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Archive for the ‘physics’ category: Page 60

Jul 12, 2023

Optoelectronics Nanotechnology Innovation: MIT Grows Precise Arrays of nanoLEDs

Posted by in categories: biological, chemistry, nanotechnology, physics

A new technique produces perovskite nanocrystals right where they’re needed, so the exceedingly delicate materials can be integrated into nanoscale.

The nanoscale refers to a length scale that is extremely small, typically on the order of nanometers (nm), which is one billionth of a meter. At this scale, materials and systems exhibit unique properties and behaviors that are different from those observed at larger length scales. The prefix “nano-” is derived from the Greek word “nanos,” which means “dwarf” or “very small.” Nanoscale phenomena are relevant to many fields, including materials science, chemistry, biology, and physics.

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

Starlink Satellites Are Flooding Sky with Radiation- Why is That a Problem?

Posted by in categories: internet, physics, satellites

This post is also available in: he עברית (Hebrew)

There are currently thousands of Starlink satellites that belong to SpaceX, and they are causing a lot of disputes in the science and astronomy communities. They are disrupting scientific research by causing streaks in deep space photos, and according to a new study are also dumping “unintended electromagnetic radiation” into space, which could be a major problem for Earth-bound astronauts.

The study published in Astronomy & Astrophysics states that the satellites in low Earth orbit could be muddling or even drowning out signals from deep space that radio astronomers search for.

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 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 7, 2023

Carbonated Ice Cream Is a Feat of Physics—and It Actually Tastes Good

Posted by in category: physics

Year 2020 face_with_colon_three


Behold, the delicious power of pressurized CO2.

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 5, 2023

Long-sought hum of gravitational waves from giant black holes heard for first time

Posted by in categories: cosmology, physics

Subtle shifts in stellar signals reveal pervasive waves from mergers of giant black holes.

Jul 5, 2023

Scientists Discover Exotic New Patterns of Synchronization

Posted by in category: physics

In a world seemingly filled with chaos, physicists have discovered new forms of synchronization and are learning how to predict and control them.

Jul 4, 2023

Astronomers witness energetic switch on of black hole

Posted by in categories: cosmology, physics

A team of astronomers led by researchers from the University of Birmingham, University College London and Queen’s University Belfast have discovered one of the most dramatic ‘switches on’ of a black hole ever seen. They will present their findings on Tuesday 4 July at the 2023 National Astronomy Meeting in Cardiff. The work will also be published in Monthly Notices of the Royal Astronomical Society.

J221951-484240, known as J221951, is one of the most luminous transients—astrophysical objects that change their brightness over a short period of time—ever recorded. It was discovered by Dr. Samantha Oates, an astronomer at the University of Birmingham, and her team, in September 2019 while searching for the electromagnetic light from a gravitational wave event. The team were using the Ultra-Violet and Optical Telescope on board the Neil Gehrels Swift Observatory to look for a kilonova, the sign of a neutron star merging with another neutron star or a black hole. A kilonova typically appears blue, then fades and turns more red in color over a timescale of days. What they found instead something even more unusual: J221951. The transient appeared blue, but didn’t change color or fade rapidly as a kilonova would.

Multiple telescopes were used to follow-up J221951 and determine its nature, including NASA’s Swift/UVOT and Hubble Space Telescope, the South African Large Telescope, and ESO facilities such as the Very Large Telescope and the GROND instrument on the MPG/ESO 2.2-meter telescope at the La Silla Observatory.

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