Rogue Planet, Dangerous Dance, and SpaceX – Electric Propulsion are among the NASA images of the week.


This /ESA image features two interacting galaxies that are so intertwined, they have a collective name – Arp 91. Their delicate galactic dance takes place more than 100 million light-years from Earth. The two galaxies comprising Arp 91 have their own names: the lower galaxy, which looks like a bright spot, is NGC 5953, and the oval-shaped galaxy to the upper right is NGC 5954. In reality, both of them are spiral galaxies, but their shapes appear very different because of their orientation with respect to Earth.

Arp 91 provides a particularly vivid example of galactic interaction. NGC 5953 is clearly tugging at NGC 5954, which looks like it is extending one spiral arm downward. The immense gravitational attraction of the two galaxies is causing them to interact. Such gravitational interactions are common and an important part of galactic evolution. Most astronomers think that collisions between spiral galaxies lead to the formation of another type of galaxy, known as elliptical galaxies. These extremely energetic and massive collisions, however, happen on timescales that dwarf a human lifetime. They take place over hundreds of millions of years, so we should not expect Arp 91 to look any different over the course of our lifetimes!

On October 4, 2021, the seven-member Expedition 65 crew gathered for a portrait inside the vestibule in between the International Space Station’s Unity module and Tranquility module. In the front row from left are; Commander Thomas Pesquet of the European Space Agency; and NASA astronauts Megan McArthur and Shane Kimbrough. In the back are: Roscosmos cosmonaut Oleg Novitskiy; astronaut Akihiko Hoshide of the Japan Aerospace Exploration Agency; NASA astronaut Mark Vande Hei; and Roscosmos cosmonaut Pyotr Dubrov.

This artist’s conception illustrates a -like planet alone in the dark of space, floating freely without a parent star.

Exoplanet hunters have found thousands of planets, most orbiting close to their host stars, but relatively few alien worlds have been detected that float freely through the galaxy as so-called rogue planets, not bound to any star. Many astronomers believe that these planets are more common than we know, but that our planet-finding techniques haven’t been up to the task of locating them.

A planet survey, called the Microlensing Observations in Astrophysics (MOA), scanned the central bulge of our galaxy from 2006 to 2007. It used a 5.9-foot (1.8-meter) telescope at Mount John University Observatory in New Zealand, and a technique called gravitational microlensing. In this… Brinkwire News Summary.


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