Single particles fired one at a time still build a wave pattern until someone checks which slit they went through

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Single particles fired one at a time still build a wave pattern until someone checks which slit they went through

the gist

When light or electrons are sent through two narrow slits, they land on a screen in bands of brightness and darkness, the signature of waves interfering with each other. Yet each electron or photon hits the screen at one point, like a particle. The pattern only disappears when a detector reveals which slit each one passed through. Thomas Young showed the wave effect with light in 1801, and in 1927 electrons were found to behave the same way.

how it works

Each particle's arrival is random, but across many arrivals the probabilities form bands. Where waves from both slits arrive in step they reinforce, and where they arrive out of step they cancel. If a detector marks which slit was used, the paths become distinguishable and the interference vanishes.

so what

The experiment is the core puzzle of quantum mechanics: matter is neither simply a wave nor simply a particle, and measurement changes the outcome. It underpins modern quantum technologies and is still tested with ever larger molecules.

fun fact

Richard Feynman called the double-slit experiment the only mystery of quantum mechanics.

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 ↗