few nights ago I saw on TV the movie Deep Impact , 1998, produced by Steven Spielberg. He whipped his head in this post for a while 'time, and especially I stopped to consider whether to inform / misinform people with a film that certainly has no scientific pretensions, but very little was enough to give him an aura of greater verisimilitude. We have to make a hand accounts with me?
A bit 'of data.
In the film a comet is discovered on a collision course with the earth. The star, named Wolf-Biederman is a beast from about 12 km in diameter, " wide enough to clear the ground on impact ," is said.
the operation is launched Messiah, which aims to nuke the comet, but this can only break it into two parts, from the first 2.4 km and 9.7 km from the second. The first fragment
impact with Earth just above Bermuda, and there happens to data known.
Unfortunately, two core values \u200b\u200bare unknown: the speed of the comet, el ' angle of impact. Assuming, hypothetically, that are the worst ever for the earth: the angle of 65 ° and speeds of 70 meters per second. Usually comets are made of rock and ice, so we estimate a density of 1500 kg per cubic meter, as a porous rock. Moreover, as we said, the piece hits the Atlantic Ocean just over Bermuda, say 200 km, the sea there is already 5000 meters deep.
Ok, we have all the data ... simulate.
WHAT HAPPENS TO BERMUDA - 200 km south of the impact
The impact energy is 6.54 x 10 ^ 6 megatons. The fireball resulting from the impact has a radius of 57 km, 65 volte più larga del diametro apparente del sole in cielo, e dura 13 minuti. L'irradiamento è 387 volte quello del sole.
Dopo 850 millisecondi dall'impatto l'isola viene investita da questa radiazione: la carta, il legno, l'erba, gli alberi, i vestiti si incendiano, i corpi umani direttamente esposti subiscono ustioni di terzo grazo.
Dopo 40 secondi dall'impatto arriva la scossa tellurica: non è fortissima (8° grado della scala Richter) perchè l'impatto è attutito da 5 chilometri di acqua, ma è avvertibile. Le case più fatiscenti (a Bermuda immagino molte) sono danneggiate considerevolmente, ma nelle strutture più moderne si sposta al opens up some furniture and some crack. After 4 minutes
impact come the "bullets", or debris from fallout: on average by 4 cm pieces, big enough to break windows and severely injure people who are not protected.
Unfortunately there's more (always remembering that we are still in the presence of the initial fireball!). After 10 minutes comes the shock wave. The breath is impressive traveling over 2000 km / h, almost three times the speed of sound. The intensity of the noise is more than 100 decibels, enough to cause hearing impairment. But the wind itself is causing the collapse of all the wooden buildings, precast and those with metal or plasterboard walls. Many supporting elements of the bridges are washed away. The glass is pulverized. Cars and trucks bent and distorted as if they were clay. Trees instantly eradicated. The individuals affected directly the wave to die instantly from impact injuries, trauma and internal bleeding.
If you think it over, or that someone may have saved, you are wrong. A quarter of an hour come from the impact of tsunami waves: the lowest is 134 meters. The highest of a mile. Bermuda is wiped off the face of the earth.
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WHAT IS HAPPENING IN NEW YORK - 1100 km northwest of the impact
enough, but certainly not in the photo as shown here, from the film frame. After 4 minutes the earthquake comes, but it is felt only on the top floors of skyscrapers. After 8 minutes powder comes a rather large (average 233 microns) after 55 minutes the shock wave. The windows shake, 30% of the trees of Central Park is destroyed, but nothing more. More concerned about the Tsunami: the amplitude of the waves is between 4 and 187 meters high, more or less half of the Empire State Building. With a good evacuation plan, it would be impossible save many lives, but certainly it would take a lot for the reconstruction of the city. Of course there is so much destruction that is portrayed in the film. In fact the film the shock wave propagates faster than the radiation, after only 30 seconds to dry up the American coast and the tsunami wave arrives after 40 seconds, completely enveloping the then still existing World Trade Center (526 meters to spire). Definitely an effect, but greatly exaggerated.
WHAT HAPPENS IN ITALY - 6700 km north-east of the impact
Nothing. Tremor perceptible only in the tools. After about half an hour from the impact reaches an end dust. The shock wave is a breeze. The tsunami (waves up to 10 meters, which are still ladies waves) are damped by Portugal, Spain and Morocco and slips in the Mediterranean.
physics and mathematics are not opinions ...
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