What Does It Mean for a Singularity to be Naked?
Mar 2 at 8:08pm by Aileen
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.
Popularity: 25% [?]
Meanwhile, Some Chaos in the Neighborhood
Dec 22 at 5:05pm by Aileen
There have been some interesting events going on in our solar system since the turn of the new millennium, just coming up on being 8 years old (when counted as the New Year’s transition 2000 to 2001). And the most recent situation here on planet earth bodes ill for sunbathers and electronic communications.
Our sun (Old Sol) has a predictable 11-year cycle of magnetic pole-flipping – with accompanying sunspots and coronal mass ejections [CMEs] of high-energy ions. The most recent pole-flip occurred between 2000 (north pole) and 2002 (south pole). Our planet has also been known to flip its poles, but on a much longer period cycle that averages ~500,000 years. It’s been about 780,000 years since this last occurred, so it’s probably not too surprising that by 2004 scientists were noticing that our field was fading fast.
Back then scientists were fairly convinced that the process of field reversal takes hundreds or thousands of years to accomplish, so the panic level wasn’t high. Earth’s magnetic field produces a “magnetosphere” that shields the surface and lower atmosphere from incoming solar wind, CMEs and cosmic rays by directing them around the planet. Occasional solar radiation does break through and wreak temporary havoc to our electrical grids and communications technologies. And some birds, turtles and bees rely on the magnetic field of the earth in order to navigate.
Popularity: 24% [?]
First ‘Rule’ of Evolution…
Mar 18 at 7:07pm by Aileen
Researchers at the University of Bath in England, Imperial College London, and the University of Waterloo in Canada have analyzed the last 550 million years of evolution in the fossil record, and determined that the First ‘Rule’ of Evolution Suggests that Life is Destined to Become More Complex.
This may be news to evolutionary biologists and interested laity who were taught that evolution is solely a matter of random mutation and natural selection with no direction toward greater complexity. Dr. Matthew Wills from the University of Bath explained it thus…
“If you start with the simplest possible animal body, then there’s only one direction to evolve in – you have to become more complex. Sooner or later, however, you reach a level of complexity where it’s possible to go backwards and become simple again.”
But does this happen? Wills explains…
“What’s astonishing is that hardly any crustaceans have taken this backwards route. Instead, almost all branches have evolved in the same direction, becoming more complex in parallel. This is the nearest thing to a pervasive evolutionary rule that’s been found.”
Popularity: 7% [?]
A Candidate Debate on Science and Technology?
Dec 18 at 6:06pm by Aileen
They’re calling it Science Debate 2008. It’s a grassroots initiative to petition for a Presidential candidates forum specifically about issues of science and technology. The list of science bloggers in the Blogger Coalition is impressive, and represents almost all of Seed Media Group’s ScienceBlogs stable. The list of initial signers includes Nobel Prize laureates, academics, corporate CEOs, congresscritters, political science policy advisors, journal editors and regulatory agency veterans.
I heard about the initiative from Steven “DarkSyde” Andrew’s front page post announcing it over on Daily Kos on December 10th. He called for bipartisan and independent science bloggers to sign up, so I emailed the group through their form and offered my support. I didn’t get a reply and I’m not listed as a supporter, but I’m going to talk about it anyway.
Popularity: 15% [?]
Venus and Earth: Twins Separated at Birth?
Nov 29 at 5:05pm by Aileen
On November 29 the New York Times published an article about the European Space Agency’s Venus Express mission, highlighting findings from that mission that suggest Earth and Venus are “really twins which are just separated at birth.” Hmmm…
In New Findings Underscore an Earth-Venus Kinship, author Kenneth Chang cites scientists’ surprising findings that Venus experiences lightning, wide swings in temperature, and evidence that Venus once hosted oceans covering as much of the planet as Earth’s oceans do.
Eight different articles about findings from the mission were published in the 11-29 issue of the journal Nature. The scientists speculate that Venus’ oceans evaporated to form the water vapor canopy that shrouds the planet, trapping heat in the good old ‘greenhouse effect’ to cause surface temperatures approaching 900º F, yet the mission also found that the temperature varies as much as 70º F between day and night. Which must be quite a relief in a climate hot enough during the day to melt metals!
Popularity: 10% [?]
Our Universe: Missing, Found, Then Missing Again
Nov 8 at 10:10pm by Aileen
Keeping Up With Astronomy’s Game of Hide-and-Seek
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.”
Popularity: 15% [?]
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