(ORDO NEWS) — On May 15, a large asteroid 2009 JF1 will fly past the Earth at a distance of 23 million kilometers. Although far from a collision, it is considered potentially dangerous. But what does that mean? Are there “doomsday asteroids” capable of destroying humanity? And is there a plan in case they appear?
In “childhood” the Earth (like other planets of the solar system) was constantly bombarded by asteroids and comets.
This period began approximately 4.1 billion years ago and ended 400 million years later. In memory of him, the planets left scars – like dimples on the face after teenage acne. We can judge their scale from the craters on Mars, Mercury and the Moon.
This period, according to planetary scientists, was associated with the migrations of the giant planets. When all the orbits of the planets stabilized, the intense bombardment ceased. Over the next three billion years, fairly large celestial bodies crashed into the Earth only a few times.
Encounters with asteroids have seriously influenced the history of our planet. There is even a hypothesis that the fall of debris could melt significant amounts of ice and serve as one of the reasons for the end of the ice age. And this, in turn, could contribute to the emergence of complex multicellular life on Earth.
But today, the descendants of the early inhabitants of the Earth are unlikely to welcome guests from the past. However, the threat should not be exaggerated either.
The main question is: can a stray asteroid destroy humanity? There is no exact answer, but we have an example of an extremely catastrophic scenario from the distant past.
At the end of the Cretaceous period, approximately 65.5-66 million years ago, an asteroid with a diameter of about 10-15 kilometers fell to Earth. It is also important that it fell at a very dangerous angle – about 60 ° to the horizon.
As a result, the maximum amount of dust got into the atmosphere. It dissipated all over the planet, which led to the onset of a kind of “nuclear winter”. At an angle of 15°, the amount of emissions would be about three times less. And with a vertical – ten times.
According to the calculations of geophysicists, the impact caused giant waves 50-100 meters high, which went far deep into the continents. The planet was enveloped in a huge dust plume, which plunged it into twilight – the sun’s rays could not break through the thickness of dust and soot.
As a result, the temperature on the continents dropped by 28°C, and in the oceans by 11°C. Entire species of animals (primarily giant dinosaurs and mammals) perished, while the spread of the rest was greatly slowed down. However, as we see, life on Earth is still preserved.
According to Richard Binzel, professor of planetary science at the Massachusetts Institute of Technology, there are no asteroids of this size known to science in space that would threaten the Earth. At least, science does not yet know about such. But of course even smaller bodies can cause massive damage.
“And rained down fire and brimstone…”
In the history of mankind, events have already occurred that modern studies correlate with the fall of large meteorites.
Historians suggest that the echo of such a catastrophe is the biblical description of the death of Sodom and Gomorrah. In 2021, archaeologists, based on excavations in Jordan, near the shores of the Dead Sea, came to the conclusion that the same legendary city was destroyed in this way.
Their attention was attracted by a very thick, one and a half meter layer, almost entirely consisting of burnt organic matter and ash. Radiocarbon analysis dates it to 1650 BC. e. Scattered fragments of skeletons were found in the layer (some of them were burnt).
But the main thing is that the layer survived heating up to 2-2.5 thousand degrees (this is obvious from the samples of molten metal). This is an absolutely atypical picture for any fires of that time, and is more like the consequences of … a nuclear explosion.
Obviously, in the XVII century BC. e. there were no atomic tests yet (if you do not seriously consider the version with the visit of aliens). There were no volcanic eruptions of this magnitude nearby either. Most likely: a meteorite with a diameter of 800 m to 1.5 km exploded over the city.
Judging by the size of the affected area – fifty kilometers – the explosion could not be weaker than 12-23 megatons, and this is a thousand Hiroshima. It is difficult to estimate the specific yield because the impact of the explosion on the land surface depends on the angle at which the blast wave and radiation from the flash reached the surface.
In the Old Testament, the fate of Sodom and Gomorrah is written as follows: “And the Lord rained on Sodom and Gomorrah brimstone and fire from the Lord from heaven, and overthrew these cities, and all this region, and all the inhabitants of these cities.” It goes on to say that the crops also perished.
Only Lot was saved, and his wife, looking around, turned into a pillar of salt. All this, according to the authors of the article, is very similar to the real picture of the explosion. Light radiation looks like fire from the sky and leaves deadly burns on everyone who is in the epicenter. And the salt probably got on the bodies from the Dead Sea.
If something similar happened 3.5 thousand years ago, then the probability of finding this event in our time is no longer so low. And here is another frightening assumption: what if there were even more such events?
It’s just that in the era of the existence of Sodom and Gomorrah, there were not so many settlements, and written evidence of such catastrophes might not have reached us (if they existed at all). In any case, the destruction of a large city by an asteroid is a very real risk.
Track first, act later
Several organizations are engaged in the detection of dangerous asteroids and comets, their study and risk assessment. One of the largest is NASA‘s Planetary Defense Coordinating Bureau.
He now has about 27,000 near-Earth asteroids on his list, 2,224 of which are large enough to be considered potentially dangerous. But what does “potentially dangerous” mean? Maybe these words are just a formality, and there is nothing to worry about?
“When assessing a potential threat, two factors are taken into account: the size of the object and the distance, and not even between the asteroid and the Earth, but between their orbits.
“When we observe an asteroid, we we see it as a point. In fact, we can only evaluate asteroids by their brilliance. Potentially dangerous are those whose absolute magnitude is not weaker than twenty-two.”
Collisions of the Earth with dangerous space objects do not occur when they move along the same trajectory, but at different times. However, the orbits are constantly changing. This is due to many factors.
For example, with the fact that the shape of asteroids is not as correct as that of the planet. Most asteroids are dirty “snowballs” of rubble and ice that spin unsteadily. This also affects the flight path – as does the gravity of large celestial bodies that are in the way, and the pressure of sunlight.
There are also cases where threats come into view quite unexpectedly. For example, on March 23, 1989, the asteroid Asclepius flew at a distance of only 684 thousand km from the Earth, which is two radii of the lunar orbit. In fact, he was “late” to the meeting with our planet by only six hours.
And they discovered it only nine days later than this event. According to scientists, in the event of a collision, the energy from the impact would be 600 megatons. By the way, astronomers have been celebrating March 23 as Near Miss Day.
Prediction methods are constantly improving. For example, twenty years ago, scientists were worried about the newly discovered 270-meter asteroid Apophis. The probability of its collision with the Earth in 2029 was estimated relatively high (up to 2.7%).
But refined calculations have reduced these data to fractions of a percent. And although the probability of a major collision in the near future (within 100 years) is small, it is almost certain that it will happen sooner or later. Not with one, so with another. Are we ready for this?
Blast, repel or paint
Opportunities largely depend on how soon we detect a dangerous object. For example, to destroy a huge object that has come close enough to the Earth, there is so far the only option – to blow it up with a nuclear bomb.
But now such a project is hampered by a treaty banning the use of nuclear weapons in outer space. If this is allowed in principle, the question of collective security will arise: after all, the presence of nuclear weapons in orbit can create more risks than even an asteroid.
The same applies to the plan, which involves the use of powerful ground-based lasers. With their help, it is theoretically possible to vaporize a space alien, but allowing their use will change the balance of power. After all, such a laser can be used against satellites, and against missiles or shuttles. And it will be extremely difficult to reflect the beam or somehow protect yourself from it.
A more realistic option is to try to change the asteroid’s orbit in order to deviate it from its course. In 2021, NASA astronomers reported that it could take 5 to 10 years of preparation to realize this plan. However, there is also a risk of failure here.
For example, five years ago, as part of a simulation, a virtual asteroid fell on the American city of Denver, and a virtual ship collided with it and changed its course. But it only got worse: the deviation turned out to be insignificant, and the asteroid “collapsed” no longer on Denver, but on New York.
NASA ahead, China catching up
However, real tests of the space ram are already underway. The first option – to use a propulsion system that knocks an asteroid off its trajectory – is currently being tested by NASA. In November 2021, the agency launched a probe to the double asteroid Didim Dimorph. It orbits around the Sun and so far does not pose a threat to our planet, although it periodically approaches the Earth.
The purpose of the device is to crash into Dimorph at a speed of 25 thousand km / h and move it a little. As a result, the time for which it makes one revolution around Didyma will be reduced by several minutes. Although the deviation will not be too large, it will be enough for it to be fixed using telescopes from Earth.
Another way that seems pretty funny at first glance is to simply smash a barrel of paint on an asteroid. In this case, it can also change its trajectory: if part of the asteroid is more reflective (due to color), then the other will heat up more. As a result, gases will begin to be released, which themselves will create a reactive moment and push the asteroid off its trajectory.
Paint should be used as dark as possible because it has less reflectivity. The side that is painted with dark paint will heat up more. Asteroids are supposed to be painted with titanium dioxide (white) or soot (black).
Another promising way is to place a gravitational tractor near the asteroid. “The gravity tractor is a spacecraft that will hover on the side of the asteroid,” says Lindley Johnson, head of NASA’s Space Object Defense Office. “Its natural gravity, acting like a rope, will slowly pull the asteroid away from the trajectory that threatens the Earth.” .
China is also creating its own protection system. In 2022, the National Space Agency announced that in the next 3-4 years it will create a comprehensive threat alert system, as well as test ways to deal with them. Specialists have not yet disclosed specific methods. But, judging by the general words, they will also be associated with pushing the asteroid out of orbit.
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