One-In-A-Million Collisions

March 17, 2009 at 8:33 am (randoms)

Not enough space in the Universe? or did somebody switch on the Improbability Drive?

Collisions of an unusual nature have been in the news lately. First, we had the story about the satellites, one Russian and one American, colliding in space and then only days later, two heavily armed and highly dangerous nuclear submarines belonging to Britain and France collided in the vast empty spaces beneath the Atlantic Ocean. Two one-in-a-million collisions, it would seem.


Space junk, lots of it – image via

1. In Space

Space objects have collided accidentally in orbit before, but these were considered minor incidents and involved either leftover portions of used rockets or small satellites. The February 2009 collision, five hundred miles above Siberia, was the first impact at high-speed involving two intact spacecraft – a derelict Russian satellite and a working American Iridium satellite. Watch a good news coverage of this collision here.



(images via 1, 2)

The Iridium network consists of sixty six very fast moving communications satellites in relatively low orbit. Most communications satellites circle the planet in higher orbits, making collisions much less likely. The collision at 26,000 mph completely destroyed both the Kosmos 2251, a former military communications craft, weighing 2000 lbs, and the Iridium orbiter, which was 1235 lbs. The American satellite was operational at the time of the collision, but its Russian counterpart had been inoperative since at least 1995. The crash created debris clouds traveling at about 660 feet per second, between 300 and 800 miles above the surface of the Earth.

Space Junk Inc.

At the beginning of 2009, there were estimated to be 17,000 man-made objects classed as debris in orbit, but both American and Russian experts still have no idea how much space junk came out of the collision or how large the pieces are, although there could eventually be thousands of them. Both space agencies however agree that the collision posed no immediate danger to the International Space Station, which operates at a lower altitude than the orbit where the crash occurred, which contains a multitude of telecommunication, weather and earth tracking satellites.

However, the debris may threaten these spacecraft and even tiny fragments could later trigger a chain of collisions. Read this latest news headline: “Station crew has close call with space junk”click to read the story

“The three crewmembers of the International Space Station had to take refuge Thursday in an escape pod while a piece of space junk big enough to punch a hole in the station hurtled dangerously nearby. The crew spent 11 minutes in the Russian spaceship called the Soyuz. Any hole in the station’s walls could allow the oxygen to leak out, depriving the crew of air. The piece of debris was more than 10 times bigger than the smallest object that can penetrate the station’s shielding”

Wayward debris in orbit is classed as the number one threat to the safety of a space shuttle when actually in space, exceeding the hazards present during take off and landing. Space is certainly a crowded place these days. Some satellites come as close as only a few hundred meters of each other every day of the week, but given the increasingly congested environment and the lack of a method to remove dangerous debris from orbit, there are bound to be more crashes sooner rather than later.

2. In the ocean depths:

Not as vast as space but big enough to intimidate human imagination, Earth’s ocean depths would be an unlikely place for collisions. And yet in the depths of the Atlantic, two nuclear submarines, bristling with weapons of mass destruction, hit each other in yet another one in a million collision. Both vessels, HMS Vanguard and a French submarine of the Triomphant class, were damaged while on a routine patrol at relatively low speeds in the word’s second largest ocean, although no one was injured.



(images via 1, 2)

Despite what we see in movies, submarines do not travel around the world pinging their sonar to see what is out there, since this gives away their own position. As part of its nuclear deterrent, Britain maintains at least one submarine in the Atlantic twenty four hours a day, 365 days a year. HMS Vanguard carries 16 Trident missiles with a maximum of 48 nuclear warheads. Its French counterpart is no doubt similarly equipped. The odds of this happening may seem high, but it is clearly possible and if a bigger collision had occurred, an explosion involving multiple warheads, as well as two nuclear reactors, would have been catastrophic.


Test firing of a hopefully unarmed nuke from Vanguard; images via

This wasn’t the first such accident either. In recent years, there have been numerous submarine collisions with icebergs, rocks, underwater mountains and of course other undersea vessels, as well as numerous incidents from the Cold War that were long kept secret. Engaged in covert surveillance, NATO and Soviet submarines would engage in deadly games of cat and mouse, coming as close as they dared to their adversaries. Collisions were inevitable and although many weren’t too troubling, some were very serious, since even a slight bump between two vessels weighing in at 4000 tons could have disastrous consequences.

Here are some abandoned Russian submarines, left out to rust in Nezametnaya Bay (photo taken in 2005):


(images via)

While the damage to the British and French submarines is reported as minor, the same cannot be said for the nuclear powered US submarine San Francisco, which in early 2005 plowed into an undersea mountain in the Pacific. The mountain apparently did not appear on the navigational charts of the area. The head on crash occurred some 500 feet below the surface, destroying a sonar dome on the sub’s nose and peeling back a large portion of the vessel’s outer hull. Fortunately the inner hull, protecting the living quarters and operational areas of the submarine, was largely undamaged, although crew members were forced to take emergency measures to reach the surface before limping back to Guam. One man was killed and sixty others injured in the incident.


(image via)

3. In the air:

This is not the place to discuss aircraft collisions, but one in particular bears mentioning in the context of unlikely collisions. Antarctica is largely deserted and desolate and perhaps the last place you’d expect a plane to be involved in a collision. However, back in November 1979, Air New Zealand flight 901 set off from Auckland for a sightseeing tour of Antarctica. Mt Erebus, one of the major attractions, is the southernmost active volcano on earth and part of the Pacific Ring of Fire. Empty skies, no other air traffic and no real obstacles should have meant a perfect flight over the polar region and back home. Yet, in what is known as sector whiteout conditions, the flight crashed into the volcano, killing all 257 passengers and crew. During the summer months, melting snow on the volcano still reveals wreckage, almost thirty years later.


(images via)

4. Potential collisions with comets and asteroids:

One-in-a-million might describe the Earth’s potential collision with comets, asteroids and meteors, taking into account the sheer vastness of space when compared to the size of our planet. However, impacts with heavenly are far from rare and often cataclysmic. When Comet Shoemaker-Levy 9 collided with Jupiter in 1994, the incident provided considerable new information about the giant planet. The comet’s fragments collided with Jupiter’s southern hemisphere at sixty kms per second and the scars from the impacts were more easily visible than the famous Red Spot for several months.



(images credit: Don Dixon, NASA)

Most members of the scientific community are in agreement that the earth will experience something similar at some point in the future and there is ample evidence that the planet has suffered such impacts in the past. The best known is the one which most likely ended the reign of the dinosaurs some 65 million years ago, but there is a more recent incident.

The Tunguska Event was a powerful explosion in a remote and sparsely inhabited region of Siberia in June 1908. The exact cause of the blast is still in dispute, but was most likely the result of the air burst of a large meteorite or comet fragment between three and six miles above earth’s surface.

The object is estimated to have been up to a hundred feet across, traveling at 21,000 mph when it exploded. The energy released by the blast is still the source of debate, but could have been around ten to fifteen megatons, or around 1,000 times more powerful than the Hiroshima bomb. An estimated 80 million trees over 830 square miles were simply blown over and the accompanying earthquake would have measured 5.0 on the Richter scale. The remoteness of the Tunguska region, combined with the chaotic aftermath of the Russian revolution and civil war, delayed any investigation of the incident until 1927, when the Soviet Academy of Sciences dispatched an expedition to the area.


(images via 1, 2)

The pattern of destruction in the surrounding forest indicated a powerful detonation followed by shock waves spreading outwards from the centre. High levels of iridium and nickel, usually found in meteorites, were discovered in samples from the local soil. Eyewitnesses reported seeing a blue fireball in the sky, followed by a flash and a deafening explosion that apparently was heard three hundred miles away. The ground shook and people spoke of a strange, hot wind, which swept across the land, shattering windows and even burning crops in the fields.


(art by Korado Korlevic and Leonid Kulik)

Close call for Europe –
Interestingly, had the meteorite struck 4 hours, 47 minutes later, based on the rotation of the earth, it would have hit St. Petersburg, the nation’s capital, rather than some remote area of the country. A few hours later, the impact site would have been in Western Europe, just six years before the outbreak of the First World War. The ways in which history might have unfolded differently, had this one in a million collision occurred at a slightly different time, truly boggle the mind.


(art by Don Davis)

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