NASA Astronomy Picture of the Day

May 20, 2024

Aurora Dome Sky

It seemed like night, but part of the sky glowed purple. It was the now famous night of May 10, 2024, when people over much of the world reported beautiful aurora-filled skies. The featured image was captured this night during early morning hours from Arlington, Wisconsin, USA. The panorama is a composite of several 6-second exposures covering two thirds of the visible sky, with north in the center, and processed to heighten the colors and remove electrical wires. The photographer (in the foreground) reported that the aurora appeared to flow from a point overhead but illuminated the sky only toward the north. The aurora's energetic particles originated from CMEs ejected from our Sun over sunspot AR 3664 a few days before. This large active region rotated to the far side of the Sun last week, but may well survive to rotate back toward the Earth next week.

https://apod.nasa.gov/apod/astropix.html?

Vipin Narang Named DOD Acting Assistant Secretary for Space Policy

MAY 20, 2024

Vipin Narang, principal deputy assistant secretary for space policy at the Department of Defense, will take on the role of acting assistant secretary of defense for space policy on Monday, May 20.

Amanda Dory, acting undersecretary of defense for policy, said in a release published Friday Narang will replace John Plumb, who was confirmed as the first assistant secretary of defense for space policy in March 2022.

In his role as principal deputy assistant secretary, Narang oversees a portfolio that includes space, cyber, missile defense, nuclear and policy focused on countering weapons of mass destruction. He also serves as the principal cyber adviser to the secretary of defense.

He is on public service leave from MIT, where he serves as the Frank Stanton Professor of Nuclear Security and Political Science.

Dory acknowledged and thanked Plumb’s contributions to DOD, including his role in managing the department’s strategic capabilities for integrated deterrence, overseeing the cyber policy portfolio, advancing space security and implementing the commercial space integration policy.

https://www.govconwire.com/2024/05/vipin-narang-named-dod-acting-assistant-secretary-for-space-policy/

https://www.space.com/egyptian-goddess-of-the-sky-astronomy-milky-way

https://www.sciengine.com/JAHH/doi/10.3724/SP.J.1440-2807.2024.01.02;JSESSIONID=d4e0717f-a8f6-444c-b1db-776f84a1189b

The ancient Egyptian goddess of the sky and how I used modern astronomy to explore her link with the Milky Way

May 20, 2024

What did our ancestors think when they looked up at the night sky? All cultures ascribed special meaning to the sun and the moon, but what about the pearly band of light and shadow we call the Milky Way?

My recent study showed an intriguing link between an Egyptian goddess and the Milky Way.

Slowly, scholars are putting together a picture of Egyptian astronomy. The god Sah has been linked to stars in the Orion constellation, while the goddess Sopdet has been linked to the star Sirius.

Where we see a plough (or the big dipper), the Egyptians saw the foreleg of a bull. But the Milky Way’s Egyptian name and its relation to Egyptian culture have long been a mystery.

Several scholars have suggested that the Milky Way was linked to Nut, the Egyptian goddess of the sky who swallowed the sun as it set and gave birth to it once more as it rose the next day.

But their attempts to map different parts of Nut's body onto sections of the Milky Way were inconsistent with each other and didn't match the ancient Egyptian texts.

In a paper published in the Journal of Astronomical History and Heritage, I compared descriptions of the goddess in the Pyramid Texts, Coffin Texts, and the Book of Nut to simulations of the Milky Way’s appearance in the ancient Egyptian night sky.

Carved onto the walls of the pyramids more than 4,000 years ago, the Pyramid Texts are a collection of spells to aid the kings’ journey to the afterlife.

Painted on coffins a few hundred years after the age of the pyramids, the Coffin Texts were a similar collection of spells. The Book of Nut described Nut’s role in the solar cycle. It has been found in several monuments and papyri, and its oldest version dates back some 3,000 years ago.

The Book of Nut described Nut's head and groin as the western and eastern horizons, respectively. It also described how she swallowed not only the sun but also a series of so-called "decanal" stars that are thought to have been used to tell time during the night.

From this description, I concluded that Nut's head and groin had to be locked to the horizons so that she could give birth and later swallow the decanal stars as they rose and set throughout the night.

This meant that she could never be mapped directly onto the Milky Way, whose different sections rise and set as well.

I did, however, find a possible link to the Milky Way in the orientation of Nut's arms. The Book of Nut describes Nut's right arm as lying in the northwest and her left arm in the southeast at a 45 degree angle to her body.

My simulations of the Egyptian night sky using the planetarium software Cartes du Ciel and Stellarium revealed that this orientation was precisely that of the Milky Way during the winter in ancient Egypt.

The Milky Way is not a physical manifestation of Nut. Instead, it may have been used as a figurative way to highlight Nut's presence as the sky.

During the winter, it showed Nut's arms. In the summer (when its orientation flips by 90 degrees) the Milky Way sketched out her backbone.

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>>20891626

Nut is often portrayed in tomb murals and funerary papyri as a naked, arched woman, a portrayal that resembles the arch of the Milky Way.

However, Nut is also portrayed in ancient texts as a cow, a hippopotamus and a vulture, thought to highlight her motherly attributes.

Along the same lines, the Milky Way could be thought of as highlighting Nut's celestial attributes.

The ancient Egyptian texts also describe Nut as a ladder or as reaching out her arms to help guide the deceased up to the sky on their way to the afterlife.

Many cultures around the world, such as the Lakota and Pawnee in North America and the Quiché Maya in Central America, see the Milky Way as a spirits’ road.

The Book of Nut also describes the annual bird migration into Egypt and ties it both to the netherworld and to Nut.

This section of the Book of Nut describes Ba birds flying into Egypt from Nut's northeast and northwest sides before turning into regular birds to feed in Egypt’s marshes.

The Egyptians considered the Ba, portrayed as a human-headed bird, to be the aspect of a person that imbued it with individuality (similar, but not identical, to the modern Western concept of the “soul”).

The Bas of the dead were free to leave and return to the netherworld as they wished.

Nut is often shown standing in a sycamore tree and providing food and water to the deceased and their Ba.

Once again, several cultures across the Baltics and northern Europe (including the Finns, Lithuanians, and Sámi) view the Milky Way as the path along which birds migrate before winter.

While these links don’t prove a connection between Nut and the Milky Way, they show that such a connection would place Nut comfortably within the global mythology of the Milky Way.

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China launches four high-resolution remote sensing satellites

May 20, 2024

HELSINKI — China sent a new set of four Beijing-3 optical remote sensing satellites into orbit late Sunday.

A Long March 2D rocket lifted off at 11:06 p.m. Eastern, May 19 (0306 UTC, May 20), from the Taiyuan Satellite Launch Center, north China.

The China Aerospace Science and Technology Group (CASC) confirmed launch success within an hour of liftoff.

Aboard were four Beijing-3C remote sensing satellites. These are likely to enter roughly circular, 600-kilometer-altitude sun-synchronous orbits.

The Long March 2D notably carried grid fins to help constrain the landing zone of its first stage.

Taiyuan is deep inland and falling spent rocket stages can prove hazardous and disruptive downrange.

The satellites were launched for Twenty First Century Aerospace Technology Co. Ltd. (21AT) of Beijing.

The satellites were built by CASC’s China Academy of Space Technology (CAST). 21AT has earlier ordered satellites from Surrey Satellite Technology Ltd. (SSTL) of the United Kingdom.

The Beijing-3C constellation consists of four 0.5-meter panchromatic, 2-meter multispectral resolution intelligent remote sensing satellites. Two of the quartet are also known as Nanning-2 and Zhengzhou Airport Satellite, according to 21AT. The former will provide services to Nanning, capital of Guangxi Zhuang Autonomous Region, and the region itself.

The constellation will work with other, previously launched Beijing-3 satellites.

These will combine to provide high-resolution remote sensing satellite data.

They will also assist the development of new productive forces in commercial aerospace, and contribute to the modernization of the national governance system and governance capabilities, according to 21AT.

The Beijing constellation is far from China’s largest remote sensing constellation. Changguang Satellite Technology (CGST), a spinoff from the Chinese Academy of Sciences’ CIOMP, has more than 100 Jilin-1 series satellites in orbit.

These include optical and video satellites, with panchromatic resolution of around 0.70 meters. In 2022 it expanded its plans to launch 300 satellites by 2025.

Sunday’s launch was China’s 23rd orbital launch of 2024.

The country aims to launch around 100 times this year, with roughly 30 planned to be conducted by commercial launch service providers.

Kuaizhou-11 and Ceres-1 solid rockets from commercial entities Expace and Galactic Energy respectively are expected to launch in the coming days.

China’s Chang’e-6 lunar far side sample return spacecraft is currently in lunar orbit, awaiting an opportunity to land.

https://spacenews.com/china-launches-four-high-resolution-remote-sensing-satellites/

>>20891724

>Don't let them take you down.

"We will always fight on to victory"