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Archive for the ‘cosmology’ category: Page 114

Jul 12, 2023

Reinventing cosmology: uOttawa research puts age of universe at 26.7 — not 13.7 — billion years

Posted by in categories: cosmology, physics

Our universe could be twice as old as current estimates, according to a new study that challenges the dominant cosmological model and sheds new light on the so-called “impossible early galaxy problem.”

“Our newly-devised model stretches the galaxy formation time by a several billion years, making the universe 26.7 billion years old, and not 13.7 as previously estimated,” says author Rajendra Gupta, adjunct professor of physics in the Faculty of Science at the University of Ottawa.

For years, astronomers and physicists have calculated the age of our universe by measuring the time elapsed since the Big Bang and by studying the oldest stars based on the redshift of light coming from distant galaxies. In 2021, thanks to new techniques and advances in technology, the age of our universe was thus estimated at 13.797 billion years using the Lambda-CDM concordance model.

Jul 11, 2023

Gravitational waves spark hunt for cosmic strings and dark matter

Posted by in categories: cosmology, physics

The discovery of low-level ripples throughout the universe called the gravitational wave background has set physicists looking for exotic explanations.

By Alex Wilkins

Jul 10, 2023

Astronomers spot exoplanet creating spiral arms around star

Posted by in category: cosmology

When you imagine a galaxy like our Milky Way, you’re probably picturing a swirl shape with arms reaching out from a central point. These spiral arms are a classic feature of many galaxies. Similar structures can be found around young stars which are surrounded by disks of matter from which planets form, called protoplanetary disks. Now, astronomers have discovered evidence that these structures could be created by recently formed exoplanets.

Astronomers used Large Binocular Telescope in Arizona to investigate a giant exoplanet named MWC 758c which seems to be forming the spiral arms around its host star. Located 500 light-years away, the star is just a few million years old, making it a baby in cosmic terms. “Our study puts forward a solid piece of evidence that these spiral arms are caused by giant planets,” said lead researcher Kevin Wagner of the University of Arizona in a statement. “And with the new James Webb Space Telescope, we will be able to further test and support this idea by searching for more planets like MWC 758c.”

The star still has its protoplanetary disk of dust and gas around it, making it comparable to the early stages of our own solar system. “I think of this system as an analogy for how our own solar system would have appeared less than 1% into its lifetime,” Wagner said. “Jupiter, being a giant planet, also likely interacted with and gravitationally sculpted our own disk billions of years ago, which eventually led to the formation of Earth.”

Jul 9, 2023

Webb telescope discovers oldest active supermassive black hole ever seen and it’s ‘tiny’

Posted by in category: cosmology

NASA’s James Webb Space Telescope has broken a new record by detecting what is now considered the most distant active supermassive black hole to date.

Jul 9, 2023

Light supergiant reveals a missing evolutionary stage

Posted by in categories: cosmology, physics

Dr. Varsha Ramachandran from the Center for Astronomy of Heidelberg University (ZAH) and her colleagues uncovered the first “stripped” star of intermediate-mass. This discovery marks a missing link in our picture of stellar evolution toward systems with merging neutron stars, which are crucial to our understanding of the origin of heavy elements, such as silver and gold. Dr. Ramachandran is a postdoc in the research group of Dr. Andreas Sander, located at ZAH’s Astronomisches Rechen-Institut (ARI). These results were now published in Astronomy & Astrophysics.

The team of researchers discovered the first representative of the long-predicted, but as yet unconfirmed population of intermediate-mass stripped stars. “Stripped stars” are stars that have lost most of their outer layers, revealing their hot and dense helium-rich core, which results from the nuclear fusion of hydrogen to helium. Most of these stripped stars are formed in in which one star’s strong gravitational pull peels off and accretes matter from its companion.

For a long time, astrophysicists have known of low-mass stripped stars, known as subdwarfs, as well as their massive cousins, known as Wolf-Rayet stars. But until now, they have never been able to find any of the so-called “intermediate-mass stripped stars,” raising questions whether our basic theoretical picture needs a major revision.

Jul 8, 2023

Webb telescope finds strange galaxy in the deepest realms of space

Posted by in category: cosmology

Scientists pointed the James Webb Space Telescope at a distant galaxy called CEERS 1019. They found it might be a merger of three galaxies and contains an extremely ravenous black hole.

Jul 8, 2023

Webb Space Telescope Illuminates Earliest Strands of the Cosmic Web

Posted by in categories: cosmology, particle physics, space travel

Woven across our universe is a weblike structure of galaxies called the cosmic web. Galaxies are strung along filaments in this vast web, which also contains enormous voids. Now, astronomers using Webb have discovered an early strand of this structure, a long, narrow filament of 10 galaxies that existed just 830 million years after the big bang. The 3 million light-year.

A light year is the distance that a particle of light (photon) will travel in a year—about 10 trillion kilometers (6 trillion miles). It is a useful unit for measuring distances between stars.

Jul 7, 2023

Gravitational Waves Will Help Us Find ‘Dark Matter,’ Say Scientists

Posted by in categories: cosmology, physics

The announcement last week of the discovery of the gravitational wave background has rocked astronomy, but work has already begun on how this new window to the universe can be used to tease apart how the universe works.

At this week’s National Astronomy Meeting 2023 at Cardiff University in Wales, UK, an international team of cosmologists revealed that observations of gravitational waves from merging black holes may reveal the true nature of “dark matter.”


Observations of gravitational waves from merging black holes—and their absence—may unveil the true nature of dark matter, according to new research.

Continue reading “Gravitational Waves Will Help Us Find ‘Dark Matter,’ Say Scientists” »

Jul 6, 2023

Gargantuan black hole ‘switches on,’ becoming one of the brightest objects ever seen

Posted by in category: cosmology

A black hole 10 billion light-years away suddenly ‘switched on’, becoming one of the brightest transient objects ever detected.

Jul 6, 2023

The Earliest Supermassive Black Hole Ever Found Has Been Identified

Posted by in category: cosmology

An object lurking in the foggy dawn of the Universe has given astronomers a big surprise.

Observations collected through the James Webb Space Telescope have revealed an active supermassive black hole 9 million times the mass of the Sun – one that is actively growing as it slurps up matter from the space around it.

Continue reading “The Earliest Supermassive Black Hole Ever Found Has Been Identified” »