The Milky Way is not alone in its neighborhood. It has captured smaller galaxies in its orbit, and the two largest are known as the Small and Large Magellanic Clouds, visible as twin dusty smears in the Southern Hemisphere.

As the Magellanic Clouds began circling the Milky Way billions of years ago, an enormous stream of gas known as the Magellanic Stream was ripped from them. The stream now stretches across more than half of the night sky. But astronomers have been at a loss to explain how the stream became as massive at it is, over a billion times the mass of the sun.

Now, astronomers at the University of Wisconsin-Madison and their colleagues have discovered that a halo of warm gas surrounding the Magellanic Clouds likely acts as a protective cocoon, shielding the dwarf galaxies from the Milky Way’s own halo and contributing most of the Magellanic Stream’s mass. As the smaller galaxies entered the sphere of the Milky Way’s influence, parts of this halo were stretched and dispersed to form the Magellanic Stream. The researchers published their findings today (September 9, 2020) in the journal Nature.

It’s good news for anyone planning on spending months floating around in the International Space Station (ISS) or for those who might one day find themselves on a long-haul flight to Mars, as researchers imaging the brains of Russian cosmonauts have found that while the brain does undergo changes in a microgravity environment, it doesn’t deteriorate.

New research suggests prolonged exposure to microgravity does cause parts of the brain to reorganise itself, but does not trigger loss of brain tissue.

NASA changed its mind and decided not to buy a seat on Russia’s Soyuz spacecraft to deliver its astronaut to the International Space Station (ISS) in the spring of 2021, according to Roscosmos’ 2019 annual report.

In May, NASA chief Jim Bridenstine announced that the option of acquiring a seat on the Soyuz MS-18 manned spacecraft, which would be launched in April 2021, is being considered. In August, a source in the space industry said that for the first time in the history of the ISS, a crew consisting of only Russian cosmonauts would fly on Soyuz MS-18, but there was no official confirmation of this so far.

“At the beginning of 2020, the US side announced its readiness to purchase services for the delivery of only one astronaut in the fall of 2020: the conditions are currently being discussed, the modification project is being adjusted,” the report says. In December 2019, Roscosmos chief Dmitry Rogozin announced the decision to provide NASA with one seat on the Soyuz MS-17 spacecraft to be launched in October 2020 and Soyuz MC-18 to be launched in April 2021.

Many colorful stars are packed close together in this image of the globular cluster NGC 1805, taken by the NASA /ESA Hubble Space Telescope. This tight grouping of thousands of stars is located near the edge of the Large Magellanic Cloud, a satellite galaxy of our own Milky Way. The stars orbit closely to one another, like bees swarming around a hive. In the dense center of one of these clusters, stars are 100 to 1000 times closer together than the nearest stars are to our Sun, making planetary systems around them unlikely.

The striking difference in star colors is illustrated beautifully in this image, which combines two different types of light: blue stars, shining brightest in near-ultraviolet light, and red stars, illuminated in red and near-infrared. Space telescopes like Hubble can observe in the ultraviolet because they are positioned above Earth’s atmosphere, which absorbs most of this wavelength, making it inaccessible to ground-based facilities.

This young globular cluster can be seen from the southern hemisphere, in the Dorado constellation, which is Portugese for dolphinfish. Usually, globular clusters contain stars which are born at the same time; however, NGC 1805 is unusual as it appears to host two different populations of stars with ages millions of years apart. Observing such clusters of stars can help astronomers understand how stars evolve, and what factors determine whether they end their lives as white dwarfs, or explode as supernovae.

NASA released the highest-resolution panorama that the Mars Curiosity rover has ever taken, at close to 1.8 billion pixels.