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History and Famous Astronomers

Articles about the history of astronomy and famous astronomers who made important discoveries.

Chandra’s Limit

February 25, 2023 by Brian Ventrudo Filed Under: History and Famous Astronomers

A white dwarf accreting matter from a nearby companion star explodes as a Type Ia supernova when its mass reaches the Chandrasekhar Limit (credit: NASA)
A white dwarf accreting matter from a nearby companion star explodes as a Type Ia supernova when its mass reaches the Chandrasekhar Limit (credit: NASA)

Somehow in my younger days, in my haste to get out into the ‘real world’, I ended up spending five years in graduate school. Part of that time, in the summers, I studied and conducted research at the University of Chicago where I helped use laser systems to measure properties of molecules found in planetary atmospheres and the interstellar medium.

Chicago is one of the world’s great universities. Nearly 100 of its students and professors have won Nobel Prizes. But it’s not a particularly big place, so a chance sighting of a famous professor is not unusual. Still, I stopped in my tracks during my first week on campus when, on the way back to the lab from lunch, I passed on the sidewalk an older, slight man of Indian descent with thinning grey hair and alert eyes wearing a crisp white shirt and tie. I instantly recognized him as Subrahmanyan Chandrasekhar, more commonly known as Chandra, the discoverer of the Chandrasekhar Limit, winner of the 1983 Nobel Prize in Physics, and one of the most revered astrophysicists in the world [Read more…] about Chandra’s Limit

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Filed Under: History and Famous Astronomers chandra, white dwarf

Was the Christmas Star Real?

November 27, 2020 by Brian Ventrudo Filed Under: History and Famous Astronomers

Sirius, the brightest star in the sky, over a snow-covered spruce tree in December 2019. Image credit: Brian Ventrudo.

O star of wonder, star of night,
Star with royal beauty bright,
Westward leading, still proceeding,
Guide us to thy perfect light.

The Christmas Star – it may be the most famous “star” in history. But was it real? Mentioned just once in the gospel of Matthew, the “Star of Bethlehem”, or the “Christmas Star”, may have guided three wise men from the East in search of a newborn king. A few words written on a scroll two thousand years ago isn’t much to go on, but astronomers have a few ideas that may explain the apparition of a star near the time of the birth of Jesus [Read more…] about Was the Christmas Star Real?

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Filed Under: History and Famous Astronomers

The Greatest Astrophoto in History (So Far)

October 11, 2018 by Brian Ventrudo Filed Under: History and Famous Astronomers

Fifty years ago this December, at the end of a ghastly year of assassinations, riots, war, and political unrest, three astronauts became the first humans to leave the gravitational embrace of Earth, orbit another world, and return safely back home. Apollo 8 was a mission of astonishing audacity, put together in great haste to counter a possible Soviet lunar mission which U.S. intelligence sources believed was imminent. And it served as a major step to fulfill President Kennedy’s promise to land a man on the Moon and return him safely to Earth by the end of the 1960s [Read more…] about The Greatest Astrophoto in History (So Far)

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A Visit to Mount Wilson Observatory

September 17, 2018 by Joe Bergeron Filed Under: History and Famous Astronomers

The dome of the 100″ Hooker telescope at Mt. Wilson Observatory and tour guide Nik Arkimovich. Image credit: Joe Bergeron.

One hundred years ago, the universe was quite small, or at least people thought it was. Not so small that you could put it in your pocket, but limited to the Milky Way Galaxy only, which was thought to be about 30,000 light-years across, or maybe a little more.

Beyond that, if there was anything at all, it was simply an empty void.

That’s because no one was sure what the so-called “spiral nebulae” really were. They were dotted across the sky, often in clusters, though they were scarce along the band of the Milky Way. When astrophysicists analyzed their light spectroscopically, those spectra showed star-like characteristics, but no telescope on Earth could reveal individual stars, either visually or photographically. They remained mysterious, and often beautiful, whirlpools of light.

So although some astronomers suspected these spirals were in fact remote “island universes”, more of them believed they were closer, lesser things, perhaps infant solar systems in the process of forming.

Slightly less than one hundred years ago, these questions were resolved, along with the galaxies themselves, and the size of the known universe expanded one hundred thousand times or more, almost overnight.

And that’s where the Mount Wilson Observatory in California comes in. Its namesake mountain sits at the edge of the vast carpet of artificial lights known as the Los Angeles Basin, looking down on it from 5700 feet above the not-so-distant Pacific Ocean. Today that massive light pollution renders the observatory useless for most kinds of nighttime astronomical research. In its heyday in the early 20th Century, it was the world’s greatest center of astronomical discovery. It was one of the first observatories ever to be sited on a mountaintop for performance, not in or near a city for convenience. Back then it could ignore the feeble lights of Los Angeles and the other small communities flickering below [Read more…] about A Visit to Mount Wilson Observatory

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Filed Under: History and Famous Astronomers hubble, mount wilson, observatory

A Requiem for Yerkes Observatory

August 3, 2018 by Brian Ventrudo Filed Under: History and Famous Astronomers

The main dome that houses the 40″ refractor at Yerkes Observatory in Williams Bay, WI.

“All things lovely will have an ending”, wrote author Conrad Aiken, and the end is coming soon for the venerable Yerkes Observatory on Lake Geneva in the pleasant resort village of Williams Bay, Wisconsin. The University of Chicago, which operates the observatory, announced earlier this year that Yerkes will close on October 1, 2018, and all public tours and scientific and educational activities will cease after more than 120 years of operations [Read more…] about A Requiem for Yerkes Observatory

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Filed Under: History and Famous Astronomers observatory, refractor, yerkes

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