History Archives

October 31, 2024October 31, 2024 by Nancy Atkinson

Astronomer Calculates When van Gogh Painted This

van Gogh's 'Lane of Poplars at Sunset' painting. Image courtesy Texas State University.

One of my favorite paintings is Starry Night by Vincent van Gogh — for obvious astronomical reasons. But another favorite of van Gogh’s works is Lane of Poplars at Sunset. This painting depicts the setting Sun perfectly aligned with a long lane of trees, casting long shadows.

The geometry of the Earth and Sun means that this scene had to be painted on one specific day of the year when the alignment would be possible. An astronomer has now used 19th-century maps to discover where the lane was, and then used astronomical calculations to determine which date the Sun would be in the exact position as the painting. His result? The painting depicts a stretch of road known as Weverstraat in the Dutch town of Nuenen, on November 13 or 14, 1884.

September 7, 2024September 7, 2024 by Jon Voisey

Why Did Copernicus Reject Geocentrism?

Astronomer Copernicus, or Conversations with God, by Matejko. Credit: frombork.art.pl/pl/

Popular science history paints a picture of the Greek geocentric model dominating astronomical thought beginning around the 3rd century BCE, and being the favored model for ~1,500 years. Then, suddenly (it suggests), astronomical thought was overhauled at the birth of the Renaissance by brilliant astronomers such as Copernicus, Kepler, and Galileo, all of whom rejected placing the Earth at the center of the cosmos.

But these sources are generally quiet on why this shift occurred. If mentioned at all, sources generally suggest that it was because the Ptolemaic geocentric model was too complicated – overly burdened with epicycle and equants. Heliocentrism, in comparison, was simple – elegant, even.

Yet, Copernicus’ heliocentric model was still rooted in the Greek philosophical principles of uniform circular motion. Thus, it too was forced to adopt many of the complications we’re regularly told were the reason for rejecting Ptolemy’s model – epicycles included.

So, why then, did Copernicus actually turn his back on over 1,500 years of astronomical thought?

The answers are an interesting glimpse into the astronomical paradigm of the 16th century.

January 2, 2024January 2, 2024 by Mark Thompson

An Ancient Stone Found in Italy is an Accurate Map of the Night Sky

Digital elevation model of the frontal face of Rupinpiccolo stone disk from an adaptation of fig. 1 of Bernardini et al. (2022). The orientation is arbitrary

You know how some constellations take a little bit of imagination to see? Yes, Leo looks a bit like a lion and Orino a bit like a hunter but then we drift into the realms of powerful levels of imagination to be able to see Pegasus as a flying horse or Telescopium as a telescope! Even squinting or tilting your head really doesn’t make them visible. I found the same problem when looking at images of two stone disks discovered in Italy recently at the entrance to an ancient fort! Teams that have examined the stones have matched the subtle markings on them to positions of 28 bright stars in the sky! I had to really look to see it but I think they might actually be right!

November 29, 2023December 5, 2023 by David Dickinson

The Solar Radius Might Be Slightly Smaller Than We Thought

SDO Sol — NASA SDO's view, of our tempestuous host star. NASA/SDO

A pioneering method suggests that the size of our Sun and the solar radius may be due revision.

Our host star is full of surprises. Studying our Sun is the most essential facet of modern astronomy: not only does Sol provide us with the only example of a star we can study up close, but the energy it provides fuels life on Earth, and the space weather it produces impacts our modern technological civilization.

Now, a new study, titled The Acoustic Size of the Sun suggests that a key parameter in modern astronomy and heliophysics—the diameter of the Sun—may need a slight tweak.

August 9, 2023April 14, 2024 by Matt Williams

Penn State SETI Symposium Opens with Commemoration of Dr. Frank Drake

Dr. Frank Drake (1930 -2022). Credit: Danielle Futselaar

Is humanity alone in the Universe? Is anyone out there? Where is everybody? And what happens if and when we make contact with them? These and other questions were the subjects of the 2023 Penn State SETI Symposium hosted by the Penn State Extraterrestrial Intelligence Center (PSETI) from June 19th-22nd, 2023. The event featured prominent speakers from various research fields and disciplines discussing the challenges, history, and future of SETI. In the great tradition established by Dr. Frank Drake, they also addressed key issues related to the search for intelligent life and what we might find someday.

The summit opened with a series of overviews, a review of the past year (since the last summit), and a presentation by Dr. Rebecca Charbonneau, a science historian and Jansky Fellow at the National Radio Astronomy Observatory (NRAO). Her presentation, titled “Frank Drake and his Place in History,” provided a retrospective on the life and accomplishments of famed radio astronomer and SETI pioneer Dr. Frank Drake (for whom the Drake Equation is named), how he altered the character of the field, and how history will remember him.

February 2, 2023December 16, 2023 by Jon Voisey

The Historic Discussion of Ptolemy’s Star Catalog

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 observational 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.

November 27, 2022December 6, 2022 by Matt Williams

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.

October 23, 2022October 23, 2022 by Brian Koberlein

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?

May 11, 2022May 11, 2022 by Scott Alan Johnston

‘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:

February 11, 2022February 11, 2022 by Evan Gough

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.