A pair of galaxies looks like a smiling face because gravity bends their light into arcs

the gist

Two faint galaxies in this Hubble image appear to form a face, with the arcs of light acting as a smile. The arcs are not part of the galaxies; they are images of a background galaxy stretched by strong gravitational lensing. Massive foreground structures warp spacetime, and that bending magnifies and distorts light from objects behind them, as predicted by Einstein's general relativity.

how it works

Mass curves spacetime, so light passing near a massive galaxy or cluster follows a bent path. This can magnify a distant object and stretch its image into arcs. If source, lens and observer line up almost perfectly, the arcs close into a ring.

so what

Lensing lets astronomers measure the mass of galaxy clusters and see galaxies too far away to view directly. When the alignment is exact, the light forms a full ring known as an Einstein ring.

fun fact

Albert Einstein published the idea that gravity could bend light in his general theory of relativity in 1915.

ESA/Hubble · CC BY 4.0

Image: NASA & ESA Acknowledgement: Judy Schmidt ( geckzilla.org )

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 ↗