The Cosmic Quintessence

http://www.forteantimes.com/strangedays/science/4345/the_cosmic_quintessence.html

The Cosmic Quintessence
From earliest times, humans have wondered about the Universe – how did it come into being and what is it made of? It seems that answers remain beyond our grasp.
David Hambling
September 2010
FT267

Something is wrong with the Universe, or at least our understanding of it. Previously, in the words of Arthur Dent, “Most of it seemed to make sense at the time.” But new discoveries have upset our tidy view of the Cosmos, filling it with inexplic­able Dark Matter and Dark Energy. As the magazine of unexplained phenomena, FT should cover most of the Universe. Or might scientists be able to make sense of it all again?

Things started well at the beginning of the 20th century. Astronomers discovered that in every direction there were galaxies moving away from us. They also found that the further away a galaxy was, the faster it was going. Their measurements showed that this expansion was consistent with all observed matter having exploded outward from a single point in the distant past. The rate of expansion was slowing down due to the effect of gravity, and the only question was whether there was enough mass to cause the Universe to eventually collapse in on itself again.

While consistent enough, the new notion went down badly with those who preferred an eternal ‘steady state’ theory of the Universe. Fred Hoyle dismissively referred to the new theory as “this ‘big bang’ idea” in a BBC radio broadcast in 1949. The name stuck, and the Big Bang has been with us ever since.

However, close observations of galaxies revealed that something was missing. The amount of material that astronomers could see in stars and nebulæ was not enough to account for the gravit­ational force holding galaxies together. The missing material, known as Dark Matter, weighs about five times as much as visible matter. [1] There have been various theories about where this invisible material might be hiding.

Early suggestions of galaxies shielded by dust clouds, or antimatter galaxies, were ruled out as these would have been detected by the radiation they emitted. Giant black holes were also excluded, as they can be spotted by ‘gravitational lensing’ effects. One possibility is that the Dark Matter might take the form of invisible brown dwarf stars – like the one that Andy Lloyd thinks is lurking at edge of the Solar System [FT265:38]. Such objects are known as Massive Compact Halo Objects or MACHOs. This is to contrast them with the other likely contender, elusive subatomic part­icles which have mass but do not interact with ordinary matter, known as Weakly Interact­ive Mass­ive Particles or WIMPs. (That’s physicist humour for you).

Neutrinos are ghostly sub­atomic particles; they are emitted by the Sun, and thousands are streaming through you at this moment without ever being noticed. Originally they were thought to be massless, but in 2002 they were shown to have mass. Was this the missing Dark Matter? Unfortunately not; each neutrino weighs about a millionth as much as an electron, not nearly enough to account for the missing matter.

The giant orbiting Hubble telescope should have helped clear things up. Instead, it made things much worse. In 1998, precise measurements from very distant galaxies showed that the rate of expansion of the Universe was not decreasing due to gravitational pull, as expected. It was accelerating. Some sort of immense force is pushing everything outwards. Known as Dark Energy, this turns out to be even greater than Dark Matter. The latest figures for the Universe are: Dark Energy – 70 per cent; Dark Matter – 25 per cent; Actual Things We Can See And Know About – 5 per cent.

Dark Energy might simply be a property of space. Or it might be some sort of dynamic energy field that fills space and creates a force; this possible field has been called Quintessence after the fabulous Fifth Element postulated by alchemists.

“If Quintessence is the answer, we still don’t know what it is like, what it interacts with, or why it exists,” concludes a description on NASA’s website, [2] succinctly describing our current state of ignorance. NASA’s response is to build an even bigger and better telescope in a Joint Dark Energy Mission to get an accurate picture of the historic expansion of the Universe and how it has changed. If they can get funding.
There are other problems much closer at hand. Probes sent to the edges of the Solar System are not where they ought to be. In particular, two Pioneer probes, 10 and 11, which were sent far beyond Jupiter, have instruments that allow their location and speed to be measured with very high precision. Both are subject to an unexplained slowing-down force.

Another anomaly crops up right next to the Earth. For years, scientists have been using the “slingshot effect” to give spacecraft a boost by having them pass close to a planet. In some cases, probes have a complicated traject­ory that uses the Earth for this effect. Except that the change in speed has not been as expected: sometimes they end up measurably faster than ought to be poss­ible. The Rosetta spacecraft has passed by the Earth three times, but has experienced the anomaly only once. [3]

Perhaps some new Einstein will succeed in drafting a new set of laws of physics that will neatly account for these anomalies. Certainly, plenty of scientists are trying. If they succeed, then we may be able to discard weird notions like Dark Energy and Dark Matter, and our spacecraft will behave themselves. Until then, those who think we understand the Universe are approximately 95 per cent wrong.

Notes

1 What Is Dark Matter: http://tinyurl.com/2ujhosz (xs4all.nl).
2 NASA page on Dark Energy: http://tinyurl.com/33g8dcj (science.nasa.gov).
3 The Universe Today: http://tinyurl.com/yj9cn3p (universetoday.com).

Our Universe at Home Within a Larger Universe?

http://www.sciencedaily.com/releases/2010/04/100406172648.htm

Our Universe at Home Within a Larger Universe? So Suggests Physicist's Wormhole Research

ScienceDaily (Apr. 7, 2010) — Could our universe be located within the interior of a wormhole which itself is part of a black hole that lies within a much larger universe?

Such a scenario in which the universe is born from inside a wormhole (also called an Einstein-Rosen Bridge) is suggested in a paper from Indiana University theoretical physicist Nikodem Poplawski in Physics Letters B. The final version of the paper was available online March 29 and will be published in the journal edition April 12.

Poplawski takes advantage of the Euclidean-based coordinate system called isotropic coordinates to describe the gravitational field of a black hole and to model the radial geodesic motion of a massive particle into a black hole.

In studying the radial motion through the event horizon (a black hole's boundary) of two different types of black holes -- Schwarzschild and Einstein-Rosen, both of which are mathematically legitimate solutions of general relativity -- Poplawski admits that only experiment or observation can reveal the motion of a particle falling into an actual black hole. But he also notes that since observers can only see the outside of the black hole, the interior cannot be observed unless an observer enters or resides within.

"This condition would be satisfied if our universe were the interior of a black hole existing in a bigger universe," he said. "Because Einstein's general theory of relativity does not choose a time orientation, if a black hole can form from the gravitational collapse of matter through an event horizon in the future then the reverse process is also possible. Such a process would describe an exploding white hole: matter emerging from an event horizon in the past, like the expanding universe."

A white hole is connected to a black hole by an Einstein-Rosen bridge (wormhole) and is hypothetically the time reversal of a black hole. Poplawski's paper suggests that all astrophysical black holes, not just Schwarzschild and Einstein-Rosen black holes, may have Einstein-Rosen bridges, each with a new universe inside that formed simultaneously with the black hole.

"From that it follows that our universe could have itself formed from inside a black hole existing inside another universe," he said.

By continuing to study the gravitational collapse of a sphere of dust in isotropic coordinates, and by applying the current research to other types of black holes, views where the universe is born from the interior of an Einstein-Rosen black hole could avoid problems seen by scientists with the Big Bang theory and the black hole information loss problem which claims all information about matter is lost as it goes over the event horizon (in turn defying the laws of quantum physics).

This model in isotropic coordinates of the universe as a black hole could explain the origin of cosmic inflation, Poplawski theorizes.

Poplawski is a research associate in the IU Department of Physics. He holds an M.S. and a Ph.D. in physics from Indiana University and a M.S. in astronomy from the University of Warsaw, Poland.

Source of Mysterious Antimatter Found

http://www.space.com/scienceastronomy/080111-antimatter-space.html

Source of Mysterious Antimatter Found
Charles Q. Choi
Special to SPACE.com
Fri Jan 11, 2008

Antimatter, which annihilates matter upon contact, seems to be rare in the universe. Still, for decades, scientists had clues that a vast cloud of antimatter lurked in space, but they did not know where it came from.

The mysterious source of this antimatter has now been discovered — stars getting ripped apart by neutron stars and black holes.

While antimatter propulsion systems are so far the stuff of science fiction, antimatter is very real.

What it is

All elementary particles, such as protons and electrons, have antimatter counterparts with the same mass but the opposite charge. For instance, the antimatter opposite of an electron, known as a positron, is positively charged.

When a particle meets its antiparticle, they destroy each other, releasing a burst of energy such as gamma rays. In 1978, gamma ray detectors flown on balloons detected a type of gamma ray emerging from space that is known to be emitted when electrons collide with positrons — meaning there was antimatter in space.

"It was quite a surprise back then to discover part of the universe was made of antimatter," researcher Gerry Skinner, an astrophysicist at Goddard Space Flight Center in Greenbelt, Md., told SPACE.com.

These gamma rays apparently came from a cloud of antimatter roughly 10,000 light-years across surrounding our galaxy's core. This giant cloud shines brightly with gamma rays, with about the energy of 10,000 suns.

What exactly generated the antimatter was a mystery for the following decades. Suspects have included everything from exploding stars to dark matter.

Now, an international research team looking over four years of data from the European Space Agency's International Gamma Ray Astrophysics Laboratory (INTEGRAL) satellite has pinpointed the apparent culprits. Their new findings suggest these positrons originate mainly from stars getting devoured by black holes and neutron stars.

As a black hole or neutron star destroys a star, tremendous amounts of radiation are released. Just as electrons and positrons emit the tell-tale gamma rays upon annihilation, so too can gamma rays combine to form electrons and positrons, providing the mechanism for the creation of the antimatter cloud, scientists think.

Billions and billions

The researchers calculate that a relatively ordinary star getting torn apart by a black hole or neutron star orbiting around it — a so-called "low mass X-ray binary" — could spew on the order of one hundred thousand billion billion billion billion positrons (a 1 followed by 41 zeroes) per second. These could account for a great deal of the antimatter that scientists have inferred, reducing or potentially eliminating the need for exotic explanations such as ones involving dark matter.

"Simple estimates suggest that about half and possibly all the antimatter is coming from X-ray binaries," said researcher Georg Weidenspointner of the Max Planck Institute for Extraterrestrial Physics in Germany.

Now that they have witnessed the death of antimatter, the scientists hope to see its birth.

"It would be interesting if black holes produced more matter than neutron stars, or vice versa, although it's too early to say one way or the other right now," Skinner explained. "It can be surprisingly hard to tell the difference between an X-ray binaries that hold black holes and neutron stars."

Weidenspointner, Skinner and their colleagues, detailed their findings in the Jan. 10 issue of the journal Nature.