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Archive for the ‘cosmology’ category: Page 76

Jan 9, 2024

Nube, the almost invisible galaxy that challenges the dark matter model

Posted by in category: cosmology

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 to 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. This is because its stars are so spread out in such a large volume that “Nube” (Spanish for “Cloud”) was almost undetectable.

This newly discovered galaxy has a set of specific properties which distinguish it from previously known objects. The research team estimate that Nube is a 10 times fainter than others of its type, but also 10 times more extended than other objects with a comparable number of stars.

Jan 9, 2024

Study explores the properties of a faint tidal disruption event

Posted by in categories: cosmology, evolution, physics

Using a spectral synthesis code designed to simulate conditions in interstellar matter, astronomers have explored a faint tidal disruption event (TDE) designated iPTF16fnl. Results of the study, published Dec. 29 on the pre-print server arXiv, deliver important insights into the properties of this TDE.

TDEs are astronomical phenomena that occur when a star passes close enough to a and is pulled apart by the black hole’s tidal forces, causing the process of disruption. Such tidally-disrupted stellar debris starts raining down on the black hole and radiation emerges from the innermost region of accreting debris, which is an indicator of the presence of a TDE. All in all, the debris stream-stream collision causes an energy dissipation, which may lead to the formation of an accretion disk.

Therefore, TDEs are perceived by as potentially important probes of strong gravity and accretion physics, providing answers about the formation and evolution of supermassive .

Jan 9, 2024

Why is the universe ripping itself apart? A new study of exploding stars shows dark energy may be more complicated than we thought

Posted by in category: cosmology

After a decade studying thousands of supernovae, astronomers are still perplexed by the enigma that led Einstein to his ‘greatest mistake’

Jan 8, 2024

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

Posted by in categories: cosmology, physics

Thanks to the LIGO and Virgo detectors, researchers now regularly observe ripples in spacetime known as gravitational waves, which are caused by catastrophic cosmic events such as black-hole mergers, star explosions, or the big bang itself.


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.

Continue reading “Scientists flip around gravitational-wave data analysis: Have LIGO and Virgo detected a merger of dark-matter stars?” »

Jan 7, 2024

Complexity, Evolution And Intelligence

Posted by in categories: biological, cosmology, evolution

Over the past few decades, it has become quite obvious that humans are not the only living organisms with intelligence.

The story of intelligence you are about to experience goes back 13.8 billion years, back to the moment the universe was born: the Big Bang. It’s a story of time and space, matter and energy. It is a story of unfolding, It’s the story of how the very nature of the physical universe from its very inception led to the universe getting to know itself and eventually, to reflect.

Continue reading “Complexity, Evolution And Intelligence” »

Jan 7, 2024

‘It could be profound’: How astronomer Wendy Freedman is trying to fix the universe

Posted by in category: cosmology

The problem is known as the Hubble tension, and it centers around figuring out a number for the universe’s expansion rate, called the Hubble constant. To find it, scientists have pored over tiny fluctuations in the cosmic microwave background (CMB) — an ancient relic of the universe’s first light — and built cosmic distance ladders to remote, pulsating stars called Cepheid variables.

But the best experiments using these two methods disagree. The difference in results may have seemed small, but it was enough to spark a major crisis in cosmology.

Wendy Freedman, an astrophysicist at the University of Chicago, has spent four decades studying the Hubble constant.

Jan 6, 2024

Is a black hole stuck inside the sun? No, but here’s why scientists are asking

Posted by in categories: cosmology, particle physics

To that end, Caplan is part of a crew that posits the dark matter portion of the dark universe could very well be made up of not particles like we imagine, but instead a huge number of atom-size black holes produced during the dawn of the universe, each of which is about as massive as a typical asteroid in our own solar system. “I think all dark matter candidates are just a little bit wild,” Caplan, who is an assistant professor of physics at Illinois State University, told Space.com. “Some guesses are better than others, and primordial black holes are taken seriously. I’ll go so far as to say I think they’re popular.”

But to turn the hypothesis into fact, he says, scientists have to actually find one of these miniscule ancient voids — which brings us to this new black-hole-sun conversation. Potentially, Caplan and his co-authors say in their papers, some of those ultrasmall black holes might’ve gotten caught up in dust clouds in the midst of forming stars. Potentially, they might’ve ended up literally lodged in those eventual sparkling oceans of plasma. Potentially, they might still be there.

So, no, there is probably not a black hole in the center of our star — but there might be other stars gallivanting through space with black holes indeed wedged within their hearts.

Jan 6, 2024

Neutron Stars — The Most Extreme Things that are not Black Holes

Posted by in categories: cosmology, futurism

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This year’s calendar focuses on the future of humanity and how we will explore space in the next 10,000 years.

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Continue reading “Neutron Stars — The Most Extreme Things that are not Black Holes” »

Jan 5, 2024

A method to straighten curved space-time

Posted by in categories: cosmology, mathematics, particle physics, quantum physics

One of the greatest challenges of modern physics is to find a coherent method for describing phenomena, on the cosmic and microscale. For over a hundred years, to describe reality on a cosmic scale we have been using general relativity theory, which has successfully undergone repeated attempts at falsification.

Albert Einstein curved space-time to describe gravity, and despite still-open questions about or , it seems, today, to be the best method of analyzing the past and future of the universe.

To describe phenomena on the scale of atoms, we use the second great theory: , which differs from general relativity in basically everything. It uses flat space-time and a completely different mathematical apparatus, and most importantly, perceives reality radically differently.

Jan 5, 2024

Magnetic Mystique: A Deeper Look at Massive Star Systems

Posted by in categories: cosmology, evolution, physics

A new study reveals that magnetic fields are common in star systems with large blue stars, challenging prior beliefs and providing insights into the evolution and explosive nature of these massive stars.

Astronomers from the Leibniz Institute for Astrophysics Potsdam (AIP), the European Southern Observatory (ESO), and the MIT Kavli Institute and Department of Physics have discovered that magnetic fields in multiple star systems with at least one giant, hot blue star, are much more common than previously thought by scientists. The results significantly improve the understanding of massive stars and their role as progenitors of supernova explosions.

Characteristics of O-type Stars.

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