Clipmarks | Silkweaver's 'astronomy' clips

50 Billion Suns! -The Biggest Single Object in the Universe

Fri, 05 Sep 2008 01:17:51 GMT

clipped by: Silkweaver
clipper's remarks: Based on this self-regulating maximum rate, scientists at the Harvard-Smithsonian Center for Astrophysics, Massachusetts, and the European Southern Observatory, Chile, have calculated an upper limit for these mega-mammoth masses. Fifty billion suns, that's 100 000 000 000 000 000 000 000 000 000 000 000 000 000 kg, otherwise known as "ridiculously stupidly big" and triple the size of the largest observed black hole, OJ 287.

Clip Source: www.dailygalaxy.com

Scientists have determined the mass of the largest things that could possibly exist in our universe, and they don't appear in the Oprah studio audience.

New results have placed an upper limit on the current size of black holes - and at fifty billion suns it's pretty damn big. That's a hundred thousand tredagrams, and you'll never get the chance to use that word in relation to anything else.

While there's theoretically no upper limit on how big a black hole can be, there are hard limits on how big they could have become by now. The universe has only existed for a finite amount of time, and even the most voracious black hole can only suck in matter at a certain rate. The bigger the black hole, the bigger the gravitational field and the faster it can pull in matter - but that same huge gravitational gradient means that the same matter can release huge amounts of radiation as it falls, blasting other matter further away.

Tags: astronomy, cosmology

5 extremely cool research facilities

Wed, 27 Aug 2008 22:30:48 GMT

clipped by: Silkweaver
clipper's remarks: Some more interesting stuff at site. Especially a short video on measuring gravitational waves.

Clip Source: deputy-dog.com

1. large helical device, gifu, japan

the phenomenal photo above shows superconducting coils within the large helical device in japan, a machine which holds the title of ‘largest superconducting stellarator in the world’.

2. odeillo solar furnace, odeillo, france

this brilliantly shiny oddity is the 8-storey high odeillo solar furnace in france: at present the largest on the planet.

using this method, temperatures can reach an unbelievably hot 3400°C.

3. atf fire research laboratory, maryland, usa

measuring a whopping 60ft x 60ft, this is the largest calorimetry hood on earth and is an essential part of the atf fire research laboratory.

4. ligo observatories, louisiana & washington, usa

ligo’s hanford observatory, one of 2 main facilities used by ligo to detect ‘ripples’ or gravitational waves in space-time.

5. arecibo observatory, arecibo, puerto rico

arecibo observatory in puerto rico contains the largest curved focusing dish on earth and is used for 3 main research purposes: radio astronomy

Tags: science, technology, research

Does the Milky Way Influence Earth's Biodiversity Cycles? Research Says "Yes"

Wed, 13 Aug 2008 21:49:25 GMT

clipped by: Silkweaver
clipper's remarks: The boost in cosmic-ray exposure may have a direct effect on Earth's organisms, according to paleontologist Bruce Lieberman. The radiation would lead to higher rates of genetic mutations in organisms or interfere with their ability to repair DNA damage. In this way, the process could lead to new species while killing off others.

If future studies confirm the galaxy-biodiversity link, it would force scientists to broaden their ideas about what can influence life on Earth. "Maybe it's not just the climate and the tectonic events on Earth," Lieberman said. "Maybe we have to start thinking more about the extraterrestrial environment as well."

Clip Source: www.dailygalaxy.com

Horoscope enthusiasts will be happy to hear that a grand cosmic force does indeed seem to be responsible for controlling the direction of all life on Earth. However, this grand cosmic cycle has more to do with extinction than finding a tall, handsome stranger.

Research has revealed that the rise and fall of species on Earth seems to be driven by the undulating motions of our solar system as it travels through the Milky Way.

Some scientists believe that this cosmic force may offer the answer to some of the biggest questions in our Earth’s biological history—especially where evolution has fallen short.

Researchers at the University of California, Berkeley found that marine fossil records show that biodiversity increases and decreases based on a 62-million-year cycle.

Our own star moves toward and away from the Milky Way's center, and also up and down through the galactic plane. One complete up-and-down cycle takes 64 million years- suspiciously close to the Earth's biodiversity cycle.

Tags: astronomy, life cycles, evolution, biodiversity

Is our universe fine-tuned for life? The Anthropic Principle Under Scrutiny

Sun, 10 Aug 2008 22:21:43 GMT

clipped by: Silkweaver
clipper's remarks: Adams selected a range of possible values for each of these constants, then put them into a computer model that created a multitude of universes, or a virtual "multiverse". Each universe within the multiverse used different values for the three constants and was subject to slightly different laws of physics.

About a quarter of the resulting universes turned out to be populated by energy-generating stars. "You can change alpha or the gravitational constant by a factor of 100 and stars still form," Adams says, suggesting that stars can exist in universes in which at least some fundamental constants are wildly different than in our universe.

Clip Source: space.newscientist.com

DON'T take our starry skies for granted. If you were unlucky enough to be living in some other universe, you might have nothing to stare at but black holes.

At least, that's the view of a new study that examines the nature of other universes that might support life and suggests that our cosmic habitat is nothing special after all - wondrously starry skies apart.

The idea that certain aspects of our universe make it uniquely suited to life has never been properly tested, says Fred Adams

You hear people say our universe is fine-tuned for life, that stars are rare and couldn't form if certain things were different," he says. "The truth is, no one has done the calculations." Adams has now rectified that situation and found that it is not unusual for stars to form that can support life.

Adams reckons his results, which will be published in the Journal of Cosmology and Astroparticle Physics, suggest that the "specialness" of our universe could well be an illusion

Tags: astronomy, anthropic principle, multiverse

Massive Radio-telescope in China to Explore 'Dark Age' of Early Universe

Tue, 05 Aug 2008 18:23:18 GMT

clipped by: Silkweaver
clipper's remarks: The new study is part of a broader effort to understand the early years of the universe, after the big bang using computer simulations can help scientists understand events like the birth of the first stars in the universe. During much of the universe's first billion years, the awesome brilliance born of the big bang faded to black. This dark age represents the least-understood chapter in the history of the cosmos scientists have compiled.

Clip Source: www.dailygalaxy.com

Astronomers in the U.S. and China are also building an enormous radiotelescope array consisting of about 10,000 antennas in China's Xinjiang Province.

They plan to use it to map the first glowing "bubbles" that appear as radiation from galaxies begins to ionize the dense fog of hydrogen between them and light it up.

"The only way we're ever going to understand this is when the theoretical work that's progressing rapidly in this field meets up with the observations work, which is coming from the other direction" of the timeline,

"It's a big puzzle," she adds, and the new results, which appear in Friday's edition of the journal Science, represent a small but important piece.

Researchers reported they have glimpsed – using computer simulations – the birth of the first small, stable clumps of gas that would have served as seeds for the first generation of stars.

Within 10,000 years, the scientists say, these seeds would blossom into blazing orbs at least 100 times more massive than the sun.

Tags: astronomy, cosmology

Quiet Explosion: Object Intermediate Between Normal Supernovae And Gamma-ray Bursts Found

Fri, 25 Jul 2008 14:17:38 GMT

clipped by: Silkweaver
clipper's remarks: Stars that were at birth more massive than about 8 times the mass of our Sun end their relatively short life in a cosmic, cataclysmic firework lighting up the Universe. The outcome is the formation of the densest objects that exist, neutron stars and black holes. When exploding, some of the most massive stars emit a short cry of agony, in the form of a burst of very energetic light, X- or gamma-rays.

Clip Source: www.sciencedaily.com

A European-led team of astronomers are providing hints that a recent supernova may not be as normal as initially thought.

Instead, the star that exploded is now understood to have collapsed into a black hole, producing a weak jet, typical of much more violent events, the so-called gamma-ray bursts.

The object, SN 2008D, is thus probably among the weakest explosions that produce very fast moving jets. This discovery represents a crucial milestone in the understanding of the most violent phenomena observed in the Universe.

These striking results, partly based on observations with ESO's Very Large Telescope, will appear tomorrow in Science Express, the online version of Science.

What made this event very interesting," says Mazzali, "is that the X-ray signal was very weak and 'soft' [1], very different from a gamma-ray burst

The scenario we propose implies that gamma-ray burst-like inner engine activity exists in all supernovae that form a black hole

Tags: astronomy, astrophysics, black holes, supernova

Is a 'Dark Force' Pushing the Universe Apart?

Tue, 22 Jul 2008 02:33:28 GMT

clipped by: Silkweaver
clipper's remarks: Astronomers now recognize that the eventual fate of the universe is inextricably tied to the presence of dark energy and dark matter.The current standard model for cosmology describes a universe that is 70 percent dark energy, 25 percent dark matter, and only 5 percent normal matter.

Clip Source: www.dailygalaxy.com

"Reality is nothing but a collective hunch." Lily Tomlin -Comedian and philosopher.

No observation in recent history of science has been more disturbing than the discovery of dark energy in 1998.

Dark energy seems to differ from all forms of energy and matter previously known, in that its not associated with any particles or waves. It is just there.

What happened in 1998 was that observations of supernovas in distant galaxies indicated that the universe was accelerating in that could best be explained by the existence of a dark energy.

Recent measurements with telescopes and space probes of the distribution of mass in M31 -the largest galaxy in the neighborhood of the Milky Way

have shown that a mysterious force—a dark energy—fills the vacuum of empty space, accelerating the universe's expansion.

We don't know what dark energy is, or why it exists.

A new theory of particle physics is required to explain this physical process.

Tags: astronomy, cosmology, dark energy

The Pole star comes to life again

Tue, 22 Jul 2008 02:11:53 GMT

clipped by: Silkweaver
clipper's remarks: Shakespeare was not wrong after all. Perhaps also poetry has a say in Astrophysics.

Clip Source: www.physorg.com

The Northern Star, whose vibrations were thought to be dying away, appears to have come to life again.

An international team of astronomers has observed that vibrations in the Pole star, which had been fading away to almost nothing over the last hundred years, have recovered and are now increasing. And the astronomers don't know why.

The astronomers were watching Polaris in the expectation that they would catch the star switching off its vibrations completely when they made the surprising observation of its revival.

Although Shakespeare's Julius Caesar declared, "I am as constant as the Northern star, Of whose true-fix'd and resting quality There is no fellow in the firmament"

Polaris is a 'Cepheid' variable star, getting brighter and fainter every four days. Cepheids do play a vital part as 'standard candles' in determining the size of the Universe, but the details of their variations are not well understood.

Tags: astronomy, astrophysics

Hubble Unveils a Mystery 1.2 Billion Light Years Distant

Thu, 10 Jul 2008 21:08:13 GMT

clipped by: Silkweaver
clipper's remarks: Nothing is too far to study....

Clip Source: www.dailygalaxy.com

While observing stars in our own Milky Way galaxy with the Hubble Space in an ongoing study that has spanned several years, astronomers stumbled upon a distant elliptical galaxy 1.2 billion light years away packed with clusters of stars too dim for most telescopes to see.

Oddly, the light from some of these clusters are not young and blue as expected, but rather, older and redder

an observation Jason Kalirai of the University of California, Santa Cruz, and colleagues are wrestling to understand.

Hubble image revealed the large elliptical galaxy that contains several hundred globular clusters, which led to the new discovery and mystery of the apparently older, reddish stars

using the Gemini Multi-Object Spectrograph on the Gemini South Telescope

They were able to determine the distance of the elliptical galaxy

This showed that the globular clusters are the most distant ever studied

observations may also allow astronomers to test for evolution in the properties of globular clusters themselves

Tags: astronomy

Proposed NASA Mission Could Explore Twisted Space Around Black Holes

Wed, 02 Jul 2008 00:14:57 GMT

clipped by: Silkweaver

Clip Source: www.physorg.com

A new NASA mission could discover the shape of space that has been distorted by a spinning black hole's crushing gravity, and explore the structure and effects of the formidable magnetic field around magnetars, dead stars with magnetic fields trillions of times stronger than Earth's.

The proposed new mission, called Gravity and Extreme Magnetism (GEMS), will use a new technique to accomplish what has been impossible until now.

It will build up a picture indirectly by measuring the polarization of X-rays emitted from these violent regions.

GEMS could reveal:

How spinning black holes affect space-time and matter as it is drawn in and compressed by strong gravitational fields.

What happens in the super strong magnetic fields near pulsars and magnetars.

How cosmic rays are accelerated by shocks in supernova remnants.

Six proposals, including GEMS, were selected for detailed concept study

following which NASA will select two of them for development in the spring of 2009.

Tags: astronomy, black holes, nasa, space

Scientists Discover Planet's Natural Radio Emissions a Signal to Exo-Worlds

Mon, 30 Jun 2008 10:09:17 GMT

clipped by: Silkweaver

Clip Source: www.dailygalaxy.com

Chirps and whistles of our planet's auroral kilometric radiation (AKR) might be the first thing an extraterrestrial civilization is likely to hear from Earth.

In reality, they are the sounds that accompany the aurora.

The European Space Agency's Cluster mission is showing scientists how to understand this emission and, in the future, search for alien worlds by listening for their sounds.

AKR is generated high above the Earth, by the same shaft of solar particles that then causes an aurora to light the sky beneath.

By analyzing 12,000 separate bursts of AKR, a team of astronomers have determined that the AKR is beamed into space in a narrow plane

Not only will this new understanding of how the AKR is beamed into space help astronomers understand the magnetic environment of those gas worlds, it will also help them search for similar planets around other stars.

AKR was discovered by satellites in the early 1970s. It is blocked from reaching the ground by the ionosphere

Tags: geophysics, astronomy

The World's Biggest Camera to Survey 300 Million Galaxies

Thu, 26 Jun 2008 16:01:22 GMT

clipped by: Silkweaver
clipper's remarks: The team’s goals are to extract cosmological information on dark energy from counting galaxy clusters and the spatial distribution of clusters, and measuring the redshift of galaxies and supernovae.

Clip Source: www.dailygalaxy.com

The Dark Energy Survey (DES) camera will map 300 million galaxies using the Blanco 4-meter telescope - a large telescope with new advanced optics at Chile’s Cerro Tololo Inter-American Observatory.

This instrument will consist of an extremely red sensitive 500 Megapixel camera, with a 1 meter diameter, 2.2 degree field of view prime focus corrector, and a data acquisition system fast enough to take images in 17 seconds.

Creating this huge map of the galaxy will enable astronomers to measure the dark energy far more precisely than current observations.

"Dark Energy is one of the biggest puzzles in the whole of Physics, going back to a concept proposed by Einstein 90 years ago. The DES observations will tell us if Einstein was right or if we need a major shift in our understanding of the universe.”

Observations are scheduled to begin in 2011, continuing until 2016.

Tags: astronomy, cosmology, dark energy, physics

New Technologies Will Soon Lead to Discovery of Earth's Twin

Thu, 26 Jun 2008 15:55:49 GMT

clipped by: Silkweaver

Clip Source: www.dailygalaxy.com

"Detecting Earth in reflected light is like searching for a firefly six feet from a searchlight that is 2,400 miles distant," wrote a panel of astronomers recently, when describing the challenges facing the search for other planets in the universe.

But nevertheless, many astronomers involved in such a search are confident that we are very close to locating a twin Earth.

Since the first planets outside of our solar system were discovered in the early 1990’s, nearly 300 planets have been discovered. However, if you were hoping to relocate, think again; most of them are Jupiter or Saturn-like planets: big, hot, and navigating very close to their star.

Two methods are used to detect planets out of our own solar system, and both are very fine edged.

But as the years go by, our technology continues to advance; it is this fact that excites astronomers, bringing us closer and closer to finding a twin-Earth.

Tags: astronomy, habitable planets

Dark, Perhaps Forever - Clueless about the universe

Mon, 09 Jun 2008 21:40:42 GMT

clipped by: Silkweaver
clipper's remarks: Whatever proposal is eventually selected, the dark energy satellite will return a tidal wave of data about the universe and its weird denizens, both visible and invisible. This data is likely to transform astronomy in unpredictable ways, but there is no guarantee that it will nail the mystery of dark energy.

“We really need new theory, and we have none,” Dr. Krauss said.

Clip Source: www.nytimes.com

A decade ago, astronomers discovered that what is true for your car keys is not true for the galaxies. Having been impelled apart by the force of the Big Bang, the galaxies, in defiance of cosmic gravity, are picking up speed on a dash toward eternity. If they were keys, they would be shooting for the ceiling.

It is still shocking. Although cosmologists have adopted a cute name, dark energy, for whatever is driving this apparently antigravitational behavior on the part of the universe

nobody claims to understand why it is happening

“The discovery of dark energy has greatly changed how we think about the laws of nature,”

By weight it is 4 percent atoms and 22 percent so-called dark matter of unknown identity

That leaves 74 percent for the weight of whatever began causing the cosmos to accelerate about five billion years ago

Clip Source: www.nytimes.com

he said, maybe physicists should give up trying to explain that number and look instead for a theory that generates all kinds of universes, a so-called multiverse.

Tags: astronomy, cosmology, dark energy

A Test of the Copernican Principle

Sun, 25 May 2008 17:54:17 GMT

clipped by: Silkweaver
clipper's remarks: Disproving the Copernican Principle would amount to a a Copernican revolution on its own account Also, certain aspects of general relativity would need a profound review. Fortunately it seems Copernicus was right after all. Or was he?

Clip Source: www.physorg.com

The Copernican principle states that the Earth is not the center of the universe, and that, as observers, we don’t occupy a special place. First stated by Copernicus in the 16th century, today the idea is wholly accepted by scientists, and is an assumed concept in many astronomical theories.

However, as physicists Robert Caldwell of Dartmouth College in Hanover, New Hampshire, and Albert Stebbins of Fermilab in Batavia, Illinois, point out, the Copernican principle has never been confirmed as a whole.

In a recent paper published in Physical Review Letters called “A Test of the Copernican Principle,” the two researchers set out to prove the 500-year-old principle using observations of the cosmic microwave background (CMB).

Then, by analyzing data for the CMB spectrum, they were able to rule out nearly all of these non-Copernican Hubble bubble void universes – meaning the Copernican principle passed this first test.

Tags: astronomy, astrophysics