that when two compact objects collide, for example a neutron star and a black hole, tremendous energy is produced and ejected from two jets. If we happened to be in the line of sight of these jets, we would detect a GRB.

After the lecture, graduate student Jingjing Chen showed the first half of a PBS movie called 'Alien Planets Revealed' which discussed transit method of detecting exoplanets used by the Kepler mission. Unfortunately, the weather was not good for stargazing, so graduate students Jeff Andrews and Aleksey Generozov gave tours of the Rutherfurd Observatory instead while undergraduate Erin Flowers and post-doc Robyn Sanderson presented a variety of astronomical phenomena with the 3D wall. 

-- Jingjing Chen (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)

April 25: The Exoplanet Revolution

Less than ten years ago, astronomers only knew about a handful of planets orbiting stars besides our Sun, and all of those are nearby.  But the Kepler spacecraft has changed all that; Kepler scientist Lucianne Walkowicz told us how the telescope has revolutionized exoplanet studies.  Kepler spent 4 years staring at one specific patch of the sky, looking for planets around stars near and far.  Kepler exponentially increased the number of known exoplanets, and found many that are thousands of light years away.

Kepler searches for planets by watching for slight brightness changes caused by a planet traveling in front of its host star. This method easily detects large planets that are close to their host star, but Kepler has also found a bunch of smaller planets (between Earth-size and Neptune size) orbiting at larger distances. Although the larger planets are easier to find, it looks like planets a little bigger than Earth may actually be the most common type of planet in the galaxy! Lucianne told us that although Kepler's main mission has ended due to a mechanical failure, the telescope will likely keep operating in a new observing mode to search for exoplanets around even more stars.

Clouds prevented any roof activities, but volunteers Jennifer Weston and David Hendel provided tours of the observatory and volunteer Claire Ding showed movies on the 3D wall.  Volunteer Alejandro Nunez also gave a short presentation in the lecture hall about the electromagnetic spectrum.

-- Steph Douglas (graduate student) 

March 28: Our Hungry Black Hole

This Friday relaunched our lecture series after both spring break and daylight savings time so we now begin at 8pm.  Graduate student Yuan Li gave a lecture on an upcoming galactic event: the closet passing of a gas cloud (called G2) to the supermassive black hole in the center of our galaxy.  After explaining the basics of black holes, Yuan showed proof for the existence of our own, called Sagittarius A*.  She then explained that with our own supermassive black hole being so long dormant, watching the feeding of a black hole up close has implications for most areas of astrophysics.

(Almost) April showers kept us from observing on the roof but roof tours were still available along with our 3D wall.  David Jaimes also gave a presentation on the exoplanets discovered by the Kepler telescope, highlighting a number of resources available on the web for those at home.

Check out this New York Times interactive graphic on different planetary systems.You can toggle between orbital size and discovery as well as hover your mouse over the orbits for various information.

-- Lauren Corlies (graduate student) 

March 7: Brain-gazing

This week we partnered with The Zuckerman Institute to help kick off Brain Awareness Week here in New York. This special event previewed a new visualization tool, Neurodome, designed to allow audiences to discover and explore the inner workings of the brain in a planetarium setting. The lecture was a blend of astronomy and neuroscience tracing the path of light through the Universe and into the brain. 

We started the evening with a fun quiz of "Space or Brain?" in which the audience had to guess if a given image was a picture of an object in space or a picture of part of the brain. Surprisingly most people were stumped at every turn! Next Matt Turk, a post-doc in the Department of Astronomy, spoke about how a particle of light, a photon, can travel from the farthest reaches of the observable universe and all the things that can happen to it along the way such as: reddening, scattering, absorption, and reemission. Matt left us and the light here on Earth and handed off the mic to Jonathan Fisher, a neuroscientist at New York Medical College. Jonathan and his colleagues then walked us through the various levels of the structure in the brain that the photon encounters and how Neurodome is allowing us to see the brain like never before. 

After the lecture, the audience was invited to tour to the rooftop observatories and further explore excerpts from Neurodome on our 3D Wall. 

We hope everyone enjoyed the interdisciplinary fun! 

-- Summer Ash (Director of Outreach)

February 21: Neutral Particle Power

Every second trillions of neutrinos cross our bodies without ever noticing. Graduate student Jia Liu guided the audience through the mysteries of these tiny particles that have puzzled scientists for decades. Neutrinos were suggested by the famous physicist Wolfgang Pauli to account for the missing energy, when a neutron splits into a proton and an electron (a process known as beta decay).

Neutrinos are abundant in nature and are produced through various processes. They are produced in the core of the stars when light nuclei merge to form heavier elements, in nuclear plants when the opposite process (heavier nuclei are divided into lighter) takes place to provide energy, in supernovae explosions and even when energetic particles from outer space interact with the atmosphere.

Neutrinos come in three varieties, have low mass and interact very weakly with matter, making their detection challenging. Next, Jia showed some of the cutting-edge operating detectors like IceCube in the South pole, ANTARES under the Mediterranean sea and Super-K in Japan, that trace neutrinos from astrophysical sources.

Finally, Jia discussed some intriguing potential (fiction-like) uses of neutrinos in the future, as proposed in serious scientific journals. Some of them included the destruction on nuclear weapons, the communication with extraterrestrial civilizations and equity trading.

After the lecture, the audience had the chance to view 3D movies of the universe on the 13th floor, to participate in roof tours and hear more about neutrino flavors from graduate student Andrew Weis. Later, as the sky cleared out and observing was possible, the few who stayed had the chance to look at Jupiter, the Orion Nebula as well as the new Supernova 2014J in nearby galaxy M82, which is the closest type-Ia supernova discovered in the past 42 years.

We hope to see you in our next event, which will entail an exciting collaboration with the neuroscience outreach group!

--Maria Charisi (graduate student)

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)

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)

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)

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)

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

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)

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)

http://www.esa.int/Our_Activities/Space_Science/Herschel

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)

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)