Our Position in the Universe

Here is Turok's cyclical theory, a Recycled Universe:

A Recycled Universe

Crashing branes and cosmic acceleration may power an infinite cycle in which our universe is but a phase
Feb 11, 2002 |By George Musser and JR Minkel
|


J. W. Stewart Advertisement

Images: after animation by Paul Steinhardt

A UNIVERSAL CYCLE of birth and rebirth occurs every trillion years or so, according to one new cosmology. Big bangs result when two 10-dimensional "branes" collide (1) and expand (2) and then collide again (4). In this scenario, our universe (3) marks just one phase in this infinite cycle.

Some questions are disquieting because they can be answered in only one of two equally mind-boggling ways. For instance, are we the sole intelligent beings in the universe, or will we find others? Another discomforting doozy is this: did the universe begin at some remote time in the past, or was it always here?

The big bang clearly marks some kind of first. That fearsome flash of energy and expansion of space set in motion everything our eyes and telescopes can see today. But on its own, the big bang theory would leave us in a curved universe where matter and energy aren't well mixed. In fact, we now know that spacetime is flat and that galaxies and radiation are evenly distributed throughout. To shore up the big bang theory, cosmologists proposed that the universe began with a burst of exponential expansion from a single uniform patch of space, whose stamp remains on the cosmos to this day. Such inflationary cosmologies have worked so well they've crowded out all the competition.

During this past year, however, one group of researchers has started to challenge that idea's preeminence, though the field of cosmology has yet to be completely taken with the new approach. Drawing on some cutting-edge but unproved notions in particle physics, the challengers interpret the big bang as a violent clash between higher-dimensional objects. In the latest installment to the saga, the authors of this interpretation have found a way to turn that single clash into a never-ending struggle that rears its fiery head every trillion years or so, making our universe just one phase in an infinite cycle of birth and rebirth.
Such cyclic ideas are not new. In the 1930s, the late Richard Tolman of the California Institute of Technology wondered what would happen if a closed universe¿in which all matter and energy are ultimately compacted in a big crunch¿were to survive its closure and burst forth again. Unfortunately, as Tolman realized, the universe would gather entropy during each new cycle; to compensate, it would have to grow every time like a runaway snowball. And just as a snowball has to begin at some point in time, so, too, would such a universe.

Then in the 1960s, physicists proved that a big crunch, too, must culminate in a singularity¿a point stuffed with infinite matter and heat¿where general relativity breaks down. The laws of physics are thus up for grabs. "The idea of a cyclic universe has been around for a long time," says Andreas Albrecht of the University of California at Davis, a co-inventor of inflation, "and it has always been plagued by a fundamental problem: what physics causes the collapsing universe to bounce back into the expanding phase?"

String-ularity

FIRST STRING. String theory has spawned more than one attempt to do away with the big bang singularity.

One potential way of getting around that problem is by supposing that elementary particles such as electrons, photons and quarks are really just manifestations of tiny strings of energy jiggling in higher dimensions. The thing is, such a string theory requires the universe to have at least 10 dimensions, as opposed to the usual three in space and one in time that we perceive. "In string theory you learn one thing¿you are in higher dimensions," says string theorist Burt Ovrut of the University of Pennsylvania. "Then the question is, where does our real world come from? That's a damn good question."

Paving the way for an answer in 1995 were Petr Horava, then at Princeton University, and Ed Witten of Princeton's Institute for Advanced Studies, who showed that strings could also exist in a more fundamental, 11-dimensional theory. They collapsed one of these dimensions mathematically into a minuscule line, yielding an 11-dimensional spacetime, flanked on either side by two 10-dimensional membranes, or branes, colorfully dubbed "end of the world" branes. One brane would have physical laws like our own universe. From there, Ovrut and colleagues reasoned that six of those 10 dimensions could be made extremely small, effectively hiding them from everyday view and leaving the traditional four dimensions of space and time.

Early in 2001, cosmologists Justin Khoury and Paul Steinhardt of Princeton, another inflationary pioneer, Neil Turok of the University of Cambridge, and Ovrut put their branes to work on the big bang. By turning back the clock in string theory, they found that as our universal brane passed through its starting singularity in reverse, it went suddenly from a state of intense but finite heat and density to one that was cold, flat and mostly empty. In the process, it shed another kind of brane into the 11-dimensional gap. Run forward in time, the big bang appeared as nothing more than two branes smacking into each other like cymbals. They christened this process the ekpyrotic model, after the ancient Greek "conflagration" cosmology wherein the universe is born in and evolves from a fiery explosion.

Without a better understanding of the singularity in string theory, however, the group could not study what would happen as our brane expands after the collision; the model only provided for a contracting universe. Then later last year, the group discovered in collaboration with Nathan Seiberg of the Institute for Advanced Study that the singularity could be interpreted as a collision between the two "end of the world" branes, in which only the gap dimension separating them shrinks down to zero for an instant. "So what looks sort of disastrously singular, when you describe it as a brane collision, is not very singular at all," Turok explains. This scenario remains a conjecture, Seiberg notes, but is mathematically identical to the description of the big bang singularity in general relativity.
The ekpyrotic model had seemed a little contrived up to this point, notes Alan Guth of the Massachusetts Institute of Technology, another author of inflation. The pre-bang universe had to be dark, flat and infinite, seemingly by fiat. But why should it have begun in such a state? The answer, according to the latest work from Steinhardt and Turok, has to do with dark energy, the force that is driving the galaxies apart at ever-increasing speeds.

Drained Branes

MODERN COSMOLOGY is a relatively new invention.

As the universe accelerates, it will become harder for light to travel between distant corners of space. Over time, galaxies will become isolated from their neighbors; stars will wink out; black holes will evaporate quantum mechanically into radiation; even that radiation will be diluted in a sea of space. The universe could end up much as the ekpyrotic model suggests it should appear before the big bang.

Steinhardt and Turok accordingly have proposed that the dark energy,
combined with the milder singularity of the ekpyrotic model, provides a tidy way of setting up a cyclic universe. Our brane and its counterpart would bounce off each other as usual, but instead of going their separate ways, they would smack each other again and again as if connected by a spring. This attractive force between branes would in fact be a special case of the kind of force that inflationary cosmologies posit to explain the early universe's blowup.

The branes' oscillating motion would work to pump space into our universe like a bellows, explaining the acceleration that we see today. So "when you ask why is the universe the way it is," Turok explains, "well, it's because it has to be that way in order to repeat the next time around." And because each brane is already infinitely large and flat, there would be no first cycle to worry about.

The model is intriguing in drawing the ultimate link between early inflation and the current acceleration of the universe, Albrecht remarks, but "the case would be a lot more compelling if they were able to really show that a cyclic universe is possible." Guth is also unmoved. He explains that although he awaits the day when cosmology merges with string theory, he expects inflation to be that cosmology. In general, not all physicists are convinced that colliding branes can generate the small fluctuations in matter and energy density that inflation neatly resolves. Such minute variations in these quantities are required to explain the way in which stars and galaxies clump together and the detailed properties of the cosmic microwave background radiation.

In the ekpyrotic model, the necessary fluctuations are supposed to arise as the branes ripple quantum mechanically, so that different areas would strike one another and take off expanding first. The ekpyrotic camp is convinced these ripples can generate the exact variations we see today. "I think it's surprising how well this model works in terms of reproducing everything we see and yet being so different," Steinhardt remarks. "That's quite shocking and, I think, important, because we thought we were converging toward something that was a unique cosmic story."
But the singularity remains as another hurdle. Despite the recent advance, no one is certain whether features such as brane ripples could actually pass unmolested from big crunch to bang. "What happens at the singularity?" Seiberg ponders. "This is a big open question." So although the singularity in string theory may be, as Turok says, the "mildest possible" one, it is still a wild card.

The dealing isn't done, however, making it too soon to say if colliding branes will hold or fold. Perhaps it will attract new players with even more imaginative ideas. "I happen to think the cyclic model is a real intriguing one," Steinhardt says. "It has a lot of new ingredients that people haven't had a chance to play with. When they play they might find other interesting things that we missed." Or not.

 

Water Vapor Seen on Distant World

Search for potentially life-sustaining worlds gets a boost with the ability to probe a common class of planets.

By Michael D. Lemonick
for National Geographic


Astronomers have found evidence of water vapor in the atmosphere of a Neptune-size planet 122 light-years from Earth—the first time water has been identified on a planet that small, despite several attempts.


The discovery offers new hope in the search for planets that could sustain life, astronomers report Wednesday in the journal Nature.
"It's a fantastic observation," says Knicole Colon, an astronomer at Lehigh University in Bethlehem, Pennsylvania, and a National Geographic Young Explorer, who was not involved in the research. "It opens up a whole new regime in our attempt to understand how exoplanets form and what they're made of."


The detection of water will prove crucial in the search for life in the universe, since water is considered one of the essential ingredients for life as we know it. It's highly unlikely that this world, known as HAT-P-11b, could support life. Located about 122 light-years away in the constellation Cygnus, the planet is about five times as big as Earth and probably has a deep gaseous atmosphere like Neptune. (See "The Hunt for Life Beyond Earth.")


Beyond that, HAT-P-11b orbits its parent star at a distance of less than five million miles (eight million kilometers), compared with Earth's 93-million-mile distance (150 million kilometers) from the sun. Its "year" is less than five days long, and its surface temperature is above 1,100°F (600°C).


Nevertheless, says Colon, detecting water even on this hellish world is important. "Eventually," she says, "we'll be able to study smaller, Earthlike planets, but if we can pin down the properties of larger planets and perfect our observing techniques, we'll be ready."

Peering Through the Clouds
The discovery provides a much-needed sigh of relief for astronomers. "For the past two or three years, we've felt a growing concern that our efforts to study the composition of exoplanet atmospheres might be stymied," says MIT astronomer Zachory Berta-Thompson, who was not involved in the new research.


Astronomers already had a way to look for water vapor on exoplanets: They watch as a planet moves in front of its star, then carefully monitor the starlight that streams through the planet's atmosphere. In principle, atoms and molecules, including H2O, should alter the starlight, imprinting a telltale signature that can be read by powerful telescopes.


This has been done successfully for larger, Jupiter-size exoplanets. But until now, said Jonathan Fraine of the University of Maryland, College Park, lead author of the Nature report, "the light has always been blocked by haze or clouds when we tried to look at smaller planets." That's especially frustrating because planets are more numerous in smaller sizes, and because planets closer in size to Earth are considered more likely to be habitable—and maybe even inhabited.


Using the Hubble and Spitzer Space Telescopes in tandem, the new study finally did manage to pick up water's signature in the starlight passing through HAT-P-11b's atmosphere, simply because the planet has clear skies. If other exoplanets this size have similarly clear skies, there's no reason astronomers couldn't detect water or other molecules there as well.



In theory, says Fraine, it should also work for even smaller planets.
One reason this planet may have clear skies while others of similar size are thickly clouded over, says Fraine, might have to do with temperature. Hot as it is, HAT-P-11b is cooler than the similar-size exoplanets whose atmospheres have been probed before. "Maybe it's like Earth and Venus, which have a similar chemical composition and size, but one ended up with an incredibly cloudy carbon-dioxide-rich atmosphere and the other relatively clear and nitrogen-rich," he says.


That could be the explanation, or it could be something else—but whatever it ultimately turns out to be, says Laura Kreidberg of the University of Chicago, "it speaks to the extraordinary diversity of exoplanets."
Astronomers will have many more planets to explore, with results still rolling in from NASA's Kepler planet-hunting mission and another huge haul that could come from the planned Transiting Exoplanet Survey Satellite (TESS) mission.

 

Geek / By Robin Burks / September 25, 2:35 PM
Physics professor says black holes are mathematically impossible




Black holes don't exist, at least according to mathematical calculations done by a physics professor, Laura Mersini-Houghton, at the University of North Carolina at Chapel Hill.

Black holes have long been one of the greatest mysteries of the Universe, so, obviously, Mersini-Houghton's statement that they don't exist has caused much controversy. However, the concept of black holes is more complicated when looked at from a math and physics point of view. Most of us think of black holes as stars that collapse in massive explosions, which causes them to become smaller and denser. Mersini-Houghton isn't questioning the existence of that. What she is questioning, however, are what properties black holes are attributed with, such as a singularity within the star's explosion that creates the event horizon. An event horizon is a point so strong that nothing can escape the pull of the black hole, once something goes into a black hole, it disappears.

The two leading theories about the Universe contradict this, though. Albert Einstein's theory of gravity predicts that black holes can form, but his law of quantum theory says that nothing from the Universe can ever disappear.
So how can both theories be correct? The only way to combine the two is by stating that some properties that we associate with black holes don't exist, meaning that black holes, as scientists know them, are impossible.
"I'm still not over the shock," says Mersini-Houghton. "We've been studying this problem for a more than 50 years and this solution gives us a lot to think about."

Stephen Hawking once used quantum mechanics for explaining how black holes throw off radiation when a star collapses. Since then, we've detected radiation across the Universe, using that for discovering black holes. Mersini-Houghton believes that radiation is still emitted, but suggests that when a star explodes like that, it quickly loses too much mass to have the density to become a black hole, as we know it. This means that there is no singularity creating an event horizon. So, according to Mersini-Houghton, if black holes exist, they're not really black holes in scientific terms.

However, if Mersini-Houghton is right, this changes what we know about the Big Bang that created the Universe, too, which scientists believe started with a singularity. If a singularity is impossible, many Big Bang theories could be debunked. "Physicists have been trying to merge these two theories— Einstein's theory of gravity and quantum mechanics— for decades, but this scenario brings these two theories together, into harmony," says Mersini-Houghton. "And that's a big deal."

Mersini-Houghton's work has not yet been reviewed by her peers, so only time will tell if she's right.

 

If the Universe was not created in a singularity or big bang, is it possible that the Recycled Universe theory may be correct? That the Universe has no defined beginning and always has been?

 

I dont think we will ever know.

 

I agree man. lol

Pretty cool to have all these recent findings come out though. No gravitational waves, now black holes being an mathematical impossibility. I wonder what we are seeing when we view black holes? Maybe they are actually wormholes after all and not a point of complete destruction?

One of the main points of criticism that the EU model runs up against is that we should be able to view or find the plasma currents that supposedly link the Universe electrically. Could there be a connection with this physicist's revelation? One of these physicists need to develop the mathematical formula to prove that theory. As far as I have been able to research, there hasn't been one yet.

 

Cool thread! I love space! Sometimes when I'm out in the yard with our dog late at night I catch myself looking up and just staring at the stars. We are so tiny.

 

AMAZING--

 

Im not sure about the black hole debate. The existance of our universe is a mathematical impossibility...haha The big bang or creation. neither can be proven. We just try and rationalize what we can with what we currently know.

 

greater awe=less hubris=ataraxia


OR


recondite conundrums= less smartypantsness=nirvana


etc.

 

Scifi short promotes Rosetta comet mission

By Jonathan Amos Science correspondent, BBC News

The European Space Agency has released a short scifi movie to promote its audacious Rosetta comet mission.

Called, suitably, Ambition, it stars Game of Thrones' Aidan Gillen and actress Aisling Franciosi as master and apprentice on an alien world.

In the seven-minute drama, the pair discuss the presence of water on planets and the origin of life.

These are themes Esa's Rosetta probe hopes to address in its study of Comet 67P/Churyumov-Gerasimenko.

Next month, the spacecraft will drop a small robot on to the surface of the 4km-wide ice body to analyse its chemistry.

Theory holds that comets may have been responsible for delivering water to the planets early in the Solar System's history. They could even have delivered important chemistry that helped to kick-start biology. The mission intends to test these ideas.

Esa hopes the movie-short will explain the goals of Rosetta to a wider audience and heighten excitement ahead of the landing attempt on 12 November.

Ambition was shot on location in Iceland, and was directed by Poland's Tomek Bagiński, who received an Oscar nomination in 2003 for his animated short Katedra.

It is available to view online, and will be the first thing visitors to the Esa website see over the weekend.

The mission "trailer" is starting to look like an essential part of the outreach activities for the biggest space ventures.

Nasa, the American equivalent of Esa, created a buzz ahead of its Curiosity rover landing in 2012 with a short called Seven Minutes of Terror. It described the engineering challenges of putting a one tonne robot on the surface of the Red Planet.

The comet landing will be more like seven hours of terror. That is how long it will take the little robot called Philae to reach the surface of 67P after being ejected by the Rosetta "mothership".

http://youtu.be/H08tGjXNHO4

 

Just a few weeks until we see if that comet is in fact an ice body, or if it is solid rock like the EU theorists believe. So far, the initial scans have shown it's dark and black, like coal with no ice found...

 

Getting closer and closer to 11/12.

http://youtu.be/U-Ew7NKf7Bg?list=UUvHqXK_Hz79tjqRosK4tWYA

 

The universe world was created by God.

 

That's one theory

 

albeit the correct one

 

It would be great if you didn't get this thread locked just because you have no interest in it

Thanks for your cooperation

 

how do you know I have no interest in it.

 

<--- Hawking's expression