You are currently browsing the tag archive for the ‘dart’ tag.

The Dart Impactor (gold) being loaded into the faring of the launch vehicle at Vandenberg Launch Facility

Wow! Have you been following NASA’s DART mission? “DART” is one of those Ghastly-Acronyms-which-Spell-out-the-Project (GASP!) which stands for “Double Asteroid Reflection Test”. Scientists are always discouraged that their jaw-dropping projects conducted in outer space can never garner the same level of attention as inane sports and celebrity folderol–so they give missions these names with futile hopes of grasping the popular imagination. Speaking of whipping up attention, you should immediately google “DART” to see Google’s unprecedented graphic/animation (uh, and all of the information and scientific details about this project, of course).

Anyway, the project’s name aside, DART is a smashing success and something which humankind should have been working on since the dawn of the space age. Ever since we finally understood what caused those craters on the moon (which took longer than you might expect) and the Alvarez hypothesis explained what caused the Cretaceous-Paleogene mass extinction, scientists and engineers have realized that humankind needs a proper planetary defense system to protect us from meteors, bolides, comets, space shards, and whatever cosmic flotsam and jetsam has been drifting around out there waiting to wreck us the same way the poor dinosaurs got creamed.

“Grawwwwwr! Why did we spend so much on stock buybacks and so little on basic science?”

Although some previous asteroid and comet exploration missions have edged towards testing the behaviors of space objects subjected to manmade impacts and forces, the DART mission was designed specifically for the purpose of finding out about such things. Back in November of 2021 NASA launched a 610 kilogram impactor spacecraft to crash into Dimorphos (a tiny asteroid which orbits the larger asteroid Didymos). On September 26 (2022) the impactor crashed into Dimorphos as the Italian mini-satellite LICIACube looked on (as did many of our best telescopes).

Here is a NASA schematic which explains the mission (and its hypothesized outcome) far better than I could.

Of course in the grand scheme of things 610 kilograms is not very much mass–although a 610 kilogram (1340 lb) linebacker smashing into you would probably wreck your day–especially if he was running 6.6 kilometers per second (15,000 miles per hour) which was the closing velocity of the projectile and Dimorphos. Indeed, the Hubble and Webb space observatories were both keeping an eye on the collision and the results were pretty explosive.

We will await the exact numbers (scientists speculate that such an impact should release 20-30 gigajoules of energy–approximately equivalent to detonating 6 or 7 tons of TNT). Also, an EU spaceship named Hera is being dispatched to survey the results in 2026 (so more to follow). For now though, I am already breathing easier knowing that someone is finally working on this problem. Now we just need to work on the 8 billion other problems which are affecting Earth and casting a pall over humankind’s glorious future,

Advertisement

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.

Ye Olde Ferrebeekeeper Archives

February 2023
M T W T F S S
 12345
6789101112
13141516171819
20212223242526
2728