Thursday, September 9, 2010

On the persistence of time dilation

Cool thought: Einstein's Special Theory of Relativity, which isn't so much a theory anymore for reasons I'll discuss later, tells us that increased speeds results in a slower clock rate for that object relative to a slower one (sorry, time isn't a fixed or constant thing across the Universe, get used to it). But Einstein didn't stop there. He also went on to describe his General Theory of Relativity in which he showed that gravity produces a similar time dilation effect; the heavier the gravity, the slower the clock.

So, as Einstein famously noted in his space-faring twin thought experiment, the returning twin, because he was moving faster relative to his Earth-bound sibling, will have aged less than his counterpart. Similarly, because of gravitational time dilation, a clock on Jupiter would run slower than a clock on Earth on account of its great size. I know it doesn't sound intuitive, but that's Relativity for you and why Einstein is considered such a genius for figuring this out.

Now, as messed as this sounds, this effect is becoming more perceptible to us, particularly as we travel faster and venture further into space. Gravitational time dilation has been experimentally measured using atomic clocks on airplanes and the effect is significant enough that the Global Positioning System's artificial satellites need to have their clocks corrected regularly. The International Space Station, because it is moving faster relative to Earth, and because it experiences less gravity, is subject to both effects; a faster speed means a slower clock, but less gravity means a faster clock! NASA's mathematicians must be having a blast trying to keep their clocks in synch with the ISS's.

And if you think that's complicated, we also have to deal with our robots on Mars where we need to account for the speed of Mars relative to Earth's and factor in the gravitational differences between the two planets. What blows my mind is that the Mars Rover is experiencing the passage of time at a slightly different rate than what we're experiencing on Earth.

Yikes. Problems like these remind me why I dropped out of high school math.

Telomerase-activating compound may help reverse aging

Researchers have discovered a telomerase-activating compound which could eventually be used to reverse aging in humans.

Specifically, a naturally derived compound known as TA-65 has been shown to activate the telomerase gene in humans. The researchers, a collaboration of scientists from Sierra Sciences, TA Sciences, Geron Corporation, PhysioAge, and the Spanish National Cancer Research Center, discovered that activating this gene could prevent the shortening of telomeres at the ends of chromosomes, thereby slowing or even stopping the cellular aging process.

While TA-65 is probably too weak to completely arrest the aging process, it is the first telomerase activator recognized as safe for human use.

"We are on the cusp of curing aging," said William Andrews, Ph.D., co-author of this study and President and CEO of Sierra Sciences, LLC. "TA-65 is going to go down in history as the first supplement you can take that doesn't merely extend your life a few years by improving your health, but actually affects the underlying mechanisms of aging. Better telomerase inducers will be developed in the coming years, but TA-65 is the first of a whole new family of telomerase-activating therapies that could eventually keep us young and healthy forever."

As excited as I am by this discovery, I believe Andrews's statement is considerably overstated. We are still quite a ways off from having interventions that will "keep us young and healthy forever," and it will unlikely be accomplished through the exclusive use of telomerase-activating therapies. Aging is a multi-faceted process that will inevitably require a cocktail of therapies. Moreover, as healthy life span is continually extended, new and unanticipated age-related diseases will crop up.

It's worth noting that, in addition to slowing the cellular aging process, the researchers hope that TA-65 may also help treat diseases which attack the immune system such as HIV/AIDS.

Press release.

Monday, September 6, 2010

NASA's warnings on the dangers of severe space storms

Back in June I blogged about the potential dangers arising from space storms that could spawn devastating solar flares. This is no joke, nor is it part of the laughable (but conveniently co-incidental) 2012 doomsday nonsense. There's actual science involved here; NASA issued a solar storm warning back in 2006 in which it predicted that the worst of it could come sometime between 2011 and 2012. Last year they slightly downgraded their warning, while extending their forecast to 2013—May 2013 to be exact, which sounds eerily specific.

According to NASA, we are currently in a solar maximum period. These cycles are capable of creating space storms—what are known as "Carrington Events," named after astronomer Richard Carrington who witnessed a particularly nasty solar flare back in 1859. The flare he documented resulted in electrified transmission cables, fires in telegraph offices, and Northern Lights so bright that people could read newspapers by their red and green Mexico.

If this is what happened in 1859, imagine what would happen today. Well, we're starting to have some idea—and the news is pretty bad.

A recent report by the National Academy of Sciences found that if a similar storm occurred today, it could cause $1 to 2 trillion in damages to society's high-tech infrastructure and require four to ten years for complete recovery. It could damage everything from emergency services’ systems, hospital equipment, banking systems and air traffic control devices, through to everyday items such as home computers, iPods and GPS's. Because of our heavy reliance on electronic devices, which are sensitive to magnetic energy, the storm could leave a multi-billion dollar damage bill and cataclysmic-scale problems for governments.

Worse than this, however, would be the potential length of blackouts. According to a Metatech Corporation study, an event like the 1921 geomagnetic storm would result in large-scale blackouts affecting more than 130 million people and would expose more than 350 transformers to the risk of permanent damage. It could take months—if not years—to put everybody back on the grid.

For more reading, I recommend the NASA report, "Severe Space Weather Events--Understanding Societal and Economic Impacts: A Workshop Report" (2008). Excerpt:
Modern society depends heavily on a variety of technologies that are susceptible to the extremes of space weather—severe disturbances of the upper atmosphere and of the near-Earth space environment that are driven by the magnetic activity of the Sun. Strong auroral currents can disrupt and damage modern electric power grids and may contribute to the corrosion of oil and gas pipelines. Magnetic storm-driven ionospheric density disturbances interfere with high-frequency (HF) radio communications and navigation signals from Global Positioning System (GPS) satellites, while polar cap absorption (PCA) events can degrade—and, during severe events, completely black out—HF communications along transpolar aviation routes, requiring aircraft flying these routes to be diverted to lower latitudes. Exposure of spacecraft to energetic particles during solar energetic particle events and radiation belt enhancements can cause temporary operational anomalies, damage critical electronics, degrade solar arrays, and blind optical systems such as imagers and star trackers.

The effects of space weather on modern technological systems are well documented in both the technical literature and popular accounts. Most often cited perhaps is the collapse within 90 seconds of northeastern Canada’s Hydro-Quebec power grid during the great geomagnetic storm of March 1989, which left millions of people without electricity for up to 9 hours. This event exemplifies the dramatic impact that extreme space weather can have on a technology upon which modern society in all of its manifold and interconnected activities and functions critically depends.

Nearly two decades have passed since the March 1989 event. During that time, awareness of the risks of extreme space weather has increased among the affected industries, mitigation strategies have been developed, new sources of data have become available (e.g., the upstream solar wind measurements from the Advanced Composition Explorer), new models of the space environment have been created, and a national space weather infrastructure has evolved to provide data, alerts, and forecasts to an increasing number of users.

Now, 20 years later and approaching a new interval of increased solar activity, how well equipped are we to manage the effects of space weather? Have recent technological developments made our critical technologies more or less vulnerable? How well do we understand the broader societal and economic impacts of extreme space weather events? Are our institutions prepared to cope with the effects of a “space weather Katrina,” a rare, but according to the historical record, not inconceivable eventuality?
Read more.

Hitchens: Domesticating religion an unceasing chore of civilization

Writing in Slate, Christopher Hitchens says the taming and domestication of religious faith is one of the unceasing chores of civilization. In the article, titled "Free Exercise of Religion? No, Thanks.", Hitchens asks himself: Am I in favor of the untrammeled "free exercise of religion"? Not surprisingly, his answer is no.

He tasks a number of religions to task for what he sees as moral inconsistencies and hypocrisies, everything from the Mormons through to Roman Catholicism. He writes:
The Church of Scientology, the Unification Church of Sun Myung Moon, and the Ku Klux Klan are all faith-based organizations and are all entitled to the protections of the First Amendment. But they are also all subject to a complex of statutes governing tax-exemption, fraud, racism, and violence, to the point where "free exercise" in the third case has—by means of federal law enforcement and stern public disapproval—been reduced to a vestige of its former self.
And concludes:
Reactions from even "moderate" Muslims to criticism are not uniformly reassuring. "Some of what people are saying in this mosque controversy is very similar to what German media was saying about Jews in the 1920s and 1930s," Imam Abdullah Antepli, Muslim chaplain at Duke University, told the New York Times. Yes, we all recall the Jewish suicide bombers of that period, as we recall the Jewish yells for holy war, the Jewish demands for the veiling of women and the stoning of homosexuals, and the Jewish burning of newspapers that published cartoons they did not like. What is needed from the supporters of this very confident faith is more self-criticism and less self-pity and self-righteousness.

Those who wish that there would be no mosques in America have already lost the argument: Globalization, no less than the promise of American liberty, mandates that the United States will have a Muslim population of some size. The only question, then, is what kind, or rather kinds, of Islam it will follow. There's an excellent chance of a healthy pluralist outcome, but it's very unlikely that this can happen unless, as with their predecessors on these shores, Muslims are compelled to abandon certain presumptions that are exclusive to themselves. The taming and domestication of religion is one of the unceasing chores of civilization. Those who pretend that we can skip this stage in the present case are deluding themselves and asking for trouble not just in the future but in the immediate present.
Read more.

Novae produce gamma-rays. Damn.

Bad news: Novae emit gamma-rays.

We've known for a long time that supernovae produce gamma-rays, but until now it was assumed that novae lacked the power to emit such high-energy radiation. This is bad because novae occur at much greater frequency than super- and hypernovae; we are therefore at a much greater risk of being wiped out by a blast of gamma-ray radiation than previously thought.

The Milky Way experiences about 30 to 60 novae per year, with a likely rate of about 40. Roughly 25 novae brighter than about magnitude 20 are discovered in the Andromeda Galaxy each year and smaller numbers are seen in other nearby galaxies.

Contrast that with supernovae which occur about five times every hundred years.

A nova event should not be confused with a supernova. It is a cataclysmic nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner. A supernova, on the other hand, is a stellar explosion that is more energetic than a nova. Supernovae are extremely luminous and cause a burst of radiation that can outshine an entire galaxy before fading from view over several weeks or months. During this short interval a supernova can radiate as much energy as the Sun is expected to emit over its entire life span. The explosion expels much or all of a star's material at a velocity of up to 30,000 km/s (10% of the speed of light), driving a shock wave into the surrounding interstellar medium.

Though not as powerful as a supernova, novae are still immensely energetic, emitting the equivalent of about 1,000 times the energy emitted by our Sun every year. And now we can add gamma-rays to its list of nasty excretions.

To say that a gamma-ray blast would be bad for us here on Earth would be a gross understatement. Combined with the effects of a cataclysmic stellar explosion, it is one of the most powerful forces in the Universe, able to sterilize massive swaths of the galaxy. Supernovae can shoot out directed beams of gamma-rays to a distance of 100 light years, while hypernovae disburse gamma ray bursts as far as 500 to 1,000 light years away.

As for novae, the explosion creates a hot, dense, expanding shell called a shock front, composed of high-speed particles, ionized gas and magnetic fields. These shock waves expand at 7 million miles per hour—or nearly 1% the speed of light. The magnetic fields trap particles within the shell and whip them up to tremendous energies. Before they can escape, the particles reach velocities near the speed of light. Scientists say that the gamma rays likely result when these accelerated particles smashed into the red giant's wind.

Previous to this discovery, it was known that the remnants of much more powerful supernova explosions can trap and accelerate particles like this, but no one suspected that the magnetic fields in novae were strong enough to do it as well. Supernova remnants endure for 100,000 years and produce radiations that affect regions of space thousands of light-years across.

These explosions produce highly collimated beams of hard gamma-rays that extend outward from a nova or supernova. Any unfortunate life-bearing planet that should come into contact with those beams would suffer a mass extinction (if not total extinction depending on its proximity to the event). Gamma-rays would eat up the ozone layer and indirectly cause the onset of an ice age due to the prevalence of NO2 molecules.

Life on Earth just got that much more tenuous.