NASA’s Swift telescope has burned up, months after a robot sent to save it failed – here’s why it’s so hard to boost a satellite

the gist

NASA's Neil Gehrels Swift Observatory, launched in 2004 to study gamma-ray bursts, has burned up in the atmosphere after a robotic rescue mission to boost its orbit failed months earlier. Satellites in low Earth orbit slowly lose height because of friction with the thin upper atmosphere, and solar activity speeds that up. Raising an orbit means grabbing a satellite that was not designed to be serviced. If the rescuer bumps it, it can start tumbling, and a tumbling spacecraft is very hard to hold. The rescuer must therefore be extremely steady and precise.

so what

Swift made thousands of discoveries about exploding stars and black holes, and its loss shows how hard it is to repair or move satellites in orbit. Future spacecraft may be designed to be serviced.

fun fact

Swift detected hundreds of gamma-ray bursts, brief flashes from the death of massive stars or merging neutron stars.

Illustrative photo · NASA E/PO, Sonoma State University/Aurore Simonnet, Public domain, via Wikimedia Commons

source: The Conversation ↗

historyWikipediaclassic1336–1565 · Karnataka, India

Hampi was once one of the world's largest cities, until its Vijayanagara capital was destroyed in 1565

the gist

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.

how it works

The city was built around a fortified core with temples, markets and water structures along the river, supplied by an extensive network of roads and waterworks. When the empire fell, the city was not rebuilt, so its stone monuments were left standing.

so what

Hampi shows how quickly a great city can vanish after a military defeat, and how a ruined capital can remain sacred. Its ruins give historians a view of medieval South Asia that few other sites can match.

fun fact

The name Hampi comes from Pampa, an old name for the Tungabhadra River.

From Wikipedia, the free encyclopedia · text CC BY-SA 4.0

Image: Wikimedia Commons

source: Wikipedia ↗

2 min

politicsshortCNA2:01

False allegations about Singapore’s hand in Indonesia’s markets and a made-up meeting

from CNA

CNA Verify has found close to 400 posts pushing falsehoods tying Singapore to Indonesia’s stock market rout and to a secret meeting that never took place. Together, they drew nearly 12 million views, and some were circulated by accounts that appeared to be working in concert, across multiple social media platforms.

Here’s how the disinformation campaign targeting Singapore was uncovered.

on YouTube: CNA ↗