We have been consumed by trivialities of late -- necessary trivialities, given the complexities of a cross-country move, but trivial matters, nonetheless. After yet another week frittered away chasing down various loose ends and petty details, it's becoming rather distressing to feel one's once-expansive world slowly shrinking. That might explain why I was inexplicably outraged by the fact that Melinda Doolittle was booted from the American Idol finals in favor of an obnoxious Justin-Timberlake-wannabe named Blake. It's all the more ironic because truthfully, I don't even watch American Idol. I just keep catching the last five minutes because the show airs right before House. (Jen-Luc Piquant has a major meta-crush on Hugh Laurie.)
This past week, I tuned in just in time to catch Ms. Doolittle's smokin' hot covers of Ike and Tina Turner's classic "Nutbush City Limits," and "I'm a Woman," and was so blown away by her performance, I tuned in the next night for the voting results. Even that chronic curmudgeon Simon Cowell loved her, and wasn't shy about expressing his displeasure at her ouster: "I felt it was unfair to her. She had delivered 10 weeks in a row." Given the fact that American Idol is little more than a teeny-bopper popularity contest, neither Simon nor myself should have been surprised by the outcome, but some tiny part of me still wants genuine talent and substance to win out over youth and superficial charisma. A girl can dream.
Still, it's not the end of the world or anything. Clearly, I needed something to jolt me back into a wider worldview beyond the limited confines of reality TV, inadequate storage, and the mystery of why we need four remotes to operate the TV/DVD/VCR setup. Something cosmic in scale. So it actually came as a relief when I received a press release from the Harvard-Smithsonian Center for Astrophysics informing me that the Milky Way galaxy is on a collision course with the nearby Andromeda galaxy. It turns out that the world might be spared a solo record from Blake, because human life might not survive such a major cosmic realignment -- although the planet might.
Astronomers have known for awhile about the impending galactic collision, but there's been considerable scientific debate over what such an event might mean for our puny (comparatively speaking) solar system. CfA theorists T.J. Cox and Avi Loeb announced earlier this week that they've performed new calculations via computer simulations indicating that our little family of planets will be "sent to a retirement home in the country," according to Cox, who added, "We're living in the suburbs of the Milky Way right now, but we're likely to move much farther out after the coming cosmic smash-up." Perhaps there'll be a planetary bingo night to offset the tedium of our forced retirement.
True, this cosmic relocation is going to happen in 2 billion years, not the next 20 years, which means we might have to endure that Blake Lewis record after all. By then, says Cox, the sun will be burning a bit brighter and hotter, sufficient to "boil the oceans from the earth." The stars in both galaxies will intermingle because of the powerful gravitational forces pulling them out of their comfortable orbits, and eventually -- in about 5 billion years, close to the end of the sun's expected lifetime -- they will have completely recombined to form one gigantic elliptical galaxy. And our solar system will be four times farther away from the center of the new galaxy as we are now from the center of our Milky Way.
Ironically, the Harvard press release makes statements like "Any descendants of humans observing the future sky will experience a very different view" in the night sky. That's pretty optimistic, considering the "boiling away the oceans" comment just two paragraphs earlier. I guess they're assuming that we'll figure out some water substitute to take the place of our oceans by then. Which doesn't address the problem of the sun's sudden billowing outward as it moves into its red giant phase, an event astronomers expect will pretty much obliterate Earth. All of this in turn assumes that human life isn't wiped out long before then by some other major catastrophe -- say, a giant asteroid, like the one that caused the mass extinction of the dearly departed dinosaurs before us.
Known as Near-Earth Objects (NEOs) in NASA parlance, asteroids have been around a long, long time. We've only known about them for a few hundred years, however. On January 1, 1801, an Italian astronomer named Giuseppe Piazzi observed an object that he initially thought was a comet. Further observations revealed it more closely resembled a small planet -- in fact, asteroids in the past have been considered minor planets, despite being metallic rocky bodies without atmospheres. (Who knows what they're called these days, in the wake of the whole Pluto dust-up.) Piazzi named his object Ceres, after the Sicilian goddess of grain. And he started a major astronomical trend: over the next few years, three more similar small bodies were discovered -- Pallas, Juno and Vesta -- and by the end of the 19th century, scientists had discovered several hundred.
Today there are over 330,795 named asteroids, and more are constantly being discovered. Most are located in the asteroid belt orbiting the sun between Mars and Jupiter. Where did they come from? One hypothesis is that they are pieces that broke off a mother planet that once existed between Mars and Jupiter. Another, more likely hypothesis is that they are primordial detritus from the formation of the solar system's planets 4.6 billion years ago, prevented from forming into planets themselves by Jupiter's powerful gravitational influence.
Astronomers have learned some surprising new facts about the asteroid Vesta from Hubble Telescope images, beginning in 1994, that could offer new clues about the origin of the solar system and the interior makeup of the rockier planets, because it seems to have survived largely intact since the planets formed. It turns out that Vesta is quite diverse, geologically speaking, on a par with more terrestrial worlds like Earth or Mars, with basaltic evidence of ancient lava flows on its surface. This means that Vesta once had a molten interior. It's possible that when Vesta first formed, some of its material components included radioactive debris from a nearby supernova explosion -- like the isotope aluminum 26. This hot isotope could have melted the core, so that the denser stuff sank to the core and the lighter rock rose to the surface -- a process more typical of terrestrial planets than asteroids. We'd like to know more about this atypical asteroid, which is why NASA will soon launch a spacecraft to make further observations, with better image resolution.
Even though the total mass of all those asteroids combined is less than that of the moon, they still pose a viable threat to human existence. Think the devastation depicted in the film Deep Impact was just a Hollywood exaggeration, a trick of computer-generated special effects? Think again. The underlying science was surprisingly accurate (according to Emory University physicist Sid Perkowitz, who gave a public lecture last month as part of a "Communicating Science" workshop in Lincoln, Nebraska). Smaller asteroids -- which strike Earth every 1000 to 10,000 years -- would hit hard enough to destroy a city or give rise to tsunamis. An asteroid more than a quarter of a mile in diameter would cause global devastation, perhaps giving rise to a "nuclear winter" with serious consequences for agriculture around the world.
NASA, for one, takes the asteroid threat very seriously, even though asteroids of that magnitude only strike the earth once every 1000 centuries or so. The agency is concerned enough to have set up the Near-Earth Asteroid Tracking (NEAT) program to keep tabs on any potentially dangerous bodies. The University of Arizona sponsors a similar Spacewatch program, while an international organization called the Spaceguard Foundation was set up in 1996 in Rome. So far, NASA has identified 160 "potentially hazardous" asteroids. The tracking programs should give us 30-40 years' notice to come up with some means of dispelling the threat. Popular options include exploding the object, or diverting its path.
As if asteroids weren't enough, there's also the risk of giant gamma ray bursts (GRBs). The dinosaurs might have been wiped about by a giant asteroid, but scientists are still casting about for convincing explanations for the first of five great extinctions in the Earth's history some 443 million years ago, called the Ordovician extinction. It killed off as much as 60% of animal species, primitive sea creatures, for the most part, especially those who lived in shallow waters. Other theories hold that the mass extinction was due to the onset of an ice age, but that didn't explain what caused the sudden ice age in the first place. A GRB could provide an answer.
A few years ago, Adrian Melott, an astrophysicist at the University of Kansas in Lawrence, advanced the hypothesis that a devastating burst of gamma rays may have caused that mass extinction, based on his analysis (with paleontologist Bruce Lieberman) of the pattern of extinction in fossilized trilobites during the late Ordovician period. GRBs are a byproduct of giant stars collapsing into black holes at the end of their lifetimes, firing intense pulses of gamma rays from their poles -- almost like stellar distress flares. Astronomers have detected all kinds of gamma rays bursts, mostly from distant galaxies, which have been harmless to Earth. However, Melott thinks a GRB within our galaxy, focused straight at Earth, would have devastating effects.
Just how devastating? A ten-second burst would react with nitrogen in the atmosphere to create nitrogen oxide (an ozone-depleting compound), boosting ozone levels by as much as 50%, thereby exposing us to significantly higher levels of ultraviolet rays. Nitrogen oxide also absorbs light, leading to significant global cooling -- i.e., another Ice Age. Melott estimates that a dangerous gamma ray burst occurs every few hundred million years. "It could happen tomorrow, or it could be millions of years."
The upshot is that the Earth is doomed. Doomed, I say. There's just so many different ways for life as we know it to come to an end. (Global warming, anyone? A giant nuclear fireball? A worldwide pandemic?) Kinda puts all those petty trivial details into perspective, doesn't it? While we're all waiting to find out which potential apocalypse will strike first, feel free to nominate your favorite blog posts about physics for the upcoming carnival Philosophia Naturalis, hosted next by Stuart at Daily Irreverence. I've got storage solutions to contend with.