Lunar Eclipse over the ESO’s VLT, Chile
There's your winning smile, a bright summers day, then there's Quasars ! Unlike the latter, Quasars are amongst the brightest objects in the Universe, often shining out more energy than the entirety of the galaxy that hosts them.
While we know a fair bit about what they are, how they begin has been a debate since they were first found.
Most galaxies have a supermassive black hole at their centre, our Milky Way has one 4.5 million times the mass of our own Sun, and in galactic terms, that's fairly light weight, there are black holes within 60 million light years of us several billion times the mass of our Sun, real goliaths, which tend to sit at the centre of Elliptical Galaxies.
Qasars are incredibly active supermassive black holes, so the question remains, why are some quasars and others not, what causes this to happen ?
A team of astronomers from the Universities of Sheffield and Hertfordshire have found an interesting bit of information which may hint towards the answer. In a study of Quasars, they have discovered that galaxies that are home to a Quasar are three time more likely to be in a state of interaction or collision with another galaxy.
This leads them to believe that the galaxy merger is responsible for piling an enormous quantity of material towards the black hole, causing it to grow incredibly quickly but also as messy eaters, pushing out much of it in the form of radiation in beams emanating from the poles.
One consequence of this is the galaxy is quenched of dust and gas, the very elements needed to create new stars, and is likely the reason most elliptical galaxies have such monster black holes, the remnants of all the star making material consumed, and that pushed out, leaving behind stars old enough to live on since that happened.
Source :
Blog#123
Wednesday, September 15th, 2021
Welcome back,
Neutrinos are elusive subatomic particles created in a wide variety of nuclear processes. Their name, which means “little neutral one,” refers to the fact that they carry no electrical charge. Of the four fundamental forces in the universe, neutrinos only interact with two — gravity and the weak force, which is responsible for the radioactive decay of atoms. Having nearly no mass, they zip through the cosmos at almost the speed of light.
Countless neutrinos came into existence fractions of a second after the Big Bang. And new neutrinos are created all the time: in the nuclear hearts of stars, in particle accelerators and atomic reactors on Earth, during the explosive collapse of supernovas and when radioactive elements decay. This means that there are, on average, 1 billion times more neutrinos than protons in the universe, according to physicist Karsten Heeger of Yale University in New Haven, Connecticut.
Despite their ubiquity, neutrinos largely remain a mystery to physicists because the particles are so tough to catch. Neutrinos stream through most matter as if they were light rays going through a transparent window, scarcely interacting with everything else in existence. Approximately 100 billion neutrinos are passing through every square centimeter of your body at this moment, though you won’t feel a thing.
Neutrinos were first posited as the answer to a scientific enigma. In the late 19th century, researchers were puzzling over a phenomenon known as beta decay, in which the nucleus inside an atom spontaneously emits an electron. Beta decay seemed to violate two fundamental physical laws: conservation of energy and conservation of momentum. In beta decay, the final configuration of particles seemed to have slightly too little energy, and the proton was standing still rather than being knocked in the opposite direction of the electron. It wasn’t until 1930 that physicist Wolfgang Pauli proposed the idea that an extra particle might be flying out of the nucleus, carrying with it the missing energy and momentum.
“I have done a terrible thing. I have postulated a particle that cannot be detected,“ Pauli said to a friend, referring to the fact that his hypothesized neutrino was so ghostly that it would barely interact with anything and would have little to no mass.
More than a quarter century later, physicists Clyde Cowan and Frederick Reines built a neutrino detector and placed it outside the nuclear reactor at the atomic Savannah River power plant in South Carolina. Their experiment managed to snag a few of the hundreds of trillions of neutrinos that were flying from the reactor, and Cowan and Reines proudly sent Pauli a telegram to inform him of their confirmation. Reines would go on to win the Nobel Prize in Physics in 1995 — by which time, Cowan had died.
But since then, neutrinos have continually defied scientists’ expectations.
The sun produces colossal numbers of neutrinos that bombard the Earth. In the mid-20th century, researchers built detectors to search for these neutrinos, but their experiments kept showing a discrepancy, detecting only about one-third of the neutrinos that had been predicted. Either something was wrong with astronomers’ models of the sun, or something strange was going on.
Physicists eventually realized that neutrinos likely come in three different flavors, or types. The ordinary neutrino is called the electron neutrino, but two other flavors also exist: a muon neutrino and a tau neutrino.
As they pass through the distance between the sun and our planet, neutrinos are oscillating between these three types, which is why those early experiments — which had only been designed to search for one flavor — kept missing two-thirds of their total number.
But only particles that have mass can undergo this oscillation, contradicting earlier ideas that neutrinos were massless. While scientists still don’t know the exact masses of all three neutrinos, experiments have determined that the heaviest of them must be at least 0.0000059 times smaller than the mass of the electron.
Eclipse
Today there was a partial solar eclipse visible in mid to eastern europe.
In Germany we could see how the moon covers between 20 and 30% of the sun
"average person knows 3 astrophysics things" actualy just statistical error. average person knows 1 astrophysics thing. Astrophysics Georg, who lives in space and knows 10,000 astrophysics things, is an outlier adn should not have been counted
A philosopher once asked, "Are we human because we gaze at the stars, or do we gaze at them because we are human?" Pointless, really..."Do the stars gaze back?" Now, that's a question.
- Neil Gaiman, Stardust
Blog# 198
Saturday, June 4th, 2022
Welcome back,
What – one vast, ancient and mysterious universe isn’t enough for you? Well, as it happens, there are others. Among physicists, it’s not controversial. Our universe is but one in an unimaginably massive ocean of universes called the multiverse.
If that concept isn’t enough to get your head around, physics describes different kinds of multiverse. The easiest one to comprehend is called the cosmological multiverse. The idea here is that the universe expanded at a mind-boggling speed in the fraction of a second after the big bang. During this period of inflation, there were quantum fluctuations which caused separate bubble universes to pop into existence and themselves start inflating and blowing bubbles.
Russian physicist Andrei Linde came up with this concept, which suggests an infinity of universes no longer in any causal connection with one another – so free to develop in different ways.
Cosmic space is big – perhaps infinitely so. Travel far enough and some theories suggest you’d meet your cosmic twin – a copy of you living in a copy of our world, but in a different part of the multiverse. String theory, which is a notoriously theoretical explanation of reality, predicts a frankly meaninglessly large number of universes, maybe 10 to the 500 or more, all with slightly different physical parameters.
And then there’s the quantum multiverse. Physicist Hugh Everett came up with this idea, which is predicted by his “many worlds” interpretation of quantum physics. Everett’s theory is that quantum effects cause the universe to constantly split. It could mean that decisions we make in this universe have implications for other versions of ourselves living in parallel worlds.
Was out filming with the telescope and first of all, I have it on the porch, which is shared with our neighbors. One of them came out and saw me with the telescope and I was like straddling it because it’s the only way I can use the viewfinder on that thing and conversation was just:
Him: uhhh-
Me: don’t
Him: -yes ma’am
And then I met our other neighbors, some drunk girls, who thought it was a /cannon/. So I put it on the Moon and was like “wanna see?” And they were about as excited as your typical 4 year olds to see the moon and when I told them they could take pictures through the eyepiece (the eyepiece I was using was a wide angle plossl) they could not have been more excited
This is a season where our thoughts turn to others and many exchange gifts with friends and family. For astronomers, our universe is the gift that keeps on giving. We’ve learned so much about it, but every question we answer leads to new things we want to know. Stars, galaxies, planets, black holes … there are endless wonders to study.
In honor of this time of year, let’s count our way through some of our favorite gifts from astronomy.
So far, there is only one planet that we’ve found that has everything needed to support life as we know it — Earth. Even though we’ve discovered over 5,200 planets outside our solar system, none are quite like home. But the search continues with the help of missions like our Transiting Exoplanet Survey Satellite (TESS). And even you (yes, you!) can help in the search with citizen science programs like Planet Hunters TESS and Backyard Worlds.
Astronomers found out that our Milky Way galaxy is blowing bubbles — two of them! Each bubble is about 25,000 light-years tall and glows in gamma rays. Scientists using data from our Fermi Gamma-ray Space Telescope discovered these structures in 2010, and we're still learning about them.
Most black holes fit into two size categories: stellar-mass goes up to hundreds of Suns, and supermassive starts at hundreds of thousands of Suns. But what happens between those two? Where are the midsize ones? With the help of NASA’s Hubble Space Telescope, scientists found the best evidence yet for that third, in between type that we call intermediate-mass black holes. The masses of these black holes should range from around a hundred to hundreds of thousands of times the Sun’s mass. The hunt continues for these elusive black holes.
When looking at this stunning image of Stephan’s Quintet from our James Webb Space Telescope, it seems like five galaxies are hanging around one another — but did you know that one of the galaxies is much closer than the others? Four of the five galaxies are hanging out together about 290 million light-years away, but the fifth and leftmost galaxy in the image below — called NGC 7320 — is actually closer to Earth at just 40 million light-years away.
Astronomers found a six-star system where all of the stars undergo eclipses, using data from our TESS mission, a supercomputer, and automated eclipse-identifying software. The system, called TYC 7037-89-1, is located 1,900 light-years away in the constellation Eridanus and the first of its kind we’ve found.
In 2017, our now-retired Spitzer Space Telescope helped find seven Earth-size planets around TRAPPIST-1. It remains the largest batch of Earth-size worlds found around a single star and the most rocky planets found in one star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on a planet’s surface.
Further research has helped us understand the planets’ densities, atmospheres, and more!
The primary mirror on our Nancy Grace Roman Space Telescope is approximately eight feet in diameter, similar to our Hubble Space Telescope. But Roman can survey large regions of the sky over 1,000 times faster, allowing it to hunt for thousands of exoplanets and measure light from a billion galaxies.
In 2017, the National Science Foundation (NSF)’s Laser Interferometer Gravitational-Wave Observatory (LIGO) and European Gravitational Observatory’s Virgo detected gravitational waves from a pair of colliding neutron stars. Less than two seconds later, our telescopes detected a burst of gamma rays from the same event. It was the first time light and gravitational waves were seen from the same cosmic source. But then nine days later, astronomers saw X-ray light produced in jets in the collision’s aftermath. This later emission is called a kilonova, and it helped astronomers understand what the slower-moving material is made of.
Our NuSTAR X-ray observatory is the first space telescope able to focus on high-energy X-rays. Its ten-meter-long (33 foot) mast, which deployed shortly after launch, puts NuSTAR’s detectors at the perfect distance from its reflective optics to focus X-rays. NuSTAR recently celebrated 10 years since its launch in 2012.
How long did our Hubble Space Telescope stare at a seemingly empty patch of sky to discover it was full of thousands of faint galaxies? More than 11 days of observations came together to capture this amazing image — that’s about 1 million seconds spread over 400 orbits around Earth!
Pulsars are collapsed stellar cores that pack the mass of our Sun into a whirling city-sized ball, compressing matter to its limits. Our NICER telescope aboard the International Space Station helped us precisely measure one called J0030 and found it had a radius of about twelve kilometers — roughly the size of Chicago! This discovery has expanded our understanding of pulsars with the most precise and reliable size measurements of any to date.
Stay tuned to NASA Universe on Twitter and Facebook to keep up with what’s going on in the cosmos every day. You can learn more about the universe here.
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