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Congratulations to the European Space Agency for successfully landing the robot probe “Philae” on comet 67P! The lander, which is about the size of a washing machine, made a soft touch-down on the comet at 3:30 a.m. Brooklyn time. The comet itself has a diameter of four kilometers (2.5 miles) meaning it is approximately as wide as the Verrazano Bridge is long. To bring such objects together as they hurtle at ridiculous speeds through the vast darkness of space is a tremendous feat of engineering. Ferrebeekeeper described the long and complex journey of Philae’s mothership, Rosetta, in this previous post.
An artist’s mock-up of how the probe might look on the comet’s surface (the underdressed astrophysicist is added for scale and is presumably not there)
Philae is equipped with space harpoons which are designed to fire into the comet’s surface–thus securing the craft to the flying iceball with lamprey-like tenacity. Actually, a lamprey might be the wrong comparison: the lander looks astonishingly like a bacteriophage (a fact which I think is exceedingly strange and funny). At any rate, it is presently unclear whether the landing harpoons correctly deployed into the comet’s surface. We’ll know more in coming days.
Indeed, in coming days we should be finding out lots of things regarding the comet. The lander has a small drill which is meant to mine 20 cm (8 inches) into the icy substrate. The sophisticated machine is also equipped with devices to analyze the core sample, gas analyzers to identify any complex organic compounds, and instruments to measure the comet’s magnetic field. Scientists will be keeping a close eye on the comet to see what effect the solar wind has on it as 67P sweeps in close to the sun in coming months.
November 13th UPDATE: It seems the plucky lander had a more adventuresome landing than yesterday’s rosy headlines may have indicated. Apparently Philae landed not once, but multiple times as it bounced down a cliff and fetched up (on two of three legs) in a shadow. Mission controllers are contemplating whether to fire the landing harpoons, but are concerned that the resultant explosion could send Philae careening off the comet into the outer dark. Anyone who has thrown a washing machine down an ice cliff in low gravity will surely sympathize with their predicament…
An Artist’s Rendering of Rosetta Approaching the Comet (ESA)
Today a winter snow storm has transformed Brooklyn into a huge ice ball–at least metaphorically speaking–but the weather will surely improve. Home will not be a ball of ice forever. The same cannot be said for the Philae robotic lander which is currently aboard the European Space Agency’s Rosetta spacecraft (which, in turn, is currently in outer space returning to the inner solar system after 31 months in the dark cold outer solar system). If all goes according to plan, the Rosetta spacecraft will enter a slow orbit around comet 67P/Churyumov–Gerasimenko in May of 2014. Once the space probe is in orbit around the comet, it will (eventually) fire the Philae probe onto the comet itself. Philae is equipped with space harpoons to latch on to the comet’s surface and cling to the hurtling slushball. Once there, the little robot lander will assay the comet with its drill and ten onboard sensors in order to learn more about the birth of the solar system–when the comet (probably) came into existence.
An artist’s rendering of Philae Making a Soft Landing on the Comet this coming November (ESA)
There are many remarkable aspects to this astonishing mission (which launched a decade ago), but one of the most harrowing periods just ended. Because the spacecraft is powered by solar panels, it did not receive sufficient energy to operate during its long sojourn through the outer solar system. For two-and-a-half years, the mission controllers in Darmstadt, Germany have been in suspense waiting to see if Rosetta had survived being all but shut down (because of a last-minute mission rewrite, the craft was not designed for any such suspended animation). Yesterday the spaceship woke up and radioed back to Earth! The mission is on! I can hardly wait for May (for multiple reasons).
Marbled cone snail (Conus marmoreus) by shadowshador
In olden days, in Australia, young healthy beachgoers were sometimes found lying on the shore dead. Their bodies gave no evidence of trauma, indeed they had not even gone into the water. Something just struck them down as they sauntered along the beach. It was not until 1936 that the mysterious killer was finally revealed when a beachcomber picked up a colorful snail and began to scrape its shell with his knife. The unlucky young man uttered a cry as the snail somehow pricked him. He then fell down, went into a coma, and shortly died. Because of witness testimony, coroners knew what to look for and they removed a tiny poisonous harpoon the size of a small hair from the victim’s hand. The culprit turned out to be a cone snail, one of a diverse group of deadly gastropod mollusks.
The Geographic Cone Snail (Conus geographus) shows its siphon and proboscis. This snail is also humorously called “the cigarette snail” since if one stings you, you allegedly have time for one cigarette before dying.
There are over 600 different species of snail within the genus Conus and they are all poisonous predatory hunters. The smaller cone snails hunt tiny mollusks and worms but the larger snails feed on fish, which need to be quickly subdued (so that they do not injure the snail by thrashing about) and then consumed with equal dispatch so that other ocean creatures do not steal the meal. In order to quickly dispatch their prey (and defend against larger predators), Cone snails have a sophisticated weapon–a modified radula tooth which directly injects potent venom by means of a tiny harpoon-like “dart.” The snail finds prey by carefully testing/sniffing the water with a siphon. It then stretches out a long flexible proboscis and fires the disposable hollow radula tooth (filled with venom) into the prey by means of a powerful muscle contraction. Below is a shocking film which shows a cone snail killing and consuming a clown fish by such means. It is not for the faint of heart!
Although cone snails are obviously alarming to divers and shell collectors (particularly in warm tropical reefs where the large poisonous specimens live), the potent cocktail of neurotoxins utilized by the creatures is of great interest to pharmaceutical researchers. Since each species of cone snail has a very large number of different “conotoxins” in its poison, scientists have been struggling to catalog and understand the dangerous mixtures. These conotoxins are generally peptides which interfere with the ability of nerve cells to communicate with one another. Not only might such chemicals provide the key to curing neurodegenerative diseases and brain cancers, conotoxin research is now the most promising avenue towards effective medications to deal with certain sorts of chronic pain.
A lovely diagram of Conotoxin Peptides from “The Journal of Neuroscience”
Unfortunately all of this research has not provided any effective antitoxins for victims of cone snail stings. If a person is fully darted by one of the large poisonous specimens, their best hope is to go on a ventilator until their body expunges all of the poison—an uncertain prospect at best.
A Tiny Sample of the Exquisite Variety of Cone Snail Shells (Photo by Pet/Wikimedia Commons)
Many cone snails have beautiful colorful shells marked with vivid abstract patterns. Some of the most valuable shells ever came from cone snails–which continue to fascinate conchologists and shell collectors. Even today divers and beach combers are sometimes overwhelmed by the beauty of cone snails and reach out to grab the lovely creatures. Hopefully this article has convinced you that doing so is a very bad idea.
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