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What If Our Universe Collides With Another?

August 24, 2011 Leave a comment

“In current mainstream models, where dark energy and inflation are strapped on like a sort of prosthetic, there is just one Universe, and being alone, it can’t collide with anything. But in models derived from string theory, dark energy and inflation turn up naturally, which is nice. The catch is that, in these models, our Universe might not be alone.

We don’t know how many bubbles of inflationary universes might have seeded in some sort of over-arching background called a “false vacuum.” This is a part of a larger string theory problem: it is so generic that the number of universes and the values of fundamental constants in those universes are largely unconstrained. One way to narrow the field is to look for evidence of these other bubbles. This is exactly what a group of researchers has done.

WAAAAAIT, I hear you cry. Surely, by definition, we cannot see other universes. You would be correct. But in a Multiverse that is crammed with bubble universes, they may sometimes collide. When they do so, they will stretch space-time at the location of the collisions.”

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Graphene Occurs Naturally In Space?

August 18, 2011 Leave a comment

An artist's concept of graphene, buckyballs and C70 superimposed on an image of the Helix planetary nebula (Image: IAC/NASA/NOAO/ESA/STScI/NRAO)

 

“Human beings may have only discovered how to create the one-atom-thick sheets of carbon atoms known as graphene in 2004, but it appears the universe could have been churning out the stuff since much earlier than that.

While not conclusive proof its existence in space, NASA’s Spitzer Space Telescope has identified the signature of graphene in two small galaxies outside our own.

If confirmed, it would be the first-ever cosmic detection of the material and could hold clues to how carbon-based life forms such as ourselves developed.

The infrared-sensing Spitzer telescope identified signs of graphene in planetary nebulae – the material shed by dying stars – within the Magellanic Clouds galaxies that orbit our Milky Way galaxy.”

Do Neutrons Become Cube-Shaped Inside Super-Dense Stars?

August 16, 2011 Leave a comment

“Deep inside the super-dense hearts of exploding stars, gravity may squash neutron particles from spheres into cubes.

The idea could mean that neutron stars, as researchers call the stellar corpses, are denser than anyone expected. It could also question what stops them from collapsing into black holes and out of existence….

Late last year, astronomers discovered the biggest-ever neutron star, called J1614-2230, that weighed in at 1.97 times the sun’s mass. Prior to its discovery, the most massive neutron weighed 1.67 solar masses.

The find left more than a few astrophysicists scratching their heads. Its existence ruled out some models of neutron stars that relied on exotic forms of matter to explain why they didn’t collapse farther, and instead supported models of neutron stars as containing only neutrons and protons…

Gravity shapes aggregate particles of matter into the simplest, most efficiently-packed object possible, normally a sphere like the Earth. The particles themselves, though, remain individually unaffected; gravity is too weak to overcome the strong interactions that hold neutrons and other particles together. But if gravity becomes intense enough, it might overpower the interactions.

So deep within a neutron star, a neutron’s most efficient shape may be a cube. “They’ll be flattened on all sides, like dice,” Llanes-Estrada said.”

So, What Is Dark Matter?

August 16, 2011 Leave a comment

“Dark matter has been a polarizing subject. It hasn’t been detected, the name implied it was a mystery, and it started out as an explanation for the apparent extra but invisible mass in galaxies.

But the evidence that something unknown is out there has become rather encompassing, appearing in the cosmic microwave background, galaxy clusters, and even apparently empty space. Even if dark matter doesn’t exist, something will have to fill a whole bunch of gaps at many different scales of the Universe.

Nevertheless, it is a placeholder concept, a hole in our knowledge that we can feel the shape of but haven’t yet managed to capture in the spotlight.

So, what is dark matter?

One possible answer is a modified theory of gravity, but the favorite proposal at the moment is a class of particles called weakly interacting massive particles (WIMPs). The distinguishing feature of WIMPs is that they are not dark at all—instead, they interact so rarely with normal matter that our current instrumentation is blind to their effects.

The fact that these particles interact at all is probably one of the main reasons that physicists prefer the WIMP explanation: if WIMPs exist, we could build an instrument to see them.

And build them we have. Two teams have now claimed to have detected dark matter particles. But last month the XENON100 team published its own data, claiming that the earlier results are bunk and dark matter cannot possibly have been detected.”

Non-Terrestrial DNA Trace Found on Meteorites?

August 9, 2011 Leave a comment

“Past research had revealed a range of building blocks of life in meteorites, such as the amino acids that make up proteins. Space rocks just like these may have been a vital source of the organic compounds that gave rise to life on Earth.

Investigators have also found nucleobases, key ingredients of DNA, in meteorites before. However, it has been very difficult to prove that these molecules are not contamination from sources on Earth. [5 Bold Claims of Alien Life]

“People have been finding nucleobases in meteorites for about 50 years now, and have been trying to figure out if they are of biological origin or not,” study co-author Jim Cleaves, a chemist at the Carnegie Institution of Washington, told SPACE.com.

To help confirm if any nucleobases seen in meteorites were of extraterrestrial origin, scientists used the latest scientific analysis techniques on samples from a dozen meteorites — 11 organic-rich meteorites called carbonaceous chondrites and one ureilite, a very rare type of meteorite with a different chemical composition. This was the first time all but two of these meteorites had been analyzed for nucleobases.

The analytical techniques probed the mass and other features of the molecules to identify the presence of extraterrestrial nucleobases and see that they apparently did not come from the surrounding area.

Two of the carbonaceous chondrites contained a diverse array of nucleobases and structurally similar compounds known as nucleobase analogs.

Intriguingly, three of these nucleobase analogs are very rare in Earth biology, and were not found in soil and ice samples from the areas near where the meteorites were collected at the parts-per-billion limits of their detection techniques.”

Star Torn Apart by a Black Hole!

April 9, 2011 Leave a comment

“On March 28, 2011, NASA’s Swift satellite caught a flash of high-energy X-rays pouring in from deep space. Swift is designed to do this, and since its launch in 2004 has seen hundreds of such things, usually caused by stars exploding at the ends of their lives.

But this time was hardly “usual”. It didn’t see a star exploding as a supernova, it saw a star literally getting torn apart as it fell too close to a black hole!

The event was labeled GRB 110328A –a gamma-ray burst seen in 2011, third month (March) on the 28th day (in other words, last week). Normal gamma-ray bursts are when supermassive stars collapse (or ultra-dense neutron stars merge) to form a black hole. This releases a titanic amount of energy, which can be seen clear across the Universe.

And those last two characteristics are certainly true of GRB 110328A; it’s nearly four billion light years away*, and the ferocity of its final moments is not to be underestimated: it peaked at a solid one trillion times the Sun’s brightness!”

 

Antikythera: The Ancient Greek Computer

April 2, 2011 Leave a comment

“The world’s oldest astronomical calculator is famous for having intricate gear systems centuries ahead of their time. But new work shows the Antikythera mechanism used pure geometry, as well as flashy gears to track celestial bodies’ motion through the heavens.

The device, a 2,000-year-old assemblage of gears and wheels that matched 19th century clocks in precision and complexity, was salvaged from a shipwreck off the Greek island of Antikythera in 1901.

Called the Antikythera mechanism, the machine gracefully kept track of the day of the year, the positions of the sun and the moon, and perhaps the other planets. It also predicted eclipses and kept track of upcoming Olympic games.

Most of the mechanism’s calculations were driven by a series of 37 interlocking dials, which may have been manipulated by a hand crank. The front of the mechanism had a clock-like face that denoted the calendar date in two concentric circles, one showing the signs of the Greek zodiac, and one carrying the Egyptian months of the year. ”