Tag Archives: Universe

Missing Link Between The Universe’s Most Powerful Explosions Found

Scientists have created a simulation that proves how some of the most powerful explosions in the universe, hypernovae, can be responsible for some of its brightest and most mysteriousevents, gamma ray bursts (GRBs). Incredibly, this is all based on just the first 10 milliseconds (10 millionths of a second) after a massive star collapses.

The research was carried out by scientists at the University of California, Berkeley, and is published in Nature. The process itself involves a rapidly rotating star collapsing. As this happens, it spins faster and faster with its attached magnetic field, producing a dynamo effect that is a million billion times stronger than Earths magnetic field.

A dynamo is a way of taking the small-scale magnetic structures inside a massive star and converting them into larger and larger magnetic structures needed to produce hypernovae and long gamma-ray bursts, said Philipp Msta, a UC Berkeley postdoctoral fellow and first author of the paper, in a statement. People had believed this process could work out. Now we actually show it.

Hypernovae are hypothesized to be extremely powerful supernovae stellar explosions but their cause is not fully understood. In a hypernova, the inner star that is about 930 miles (1,500 kilometers) across collapses into a neutron star about 10 miles (15 kilometers) across, known as a core-collapse supernova.

GRBs, meanwhile, are among the brightest events in the universe, hugely powerful emissions of gamma rays of unknown origin lasting up to 100 seconds, while hypernovae shine more than 10 times brighter than an average supernova.

Crucially, the simulation helps to explain a missing link in connecting hypernovae with GRBs. Scientists had been unsure how a star could amplify a magnetic field not wholly dissimilar to the Suns in terms of powerinto one a quadrillion times more powerful during these explosive events.

This supercomputer visualization shows how a stars rotation can rev up its magnetic field to a million billion times the power of our Suns. UC Berkeley Campus Life

The key appears to be a shear zone 10 to 20 miles (15 to35 kilometers) from the inner star where its different layers are rotating at different speeds, creating a large amount of turbulence that causes the dynamo effect and leads to the hugely amplified magnetic fields. These in turn produce two jets in opposite directions composed of extremely energetic gamma rays, namely gamma ray bursts.

In this simulation, 130,000 computer cores at the Blue Waters supercomputer at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign were used to model the brief fraction of a second after the core collapse, producing the intriguing results.

The breakthrough here is that Philipps team starts from a relatively weak magnetic field and shows it building up to be a very strong and large-scale coherent magnetic field of the kind that is usually assumed to be there when people make models of gamma-ray bursts, said Eliot Quataert, a UC Berkeley professor of astronomy who was not involved with the study, in the statement.

The simulation shows how the dynamo effect causes a feedback loop that can create huge magnetic fields when a massive star collapses, producing both cosmic phenomena. Future simulations from the same team will seek to model more than just 10 milliseconds of a hypernovas evolution to further understand the process taking place.

Read more: http://www.iflscience.com/space/missing-link-between-universes-most-powerful-explosions-found

Newly Discovered “Cosmic Wall” Is 1.3 BILLION Light-Years Across

If we could zoom out of the universe, we would see galaxies organized in clusters, and those clusters form superclusters that are distributed along dense filaments between under-dense voids. On the largest scales the universe looks the same everywhere, but looking closer to these filaments we can see peculiar and unique structures.

One of them is the newly discovered BOSS Great Wall. The system consists of 830 galaxies and has a mass of 280 million billion suns. It is about 5 billion light-years away from the Milky Way, and it is 1.3 billion light-years in diameter.

The BOSS Great Wall is not the first cosmic wall discovered. The largest structure in the nearby universe is the Sloan Great Wall, which has about half the mass of theBOSS Great Wall. Claims on these structures are quite contentious, though, as although they appear as a single structure in the sky, they are not bound together by gravity like clusters and superclusters.

“We found two walls of galaxies […]that are larger in volume and diameter than any previously known superclusters. Together they form the system of the BOSS Great Wall, which is more extended than any other known structure,” said the researchers in the paper, which will appear in Astronomy & Astrophysics.

According to our current model of the universe, structures shouldn’tbe larger than 1.2 billion light-years, but this is not the first time that scientists have claimed the existence of structures larger than what the model predicts.

The BOSS Great Wall was discovered by Heidi Lietzen of the Canary Islands Institute of Astrophysics and her team. They were observing a large chunk of the universe between 4.5 to 6.4 billion light-years from Earth.

It was so much bigger than anything else in this volume, Lietzen said to New Scientist.

While this mass grouping is definitely interesting, other scientists are questioning the discovery.

I dont entirely understand why they are connecting all of these features together to call them a single structure, says Allison Coil of the University of California, San Diego to New Scientist. There are clearly kinks and bends in this structure that dont exist, for example, in the Sloan Great Wall.

[H/T: New Scientist]

Read more: http://www.iflscience.com/space/has-new-cosmic-wall-been-found

Our Universe Is Expanding A Lot Faster Than We Thought

The universe is expanding at an accelerating rate. This is a problem: The continuation of this will result in universe-wide cooling, eventually becoming too cold to sustain life. Ultimately, with heat evenly distributed across the cosmos, time itself will come to an end. Scientists trying to work out this expansion rate are essentially calculating the time until the universe ends.

As a new study uploaded to the arXiv server reveals, the most up-to-date measurement of universal expansion appears to be 8 percent greater than expected. This could mean that our knowledge of dark energy, the as-of-yet undetected force that is ripping our universe apart, is less robust than we think.

I think that there is something in the standard cosmological model that we don’t understand, Adam Riess, an astrophysicist at Johns Hopkins University, co-discoverer of dark energy, and lead author on the new study, toldNature.

According to the study, the universe is expanding at a rate of 73 kilometers per second per megaparsec, not 67.3 as cosmological models of the universe have estimated (one megaparsec is equal to 3.26 million light-years). To directly measure this expansion rate, which is also known as the Hubble constant, they used distant objects known as standard candles to create the most robust measurement to date, they claim.

These are light sources like stars or supernovae of known absolute brightness, or luminosity. Their observed brightness will decrease as the universe expands, and by comparing this change to their luminosity, astronomers can work out by how much the universe has expanded over time.

That bright object in the bottom left is a Type 1a supernova, one of the objects used to work out the expansion rate of the universe. NASA/ESA

Despite the gravitational pull generated by ordinary matter, and the binding effect provided by dark matter, the universe has continued to expand at an accelerating rate since the Big Bang. Researchers assume this is down to the utterly mysterious dark energy, which makes up 68 percent of the universe.

Like dark matter, it hasnt been directly detected, but its effects can be clearly seen: By all measures, something is pushing at the fabric of spacetime, forcing everything to move away from everything else. This new, higher estimate for the Hubble constant demonstrates just how powerful dark energy’s repulsive force could be.

Astronomers are also keen to predict how the rate of universal expansion will change in the future. One way to do this is to look at how mass is distributed in the universe now, and compare this with how mass used to be distributed in the early universe. By using the European Space Agencys Planck observatory, researchers are able to see the universe as it was 380,000 years after the Big Bang; consequently, they are able to predict how it will evolve.

This data can also be used to estimate what the expansion rate is right now. Each and every time a prediction is made using Plancks data, it appears to slightly disagree with the Hubble constant. This latest paper, which uses two types of standard candles in 18 different galaxies, has now given the best estimate yet of the Hubble constant.

With an 8 percent greater expansion rate, the disagreement between Planck and the Hubble constant is now greater than ever, and the team isn’t sure why. Dark matters binding effect could be weaker than predicted, or perhaps dark energy has become stronger in recent eons.

All in all, though, this new data means that, rather sadly, the universe will end faster than we previously thought.

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Read more: http://www.iflscience.com/space/our-universe-expanding-8-percent-faster-we-prevously-thought

Travel 13 Billion Years Across the Entire Known Universe in HD

Travel-13-billion-years-across-the-entire-known-universe-in-hd-e4640b2999

Space never ceases to amaze. With advanced technology, we continue to discover more unknown territory, revealing the tininess of our world.

We’ve seen everything from the Hubble Telescope’s amazing view of the universe to a whole galaxy developing — is there anything we haven’t seen? Of course there is.

Though scientists have yet to invent commercial time travel, you can journey 13.7 billion years away (in HD!) on YouTube, thanks to user stormeindustries. It begins with the Himalayas and travels across the entire known universe, which you eventually see through the afterglow of the Big Bang.

If this video doesn’t make you feel small already, it also notes the amount of unknown territory that’s yet to be explored.

Unbelievable Facts About Our Universe

Exoplanet covered in burning ice

Gliese 436 b is a Neptune-sized exoplanet located about 33 light-years away in the constellation Leo. Astronomers believe that it embodies exotic states of water that causes its surface to be covered in burning ice. The pressure on the planet forces the ice to stay solid, but the extreme surface temperature of 570° F (300° C) superheats the water, causing it to come off as steam. 

Eau de Cosmos

Though it is impossible to smell space directly or through a spacesuit, astronauts report that upon returning from a spacewalk, their gear smells distinctively like seared steak, hot metal, and arc welding fumes. The source of this odor could be byproduct from dying stars, the traces of which can be found throughout the universe. 

Image credit: Jerry Attrick

 

Intergalactic kegger

About 10,000 light-years away in the constellation Aquila, there is a cloud of alcohol with a diameter 1,000 times larger than our solar system. The amount of ethyl alcohol present in the cloud could serve up to 400 septillion (400, followed by 24 additional zeros) drinks. 

Closest neighbor

The Andromeda galaxy is our closest galactic neighbor, roughly 2.5 million light-years away. Though it is 140,000 light-years across, it isn’t bright enough to be seen in the night sky by our eyes. If it were brighter, it would appear six times larger than the full moon. 

Composite image credit: Tom Buckley-Houston, original (sans Andromeda) credit: Stephen Rahn

Earth under pressure

Black holes are formed when some very large stars collapse and condense all of their mass into a very small area, known as the Schwarzschild radius. Earth’s Schwarzschild radius is just below nine mm (1/3 inch), and if it were to be compressed below that size, our planet would become a black hole. For a person to become a black hole, they would have to be compressed smaller than a proton.

Stellar nursery

Though the birth and death of stars don’t happen instantaneously, the process happens fairly frequently. By using observed star formation and supernova events within the Milky Way, astronomers have estimated that 275 million stars are born and die throughout the observable universe each day. This totals more than 100 billion over the course of a year.

Image credit: NASA, ESA, and the Hubble SM4 ERO Team

 

Galactic year

It takes 24 hours for Earth to rotate on its axis to make a day, and 365 days to orbit around the sun for a year. It takes around 230 million years for our solar system to complete a single orbit around the Milky Way. The last time it was in its current position, the earliest dinosaurs had just appeared, and flowering plants wouldn’t evolve for another 100 million years.

Macerated Milky Way

Our solar system may smell like hot metal and seared steak, but what about the middle of the Milky Way? According to recent research from the Max Plank Institute, it smells like raspberries and tastes like rum. They found that ethyl formate, a key chemical component for both raspberries and rum, can be readily found at the center of our galaxy. Can’t choose between raspberries or rum? Why not just soak the berries in the rum and call it a party?

Image credit: Pukey Cow

Time flies

If you have ever wished there were more hours in the day, just be patient. Every century, Earth’s rotation slows down by about 1.4 milliseconds. When the dinosaurs were around, a day lasted about 23 hours. NASA reports that Earth’s rotation was exactly 24 hours in 1820, but is now off by 2.5 milliseconds.

Habitable zones

There are anywhere between 200-400 billion stars in the Milky Way and an estimated 100 billion planets. Around one in five stars are like our sun, and astronomers have estimated that about 22% of them have planets the size of Earth in their habitable zone, where water can exist as a liquid. This means there could be 8.8 billion planets within the galaxy capable of supporting life (not accounting for composition of the planet or its atmosphere).

Image credit: NASA Ames/SETI Institute/JPL-Caltech

White noise

When analog television sets aren’t tuned to a channel correctly, it results in static and white noise. Around 1% of that is radiation left over from the Big Bang, better known as the Cosmic Microwave Background (CMB). This interference between overlapping signals actually allowed Arno Penzias and Robert Wilson to discover the CMB in 1965.

Quasar query

Quasars occur when gas swirls around a black hole very quickly, and friction causes it to heat up, emitting light. Astronomers have a discovered a group of 73 quasars that are over 6.5 times larger than the average quasar group. This structure is over four billion light-years wide, and actually cannot be explained by the Theory of General Relativity. Theoretically, it shouldn’t even exist.

Image credit: ESO/M. Kornmesser

Spin cycle

Pulsars are magnetized neutron stars that spin incredibly fast and blast out a beam of radiation, kind of like a lighthouse beacon. The fastest known pulsar is PSR J1748-2446ad, located around 18,000 light-years away in the constellation Sagittarius. Though it is of average size for a neutron star, it spins an astonishing 716 times per second. This is nearly a quarter of the speed of light, and exceeds what theories say is possible.

Read more: http://www.iflscience.com/space/space-oddities-unbelievable-facts-about-our-universe

North America To Scale On Various Planets In Our Solar System

We’ve all seen images comparing the size of Earth with that of other planets in the solar system. The problem, John Brady of Astronomy Central realized, is that these images assume a grasp of Earth’s scale. So Brady decided to do something different and compare astronomical objects with pieces of the planet his readers may be familiar with

Suddenly, with the huge continent of North America dwarfed by Jupiter’s storms, the universe seems an even larger place. In the other direction, Mars looks so much more human-scaled.

John Brady/Astronomy Central. How the U.S. and Canada would measure up to Mars.

Brady has also reversed the process, showing what the solar system’s largest mountain, Olympus Mons, would look like if it replaced the Grand Canyon as Arizona’s prime tourist attraction. At 26 kilometers (85,000 ft) high, it would truly be a wonder, since the Earth’s greater gravity restricts mountains to a third of that size or less.

John Brady/Astronomy Central. If located appropriately, Olympus Mons would cover the whole state of Arizona.

Not everything makes us feel small. If you live in Liverpool, UK, you might be tempted to go for a bike ride around the area that Brady shows would be encompassed by a neutron star, or make an equivalent image for your own home with the help of satellite photos.

John Brady/Astronomy CentralNeturon stars really are the size of a city.
Brady told the Huffington Post, “I got the ‘North America on Jupiter’ image to scale by looking at size comparisons on NASA images of Earth compared to Jupiter’s Great Red Spot. The Mars image with North America placed over it was done by knowing the diameter of the red planet, then finding the distance between two U.S. cities. I used New York and San Francisco.” 

Read more: http://www.iflscience.com/space/universe-north-american-scale

Hubble Captures Image Of Galactic Merger

Oh dear, a relatively close neighbor of ours—the spiral galaxy NGC 7714—has drifted too close to another nearby galaxy, and now its spindly arms are all twisted out of shape and long streams of its stellar material have been dragged out into space. The Hubble Space Telescope captured the dramatic interaction of this merging pair, which astronomers are calling Arp 284

NGC 7714 is 100 million light-years from Earth, and it’s a typical Wolf-Rayet starburst galaxy. That means the extremely hot and bright stars within the galaxy began their lives with dozens of times the mass of our sun—but they quickly lose most of it due to strong winds.

Based on these newly released Hubble images, NGC 7714 has witnessed some violent events in its recent past. According to a European Space Agency (ESA) release, the tell-tale signs of brutality can be seen in NGC 7714’s misshaped arms and the smoky, golden haze stretching out from the center of the galaxy. Sometime between 100 and 200 million years ago, NGC 7714 drifted too close to a smaller companion galaxy named NGC 7715, and the two began disfiguring each other’s structure and shape. 

The ongoing merger has created a ring and two long tails of stars emerging from NGC 7714. These make up a bridge between the two galaxies, acting as a pipeline to funnel material from NGC 7715 towards its much larger companion and triggering bright bursts of star formation. Most of the bustle of star-forming activity is happening at the galactic center, but new stars are also being sparked throughout the whole galaxy. 

The smaller companion NGC 7715 lies just outside the frame of the composite image above (it would be off the top of the image), but you can see both of the galaxies below in this wider-field image from the Digitized Sky Survey. (The bright star on the left is around a billion times closer than the galaxy.)

Images: ESA, NASA with acknowledgement to A. Gal-Yam/Weizmann Institute of Science (top), NASA, ESA, Digitized Sky Survey 2 (bottom)

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Read more: http://www.iflscience.com/space/hubble-image-galactic-merger-reveals-recent-history-violence

Cosmography Reveals 3D Map of the Local Universe

Sun-setting-over-south-america

The three-dimensional structure of the local universe may one day become as familiar as our local geography, thanks to a new generation of maps that reveal our neighborhood’s rich complexity and our place within it.


Image courtesy of Courteois et al.

The geography of our world is one of the great cultural constants. There is hardly a person on this planet who is unfamiliar with the shape of the continents and the way they dovetail together, or who doesn’t know that Earth is a pale blue sphere orbiting the Sun with seven other planets.

When given a three-dimensional model of the solar system, almost everyone can zoom in from beyond the Oort cloud to Earth and then even further — to the street where they live, for example. It is powerful shared knowledge.

But at greater distances, our geographical knowledge becomes a little blurred. Many people will have seen the extraordinary three-dimensional models of the filamentary structures that galaxies form on the larger scales in our universe.

And yet these structures remain strangely unfamiliar. Given an unlabeled three-dimensional model of this large-scale structure of the universe, who could point to the place we call home?

All that should begin to change in the next few years with the increasingly accurate maps that cosmologists are compiling of the three-dimensional distribution of galaxies within universe.

Today, Helene Courtois at the University of Lyon in France and her research team show off this newfound knowledge in a movie (and accompanying paper) that they’ve created to explore the rich structure of our galactic neighborhood.

You can view the movie here.

One of the key questions that this data can help answer is whether the distribution of visible mass in the universe is an accurate reflection of the distribution of dark matter. Courtois and co so that the data shows that this is indeed the case.

The film does a fine job of showing the three-dimensional structure of this space. It also reveals the limitations of human language in describing this complex tapestry. That’s not so surprising given that our vocabulary has evolved to describe a geography that is essentially two-dimensional.

Just how to describe our position within the three-dimensional filamentary structure of the universe is a challenge that astronomers will have to wrestle with in the coming years.

And since this presents a rather different challenge than ordinary geography, researchers have coined a new term to describe this kind of intergalactic mapping — cosmography.

We can expect to see more of these kinds of 3D maps of the universe as the data becomes better and more easily accessible — and as cosmography grows into a science in its own right. Perhaps one day these depictions will appear as familiar to us as the shapes of continents on this pale blue dot.

Image courtesy of William L. Stefanov, NASA-JSC.

This article originally published at MIT Technology Review
here

Read more: http://mashable.com/2013/06/05/cosmography-3d-map-universe/

Primary Mirror Of NASA’s James Webb Space Telescope Finally Completed

It is several years behind schedule and billions of dollars over budget, but there is finally light at the end of the tunnel for NASAs James Webb Space Telescope (JWST). The primary mirror of the giant space telescope is now complete a significant step towards launching in 2018.

On Wednesday, February 3, the 18th and final hexagonal segment of the primary mirror was installed at NASAs Goddard Space Flight Center in Greenbelt, Maryland. Each of the segments weighs a hefty 40 kilograms (88 pounds) and measures 1.3 meters (4.2 feet) across. Together, the whole primary mirror measures 6.5 meters (21.3 feet) in diameter, about three times larger than Hubble’s, making this the most powerful space telescope ever built.

“Completing the assembly of the primary mirror is a very significant milestone and the culmination of over a decade of design, manufacturing, testing and now assembly of the primary mirror system,” said Lee Feinberg, optical telescope element manager at Goddard, in a statement. “There is a huge team across the country who contributed to this achievement.”

The mirrors took months to install, as they are incredibly sensitive. Coated in gold, they will focus the light from the distant universe onto a secondary mirror and then the on-board instruments. With the mirror complete, assembly of the rest of the telescope can begin. The mirror itself will sit on top of a vast sun shade, the size of a tennis court, while a complex instrumentation package will probe its views of the deep universe.

The telescope will be positioned beyond the orbit of the Moon. NASA

JWST is often billed as the successor to the Hubble Space Telescope, although the two are quite different. The latter is located in Earth orbit and observes the universe in visible wavelengths; JWST will be located 1.5 million kilometers (1 million miles) from Earth, beyond the orbit of the Moon, and will observe in the infrared. This will allow it to peer further back in the universe than Hubble can.

Among the science possible with the mission, JWST will study planets in solar systems beyond our own, and may even be able to characterize the atmospheres of some planetswithin 100 light-years. It will also attempt to look for the galaxies and stars that first arose after the Big Bang.

At the moment, the $9 billion (6.2 billion) JWST is scheduled to launch in 2018 from French Guiana on an Ariane 5 rocket. Given that it was originally planned to cost $1.6 billion (1.1 billion) and launch in 2011, organizers will be hoping for no more setbacks in this ambitious mission.

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Read more: http://www.iflscience.com/space/primary-mirror-nasas-james-webb-space-telescope-finally-completed