Destructive rocks

A recent study shows that the United States and China are the two countries most vulnerable to meteorites. In the absence of financial support, astronomers are struggling to control the risk of a guest from a distant universe that can destroy human civilization.

Outside the universe

There are between one and two million objects close to the earth (NEO) - that is, cosmic rocks that are orbiting the Earth within 30 million miles (about 50 million kilometers) - potentially endangering onions. Our planet. Of the 4,535 objects discovered and monitored (of which there are 704 unusually large objects) no object with route will inevitably hit the earth, but there will be millions of other objects. another potentially dangerous is hiding somewhere in the enigmatic universe.

Detect

Observation stations: The majority of observations are made by about 6-7 optical telescopes in the United States, Italy, Japan and Australia, coordinated through programs such as the left-close asteroid research project. land named Lincoln. This is a cooperative program, funded by NASA, between the Massachusetts Institute of Technology Lincoln lab and the US Air Force, primarily responsible for detecting and classifying objects near the earth. Amateur astronomers worldwide also support this work. With these collaborative efforts, the observation programs have discovered several new objects every day.

Action plan: Since 1998, NASA has funded Spaceguard, a group of active observatories to find 90% of NEOs with a diameter of about 6-700m as of 2008; so far this group has discovered three quarters of the estimated 1,100 NEO of this size. The Spaceguard's next step is to find 90% of NEOs with a size of 150m or more - estimated at 12,000 - between now and 2020, but the budget problem is not yet certain. Other large telescopes will be connected in Hawaii, Arizona and Chile in the next ten years, accelerating the speed of discovery.

Blacklist: NASA's NEO Office has a list of about 140 potentially dangerous asteroids. So far, the most dangerous is the asteroid bearing the sign Apophis 99942, about 250m in size. Discovered in 2004, the planet has a probability of 1/38 the possibility of colliding with the earth on April 13, 2029. With more data to locate the asteroid's orbit, astronomers lowered this probability to 1 / 45,000 and pushed the time to 2036. However, Apophis is still a dangerous asteroid. The most collision-causing engine in the mysterious universe.

Deflect orbit

A group of NASA-funded and privately funded B612 scientists have proposed several protocols to push or destroy or push a NEO out of orbit to hit the earth. So far, no method has been funded, although asteroids that follow Dawn's mission will be launched this month. And NASA is studying the use of existing rocket technology and spacecraft to bring an astronaut onto an asteroid. If successful, this would greatly support the design of future deviant strategies.

(Photo: Popsci.com)

Here are some plans to save the earth at the risk of collisions:

Nuclear bomb explosion: We can use nuclear bombs, but there is a risk that the nuclear bomb explosion will turn a killer asteroid into smaller smaller asteroids, flying unspecified orbits and carry radiation.

Smash: A spaceship will crash into an object, make it deviate from orbit or smash it out. This may sound good, but it also has the potential to increase the risk from these fragments, like a bomb plan.

Drag - push: A spaceship will push or pull objects. Not dragging sideways because it will cost a lot of energy, but pull forward or backward to increase or decrease the asteroid's flight speed. A push for many months will change the speed of a medium-sized asteroid to slow it down for a few minutes and will deviate from the earth by a few thousand miles. A tug will connect to the asteroid and create a repulsive force that changes the speed. A gravity puller will fly close to the top of a NEO and use the gravitational force to slightly deflect the asteroid's flight path. A solar sail will impact NEO with the slight pressure of light from the sun.

Summarize, forecast collisions and almost collide

65 million years ago, an asteroid about 15 km in diameter fell to the east coast of Mexico today, making most of the earth filled with debris, fires and poisonous gas. Today scientists assume that the dinosaurs along with most other species are extinct and only the burrowing animals, ie our ancestors, are alive.

June 30, 1908: An object, possibly a comet of size 60 - 80m, exploded in the Tunguska River basin of central Siberia, Russia. Destroy more than 600 km ^{2 of} forest. There are no reports of casualties.

November 30, 1954: A nearly 20kg meteorite falls through the roof of a house in Sylacauga, Alabama, USA, bouncing on a radio and hitting Ann Elizabeth Hodges, who is taking a nap on the bench - here is the only meteor ever hit humans. She had a bruise on her hip.

January 12, 2004: When first seen and thought that the 2004 Asteroid will hit the Northern Hemisphere within a few days, astronomers are extremely confused about who to call - United Nations, president or agency NASA? The six-hour tense passed until an amateur astronomer in Colorado sent data to show that the asteroid would not hit the earth.

April 13 , 2029 : Asteroid 99942 Apophis will pass by, nearly 35,000km from the earth - which is closer than any other 8,000km weather satellite. It can be seen with the naked eye. At the same time the earth's gravity will disturb the movement of this 250m asteroid, increasing the likelihood that it will return and crash into the earth on April 13, 2036.

March 16, 2880: Asteroid 1950 DA, with a size of about 800m, has a probability of 1/300 of the ability to hit the earth, the highest probability today for any object. But in 873 years, know what will happen.

Leaf