A black hole 13 million light-years away is blasting a 1,000-light-year bubble of hot gas

the gist

Astronomers have found a microquasar inside NGC 7793, a spiral galaxy about 13 million light-years away in the constellation Sculptor. A microquasar is a stellar-mass black hole that pulls in gas from a companion star, forming a swirling disc of material around it. Some of that infalling gas is flung outward at extreme speeds, producing twin jets that shoot out in opposite directions. Quasars are usually found at the centres of galaxies, so finding one in the disc is unusual. Microquasars are useful because they act as smaller-scale versions of the giant quasars, letting astronomers study the same processes up close. In NGC 7793 the jets are powerful enough to be inflating a bubble of hot gas about 1,000 light-years across.

how it works

Material falls toward the black hole and forms an accretion disc. Magnetic fields and intense pressure near the black hole launch part of that gas outward along the poles as narrow jets moving at a large fraction of light speed. When the jets push into the surrounding gas, they heat it and inflate a bubble that keeps growing.

so what

The find shows that a single black hole in an ordinary-looking spiral can reshape gas across a region the size of a large star cluster, and it gives astronomers a nearby laboratory for the physics that drives quasars across the universe.

ESA/Hubble · CC BY 4.0

Image: ESA/Hubble & NASA Acknowledgement: D. Calzetti (University of Massachusetts) and the LEGUS Team

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 ↗