Fascinating discoveries | In the four corners of the cosmos

Life on a moon of Saturn, rings around our Earth, a virtually neighboring exoplanet that is habitable and has an atmosphere. Advances in astronomy are dizzying. Here are some fascinating recent discoveries.

News fromIngenuity

The epitaph for NASA’s Mars helicopter was delivered at the annual meeting of the American Geophysical Union (AGU) in December in Washington. Despite his crushing at his 72^e flight last January, Ingenuity will store weather data and images for 20 years, NASA announced. Its partner, the rover Perseverancewill not be able to relay weather data for a very long time, because it is moving away from it, currently being 3 km fromIngenuitybut NASA is still hopeful of recovering them. Originally, the mission planned only five flights to Ingenuitywhich was supervised by Quebec engineer Farah Alibay.

An eclipse 6000 years ago

It’s not just 2024 that eclipses have fascinated us. Indian and Japanese astronomers have discovered that a sacred Hindu text, the Rig Veda, described an eclipse that occurred more than 6,000 years ago. In the Journal of Astronomical History and Heritage last summer, they described how a very clear mention of an eclipse dates from 4500 BC, since it occurred at the same time as the’spring equinox when the constellation Orion was visible from India. As the Earth’s axis shifts over the centuries, this dating is relatively precise. The record for the oldest eclipse previously dated back to 3,200 years, in a Chinese text.

The rings of the Earth

For several tens of millions of years, the Earth had rings similar to those of Saturn. No humans benefited from the spectacle since it took place around 450 million years ago, well before our advent. And even well before that of the dinosaurs. They would have been responsible for one of the worst cooling events on our planet. The discovery was made by Australian geologists, who found that 21 asteroid craters from this era were all located in a single band around our planet. This bombardment was one of the most intense in Earth’s history. The rings would have been created by the disintegration of a weak asteroid, due to Earth’s gravity. The study was published in September in Earth & Planetary Science Letters.

Intriguing spot on Enceladus

A black spot that appeared 15 years ago and then quickly disappeared on Enceladus, one of Saturn’s 146 moons, caused a lot of talk at the annual meeting of the American Geophysical Union (AGU) in December in Washington. Its color is difficult to interpret, but, combined with the discovery of complex molecules in jets of steam escaping from its surface, it suggests the presence of life on Enceladus, an icy moon which probably has an underground ocean. The brevity of the observations also indicates that the quantity of vapor is 10 to 100 times greater than expected, another sign of the presence of an abundant ocean.

A habitable atmosphere

The space telescope James Webblaunched in 2021 and in orbit beyond the Moon, allowed astronomers from the University of Montreal to discover for the first time that an exoplanet is habitable and has an atmosphere. LHS 1140 b, located 48 light years away, is covered by either ice or an ocean and is a few times the size of Earth. The discovery was described last January in the Astrophysical Journal Letters.

The promises of solar sail

Last summer, NASA deployed the largest solar sail ever tested, measuring 80 square meters. Launched in April, the ACS3 mission aims to test the possibility of interstellar travel. A solar sail propelled initially by a terrestrial laser, then by photons from the Sun, could reach the nearest galaxy, Alpha Centauri, in half a century. Only two other solar sail tests, in 2010 and 2019, have taken place. Solar sails could also be used for space mining and asteroid defense.