The Historic Discussion of Ptolemy’s Star Catalog

A page from the star catalog in a 1515 printing of Ptolemy's Almagest.
A page from the star catalog in a 1515 printing of Ptolemy's Almagest.

From the time of its writing in the 2nd century CE, Claudius Ptolemy’s Almagest stood at the forefront of mathematical astronomy for nearly 1,500 years. This work included a catalog of 1,025 stars, listing their coordinates (in ecliptic longitude and latitude) and brightnesses. While astronomers within a few centuries realized that the models for the sun, moon, and planets all had issues (which we today recognize as being a result of them being incorrect, geocentric models relying on circles and epicycles instead of a heliocentric model with elliptical orbits), the catalog of stars was generally believed to be correct.

That was, until the end of the 16th century, when the renowned observation astronomer Tycho Brahe realized that there was a fundamental flaw with the catalog: the ecliptic longitudes were low by an average of 1 degree.

What’s more, Brahe proposed an explanation for why. He suggested that Ptolemy had stolen the data from the astronomer Hipparchus some 250 years earlier, and then incorrectly updated the coordinates.

The question of whether this was a cosmic coincidence or the oldest case of scientific plagiarism is a question that historians of astronomy have argued for over 400 years.

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Based on the JWST Controversy, NASA is re-Evaluating the way it Names Spacecraft

Artist conception of the James Webb Space Telescope. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez

In 2015, the naming of the James Webb Space Telescope (JWST) became the subject of controversy when it was revealed that the namesake (NASA’s administrator between 1961 and 1968) was involved in the infamous “Lavender Scare.” This refers to the period in the late 1940s and early 50s when the U.S. State Department purged thousands of individuals from their positions due to allegations of homosexuality. In 2021, NASA Administrator Bill Nelson requested a formal and public report and tasked NASA’s Chief Historian Brian C. Odom with investigating the matter.

In their final report, titled “NASA Historical Investigation into James E. Webb’s Relationship to the Lavender Scare” (aka. the NASA James Webb Historical Report). In it, NASA claimed that their investigation found no direct evidence that Webb was a “leader of or a proponent” of the policy; therefore, they would not be renaming the JWST. In a surprise twist, it appears that NASA may reexamine its naming policy and recommend changes. According to a statement released by the American Astronomical Society (AAS), Administrator Nelson agreed that the policy needs to be reevaluated.

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Scientists Find an Ancient Stellar Catalog Written by Hipparcus Hidden in a Medieval Tome

A folio from the Codex Climaci Rescriptus. Credit: Peter Malik

If you think writing paper is expensive these days, be glad you didn’t live in the middle ages. Back then, paper was as rare as hen’s teeth, so good luck finding some to write one. But if you happened to be a monk, chances are there were plenty of old books made of parchment. Many of them have useless stuff like old star catalogs, so why not just recycle the parchment for your new copy of religious literature?

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‘The Clocks are Telling Lies:’ A New Book from Universe Today Writer Scott Alan Johnston

Scott Alan Johnston (that’s me!) joined the Universe Today team just over a year ago. Since then, I’ve written over 50 space news stories for the website – time flies when you’re having fun! But when I’m not writing articles here on Universe Today, I’m a historian of science, and I recently released a new book about the history of timekeeping.

Have you ever wondered why we tell time the way we do? Well, history buffs, come along for a journey:

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We Might Know Why Mars Lost its Magnetic Field

This figure shows a cross-section of the planet Mars revealing an inner, high density core buried deep within the interior. Dipole magnetic field lines are drawn in blue, showing the global scale magnetic field that one associates with dynamo generation in the core. Mars must have one day had such a field, but today it is not evident. Perhaps the energy source that powered the early dynamo has shut down. The differentiation of the planet interior - heavy elements like iron sinking towards the center of the planet - can provide energy as can the formation of a solid core from the liquid. Credit: NASA/JPL/GSFC

Mars is a parched planet ruled by global dust storms. It’s also a frigid world, where night-time winter temperatures fall to -140 C (-220 F) at the poles. But it wasn’t always a dry, barren, freezing, inhospitable wasteland. It used to be a warm, wet, almost inviting place, where liquid water flowed across the surface, filling up lakes, carving channels, and leaving sediment deltas.

But then it lost its magnetic field, and without the protection it provided, the Sun stripped away the planet’s atmosphere. Without its atmosphere, the water went next. Now Mars is the Mars we’ve always known: A place that only robotic rovers find hospitable.

How exactly did it lose its magnetic shield? Scientists have puzzled over that for a long time.

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Remembering NASA Engineer Jerry Woodfill, the Inspiration Behind “13 Things That Saved Apollo 13”

Jerry Woodfill, an engineer who worked diligently behind the scenes during NASA’s Apollo program, has passed away at age 79. Jerry was still employed by the Johnson Space Center (JSC) at the time of his death, working there for over 57 years. Most notably, Jerry worked as the lead engineer behind the Caution and Warning System on the Apollo spacecraft, which alerted astronauts to issues such as Apollo 11’s computer problems during the first Moon landing, and the explosion of Apollo 13’s oxygen tanks.

While continuing his work as an engineer at JSC, Jerry’s infectious enthusiasm for spaceflight led him to also be part of NASA’s public and educational outreach, where he spearheaded programs for children, teachers and adults about science and space flight. He routinely gave over 40 lectures a year, both in person and online to listeners around the world. His unique sense of humor and sometimes unabashed showmanship could hold even the shortest of young attention spans. Jerry usually had his audiences either in stitches or fully captivated by his stories.  

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Alan Shepard’s Daughter Will be Flying on the Next New Shepard Flight

Jeff Bezos has hit a particular stride lately with Blue Origin, the commercial space company he founded in 2000 in the hopes of “building a road to space.” For the sake of fostering interest in the space tourism industry, testing their reusable launch vehicle, and growing his company’s brand, he’s conducting recurring launches with the New Shepard featuring high-profile clientele. At the same time, he aims to make each new launch a record-setting event.

On Nov. 23rd, Blue Origin announced the names of the six people who would fly aboard the New Shepard launch vehicle on its nineteenth flight (NS-19), scheduled for Dec. 9th. Among them is Laura Shepard Churchley, the eldest daughter of astronaut Alan Shepard, the first American astronaut to go to space, the fifth man to walk on the Moon, and for whom the New Shepard launch vehicle is named.

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Here are the First New Pictures From the Fully Operational Hubble

Normal science observations were restarted on July 17, 2021 for the Hubble Space Telescope. Credit: NASA/ESA/ StScI.

The astronomy community breathed a huge sigh of relief earlier this week when the Space Telescope Science Institute announced the Hubble Space Telescope’s major computer issues had been fixed. In a grueling month of recovery work, every expert – even retired Hubble engineers and scientists — was brought in for consultation. Their ultimate success is a tribute to the legacy of problem-solving and innovation NASA has been famous for over the years. And now, the telescope is back doing what it was built to do, taking incredible pictures of the cosmos and sending them down to Earth.  

Here are the first images since the long-distance repair, two pictures of galaxies. One shows a galaxy with unusual extended spiral arms, and the other is the first high-resolution view of an intriguing pair of colliding galaxies.

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Remembering NASA Flight Director Glynn Lunney, 1936-2021

Glynn S. Lunney at his console in the MCC during an Apollo simulation exercise in Mission Control at the Manned Spacecraft Center. Credit: NASA.

Legendary NASA flight director Glynn Lunney has passed away at age 84. Lunney played a key role in the early days of NASA, helping to create the concept and operation of what we now reverently know as Mission Control. His calm decisiveness was lauded during the Gemini and Apollo missions he guided as flight director, and his leadership was especially pivotal in bringing the crew of Apollo 13 safely back to Earth.

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Chuck Yeager, the First Man to Break the Sound Barrier has Died. He was 97

Capt. Charles E. Yeager (shown standing next to the Air Force's Bell-built X-1 supersonic research aircraft) became the first man to fly faster than the speed of sound in level flight on October 14, 1947. (U.S. Air Force photo)

On Dec.7th, 2020, World War II flying ace and legendary test pilot General Chuck Yeager passed away while in hospital in Los Angeles. He was 97 years of age and is survived by his second wife, Victoria Yeager (nee Victoria Scott D’Angelo), and his three children, Susan, Don, and Sharon. Yeager is interred at Arlington National Cemetery outside of Washington D.C. with full military honors.

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