If you ever take out the gutters on your roof, note: The dirt you throw may have come from outer space.
The new book "Cosmic Impact: Understanding the Threat to Earth from Asteroids and Comets", by Andrew May (Iconbooks) provides an overview of the potential dangers we may one day encounter from near Earth objects (NEOs) and notes that in smaller scale objects that fall to the earth from space a daily occurrence.
"On an average day, about 1
However, dust particles from space do not place the planet and its residents in deadly danger. Asteroids like the one who extinguished the dinosaurs are worrying.
The Chicxulub crater, 124 kilometers, near Mexico's Yucatan Peninsula, was forged 66 million years ago when an object about 69 miles across entered the area from space. The resulting fire and dust – the latter that covered the earth's atmosphere, which almost knocked out the sun – eventually killed by the dinosaurs.
If we were to meet with a similar object today, the result would be similar.
"The fossil would be so much larger than anything in human experience that it is difficult to imagine," writes May. "If the effect occurred in the ocean, the water would boil. If it were on land, large areas would be hardened by firestorms. The dust created by a Chicxulub size would prevent sunlight from reaching the surface of the earth for months – perhaps even years – com. "
However, the good news is that the odds of such an object that strikes the earth in our lives are near zero.
The Turin scale takes into account the size of the NEO and the chance that they will hit the earth over the next hundred years to place the possible danger on a scale of 1 to 10.
Currently, the coming century is looking free.
"There is currently no known object with a Torino rating, as high as 1," writes May. "Everything we know is either too small to hurt or there is no chance that it will collide with the earth over the next hundred years."
However, this has not always been the case. As recently as 2004, an object was discovered that had a troubling Torino number 4, which meant a decent chance of getting in touch with what would cause incredible destruction.
When scientists discovered a 350-meter asteroid that year, they estimated a greater than 1 percent chance of colliding with the Earth in 2029. Given its size, it would have led to a "thousand-megaton class" explosion well. (In comparison, May may write that the core bombs exploded over Hiroshima and Nagasaki was about 0.02 megatons each.) [Luckilysucceedingcalculations"refinedtheorbitandexcludedacollision"writesMay
But while the risk of a planet-destroying asteroid is currently zero, outer space oscillates with smaller objects that, while
is, in fact, they already have.
June 30, 1908 saw "the greatest cosmic effect in recorded history" when a "small rocky asteroid or possibly a small comet," the later est, which formed between 30 and 70 meters, exploded over the "sparsely populated Tunguska River Valley in Siberia" .
The place was happy, because the explosion, a thousand times more powerful than the bombs used in Hiroshima and Nagasaki, was not killed.
"When the Tunguska object entered the Earth's atmosphere, [there] was an explosion of the order of 10-15 megatons – typical of a cold-weapon nuclear weapon," writes May. "The most obvious effect was to score and flat trees – 80 million of them – out in a radius of 30 kilometers around Tunguska's" ground zero "."
Can quote a researcher named Gerrit Verschuur, who wrote that "estimates of accidents that would originate from a Tunguska-like event in a populated area … suggest as many as 5 million dead."
It is said that the possible effects of the impact of a smaller, non-planet-destructive NEO are not all negative, since comets can provide significant resources to our planet and may have already done so can cite Verschuur, who wrote in 1996: "A dozen or so massive comets carry enough water and organic molecules to provide the whole earth's water and biomass. " This may also apply to certain asteroids and meteorites.  Can actually write that a "significant fraction" of the earth's water and organic organisms has just come that way.
He notes that a meteorite landing in Australia in 1969 was found to have "at least 15 different types of amino acid, as well as a significant amount of water – about 10% by weight."
"Impact … was much more numerous in the Earth's early history, "he writes. "So it is not unreasonable to imagine that they brought much of the raw material needed for the formation and development of life."
Since a NEO collision with the earth is more likely to destroy life than to create it, the United States monitors the atmosphere, preparations for any intervention.
NASA is constantly watching the sky with large telescopes from points in Arizona and Hawaii. But even this defense has risks.
In February 2013, astronomers identified an asteroid as they named 367943 Duende, who would pass near the Earth, but did not make contact.
Some skeptics believed that the asteroid would strike us despite the researchers "insurance, which is not unusual. When" a large meteor exploded in the sky over Chelyabinsk [Russia] that day, "the skeptics felt righteous.
But the scientists had not been wrong At Duende, the meteor that exploded turned out to be quite another that they failed to discover because it "came from the direction of the sun, which meant" was just over the horizon in daylight when telescopes couldn't see it. "
" This blind spot around the sun is a constant annoyance for NEO hunters, "writes May." They just have to hope everything hiding there comes out before it strikes us. "
There is no way to defend Against an object that we never see if a NEO would be seen on a direct path to the earth, there are alternatives to the earth's defense. Here they are all risky. [an] ansteroid can be destroyed by detonating a nuclear weapon on it, but the many resulting fragments would continue along the same orbit, making the blow as potentially detrimental as the avoidance hit. Therefore, researchers would be much more likely to try to deflect the object to throw away its orbit completely.
NEO would have to be printed Directly from its orbit or change its speed, neither the direction nor the possible speed would mean anything that would significantly change the course of the object would prevent it The keyword there is, however, "significant".
"A NEO large enough for us to worry about will be much more massive than we are used to pushing," May writes. "
" A 1 kilometer long rock amounts to more than a billion tons – or something like 10,000 airlines. How are we going to drive it into a new orbit, even if it's just a small part? "
An answer gives us back to the nuclear asset.
Water bomb pioneer Edward Teller proposed, in this scenario, landing a nuclear explosive on the object itself, as the force of detonation would drive it out of its orbit. Unfortunately, this would require" a spacecraft matching the speeds with the asteroid and landing on it. "
It would take years and leave the project open for all kinds of complications.
Others have suggested exploding the device near the object, rather than on it, may have the same effect. Given the risk – and sending a nuclear unit into space, it would break several international treaties – the use of this method is unlikely.
However, throwing the object out of circulation would not require a nuclear unit if we could construct a spacecraft or other propellants to crush directly into it.
When NASA sent a probe to a transient comet in 2005, it was to inspect However, the speed achieved did just that, the comet's course changed by 0.00005 millimeters per second and lending credibility to the tactic, if needed.
Fortunately for us, this is probably academic, as mentioned earlier, as the chance that an NEO that is large enough to cause significant damage to the earth during our lifetime is practically zero.
Of course, if we lose it in the sun.
This article originally appeared in the New York Post. 19659049]