Category Astronomy/Space

NGC 7674, seen just above the center, is a luminous spiral galaxy with a powerful active nucleus. Credit: NASA, ESA, the Hubble Heritage Team

A study using multiple radio telescopes confirms that supermassive black holes found in the centers of galaxies can form gravitationally bound pairs when galaxies merge. “The dual black hole we found has the smallest separation of any so far detected through direct imaging,” said David Merritt, professor of physics at Rochester Institute of Technology The supermassive black holes are located in the spiral galaxy NGC 7674, ~400 million light years from earth, and are separated by a distance less than one light year...

The dotted white arrow points to curved strata recording point bar growth and river migration. The boundaries of ancient valley walls are defined by textural and albedo changes and are also associated with lateral river migration. Stacked above the point bars and completely confined within the dotted white and black lines are topographically inverted river deposits outcropping as ridges (e.g., black arrow). In places (e.g., south of the dotted white arrow), the ridges run against the dotted boundaries, suggesting flow was once redirected along a valley wall. Credit: B.T. Cardenas et al., Geological Society of America Bulletin

River deposits exist across the surface of Mars and record a surface environment from over 3.5 billion years ago that was able to support liquid water at the surface...

Sampling of a dust devil during field campaign ‘Morocco 2016’. The samples are still under analysis. Credit: Jan Raack/Dennis Reiss

Swirling columns of sand and dust, known as dust devils, are a feature of desert areas on Mars and on Earth. Now, a study of terrestrial dust devils has shown that around 2/3 of the fine particles lifted by these vortices can remain suspended in the atmosphere and be transported around the globe. The findings have implications for the climate and weather of both planets and, potentially, human health here on Earth.

The study by Raack and an international team of collaborators gives important insights into the contribution of dust devils to mineral aerosols in planetary atmospheres...

1. Atmospheric super-rotation at the upper clouds of Venus. Credit: ESA, JAXA, J. Peralta and R. Hueso 2. New types of cloud morphology on Venus. Credit: ESA, NASA, J. Peralta and R. Hueso

Scientists have used ESA’s Venus Express to characterise the wind and upper cloud patterns on the night side of Venus for the first time–with surprising results. The study shows that the atmosphere on Venus’ night side behaves very differently to that on the side of the planet facing the Sun (the ‘dayside’), exhibiting unexpected and previously-unseen cloud types, morphologies, and dynamics – some of which appear to be connected to features on the planet’s surface.

“This is the first time we’ve been able to characterise how the atmosphere circulates on the night side of Venus on a global scale,” says...