A perfectly aligned galaxy and cluster bend light from behind into a bright Einstein ring

the gist

When a massive object sits almost exactly between us and a distant galaxy, its gravity bends the galaxy's light all the way around, forming a ring. Einstein predicted this effect in his general theory of relativity, and it is called an Einstein ring. Here the central galaxy of a cluster sits nearly in line with a background galaxy, and the background image is warped and magnified into an almost perfect circle. Other galaxies in the cluster add further distortions. Such rings are useful because they magnify galaxies too faint and distant to see otherwise.

how it works

Mass bends spacetime, so light from a background galaxy follows curved paths around a foreground mass. When the alignment is nearly perfect, the light is bent around all sides, forming a ring whose brightness is magnified.

so what

Einstein rings show general relativity working on cosmic scales and give astronomers a natural magnifying glass. Each one is a rare case where the alignment is precise enough to produce a near-perfect ring.

ESA/Hubble · CC BY 4.0

Image: ESA/Hubble & NASA, S. Jha Acknowledgement: L. Shatz

source: ESA/Hubble ↗

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 ↗