Category Astronomy/Space

Nube, the Almost Invisible Galaxy that Challenges the Dark Matter Model

Nube, the almost invisible galaxy that challenges the dark matter model
The Nube galaxy. The figure is a composition of a color image and a black and white image, to pick out the background. Credit: GTC/Mireia Montes

Nube is an almost invisible dwarf galaxy discovered by an international research team led by the Instituto de Astrofísica de Canarias (IAC) in collaboration with the University of La Laguna (ULL) and other institutions.

The name was suggested by the 5-year-old daughter of one of the researchers in the group and is due to the diffuse appearance of the object. Its surface brightness is so faint that it had passed unnoticed in the various previous surveys of this part of the sky due to the object’s diffuse appearance as if it were some kind of ghost...

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Centaurs Gain Comet-like Characteristics through Close Encounters with Jupiter, Saturn

Objects that look like asteroids can still become active for numerous reasons. These objects are known as Centaurs and can have spots of activity and generate tails.
Credit: Pamela L Gay/PSI.

A rapid reshaping of orbits resulting from a close encounter with Jupiter or Saturn can lead Centaurs to exhibit comet-like activity, according to a Planetary Science Institute Senior Scientist Eva Lilly paper.

Centaurs are small bodies similar to asteroids in size but to comets in composition that revolve around the sun in the outer solar system, mainly between the orbits of Jupiter and Neptune.

“We have found some answers to the long-standing mystery of why some Centaurs became active like comets while the rest appear like regular quiet asteroids. Nobody knew why they behaved this way...

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Scientists Flip around Gravitational-Wave Data Analysis: Have LIGO and Virgo Detected a Merger of Dark-Matter Stars?

Scientists flip around gravitational-wave data analysis. Have LIGO and Virgo detected a merger of Dark-matter stars?

Gravitational waves are ripples in the fabric of spacetime that travel at the speed of light. These are produced in some of the most violent events in the universe, such as black-hole mergers, supernovae, or the Big Bang itself. Since their first detection in 2015, and after three observing runs, the Advanced LIGO and Virgo detectors have detected around 100 such waves.

Thanks to these observations, we are starting to unveil the black-hole population of our universe, study gravity in its most extreme regime and even determine the formation of elements like gold or platinum during the merger of neutron stars.

The LIGO and Virgo detectors are nothing but the most precise rulers ever built by humankind, able to measure the subtle squeezing and stretching of spacetime produced by gr...

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Space Oddity: Uncovering the Origin of the Universe’s Rare Radio Circles

Faint blue circles of light against a starry space background.
Odd radio circles, like ORC 1 pictured above, are large enough to contain galaxies in their centers and reach hundreds of thousands of light years across. (cr: Jayanne English / University of Manitoba)

Outflowing galactic winds from exploding stars may explain the enormous rings. Astronomers believe they may have found the origin of the universe’s giant odd radio circles: they are shells formed by outflowing galactic winds, possibly from massive exploding stars known as supernovae.

t’s not every day astronomers say, “What is that?” After all, most observed astronomical phenomena are known: stars, planets, black holes and galaxies...

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