The transit method has driven the discovery of thousands of exoplanets

the gist

Exoplanets, planets orbiting other stars, were first confirmed in 1992 when Aleksander Wolszczan and Dale Frail found two orbiting a pulsar 2,300 light-years away. The transit method works by watching a star's brightness: when a planet passes in front of it, the light dims by a tiny, regular amount. Measuring those dips reveals the planet's size and orbit, and the method has found far more worlds than any other technique.

so what

Transit surveys like NASA's Kepler mission showed that small planets are common in the galaxy, and they are the main reason the count of known exoplanets has climbed into the thousands.

fun fact

The first confirmed exoplanets were found orbiting a pulsar, a dead neutron star, rather than a Sun-like star.

more on this

background

An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detected in 1988, was confirmed in 2003. In 2016, it was recognized that the first possible evidence of an exoplanet had been noted in 1917, a precovery. As of 5 November 2026, there are 6,464 confirmed exoplanets in 4,849 planetary systems, with 1,074 systems having more than one planet.

There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of large planets close to the star. About 1 in 5 Sun-like stars are estimated to have an "Earth-sized" planet in the habitable zone. Assuming there are 200 billion stars in the Milky Way, it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if planets orbiting the numerous red dwarfs are included.

From Wikipedia: Exoplanet (CC BY-SA 4.0) ↗

watch · 1:51

1:51

Why you should care about Ganymede #astronomy #ganymede #jupiter #exoplanets #moons #spacescience

The Royal Institution on YouTube ↗

see

NASA/JPL-CalTech, Public domain, via Wikimedia Commons

NASA, Public domain, via Wikimedia Commons

NASA Ames/JPL-Caltech, Public domain, via Wikimedia Commons

Our World in Data · CC BY 4.0

Image: Our World in Data

source: Our World in Data ↗

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 ↗