Science is the poetry of Nature.
Contributing Authors
Posts tagged "astrophysics"

Barns Are Painted Red Because of the Physics of Dying Stars

Have you ever noticed that almost every barn you have ever seen is red? There’s a reason for that, and it has to do with the chemistry of dying stars. Seriously.

Yonatan Zunger is a Google employee who decided to explain this phenomenon on Google+ recently. The simple answer to why barns are painted red is because red paint is cheap. The cheapest paint there is, in fact. But the reason it’s so cheap? Well, that’s the interesting part.

Red ochre—Fe2O3—is a simple compound of iron and oxygen that absorbs yellow, green and blue light and appears red. It’s what makes red paint red. It’s really cheap because it’s really plentiful. And it’s really plentiful because of nuclear fusion in dying stars. Zunger explains:

The only thing holding the star up was the energy of the fusion reactions, so as power levels go down, the star starts to shrink. And as it shrinks, the pressure goes up, and the temperature goes up, until suddenly it hits a temperature where a new reaction can get started. These new reactions give it a big burst of energy, but start to form heavier elements still, and so the cycle gradually repeats, with the star reacting further and further up the periodic table, producing more and more heavy elements as it goes. Until it hits 56. At that point, the reactions simply stop producing energy at all; the star shuts down and collapses without stopping.

As soon as the star hits the 56 nucleon (total number of protons and neutrons in the nucleus) cutoff, it falls apart. It doesn’t make anything heavier than 56. What does this have to do with red paint? Because the star stops at 56, it winds up making a ton of things with 56 neucleons. It makes more 56 nucleon containing things than anything else (aside from the super light stuff in the star that is too light to fuse).

The element that has 56 protons and neutrons in its nucleus in its stable state? Iron. The stuff that makes red paint.

And that, Zunger explains, is how the death of a star determines what color barns are painted.

Day in the Life of a Living Mars

An animation showing a day on a living Mars.

Generated using data from the Mars Orbiter Laser Altimeter aboard the Mars Global Surveyor spacecraft and satellite imagery from the Blue Marble Next Generation project.

Sea level was set non-scientifically, but such that it would flood much of Valles Marineris as well as provide shoreline near the top of the cliffs on the outer edges of Olympus Mons. The clouds are straight from NASA’s Blue Marble NG project and height mapped (rather arbitrarily, but looks good) by relative opacity (The more opaque a point, the higher up in the atmosphere I put it).

The main texture was “painted” in GIMP over a two dimensional DEM I had done using MOLA elevation data from the Mars Global Surveyor. This was rendered using a digital elevation modeling program I am writing, jDem846, with some extras baked in through it’s scripting interface, and encoded to video with ffmpeg. — Kevin Gill

A huge amount of radiation is generated by the million degree accretion disk of trapped gas whirling around the 4 billion solar mass black hole at our galaxy’s heart.

Makoto Inoue of the Institute of Astronomy and Astrophysics in Taipei, and Hiromitsu Yokoo of Chiba University are proposing that advanced civilizations might pool their resources to construct a ring of “power stations” at the galaxy’s core. They would orbit the central black hole just beyond its solar system-sized accretion disk.

Some fraction of the radiation seething from the disk would be reflected and focused onto the power plants. Each power plant would transmit collected energy as a collimated microwave beam from a 100-mile diameter antenna.

ikenbot:

Monster Black Holes Are Most Massive Ever Discovered

Scientists have discovered the largest black holes yet, and they’re far bigger than researchers expected based on the galaxies in which they were found. The discovery suggests we have much to learn about how monster black holes grow, scientists said.

All large galaxies are thought to harbor super-massive black holes at their hearts that contain millions to billions of times the mass of our sun. Until now, the largest black hole known was a mammoth dwelling in the giant elliptical galaxy Messier 87. This black hole has a mass 6.3 billion times that of the sun.

Now research suggests black holes in two nearby galaxies are even bigger. The scientists used the Gemini and Keck observatories in Hawaii and the McDonald Observatory in Texas to monitor the velocities of stars orbiting around the centers of a pair of galaxies. These velocities reveal the strength of the gravitational pull on those stars, which in turn is linked with the masses of the black holes lurking there.

The new findings suggest that one galaxy, known as NGC 3842, the brightest galaxy in the Leo cluster of galaxies nearly 320 million light years distant, has a central black hole 9.7 billion solar masses large. The other, named NGC 4889, the brightest galaxy in the Coma cluster more than 335 million light years away, has a black hole of comparable or larger mass. Both encompass regions or “event horizons” about five times the distance from the sun to Pluto.

“For comparison, these black holes are 2,500 times as massive as the black hole at the center of the Milky Way galaxy, whose event horizon is one-fifth the orbit of Mercury,” said study lead author Nicholas McConnell at the University of California, Berkeley. Astronomers had suspected that black holes more than 10 billion solar masses large exist, based on light from quasars, cosmic objects from the early universe that are no more than a light year or two across but are thousands of times brighter than our entire galaxy.

The light of quasars is thought to come from matter driven to incandescent brightness as it spirals at high speeds into supermassive black holes. This is the first time scientists have detected black holes approaching such theorized giants in size.

“These two new supermassive black holes are similar in mass to young quasars, and may be the missing link between quasars and the supermassive black holes we see today,” said study co-author Chung-Pei Ma, an astrophysicist at the University of California, Berkeley.

science-junkie:

The 4 hardest computing problems on earth 

America’s most powerful supercomputer runs calculations so quickly it makes your laptop look like an abacus. The machine, called Titan, is located at the Oak Ridge National Laboratory in Tennessee. It is also the fastest supercomputer the world. It can process more than 17 petaflops of data per second — that’s roughly 20,000 trillion simultaneous calculations. Though Titan has the strength of 500,000 laptops, computer scientists are hungry for more. Already, they are dreaming of a machine that could manage an exaflop of data, which would require about 50 times more processing power than Titan. So-called exascale computing could let researchers answer some of the toughest scientific problems. 

Virtual climate
Building better climate models is becoming more important, as scientists work to predict the potential effects of a warming planet. But the best supercomputers today fall short of researchers’ goals. If you think of the globe as an image, the best supercomputers can only render pixels the size of 14 square kilometers. An exascale computer could bring that down to one square kilometer. The effect? Scientists could see the impact of minutely detailed climate factors such as individual cloud formations and ocean eddies.

Digital cells 
Much of the future of pharmaceuticals is in algorithms, not petri dishes. Researchers will develop drugs based on programs that predict how chemicals will interact with the body. In this approach to solving problems in biology, chemistry, and materials sciences, scientists model the movement of individual atoms or molecules, factoring in the various forces exerted on them.

Future fuel
With Titan, scientists can model the chemical reactions for combustion of relatively simple fuels like alcohol and butanol. But because gasoline and biodiesels are complex fuels — the molecules inside are longer and thus trickier to model — more and more powerful supercomputers will be required to parse them.

Inside supernovae
More powerful supercomputers could shine a light on some of the most foreign phenomena in the universe. For example, scientists in the future may be able to model the awesome forces that interact when a star explodes. Running programs that includes all the sciences at play would require an exaflop of data. With that much power, the next generation of supercomputers could bring the mysteries of deep space closer to home.

Source: cnn.com

electricspacekoolaid:

“Every Galaxy Has Counterparts in Other Universes” - David Deutsch

Legendary Oxford physicist David Deutsch is best known for his contributions to quantum physics, quantum computing, and a leading proponent of the multiverse (or “many worlds”) interpretation of quantum theory — the astounding idea that our universe is constantly spawning countless numbers of worlds.

In his book The Fabric of Reality, Deutsch laid the groundwork for an all-encompassing Theory of Everything by tying together four mutually supporting strands of reality: First: Hugh Everett’s many-worlds interpretation of quantum physics, “the first and most important of the four strands”; second: Karl Popper’s epistemology, especially its requiring a realist interpretation of scientific theories, and its emphasis on being  falsifiable; third: Alan Turing’s theory of computation, replaced by Deutsch’s universal quantum computer; and fourth: Richard Dawkins’neo-Darwinian evolutionary theory and the modern evolutionary synthesis.

“The quantum theory of parallel universes is not the problem, it is the solution. It is not some troublesome, optional interpretation emerging from arcane theoretical considerations,” says David Deutsch. “It is the explanation, the only one that is tenable, of a remarkable and counter-intuitive reality. Everything in our universe — including you and me, every atom and every galaxy — has counterparts in these other universes.”

“Our best theories are not only truer than common sense, they make more sense than common sense,” Deutsch wrote about the most mind-bending aspects of particle physics, including the tendency of matter to exist in more than one place at a time.

In the TED Conference video filmed at Oxford University, Deutsch will force you to reconsider your place in the world, and about our species’ significance in the universe. Far from being simply “chemical scum,” quoting Stephen Hawking, we have the ability to gain knowledge, the importance of which, he says, is that we are always equipped to solve problems (including global warming). The brain contains the tools we need: knowledge, reason and creativity. It’s a thrilling, and much needed, profoundly optimistic argument.

Read + Video + Ted

Hints of New Dark Force Seen in Galactic Smash-ups

Colliding clusters of galaxies may hold clues to a mysterious dark force at work in the universe. This force would act only on invisible dark matter, the enigmatic stuff that makes up 86 per cent of the mass in the universe.

Dark matter famously refuses to interact with ordinary matter except via gravity, so theorists had assumed that its particles would be just as aloof with each other. But new observations suggest that dark matter interacts significantly with itself, while leaving regular matter out of the conversation.

“There could be a whole class of dark particles that don’t interact with normal matter but do interact with themselves,” says James Bullock of the University of California, Irvine. “Dark matter could be doing all sorts of interesting things, and we’d never know.”

Some of the best evidence for dark matter’s existence came from the Bullet cluster, a smash-up in which a small galaxy cluster plunged through a larger one about 100 million years ago. Separated by hundreds of light years, the individual galaxies sailed right past each other, and the two clusters parted ways. But intergalactic gas collided and pooled on the trailing ends of each cluster.

Mass maps of the Bullet cluster showed that dark matter stayed in line with the galaxies instead of pooling with the gas, proving that it can separate from ordinary matter. This also hinted that dark matter wasn’t interacting with itself, and was affected by gravity alone.

Continue

spaceplasma:

ESA’s Earth Explorers satellites

Artist’s view of ESA’s Earth Explorers satellites:

  • The GOCE gravity mission launched on 17 March 2009;
  • The magnetic field mission Swarm planned for launch in 2013;
  • The ADM-Aeolus wind mission planned for launch in 2014;
  • The CryoSat ice mission launched on 8 April 2010;
  • The cloud, aerosol and radiation mission EarthCARE planned for launch in 2015;
  • And the SMOS water mission launched on 2 November 2009.

heythereuniverse:

Double-Star Systems Can Be Dangerous for Exoplanets | Space.com

Alien planets born in widely separated two-star systems face a grave danger of being booted into interstellar space, a new study suggests.

Exoplanets circling a star with a far-flung stellar companion — worlds that are part of “wide binary” systems — are susceptible to violent and dramatic orbital disruptions, including outright ejection, the study found.

Such effects are generally limited to sprawling planetary systems with at least one distantly orbiting world, while more compact systems are relatively immune. This finding, which observational evidence supports, should help astronomers better understand the structure and evolution of alien solar systems across the galaxy, researchers said.

[Read more]

electricspacekoolaid:

Dark Matter Could Play a Role in Creating Life in The Universe

First Image : A Hubble Space Telescope image of Dark Matter mapped in a 3d representation.

Second Image: Abel 1689 galaxy cluster.

Dark matter makes up the majority of mass in our universe. However, we cannot directly measure the stuff as it doesn’t interact with electromagnetic radiation (i.e. it doesn’t emit or reflect any light), but we can indirectly observe its presence. In the Hubble Space Telescope image above, the distribution of mostly dark matter has been calculated and mapped. Basically, the location and density of anything with mass has been plotted in a 3D representation of the cosmos.

A 2011 study suggests that mysterious, invisible dark matter could warm millions of starless planets in regions such as Abell 1689 (image below) and make them habitable.

image

Scientists think the invisible, as-yet-unidentified dark matter which we know exists because of the gravitational effects it has on galaxies, makes up about 85 percent of all matter in the universe.  Current prime candidates for what dark matter might be are massive particles that only rarely interact with normal matter.
These particles could be their own antiparticles, meaning they annihilate each other when they meet, releasing energy. These invisible particles could get captured by a planet’s gravity and unleash energy that could warm that world, according to physicist Dan Hooper and astrophysicist Jason Steffen at the Fermi National Accelerator Laboratory.

Hooper and Steffen’s propose that rocky “super-Earths” in regions with high densities of slow-moving dark matter could be warmed enough to keep liquid water on their surfaces, even in the absence of additional energy from starlight or other sources.The density of dark matter is expected to be hundreds to thousands of times greater in the innermost regions of the Milky Way and in the cores of dwarf spheroidal galaxies than it is in our solar system.

The scientists concluded that on planets in dense “dark-matter” regions, it may be dark matter rather than light that creates the basic elements you need for organic life without a star”

Now take a moment to think how this could change the way we view evolution of life on other worlds. A dark matter evolved life form definitely gives me tingling sensations just trying to think of it despite how theoretical the assertion may be.

(via sagansense)

thenewenlightenmentage:

Never-Before-Seen Stage of Planet Birth Revealed

Astronomers studying a newborn star have caught a detailed glimpse of planets forming around it, revealing a never-before seen stage of planetary evolution.

Large gas giant planets appear to be clearing a gap in the disk of material surrounding the star, and using gravity to channel material across the gap to the interior, helping the star to grow. Theoretical simulations have predicted such bridges between outer and inner portions of disks surrounding stars, but none have been directly observed until now.

Continue Reading

sagansense:

Supercharging the search for secrets of the universe

image 1: The Large Hadron Collider at CERN faces a two-year shutdown so engineers can ramp up its maximum energy.
image 2: Proton-proton collisions during the search for the Higgs boson. Photo: AFP
image 3: A collision event between two lead ions in the Large Hadron Collider as observed by the ALICE detector. Photo: Supplied
image 4: A simulated black hole created by the Large Hadron Collider. Photo: Supplied

When it comes to shutting down the most powerful atom smasher ever built, it’s not simply a question of pressing the off switch.

In the French-Swiss countryside on the far side of Geneva, staff at the Cern particle physics laboratory are taking steps to wind down the Large Hadron Collider. After the latest run of experiments ends next month, the huge superconducting magnets that line the LHC’s 27km-long tunnel must be warmed up, slowly and gently, from -271 Celsius to room temperature. Only then can engineers descend into the tunnel to begin their work.

The machine that last year helped scientists snare the elusive Higgs boson - or a convincing subatomic impostor - faces a two-year shutdown while engineers perform repairs that are needed for the collider to ramp up to its maximum energy in 2015 and beyond. The work will beef up electrical connections in the machine that were identified as weak spots after an incident four years ago that knocked the collider out for more than a year.

The accident happened days after the LHC was first switched on in September 2008, when a short circuit blew a hole in the machine and sprayed six tonnes of helium into the tunnel that houses the collider. Soot was scattered over 700 metres. Since then, the machine has been forced to run at near half its design energy to avoid another disaster.

The particle accelerator, which reveals new physics at work by crashing together the innards of atoms at close to the speed of light, fills a circular, subterranean tunnel a staggering eight kilometres in diameter. Physicists will not sit around idle while the collider is down. There is far more to know about the new Higgs-like particle, and clues to its identity are probably hidden in the piles of raw data the scientists have already gathered, but have had too little time to analyse.

But the LHC was always more than a Higgs hunting machine. There are other mysteries of the universe that it may shed light on. What is the dark matter that clumps invisibly around galaxies? Why are we made of matter, and not antimatter? And why is gravity such a weak force in nature? “We’re only a tiny way into the LHC programme,” says Pippa Wells, a physicist who works on the LHC’s 7000-tonne Atlas detector. “There’s a long way to go yet.”

The hunt for the Higgs boson, which helps explain the masses of other particles, dominated the publicity around the LHC for the simple reason that it was almost certainly there to be found. The lab fast-tracked the search for the particle, but cannot say for sure whether it has found it, or some more exotic entity.

“The headline discovery was just the start,” says Wells. “We need to make more precise measurements, to refine the particle’s mass and understand better how it is produced, and the ways it decays into other particles.” Scientists at Cern expect to have a more complete identikit of the new particle by March, when repair work on the LHC begins in earnest.

By its very nature, dark matter will be tough to find, even when the LHC switches back on at higher energy. The label “dark” refers to the fact that the substance neither emits nor reflects light. The only way dark matter has revealed itself so far is through the pull it exerts on galaxies.

Studies of spinning galaxies show they rotate with such speed that they would tear themselves apart were there not some invisible form of matter holding them together through gravity. There is so much dark matter, it outweighs by five times the normal matter in the observable universe.

The search for dark matter on Earth has failed to reveal what it is made of, but the LHC may be able to make the substance. If the particles that constitute it are light enough, they could be thrown out from the collisions inside the LHC. While they would zip through the collider’s detectors unseen, they would carry energy and momentum with them. Scientists could then infer their creation by totting up the energy and momentum of all the particles produced in a collision, and looking for signs of the missing energy and momentum.

One theory, called supersymmetry, proposes that the universe is made from twice as many varieties of particles as we now understand. The lightest of these particles is a candidate for dark matter.

Wells says that ramping up the energy of the LHC should improve scientists’ chances of creating dark matter: “That would be a huge improvement on where we are today. We would go from knowing what 4 per cent of the universe is, to around 25 per cent.”

Teasing out the constituents of dark matter would be a major prize for particle physicists, and of huge practical value for astronomers and cosmologists who study galaxies.

“Although the big PR focus has been on the Higgs, in fact looking for new particles to provide clues to the big open questions is the main reason for having the LHC,” says Gerry Gilmore, professor of experimental philosophy at the Institute of Astronomy in Cambridge.

“Reality on the large scale is dark matter, with visible matter just froth on the substance. So we focus huge efforts on trying to find out if dark matter is a set of many elementary particles, and hope that some of those particles’ properties will also help to explain some other big questions. So far, astronomy has provided all the information on dark matter, and many of us are working hard to deduce more of its properties. Finding something at the LHC would be wonderful in helping us in understanding that. Of course one needs both the LHC and astronomy. The LHC may find the ingredients nature uses, but astronomy delivers the recipe nature made reality from.”

Another big mystery the Large Hadron Collider may help crack is why we are made of matter instead of antimatter. The big bang should have flung equal amounts of matter and antimatter into the early universe, but today almost all we see is made of matter. What happened at the dawn of time to give matter the upper hand?

The question is central to the work of scientists on the LHCb detector. Collisions inside LHCb produce vast numbers of particles called beauty quarks, and their antimatter counterparts, both of which were common in the aftermath of the big bang. Through studying their behaviour, scientists hope to understand why nature seems to prefer matter over antimatter.

Turning up the energy of the LHC may just give scientists an answer to the question of why gravity is so weak. The force that keeps our feet on the ground may not seem puny, but it certainly is. With just a little effort, we can jump in the air, and so overcome the gravitational pull of the whole six thousand billion billon tonnes of the planet. The other forces of nature are far stronger.

One explanation for gravity’s weakness is that we experience only a fraction of the force, with the rest acting through microscopic, curled up extra dimensions of space. “The gravitational field we see is only the bit in our three dimensions, but actually there are lots of gravitational fields in the fourth dimension, the fifth dimension, and however many more you fancy,” says Andy Parker, professor of high energy physics at Cambridge University. “It’s an elegant idea. The only price you have to pay is that you have to invent these extra dimensions to explain where the gravity has gone.”

The rules of quantum mechanics say that particles behave like waves, and as the LHC ramps up to higher energies the wavelengths of the particles it collides become ever shorter. When the wavelengths of the particles are small enough to match the size of the extra dimensions, they would suddenly feel gravity much more strongly.

“What you’d expect is that as you reach the right energy, you suddenly see inside the extra dimensions, and gravity becomes big and strong instead of feeble and weak,” says Parker. The sudden extra pull of gravity would cause particles to scatter far more inside the machine, giving scientists a clear signal that extra dimensions were real.

Extra dimensions may separate us from realms of space we are completely oblivious to. “There could be a whole universe full of galaxies and stars and civilisations and newspapers that we didn’t know about,” says Parker. “That would be a big deal.”

There may be a hundred billion planetary systems in the galaxy awaiting exploration. Not one of those worlds will be identical to Earth. A few will be hospitable; most will appear hostile. Many will be achingly beautiful. In some wolds there will be many suns in the daytime sky, many moons in the heavens at night, or great particle ring systems soaring from horizon to horizon. Some moons will be so close that their planet will loom high in the heavens, covering half the sky. And some worlds will look out into a vast gaseous nebula, all those skies, rich in distant and exotic constellations, there will be a faint yellow star — perhaps barely seen by the naked eye, perhaps visible only through the telescope — the home star of the fleet of interstellar transports exploring this tiny region of the Milky Way Galaxy.

The themes of space and time are, we have seen, intertwined. Worlds and stars, like people, are born, live and die. The lifetime of a human being measured in decades; the lifetime of the Sun is a hundred million times longer. Compared to a star, we are like mayflies, fleeting ephemeral creatures who live out their whole lives in the course of a single day. From the point of view of a mayfly, human beings are stolid, boring, almost entirely immovable, offering hardly a hint that they ever do anything. From the point of view of a star, a human being is a tiny flash, one of the billions of brief lives flickering tenuously on the surface of a strangely cold, anomalously solid, exotically remote sphere of silicate and iron.

In all these other worlds in space there are events in progress, occurrences that will determine their futures. And on our small planet, this moment in history is a historical branch point as profound as the confrontation of the Ionian scientists with the mystics 2,500 years ago. What we do with our world in this time will propagate down though the centuries and powerfully determine the destiny of our descendants and their fate, if any, among the stars.

Carl Sagan — Travels in Space and TimeCosmos (via ikenbot)

thenewenlightenmentage:

How Long is a Day on Mercury?

1/3 the distance from the Sun than Earth, it should be no surprise that a day on Mercury is a real scorcher with temperatures soaring over 400 ºC. But in addition to its solar proximity it also has an extremely slow rotation: a single day on Mercury is 58.6 Earth days long… and you thought your Mondays lasted forever!

To be even more precise, for every 2 Mercury years, 3 Mercury days pass — a 3:2 spin-orbit resonance, caused by the planet’s varying elliptical orbit. (This also makes for some interesting motions of the Sun in Mercury’s sky.)

To illustrate this, UK’s The Open University has published a new video in their 60 Second Adventures in Astronomy series… check it out above (and see more of their excellent and amusing animations here.)

Video: The Open University. Narrated by David Mitchell.

(via sagansense)

skeptv:

Most Powerful Quasar Discovered

Astronomers have found a quasar that’s more than five times more powerful than any previously seen. Quasars are mega-bright geysers of matter and energy powered by super-massive black holes at the centers of young galaxies.

Credit: SPACE.com / ESO

by Video From Space.