Alien Destroyers

1996/04/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Geologia
• Astronomia

In our view in July 1994 comet Shoemaker-Levy 9 fell on Jupiter. Observing such a terrible shock can lead humans to wonder if we can suffer similar collisions and, consequently, if terrible damage can occur or destroy our species. Such events also raise the issue of gradualism versus catastrophism among geologists. The answer may be in geological history and astronomy.

If we look at the moon any clean night, we will see impact craters of asteroids, comets and meteorites jumped in it. As on the Moon, many fireballs have also hit our Earth, although almost all craters and remains have been climbed or coated. Most of these types of shocks and impacts occurred during the childhood of the Solar System, but Comet Shoemaker-Levy 9 showed us that large shocks still occur, coinciding with Jupiter's suicide. The Earth's atmosphere gives us great protection from the smaller fireballs that frequently fall, which burn with shooting stars as they enter the atmosphere. On the contrary, those who are too large to burn completely reach the Earth's surface releasing enormous energy through impacts or explosions.

For example, in 1908, after a long distance to the atmosphere, a meteorite exploded at 6-10 kilometers of altitude in Siberian Tunisia. This explosion had the strength of a 15 megaton atomic bomb that caused the fall or burning of 60 million trees. It is estimated that if New York exploded, a million people could die. It seems that with a few centuries similar events occur, very often. Moreover, if, instead of occurring at the beginning of this century, 50 years later, the third world war could erupt, as the Soviets could regard the explosion of the meteorite as one of the gates of the Americans.

Severe impacts often occur with high geological frequency. Thus, in the rocks that go from the beginning of the Cretaceous to the present day, in the last 140 million years, about 30 impact craters of greater diameter than 5 km are known, and I think that in the next few years there will be hundreds more. Moreover, in geological history more and more data are related to the impact of some biological fireball destructions. Serve as an example the Chicxulub impact crater at the end of the Cretaceous. This underground crater of Yukatán is 180 km in diameter and, according to some, the dinosaurs and ammonites that were destroyed as a result of the physical-chemical changes that suffered the atmosphere and surface of the entire Earth.

Still today there are about 2,000 fireballs of more than a kilometer that can cross into the orbit of our planet. For example, it has recently been estimated that on August 14, 2126 comet P/Swift-Tuttle may collide with Earth. Of course, the calculations do not ensure that the shock occurs, but the probability of it occurring is quite high. This comet does not stop scaring dust and waste on his journey, dirtying his path. The Earth crosses this route every year on August 11 and the entrance of waste into our atmosphere causes the famous shot of shooting stars.

As mentioned above, the impacts of meteorites, asteroids and comets can profoundly affect the biosphere and, in the opinion of some, cause species extinction. These collisions can pose a risk to our species, as they can cause our destruction. On the one hand, to predict possible shocks and, on the other, to be able to take measures to avoid them, it is necessary to conduct specific astronomical studies and observations.

Among the measures, the use of powerful nuclear explosives in military environments has been proposed to destroy or at least divert the fireball. But the strength of many fireballs is greater than that of all the explosives in the world, so other measures should be taken. Therefore, some scientists propose to strengthen space research in order to migrate to new planets to save our species in the near future.