Another quasi-miss – Skywatching



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This fall, we will have a close encounter with the asteroid 2006 QV89.

At its closest point, it is estimated at about 6.7 million kilometers (about 17 times the distance between the Earth and the Moon).

Taking into account the possible errors in the orbit calculations, the probability that it gets closer and actually hits us is about 1 in 7,300.

This object is about 40 meters in diameter and weighs about 80,000 tons. It is much smaller than the one that sealed the destiny of the dinosaurs, there are 64 million years, but it is still not to be taken lightly.

If it moved, for example, at 20 km / s, its impact would release about the same amount of energy as a four megaton nuclear bomb. If we miss it this time, as it is very likely, it will escape us again in 2032, 2045 and 2062.

It is not yet possible to predict exactly how close these encounters will be.

The moon is covered with craters formed by such impacts. We can find similar scars on Earth, for example on the Canadian Shield and Arizona, although weather erosion and plate tectonics suppress them, which does not happen on the airless, silent moon on the tectonic plane.

On July 30, 1908, something big enough slipped into the atmosphere over the Tunguska River in Siberia and exploded. The blast has shaved 2,000 square kilometers of trees.

It is believed that the object had a width of 50 to 100 meters, depending on its composition. A small change in the time of arrival would have had an impact on Western Europe, with catastrophic results.

As our lifestyles become more interconnected and interdependent, our vulnerability to natural disasters increases. Historical records show that on the human scale, the impacts of asteroids are very rare, but their consequences make it worthwhile to do our best to avoid them.

There are three facets to this.

First, we need to detect and identify asteroids that pose potential threats and update a catalog of threats.

The next step is to estimate the threat potential of each close encounter, preferably sufficiently in advance to be able to remedy it.

The last step is to do something.

The work on the first stage is well advanced and there are specific instruments sweeping the sky for asteroids, especially those with orbits that intersect or approach the Earth.

Assessing the threat potential in time to do something to mitigate the situation is more difficult. At the moment, we usually see asteroids at close approach, leaving us little time to do anything.

We need forecasts years in advance. The orbits of asteroids being constantly disturbed by the gravitational attractions of giant planets, especially Jupiter and Saturn, the challenge is daunting.

The work continues.

Attenuation is difficult. The method used in the movies, namely to fly adventurously towards the object and place a big bomb on it to explode, would make the situation worse.

Instead of being hit by an object at one place, we would be struck by several objects, all over the Earth. The idea is to spot threats long enough in advance so we can send a space mission to install a low thrust rocket engine to the surface of the asteroid.

He could use the material of the asteroid as fuel. The efficiency and thrust would be low, but the engine would run for years, gradually pushing the asteroid into a different orbit. The idea would be to push it far enough to account for any reasonable error in our orbit calculations.

Of course, for this solution to be feasible, we will need a launcher powerful enough to reach the asteroid within a reasonable time.

We are still far from it.

  • At 8:54 on June 21, the sun reaches its northernmost point on its annual voyages – the summer solstice.
  • Jupiter, who shines brightly, gets up around 22 hours.
  • Saturn rises at 23h
  • The moon will reach the last quarter on the 25th.

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