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Mercury magazine

Spring 2011 - Volume 40, Number 2

Spring 2011 - Volume 40, Number 2

Table of Contents



[12] Chandrasekhar: the Most Distinguished Astrophysicist of his Time, Richard E. White
Chandra's career, highlighted by the 1983 Nobel Prize in physics, spanned decades and continents.

[18] Chandra: The Man Behind the Science, Nalini Easwar
To the members of the family he evoked the feeling of a forbidding figure, but his gentle and approachable nature came through in every personal interaction.

[22] Extrasolar Planets: The Ongoing Saga, Paul Deans
Here is an assemblage of press releases and Web items spotlighting exoplanets, as astronomers draw closer to finding the Holy Grail of extrasolar worlds — an Earth-like planet in a star’s habitable zone.

[27] Astronomy in the News
Ripples in the rings of Jupiter, Voyager 1 nears the limit of the Sun’s solar wind, and a giant ring of black holes — these are some of the discoveries that recently made news in the astronomical community.


[4] Editorial, Paul Deans
Do You Explore?

[5] First Word, James G. Manning
Bueller Speaks

[6] Annals of Astronomy, Clifford J. Cunningham
Dual Birthdays: Wright and Pingré at 300

[7] Astronomer's Notebook, Jennifer Birriel
Refining the Extragalactic Distance Scale

[8] Planetary Perspectives, Daniel D. Durda
Swapping Comets with Our Stellar Siblings

[9] Armchair Astrophysics, Christopher Wanjek
Crunchy Neutron Stars with a Liquid Core

[10] Education Matters, David Bruning
Creating the New Age of Education, Pt. II

[11] Reaching Out, James Lochner
The Year of the What?

[32] Society Scope/ASP Supporters
Meet Us in Baltimore

[34] Sky Sights, Paul Deans
Eclipses Galore

[39] Reflections, Thierry Legault
The Sun, an Eclipse, and the ISS

Chandrasekhar: the Most Distinguished Astrophysicist of his Time

by Richard E. White

October 19, 2010, was the centenary of the birth of Subrahmanyan Chandrasekhar, known simply as "Chandra" in the astronomical community. The only person to receive the Nobel Prize in Physics for work primarily in theoretical astrophysics, he is best known for the "Chandrasekhar limit," the maximum mass of white dwarfs.

I was honored and humbled by an invitation from Chandra's niece, Nalini Easwar, to return to Smith College and the Five College Astronomy Department to review his science on the very day of the centenary. This article stems from that presentation, which I began with the words of G. Srivinasan, who edited a volume reviewing Chandra's diverse research: "The range of Chandra's contributions is so vast that no one person in the physics or astronomy community can undertake the task of commenting on his achievements."

Here I want to share the inspiration that I felt in reviewing Chandra's life and work, as well as provide a taste of the aspiration he fostered in my early career.

Chandra: The Man Behind the Science

by Nalini Easwar

As October 10, 2010 approached, excitement, inspiration, and pride swept over the members of Chandra's family. It was 100 years since the birth of their beloved Ayya Mama or Periappa (as he was referred to by his 33 nieces and nephews).

A series of events were held in India and at the University of Chicago to mark Chandra's birth centenary. The family came together to also collect pictures and share essays about their inter-actions and memories of Chandra. HarperCollins (India) recently published a collection of essays called S. Chandra, Man of Science. To commemorate Chandra's birth centenary, I invited Dick White, Professor Emeritus at Smith College, to talk on Chandra and his contributions to theoretical astrophysics. This shared experience inspired us to write these paired articles.

In 1918 Chandra's family moved from Lahore, his birthplace, to Madras (now called Chennai). Chandra and his nine siblings grew up in their home, "Chandra Vilas" ("Abode of the Moon"). His grandfather, after whom he was named, was a mathematics teacher with a wide collection of classic math texts. One text that stayed in Chandra's possession was Maxime Bocher's Introduction to Higher Algebra. According to his father, the book "put him in the way of the study of higher mathematics and its applications to problems in mathematical physics." Chandra's father was himself a musician and an avid reader of literature, and he owned a vast library that lined the walls of Chandra Vilas. This erudite environment fostered Chandra's love of literature and music in parallel.

Extrasolar Planets: The Ongoing Saga

by Paul Deans

Two years after the launch of NASA’s Kepler mission, the discovery of extrasolar planets has turned from a trickle into a torrent. As a consequence of this data flood, other extrasolar planet researchers and facilities are often overlooked, and yet they continue to make discoveries or do critical work confirming Kepler's finds. There's a lot going on!

So every now and then I'll take press releases and Web items and assemble an article on exoplanets -- probably the hottest topic in astronomy these days. (Of course, exoplanet news items will continue to appear in "Astronomy in the News.") I'll include as many hotlinks as possible so you can keep tabs on the search, as astronomers seek the Holy Grail of extrasolar planets — an Earth-size, Earth-like world in a star's habitable zone.

And where better to start than with the complete press release announcing the detection of a remarkable six-planet system surrounding the star Kepler-11, followed by the discovery of a number of Earth-sized planet candidates in stellar habitable zones. Next, in an October 2010 release (that preceded this proliferation of planet discoveries), a NASA/JPL survey suggests that Earth-size planets may be quite common. Finally, discover how you can join the search for Earth-like worlds.

Astronomy in the News
Giant Ring of Black Holes

Chandra X-ray Center

Arp 147 contains the remnant of a spiral galaxy (right side of the image) that collided with the elliptical galaxy (left of center). This collision has produced an expanding wave of star formation that shows up as a blue ring containing an abundance of massive young stars. These stars race through their evolution in a few million years or less and explode as supernovas, leaving behind neutron stars and black holes.

A fraction of the neutron stars and black holes will have companion stars, and may become bright X-ray sources as they pull in matter from their companions. The nine X-ray sources scattered around the ring in Arp 147 are so bright that they must be black holes, with masses that are likely ten to twenty times that of the Sun.

An X-ray source is also detected in the nucleus of the red galaxy on the left and may be powered by a poorly fed supermassive black hole. This source is not obvious in the composite image but can easily be seen in the X-ray image. Other objects unrelated to Arp 147 are also visible: a foreground star in the lower left of the image and a background quasar as the pink source above and to the left of the red galaxy.

Infrared observations with NASA's Spitzer Space Telescope and ultraviolet observations with NASA's Galaxy Evolution Explorer (GALEX) have allowed estimates of the rate of star formation in the ring.