One of the Oldest Astrolabes Has Both Hebrew and Arabic Markings

I always think of planispheres when I think of astrolabes! Navigators used these ancient devices (astrolabes not planispheres) to provide an accurate map of the stars in the sky. To use them you would match up the metal plates to the sky and you could calculate your location. Astrolabes date back to 220BC but one with Hebrew and Arabic markings was found and it is thought to have originated back in the 11th Century.

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Solar Physics: Why study it? What can it teach us about finding life beyond Earth?

Image of a coronal mass ejection being discharged from the Sun. (Credit: NASA/Goddard Space Flight Center/Solar Dynamics Observatory)

Universe Today has investigated the importance of studying impact craters, planetary surfaces, exoplanets, and astrobiology, and what these disciplines can teach both researchers and the public about finding life beyond Earth. Here, we will discuss the fascinating field of solar physics (also called heliophysics), including why scientists study it, the benefits and challenges of studying it, what it can teach us about finding life beyond Earth, and how upcoming students can pursue studying solar physics. So, why is it so important to study solar physics?

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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! 

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The Positions of Stars on an Ancient Navigation Device Tell us When it was Made

Astrolabes serve two purposes. First, they are useful as an astronomical tool, especially for finding a ship’s latitude. But second, they are works of art in themselves. Besides having to be precise, many are beautiful. They are even seeing a resurgence in popularity as collectors lap up even those made by modern manufacturing processes because of their aesthetic appeal. Now, a new paper adds to their uses – a self-referential ability to mark what year they were made by the patterns of the stars they reference.

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An Amateur Astronomer Discovered One-of-a-Kind Supernova Remnant

PA 30 imaged in O III on Sept 6, 2013 by KPNO from Ritter et al (2021) (left) and in S II from Fesen et al (2023) (right).

In 2013, amateur astronomer Dana Patchick was looking through images from the Wide-field Infrared Survey Explorer archive and discovered a diffuse, circular object near the constellation of Cassiopeia. He found this apparent nebula was interesting because it was bright in the infrared portion of the spectrum, but virtually invisible in the colors of light visible to our eyes. Dana added this item to the database of the Deep Sky Hunters amateur astronomers group, believing it was a planetary nebula – the quiet remnant of stars in mass similar to the sun. He named it PA 30.

However, professional astronomers who picked it up from there realized that this object is far more than it first seemed. It is, they now believe, the remnant of a lost supernova observed in 1181. And an extremely rare type at that.

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Edward Stone Has Been the Voyagers’ Project Scientist for 50 Years. He Just Retired

Artist's concept of Voyager 1 in interstellar space. Credit: NASA/JPL-Caltech

Edward Stone is retiring after 50 years as Project Scientist for the Voyager mission. The twin spacecraft revolutionized our understanding of our Solar System, and Stone was along for the ride every step of the way. Both spacecraft are still going, travelling deeper into interplanetary space, and still sending data home.

But after a long and rewarding career full of achievements and recognition, Stone is moving on.

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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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Comet Records From 1240 Accurately Date When a Byzantine Princess Died

This unprocessed image from NASA’s Parker Solar Probe shows comet NEOWISE on July 5, 2020, shortly after its closest approach to the Sun. Credits: NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher

Rome was the world’s first mega-empire. At its height it stretched from Western Europe to the Middle East, and over 50 million souls lived within its borders. Some historians think that number could’ve been way higher, up to 100 million.

Rome got its start in the mid-8th century BC. It took centuries for that small city to grow into the Roman Empire, which reached its peak around AD 100. A well-known cliche reminds us how long that took.

But the Roman Empire also took centuries to fracture and dissolve.

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A History of the Magellanic Clouds and How They Got Their Names

Image of the night sky taken at the European Southern Observatory’s Very Large Telescope in Chile. The Large and Small Magellanic Clouds are visible in the night sky. Credit: ESO, Y. Beletsky

The Magellanic Clouds are a pair of dwarf galaxies that are bound to the Milky Way. The Milky Way is slowly consuming them in Borg-like fashion, starting with the gas halo that surrounds both Clouds. They’re visible in the southern sky, and for centuries people have gazed up at them. They’re named after the Portuguese explorer Ferdinand Magellan, in our current times.

But they weren’t always called that.

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Ancient Meteorites Can be Found Embedded in Rocks, Like Fossils

Fossil meteorites from the mid-Ordovician period, around 460 million years ago, indicate that Earth may have been hit by debris from an asteroid collision at that time. Image credit - Birger Schmitz

Comets visit the inner Solar System, and leave without saying goodbye. Maybe they leave a trail of dust behind, and when the Earth passes through it, we get a pretty light show in the night sky, in the form of a meteor shower. Likewise, asteroids frequently go whizzing by, though they don’t leave us with a pyrotechnic display.

Sometimes these rocky interlopers head straight for Earth. And when they do, the results can be cataclysmic, like when an asteroid struck Earth about 66 million years ago, wiping out the dinosaurs and 75% of life on Earth. Other times, it’s not quite as cataclysmic, but still devastating, like in about 2350 BC, when debris from a disintegrating comet may have caused the collapse of an ancient empire.

But regardless of the severity of any of these individual events, the conclusion is crystal clear: Earth’s history is intertwined with the coming and going of space rocks. The evidence is all around us, sort of.

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