Thursday, November 17, 2011

It came from outer space

Image Credit: Ed Sweeney.

Guess who’s coming home for the holidays? Russia’s broken 15-ton Mars probe. Well, probably. You know how unreliable malfunctioning probes can be. Early reports claimed the unmanned spacecraft would reenter the Earth’s atmosphere around November 26, just in time for Thanksgiving leftovers, but now it’s looking more like late December or early January (which could still qualify for Christmas if you go by the Russian Orthodox calendar).* All this, of course, is assuming that the prodigal probe doesn’t change its mind again and decide to complete its originally scheduled mission to Mars.

You might be interested to know that Russia has been aiming various contraptions at the Red Planet for about half a century without much luck (I know, kind of ironic during the Soviet years). Following a 1996 mission failure, the past 15 years have been silent of Mars attempts, but on November 8th, Russia got back on the horse and launched Phobos-Grunt into space. The space-bot’s goal was a lofty one: land on the surface of Phobos – Mars’s largest moon – collect soil samples, and then bring them back to Earth. To achieve this, the probe needed to fire a second set of engines after its initial launch, which would direct it toward Mars. Everything went swimmingly for the launch, but the probe failed to activate those second phase engines. Now it’s stalled in Earth orbit, circling the planet as though it can’t find the on-ramp to the freeway.

Russian scientists are frantically working to reestablish communication with the probe. It’s seemingly intact and its fuel tanks are full and ready to complete the journey. Russia would like nothing more than to reboot the probe and send it on it way, but Phobos-Grunt is not taking their calls.

With the window to set the wayward spacecraft back on track narrowing, what you should really be asking yourself is how and where Phobos-Grunt will land, should it fall back to Earth. Because it was suited up to go all the way to Mars and back, most of the probe’s 15-ton mass is composed of fuel, which would allegedly burn up upon reentry (probably generating an impressive fireball for anyone watching). But if any of the rocket fuel does reach the ground it’s not very reassuring to know that it’s composed of toxic hydrazine. Plus there’s still the possibility of probe shards to contend with. Early projections of likely landing sights included “most of the U.S., part of Europe, all of Africa and Australia and virtually all of South America and Asia”, which pretty much translates into “somewhere on Earth”.

Before you start accusing Russia of imperiling us all, I should mention that Phobos-Grunt is poised to be the third uncontrolled spacecraft reentry this season. NASA’s UARS satellite crashed into (probably) the Pacific Ocean on September 24, and just a month later, Germany’s ROSAT came down somewhere in Southeast Asia on October 23.

Coincidentally, Phobus-Grunt was launched on the same day our planet had its much-publicized near miss with the asteroid 2005 YU55. The 400-meter (1,300-foot) diameter asteroid got within about 200,000 miles of Earth (which is closer than our moon, FYI). § The last time a huge asteroid got uncomfortably close to us was in 1976, so this isn’t exactly a once-in-a-lifetime occurrence. According to the Washington Post, NASA spends 5 million dollars annually keeping an eye out for asteroids capable of, you know, killing everything on the planet. (None scheduled for the near future, in case you’re wondering.)

So are you more likely to get hit by a satellite or an asteroid? Ugh, that question has far too many variables. Any satellite or asteroid? A specific one? Any person on earth or just you? I can tell you this much, apparently your odds of being killed by an asteroid are greater than the odds of being struck by one. And, if it’s any consolation, in all the years our species has been lobbing metal into outer space, only one person has ever been hit by the stuff on its return. That person was Lottie Williams of Tusla, Oklahoma, who in 1997 was clocked on the shoulder by a chunk of the Delta II rocket. She was fine.

* Russia being my place of birth, I use this excuse annually when presenting cards and gifts well after the western version of “the holiday season” is over.

† Hence the probe’s name. “Grunt” translates into soil. (It’s pronounced groont by the way.)

‡ ROSAT’s plunge was particularly threatening because it had primarily functioned as a telescope and, as such, was equipped with massive (over 1.5 tons total), and very heat-resistant mirrors – exactly the kind of thing you don’t want falling on your house… or your head.

§ If 400 meters sounds like an abstract and unimpressive figure to you, then you might prefer Purdue University professor Jay Melosh’s description of its potential impact, “If a space rock the size of 2005 YU55 ever hit Earth, it would explode like 500 nuclear bombs, trigger a 7.0 magnitude earthquake and, if it splashed down in the ocean, generate a 70-foot tsunami.”

Friday, November 4, 2011

Got a fever? Best to cool it on the pills.

Thermometer by Andres Rueda, pills by Tyler Sparks, collaging by yours truly.

It’s time to wake up and smell the cough syrup, people; cold and flu season is here.* Soon everyone you know will be hacking and sneezing and generally assaulting you with their horrible germs. Illness is inevitable. You will get sick. And what to do then? If you’re like me, you probably gave up on store bought cold remedies ages ago. What’s the point? They merely suppress symptoms in exchange for other side effects. All you need to battle a run-of-the-mill virus is rest, fluids and maybe some over-the-counter pain reliever (Advil or Tylenol or the like) to reduce the fever, which is really the bulk of what’s making you feel so crappy. Right? After all, blowing your nose is just inconvenient, while a fever is incapacitating.

Well, you may want to reconsider even such modest medicating, because fever does more than just make you miserable, it also restores your health. This isn’t exactly news. It’s well known that an increase in body temperature can slow down bacteria and other microscopic invaders while the immune system mobilizes against them. Fever can even help accelerate the clearing of the parasite that causes malaria. In addition to thwarting cooties, fever can also improve the body’s pathogen fighting mechanisms. A recent study in the Journal of Leukocyte Biology found that a 2 degree centigrade increase in body temperature in mice resulted in improved differentiation of the lymphocyte CD8+ T – one of the cells involved in the immune response to viruses. While it may be detrimental to your performance of normal daily tasks (like staying awake and sitting upright), a fever actually makes your immune system more efficient.

So why are we still so quick to swallow fever-reducing pills? Certainly part of it is comfort (nobody likes feeling awful), but another problem is the perception the fevers are dangerous. While fever can be a part of serious illness, many high fevers result from minor ailments (and conversely, serious illness may present with only a mild fever). 103°F is a figure frequently given as an appropriate panic point (i.e., when call a doctor). But haven’t you had a 104° fever at some point in your life and not sought medical attention? And you were fine, right? The fever didn’t keep rising exponentially until it broke the thermometer and literally cooked your brain? Same here. The reason for concern over high fevers has more to do with possible complications of elevated body temperature than the fever itself. Dehydration, seizures – these are issues that might benefit from the presence of health care professionals.

“But can’t a fever be life-threatening?” you ask, “I’m sure I saw it on television once.” You are perhaps confusing cold/flu-induced fevers with something like heatstroke. Heatstroke occurs when the body has been pushed by strenuous exercise and ridiculously hot weather (think football practice in August) to the point where standard mechanisms for thermoregulation (sweating, dilating blood vessels, etc.) aren’t doing the trick anymore. The individual’s temperature rises not as defensive response to pathogens, but because the body has lost control of its internal environment. It’s potentially fatal, and gives one a sense of what reptiles have to worry about daily.

And while we’re empathizing with snakes and lizards, it’s worth noting that ectothermic animals (often described as “cold-blooded”†) also respond to infection with fever. How? While they can’t regulate their body temperatures internally like we do, reptiles can raise or lower their temperature behaviorally – for instance, by choosing a sunnier or shadier rock to lounge on. Research has shown that reptiles injected with bacteria will aim for a slightly higher temperature than non-infected control animals. Basically, when lizards get the sniffles, they cope with a behaviorally-induced fever rather than a bottle of ibuprofen.

The fact that even reptiles exhibit a fever response tells us that it’s a pretty old strategy for fighting infection. It’s certainly been around longer than NyQuil, echinacea, and chicken soup. While nothing cures the common cold, toughing out one its more uncomfortable symptoms is more likely to speed the healing process than your favorite home remedy.

Does this mean you have to forgo the pills entirely? Hey, I’m not your mom. Do whatever you like. There are plenty of good reasons for attempting to pull yourself together for a few hours despite being sick (birthdays, rock concerts, possibly even jobs). You just need to accept that you’re in for a certain volume of misery regardless. The only real decision is whether to spread the suffering out over more days, or just get it over with already.

* Well, at least here on the northern side of the Equator. I’m guessing that might not be the case elsewhere. Feel free to tune this one out for now, Southern Hemisphere.

† Their blood isn’t actually cold, they just have to stay warm behaviorally (by basking in the sun and that sort of thing) rather than with the fancy metabolic tricks of endotherms like ourselves.