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Darkest Galaxies in the Universe Provide New Clues on Dark Matter

Source: SciTechDaily
Date: 2 January, 2020

A study by Scuola Internazionale Superiore di Studi Avanzati (SISSA) provides important information on its composition and on its interaction with luminous matter.

They are called low-surface-brightness galaxies and it is thanks to them that important confirmations and new information have been obtained on one of the largest mysteries of the cosmos: dark matter. “We have found that disc galaxies can be represented by a universal relationship. In particular, in this study we analyzed the so-called Low-Surface-Brightness (LSB) galaxies, a particular type of galaxy with a rotating disc called this way because they have a low-density brightness “says Chiara di Paolo, astrophysicist at SISSA and lead author of a study recently published in MNRAS together with Paolo Salucci (astrophysicist at SISSA) and Erkurt Adnan (Istanbul University).

The researchers analyzed the speed at which the stars and gases that compose the galaxies subject matter of the study rotate, noting that the LSBs also have a very homogenous behavior. This result consolidates several clues on the presence and behavior of dark matter, opening up new scenarios on its interactions with bright matter.

https://scitechdaily-com.cdn.amppro...he-universe-provide-new-clues-on-dark-matter/
 

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We May Finally Understand the Moments Before the Big Bang

Physicists may have solved a decades-long mystery about how our universe came to be.

Source: livescience.com
Date : 11 November, 2019

There's a hole in the story of how our universe came to be. First, the universe inflated rapidly, like a balloon. Then, everything went boom.

But how those two periods are connected has eluded physicists. Now, a new study suggests a way to link the two epochs.

In the first period, the universe grew from an almost infinitely small point to nearly an octillion (that's a 1 followed by 27 zeros) times that in size in less than a trillionth of a second. This inflation period was followed by a more gradual, but violent, period of expansion we know as the Big Bang. During the Big Bang, an incredibly hot fireball of fundamental particles — such as protons, neutrons and electrons — expanded and cooled to form the atoms, stars and galaxies we see today.

The Big Bang theory, which describes cosmic inflation, remains the most widely supported explanation of how our universe began, yet scientists are still perplexed by how these wholly different periods of expansion are connected. To solve this cosmic conundrum, a team of researchers at Kenyon College, the Massachusetts Institute of Technology (MIT) and the Netherlands' Leiden University simulated the critical transition between cosmic inflation and the Big Bang — a period they call "reheating."

https://www.livescience.com/physicists-model-reheating-universe.html
 

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We May Finally Understand the Moments Before the Big Bang

The article states:

"During the Big Bang, an incredibly hot fireball of fundamental particles — such as protons, neutrons and electrons — expanded and cooled to form the atoms, stars and galaxies we see today".

Where did those fundamental particles come from?

Just wondered... :btime:
 

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We May Finally Understand the Moments Before the Big Bang

The article states:

"During the Big Bang, an incredibly hot fireball of fundamental particles — such as protons, neutrons and electrons — expanded and cooled to form the atoms, stars and galaxies we see today".

Where did those fundamental particles come from?

Just wondered... :btime:
Maybe something to do with Heisenberg's uncertainty principle ie the particles may have just winked into existence - but no-one is certain.
 

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Asteroid in unusual orbit.

For the first time, an asteroid has been found orbiting closer to the sun than Venus — a neighborhood where asteroids are thought to be rare and tricky to find.

The space rock, designated 2020 AV2, orbits the sun once every 151 days along an elongated trajectory that keeps it between the orbits of Mercury and Venus. Such asteroids — known as Vatiras — were first predicted in 2012, but until now, no one had ever found one.

Asteroid 2020 AV2 was found January 4 by researchers at the Palomar Observatory in southern California. Following an alert by the International Astronomical Union’s Minor Planet Center, observers around the world confirmed and refined the asteroid’s orbit.

Asteroids that live inside Earth’s orbit are notoriously difficult to find because they spend most of their time close to the sun (SN: 4/3/15). Astronomers can therefore look for such objects only during brief periods of twilight.

According to computer simulations, Vatiras are rare, making up only 0.22 percent of so-called near-Earth objects. Vatiras probably start their lives in the main asteroid belt between Mars and Jupiter and end up between Mercury and Venus after a series of close encounters with rocky planets.

https://www.sciencenews.org/article/first-time-asteroid-has-been-found-nearer-sun-than-venus
 

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http://www.astronomerstelegram.org/?read=13410
Betelgeuse is now nearly as faint as (the slightly variable) B2 star Bellatrix .... Betelgeuse is currently the coolest and least luminous yet observed. Since September 2019, the star's temperature has decreased by ~100 K while its luminosity ... has diminished by nearly 25%. At face value .... this implies an increase of the star's radius of ~9%. However, as pointed out by others, the current fainting episode could also arise from expelled, cooling gas/dust partially obscuring the star. The recent changes .... seem best explained from changes in the envelop-outer convection atmosphere of this pulsating, unstable supergiant. If these recent light changes are due to an extra-large amplitude light pulse on the ~420-day period, then the next mid-light minimum is expected during late January/early February, 2020. If Betelgeuse continues to dim after that time then other possibilities will have to be considered. The unusual behavior of Betelgeuse should be closely watched.
 

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Has physicist’s gravity theory solved ‘impossible’ dark energy riddle?

Prof Claudia de Rham’s ‘massive gravity’ theory could explain why universe expansion is accelerating

Source: The Guardian online
Date: 25 January, 2020

Cosmologists don’t enter their profession to tackle the easy questions, but there is one paradox that has reached staggering proportions.

Since the big bang, the universe has been expanding, but the known laws of physics suggest that the inward tug of gravity should be slowing down this expansion. In reality, though, the universe is ballooning at an accelerating rate.

Scientists have come up with a name – dark energy – for the mysterious agent that is allowing the cosmos to expand so rapidly and which is estimated to account for 70% of the contents of the universe. But ultimately nobody knows what the stuff actually is.

“It’s the big elephant in the room,” says Prof Claudia de Rham, a theoretical physicist at Imperial College. “It’s very frustrating.”

Change could be afoot. De Rham has pioneered a radical theory that could hold the key to why the universe is expanding faster and faster and explain the nature of dark energy. The theory, known as massive gravity, modifies Einstein’s general relativity, positing that the hypothetical particles (gravitons) that mediate the gravitational force themselves have a mass. In Einstein’s version, gravitons are assumed to be massless.

If gravitons have a mass, then gravity is expected to have a weaker influence on very large distance scales, which could explain why the expansion of the universe has not been reined in.

https://amp-theguardian-com.cdn.amp...y-theory-solved-impossible-dark-energy-riddle
 

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Astronomers Have Caught a Rare And Massive 'Accretion Burst' in Our Galaxy

Source: sciencealert.com
Date: 27 January, 2020

Here on Earth, we pay quite a lot of attention to the sun. It's visible to us, after all, and central to our lives. But it is only one of the billions of stars in our galaxy, the Milky Way. It's also quite small compared to other stars – most are at least eight times more massive.

These massive stars influence the structure, shape and chemical content of a galaxy. And when they have exhausted their hydrogen gas fuel and die, they do so in an explosive event called a supernova. This explosion is sometimes so strong that it triggers the formation of new stars out of materials in the dead star's surroundings.

But there's an important gap in our knowledge: astronomers don't yet fully understand how those original massive stars themselves are initially formed. So far, observations have only yielded some pieces of the puzzle.

https://www-sciencealert-com.cdn.am...are-and-massive-accretion-burst-in-our-galaxy
 

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Most Detailed Photos Of The Sun Yet

From the new US National Solar Observatory

The US National Solar Observatory’s $344m (£265m) telescope features a four-metre mirror – the world’s largest for a solar telescope – and is located at the 3,000-metre (10,000ft) summit of the Haleakalā volcano on the island of Maui.

Valentin Pillet, the director of the National Solar Observatory, described the telescope, which had been under construction since 2013, as a “formidable technological achievement”. A major challenge was maintaining the telescope’s primary mirror at ambient temperature while it looked directly at the sun – any temperature deviation causes air turbulence that could ruin the image quality. The heat is intense enough to rapidly melt metal at the mirror’s focal point.
Keeping it cool:

Each night, a swimming pool’s worth of ice is emptied into eight tanks. During the day, coolant is routed through the ice tanks and distributed through the observatory by 7.5 miles (12km) of piping. More than 100 air jets are also positioned behind the main mirror.

Incoming light from the sun is deflected from the primary mirror into a chamber of mirrors that sits below the observatory’s dome. Here, the light is bounced from mirror to mirror as it is apportioned between spectrometers, polarimeters and other various other instruments. The observatory’s full suite of instruments, which will allow scientists to measure the magnetic field from the sun’s surface up to its outer atmosphere, will come online later this year.

“The bright features [in the image] … are the foothills of magnetic fields that extend all the way up into the corona and beyond,” said Rimmele. “With the additional instruments that will come online in the next six months, we will be able to measure the magnetic fields from the surface all the way up to 1.5 solar radii.”

The observations could help resolve longstanding mysteries of the sun, including the counterintuitive feature that the corona – the sun’s atmosphere – is heated to millions of degrees when its surface is only 6,000C. Understanding the physics of solar flares and coronal mass ejections could also significantly improve the ability to predict space weather, which can render GPS systems unreliable, take down power grids and knock out communication channels.
Photo/video at link.
 

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Space-time is swirling around a dead star, proving Einstein right again

Source: space.com
Date: 31 January, 2020

Space-time is indeed churned by massive rotating bodies, as scientists had thought.

The way the fabric of space and time swirls in a cosmic whirlpool around a dead star has confirmed yet another prediction from Einstein's theory of general relativity, a new study finds.

That prediction is a phenomenon known as frame dragging, or the Lense-Thirring effect. It states that space-time will churn around a massive, rotating body. For example, imagine Earth were submerged in honey. As the planet rotated, the honey around it would swirl — and the same holds true with space-time.

Satellite experiments have detected frame dragging in the gravitational field of rotating Earth, but the effect is extraordinarily small and, therefore, has been challenging to measure. Objects with greater masses and more powerful gravitational fields, such as white dwarfs and neutron stars, offer better chances to see this phenomenon.

Scientists focused on PSR J1141-6545, a young pulsar about 1.27 times the mass of the sun. The pulsar is located 10,000 to 25,000 light-years from Earth in the constellation Musca (the fly), which is near the famous Southern Cross constellation.

https://www-space-com.cdn.ampproject.org/v/s/www.space.com/amp/einstein-general-relativity-frame-dragging.html?amp_js_v=a2&amp_gsa=1&usqp=mq331AQCKAE=#referrer=https://www.google.com&amp_tf=From %1$s&ampshare=https://www.space.com/amp/einstein-general-relativity-frame-dragging.html#referrer=https%3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s
 
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Oddball sexaquark particles could be immortal, if they exist at all

Source: livescience.com
Date: 4, February 2020

These supremely stable particles could explain dark matter.

After decades of poking around in the math behind the glue holding the innards of all matter together, physicists have found a strange hypothetical particle, one that has never appeared in any experiment. Called a sexaquark, the oddball is made up of a funky arrangement of six quarks of various flavors.

Besides being a cool-sounding character, the sexaquark could eventually explain the ever-maddening mystery of dark matter. And physicists have found that if the sexaquark has a particular mass, the particle could live forever.

Quarks of nature

Almost everything you know and love is made of tiny particles known as quarks. There are six of them, given the names, for various nerdy reasons, of up, down, top, bottom, strange and charm. The up and down varieties are the lightest of the bunch, which makes them by far the most common. (In particle physics, the heavier you are, the more likely you are to decay into smaller, stabler things.)

The protons and neutrons inside your body are all composed of trios of quarks; two ups and a down make a proton, and two downs and an up make a neutron. Indeed, due to the complicated nature of the strong force, quarks really enjoy hanging out in groups of three, and that is also by far the stablest and most common configuration.

Occasionally in our particle colliders, we create particles each consisting of a pair of quarks; these conglomerations are unstable and quickly decay into something else. Sometimes, when we try really hard, we can glue five quarks together and make them play nicely with each other — briefly — before they, too, decay into something else.

And to date, those are all the combinations of quarks that we've been able to manufacture.

However, there may be something stranger.

https://www.google.com/amp/s/www.livescience.com/amp/sexquarks-could-explain-dark-matter.html
 

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JUST WOW

INCREDIBLE NASA VISUALIZATIONS REVEAL UNIVERSE AS YOU HAVE NEVER SEEN IT BEFORE

Source: inverse.com
Date: 31 January, 2020

NASA's Chandra X-Ray Observatory is altering our perspective on the cosmos — and it is beautiful.

Prepare to get a new perspective on the cosmos.

For as long as humans have peered into space, we have been forced to observe the beauty of the universe via flat, two-dimensional imaging techniques. As a result, certain details — the sheer size, the dynamism, and the true nature — of interstellar objects and phenomena have been somewhat obscured.

But NASA's Chandra X-ray Observatory is changing that. In a new collection of 3D visualizations, scientists from the observatory have brought some of the wonders of the cosmos to life, allowing us here on Earth to marvel at such incredible events as powerful supernovae explosions and jets of stellar material erupting in space.

The collection was created by a team at the National Institute for Astrophysics in Italy using data collected by Chandra and other X-ray observatories. The team used a computer simulation to model the geometry, velocity, and other physical properties of each of the phenomena.

https://www-inverse-com.cdn.ampproj...reveal-universe-as-you-have-never-seen-before
[END]



Universe in Hands

Source: sketchfab.com

The collection shows the results of (magneto-)hydrodynamical models of different astrophysical phenomena. The models are developed by astrophysicists of the INAF-Osservatorio Astronomico di Palermo (Italy). More information can be found at the link...

https://sketchfab.com/sorlando/collections/universe-in-hands
 

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Unusual monster galaxy discovered from early universe

The galaxy known as XMM-2599 has baffled scientists because it appears to have died during its prime star-birthing years.

Source: Sky News
Date: 5 February, 2020

Astronomers have hailed the discovery of an "unusual" monster galaxy dating back to the early universe, about 12 billion years ago.

Scientists estimate the universe is about 13.8 billion years old, and the newly discovered galaxy existed approximately 1.8 billion years on from its beginning.

According to the observations by the team at the University of California, Riverside, the galaxy, known as XMM-2599, at first formed stars at a high rate, but then mysteriously died.

"Even before the universe was two billion years old, XMM-2599 had already formed a mass of more than 300 billion suns, making it an ultramassive galaxy," said Dr Benjamin Forrest.

"More remarkably, we show that XMM-2599 formed most of its stars in a huge frenzy when the universe was less than one billion years old, and then became inactive by the time the universe was only 1.8 billion years old."

https://news-sky-com.cdn.ampproject...3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s
 
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Shall we create an Astronautics thread?

NASA astronaut Christina Koch returns to Earth after logging 328 days aboard the International Space Station
US astronaut Christina Koch, who led the first all-female spacewalk in 2019, has returned to Earth after a record stay aboard the International Space Station. Ms Koch, 41, landed in Kazakhstan on Thursday (local time), ending a 328-day mission expected to yield new insights into deep-space travel.

"I'm just so overwhelmed and happy right now," Ms Koch said, sitting in a chair wrapped in blankets as she waited to be carried into a medical tent to restore her balance in gravity.
https://www.abc.net.au/news/2020-02...h-returning-to-earth-record-breaking/11940446

Wow. That is huge. I've been observing her transit at every opportunity. Stalking? I wonder if she has a boyfriend.
:cheer:
 

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This astronomer posts regular updates about Betelgeuse. The star is slightly brighter than it was, and may be returning to normal. But this chap says it has remained constantly bright when viewed in the infra-red. That probably means this recent 'fainting' is due to dust.
http://www.astronomerstelegram.org/?read=13518
The visual fading is not connected to a major change in total energy output from the star. Thus, while Betelgeuse may explode tomorrow or any time in the next few 1e5 yr, the unprecedented current visual faintness is unlikely to be a harbinger of its impending core collapse.
 

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New Wrinkle Added to Cosmology’s Hubble Crisis

Source: quantamagazine.org
Date: 26 February, 2020

A problem confronts cosmology: Two independent measurements of the universe’s expansion give incompatible answers. Now a third method, advanced by an astronomy pioneer, appears to bridge the divide.

The big news in cosmology for several years has been the mounting evidence that the universe is expanding faster than expected. When cosmologists extrapolate data from the early universe to predict what the cosmos should be like now, they predict a relatively slow cosmic expansion rate. When they directly measure the speed at which astronomical objects are hurtling away from us, they find that space is expanding about 9% faster than the prediction. The discrepancy may mean that something big is missing from our understanding of the cosmos.

The issue reached a crescendo over the past year. Last March, the main group measuring cosmic expansion released their updated analysis, once again arriving at an expansion rate that far outstrips expectations. Then in July, a new measurement of cosmic expansion using objects called quasars, when combined with the other measurement, pushed past “five sigma,” a statistical level that physicists usually treat as their standard of proof of an unaccounted-for physical effect. In this case, cosmologists say there might be some extra cosmic ingredient, beyond dark matter, dark energy and everything else they already include in their equations, that speeds the universe up.

But that’s if the measurements are correct. A new line of evidence, first announced last summer, suggests that the cosmic expansion rate may fall much closer to the rate predicted by early-universe measurements and the standard theory of cosmology.

https://www.quantamagazine.org/new-wrinkle-added-to-cosmologys-hubble-crisis-20200226/
 

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This Gigantic Neptune-Sized Exoplanet is Incredibly Close

Source: futurism.com
Date: 26 February, 2020

A team of astronomers at Penn State just confirmed the existence of G 9-40b, a gigantic super-Earth only about 90 light years from Earth — making it one of the closest known exoplanets.

The exoplanet is at least twice as massive as Earth and may even be as large as Neptune. It was first spotted by NASA’s planet-hunting space telescope Kepler during its K2 mission in 2019.

The team used The Habitable Zone Planet Finder (HPF), a low-mass planet-hunting instrument attached to the 10-meter Hobby-Eberly Telescope at the McDonald Observatory in Texas.

But this particular planet isn’t very habitable. Its surface experiences scorching temperatures of over 3,100 degrees Celsius (5,600 Fahrenheit) — hot, but still substantially cooler than the Sun.

The fact that it’s only about 90 light years away means that it is “among the 20 closest transiting planetary systems known, and is currently the second closest transiting planets discovered by the K2 mission to date,” according to a statement by Gudmundur Stefansson, lead author of a paper about the planet published in The Astronomical Journal earlier this month.

The astronomers believe the exoplanet is an excellent candidate for a much closer look by NASA’s upcoming James Webb Space Telescope that is scheduled to launch in March 2021.

https://futurism-com.cdn.ampproject...3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s
 

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New Wrinkle Added to Cosmology’s Hubble Crisis

Source: quantamagazine.org
Date: 26 February, 2020

A problem confronts cosmology: Two independent measurements of the universe’s expansion give incompatible answers. Now a third method, advanced by an astronomy pioneer, appears to bridge the divide.

. Then in July, a new measurement of cosmic expansion using objects called quasars, when combined with the other measurement, pushed past “five sigma,” a statistical level that physicists usually treat as their standard of proof of an unaccounted-for physical effect. In this case, cosmologists say there might be some extra cosmic ingredient, beyond dark matter, dark energy and everything else they already include in their equations, that speeds the universe up.

But that’s if the measurements are correct. A new line of evidence, first announced last summer, suggests that the cosmic expansion rate may fall much closer to the rate predicted by early-universe measurements and the standard theory of cosmology.

https://www.quantamagazine.org/new-wrinkle-added-to-cosmologys-hubble-crisis-20200226/
And they just keep on moving the goalposts.
 

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Our galaxy’s huge black hole may have created organic molecules

Source: newscientist.com
Date: 26 February, 2020

The Milky Way’s black hole may have given life a helping hand

The supermassive black hole at the centre of the Milky Way may have been crucial to the evolution of life in the galaxy.

These days, the black hole, known as Sagittarius A*, is relatively calm. But there are hints that millions of years ago it may have been much more active, swallowing down matter and spewing out high-energy radiation including large amounts of X-rays.

https://www-newscientist-com.cdn.am...3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s
 

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Starter' Earth grew in a flash. Here's how the planet did it.

Source: livescience.com
Date: 24 February, 2020

If the solar system formed in 24 hours, then proto-Earth formed in just 1.5 minutes.

Dust from meteorites that crash-landed on Earth have revealed that Earth's precursor, known as proto-Earth, formed much faster than previously thought, a new study finds.

An analysis of this meteorite dust showed that proto-Earth formed within about 5 million years, which is extremely fast, astronomically speaking.

Put another way, if the entire 4.6 billion years of the solar system's existence were compressed into a 24-hour period, proto-Earth formed in just 1 minute and 30 seconds, the researchers said.

The new finding breaks with the previously held idea that proto-Earth formed when larger and larger planetary bodies randomly slammed into one another, a process that would have taken several tens of millions of years, or about 5 to 15 minutes in the fictional 24-hour timescale.

https://www-livescience-com.cdn.amp...m/meteorite-iron-shows-earth-formed-fast.html
 
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