Researchers from Oregon State University and other institutions have published an article in the journal Science that they say puts to rest a long scientific debate on the causes of periodic ice ages in the history of our planet. The conclusion? Earth Wobbles.

The last major ice age reached its peak about 26,000 years ago, held steady for about 7,000 years, then began melting 19,000 years ago. The melting was caused by an increase in solar radiation, the researchers say, and not by carbon dioxide’s “greenhouse” effect, or any changes in ocean temperatures. These mechanisms have been cited recently by some scientists trying to understand what appears to be happening now with the increase in global temperatures termed “Global Warming” and said to be caused primarily by pollution from human activities.

The researchers analyzed 6,000 dates and locations of ice sheets to define when they started to melt. This confirmed a theory developed more than fifty years ago that held small but definable changes in Earth’s rotation as the trigger for both the accumulation of ice and its melting cycle. Putting that together with changes in the Earth’s axis and rotation going back 50 million years, they found that the gravitational influences of the larger planets – primarily Saturn and Jupiter – leads to predictable cycles.

Right about now, the scientists say, we should be changing from an interglacial period toward conditions that will ultimately lead to another ice age. That is, if human contributions to Global Warming don’t thwart the process. Meanwhile, a close look at plans to mitigate global warming with ‘Geoengineering’ suggests that such plans may well do more harm than good.

Research presented at a symposium at the Ecological Society of America’s annual meeting concludes that geoengineering is potentially dangerous, and that the risks outweigh the benefits. Plans such as limited nuclear detonations and subsequent fires to release lots of carbon into the atmosphere, seeding the atmosphere with light colored sulfur particles to mimic gigantic volcanic eruptions, and seeding the oceans with iron to increase carbon uptake all come with side-effects that could be disastrous, ecologists say.

Indeed, if we are starting to ‘wobble’ to the gravitational tune of our giant planetary neighbors toward another ice age, taking big efforts to cool the planet right now could actually speed up the process! Perhaps we should put off the big projects until we know more about all this, eh?

Almost everyone who is interested enough to follow scientific developments is familiar with the good old “Black Hole” in space. This is what happens when massive stars collapse in on themselves and there’s nothing to stop it. Eventually all the mass gets crushed to infinite (or near infinite) density, creating a “Singularity.” This tiny point in spacetime exerts all the gravity of all the mass that became part of it, so their effects can be observed on other stars and matter near them.*

[* High energy physicists have suggested that singularities can come in much smaller 'mini' and 'micro' size, and are hoping to produce one at CERN if they ever get the Large Hadron Collider going.]

These black holes are said to be hidden behind an event horizon, where matter and energy being sucked in toward the singularity exceeds the speed of light. Beyond that boundary of spacetime, nothing within can ever get out again. Roger Penrose came up with the Cosmic Censorship hypothesis back in the ’70s when he and Stephen Hawking were formalizing the solutions to Einstein’s equations that predicted the existence of black holes. It seemed ‘indecent’ to Penrose that a singularity might ever exist that was not shielded from outside view by an event horizon, and that view predominated research for decades despite whispers here and there that naked singularities could indeed exist.

The axiom of cosmic censorship is that “Nature abhors a naked singularity.” Penrose complains that an indecent singularity would do some very strange things to time, making mincemeat of our notions of cause and effect. Three decades later theorists are not so sure. It was reported back in September of 2007 that…

Some Black Holes May Not Be Black – researchers from Duke University and Cambridge published in the journal Physical Review D their solutions to the equations of general relativity which predict the existence of naked singularities. Worse, they came up with some ways of testing the gravitational lensing and radiation emissions expected from such a phenomenon, that could soon be observed with current and new technology.

In the February issue of Scientific American, theorist Pankaj Joshi writes an informative 5 pages of explanation in the article -

Do Naked Singularities Break the Rules of Physics?

“If naked singularities exist, the implications would be enormous and would touch on nearly every aspect of astrophysics and fundamental physics. The lack of horizons could mean that mysterious processes occurring near the singularities would impinge on the outside world. Naked singularities might account for unexplained high-energy phenomena that astronomers have seen, and they might offer a laboratory to explore the fabric of spacetime on its finest scales.”

Some astrophysicists are probably dreading the implications, but it looks like an increasing number of others are quite excited about it as a way forward in their quest to understand the true nature of space and time and the behaviors of all things existing here. Joshi concludes his article with this enthusiasm…

“Either proving or disproving cosmic censorship would create a mini explosion of its own within physics, because naked singularities touch on so many deep aspects of current theories. What comes out unambiguously from the theoretical work so far is that censorship does not hold in an unqualified form, as it is sometimes taken to be. Singularities are clothed only if the conditions are suitable. The question remains whether these conditions could ever arise in nature. If they can, then physicists will surely come to love what they once feared.”

Links:

Wiki: Naked singularity
Do Naked Singularities Break the Rules of Physics?
Some Black Holes May Not Be Black

Researchers at Cardiff University have managed to confirm a prediction made before the British-German gravity wave detector GEO600 was up and running, and it just might open up a whole new era in fundamental physics.

The press release Cardiff researchers could herald a new era explains that the GEO600 detector has been receiving some mysterious ‘noise’ that might confirm that the true nature of the universe is holographic, as predicted by physicist Craig Hogan at Fermilab. The GEO600 team is now gearing toward further experiments that may lend further evidence in favor of this theory. New Scientist has a more in-depth article, Our world may be a giant hologram that fleshes out the concepts.

Physicists have long hypothesized that the universe is ‘grainy’ at the Planck level, which is the smallest conceptual unit of space and time. Scientists cannot hope ever to measure phenomena at that level, but if the universe is a hologram projected from those tiny “grains of sand” they may well be able to detect levels of the projection as far into the high energy/small size range as they can ever go. That projection, Hogan maintains, is the source of the noise in the detector.

Holograms are created by a special photographic process where an object is bathed in the light of a laser, then a second laser is bounced off the reflected light of the first, and the interference pattern is captured on film. When that image (which looks like a meaningless swirl of light) is illuminated by yet another polarized light source, a 3-dimensional image of the original appears. It is basically the famous double-slit effect, making specific use of the interference pattern of the light. Apart from the 3-dimensional projection, holograms are remarkable in that no matter how you subdivide them, each piece contains all the information contained in the whole. The images just get smaller with each division. Every part contains the whole.

The GEO600 detector is designed to make use of measurements made with a split-beam of polarized light at right angles to detect the tiniest changes as gravity waves pass through the earth. Those changes would show up as interference patterns of the light, thus the experiment has something in common with the process of creating and projecting holograms. That the experiment is detecting ‘noise’ – interference patterns in the light that do not indicate gravity waves – is a confirmation of the holographic universe model, Hogan says.

The GEO600 team will now attempt to fine-tune the detector to higher and higher wavelengths to see if the noise disappears at a certain level. Hogan has proposed a new experiment using an atom interferometer. These work on the same principle as laser-based detectors but instead of light they use beams of ultracold atoms.

Discovery of unexpected noise by a Bell Labs antenna in 1964 confirmed the cosmic microwave background radiation, leading to general acceptance of the Big Bang theory. This new noise could lead to a historical re-vamping of our understanding of the universe as well, so keep an eye on the GEO600 experiments!

Links:

Cardiff researchers could herald a new era
Our world may be a giant hologram
Wikipedia: Holographic principle

Atronomers and astrophysicists determined some years ago – after that strange beastie known as a “black hole” was accepted to probably be a real physical phenomenon, that there are gigantic black holes at the center of galaxies. Moreover, they found they could determine the mass of these galactic black holes via a fairly simple ratio between the mass of the central bulge of stars and the hole they surround (about 1:10,000). It has been presumed that the hole at the galactic center got there by the joining of stellar mass black holes, which then continued to grow by accretion of mass from the stars drawn into the gravity well.

More recently, however, scientists examining galaxies much farther away in space and time found a different pattern. The farther back into the history of the universe they looked, the ratio between galactic black holes and the mass of the stars surrounding them did not follow the 1:10,000 ‘rule’ – the holes account for much more of the mass, meaning they were huge even way back in the early days of the universe.

As quoted in Wired’s article Yo Galaxy’s Mama Is a Black Hole, astronomer Chris Carilli of the National Radio Astronomy Observatory said during a briefing at the American Astronomical Society’s annual meeting that “The simplest conclusion is that the black holes come first and they somehow grow the galaxy around them.”

Supermassive galactic black holes have been noted in galaxies as early as 1.7 billion years after the Big Bang, or 12 billion years ago as seen by us from here on planet earth. These might be survivors of “Primordial Black Holes” theorized to have been created by conditions of the Big Bang, which began to merge after inflation and draw to themselves ever increasing amounts of matter that formed into galaxies. Or some other origin may become apparent with further study, to be greatly enhanced by the Expanded Very Large Array radio telescope system [EVLA] in New Mexico and the Atacama Large Millimeter / submillimeter Array [ALMA] in Chile, which should be completed by 2012.

In other news, the region of our own galaxy’s core has been detailed in high resolution infrared by a composite panorama made up of snapshots by the Hubble and Spitzer space telescopes. “Hi-res” in this instance, covering an area 300 x 115 light years 26,000 light years away from here (and now) means being able to see objects as ’small’ as just 20 times the size of our solar system. Which is quite a feat, and offers an awe-inspiring glimpse of conditions near the core that should make us glad we live way out here in our relatively peaceful long arm of the galaxy instead.

Our home galaxy (the Milky Way) has also grown by 50% recently, though not by accumulating mass or anything. New measurements of how quickly our galaxy is rotating in space led a team of astrophysicists from Harvard to conclude that the mass that makes up our galaxy is 50% larger than previously believed. It may also have four arms instead of two, which would make us look to an observer in Andromeda more like a pinwheel instead of a spiral.

And while the new measurements may serve to inflate our cosmic ego a bit, it also bodes ill for the future if astronomers are correct in projecting that a heavier Milky Way will inevitably collide with its neighbor Andromeda sooner than it otherwise would have.

Links:

Yo Galaxy’s Mama Is a Black Hole
Did the big bang spawn trillions of black holes?
Black Holes Grew Fast, Merged Early
Milky Way 50 Percent Larger
Expanded Very Large Array
Atacama Large Millimeter / submillimeter Array

The annual meeting of the UK’s Royal Astronomical Society’s National Astronomy Meeting in Belfast this week has produced some cool news items on the astronomical discoveries of the past year. First up, we have some interesting findings in our own neighborhood with research focusing on our sun. An international team announced that they’d discovered the source of the solar wind.

The solar wind consists of electrically charged particles that flow away from the sun in all directions. The scientists working with the Hinode mission and the UK’s Extreme Ultraviolet imaging Spectrometer to determine that the sun’s magnetic fields create bright regions of activity on the solar surface. The edges of these bright regions emit hot gas at high speeds. The magnetic fields connect even in separated regions, and this connection (or collision) allows hot gas to escape from the sun’s gravitational field as solar wind.

In another presentation astronomers reported findings specific to the sun’s magnetic fountains. To model the fields that provide the solar wind engines computer simulations were combined with the Hinode mission probe data. Being able to make predictions about the sun’s dynamic magnetic fields and the particle fountains comprising the solar wind should allow for more precise prediction of satellite and on-earth electronic systems disruption.

Farther from home, astronomers have discovered smallest black hole ever. It’s in the Milky Way binary system known as XTE J1650-500 in the southern constellation Ara. NASA’s Rossi X-ray Timing Explorer [RXTE] satellite discovered the system in 2001, and astronomers examining the date discovered that it harbors a black hold at the very limits of minimum size according to theory. It’s just 15 miles across and its mass is just 3.8 times greater than our sun.

Further still from home, the Hubble space telescope revealed a rare view of the early stages of an exploding supernova occurring in the NGC 2397 spiral galaxy. In addition to showing an early stage view of the supernova SN 2006bc. This has allowed astronomers to investigate stars that may go supernovae and their distinguishing characteristics.

Big astrophysics science news this week that a Big Chunk of the Universe Is Missing – Again. This requires a little background for understanding how it is our universe can be so adept at playing hide-and-seek.

As much as 96% of the mass necessary to account for how our universe is observed to be has been missing for a long time. The mass is necessary to explain the gravity that holds galaxies together, but all the atomic matter we can see in planets, comets, asteroids, assorted space junk, stars and galaxies accounts for just 4% of it. In 1974 astronomer Vera Rubin discovered that instead of following a Newtonian scheme where Mercury travels faster around the sun than Neptune does, almost all stars rotating around a galaxy’s center – at any distance – all travel at the same speed.

There had to be some ‘extra’ source of gravity working in galaxies, but there wasn’t nearly enough mass to account for this anomaly. The choice was between gravity being variable (unthinkable!) or the existence of a great deal of extra mass that we couldn’t see. Scientists jumped on that answer in defense of Newtonian/Einsteinian gravity and gifted us with “Dark Matter.”

They couldn’t come up with likely candidates enough to cover more than about 21% of the necessary extra mass, so they soon came up with some fudges for gravity itself – an “anti-gravity” force called Dark Energy where they could hide the anomalous data. They were up to 4% matter + 21% Dark Matter + 75% Dark Energy. Voilå! Universe explained.

That scientists had no real grasp on what Dark Matter and Dark Energy really are did not particularly upset them, and these have become consensus theory. There are some intriguing alternative theories out there, but none enjoy consensus status and are mostly considered somewhat ‘crackpot’ – aether theories, geometrical theories, and ‘hyper’ theories that include extra large dimensions are generally frowned upon even though some of them actually do attempt to describe the empirical observations without sacrificing 96% of reality to phantom agents.

In 2000, astrophysicists thought the missing matter might be in the form of gas or plasma in the intergalactic medium. Then in 2002 the Chandra space-based telescope seemed to confirm that theory when it discovered 7% of the missing universe.

By 2007 astronomers and astrophysicists were back on the trail, reporting that they’d found hundreds of ‘missing’ black holes hiding in galaxies billions of light years away. Which translates into a finding that billions of years ago there were hundreds of black holes in some galaxies…

“Active, supermassive black holes were everywhere in the early universe,” said Mark Dickinson of the National Optical Astronomy Observatory in Tucson, Ariz. “We had seen the tip of the iceberg before in our search for these objects. Now, we can see the iceberg itself.” Dickinson is a co-author of two new papers appearing in the Nov. 10 issue of the Astrophysical Journal.

Now the new research from the University of Alabama in Huntsville [UAH] informs us that we’re 20% light again even after the discoveries in 2002 and 2005 (and all those black holes discovered just last month). Turns out that a lot of those x-rays supposedly coming from the intergalactic clouds of hot gas are instead probably caused by electrons. Electrons are a lot smaller than atoms, with a lot less mass. Those rivers can’t hold the amount of mass previously attributed to them.

Well, they still have WIMPs [Weakly Interacting Massive Particles] as a candidate for missing matter. Problem with these theoretical beasties is that they’re even less interactive than neutrinos, so much more difficult to detect. In fact, nobody’s ever seen a WIMP or measured any Dark Energy. The term “Dark” in these cases means “We Don’t Know” what the heck it is, or even if it exists at all. But the standard models of how our universe works requires filling in huge (as in 90%) gaps with whatever sounds reasonable right now. The alternative – that our standard models are wrong – is too dire to contemplate.

So anyone interested in the stars – and that’s a lot of us, young and old – should try to keep current on the question of what the “missing” 90% of our universe might be, and where it could be hiding. It’s certainly an entertaining pastime, and never dull!

Links:

Dark Matter the Answer to the “Missing Universe?”

Astronomers Find Part of Universe’s Missing Matter

Big Bang Theory Saved

Galaxy Cluster Surveys May Help Explain “Dark Energy”