Asteroids and Comets are the biggest weapons of mass destruction that can never be built by humans. An asteroid just a couple of miles in diameter can almost completely destroy the entire human population of the world.
Let’s go step by step in understanding the dangers from these celestial bodies.
The formation of the Universe
The best theory that can be associated with the development of the Universe is the ‘Big Bang’ theory.
In physical cosmology the Big Bang is a theory that the Universe emerged from a dense and hot state about 13.7-billions years ago. This dense and hot plasma was broken by the gravitational forces and that resulted in the biggest explosion in the history of the Universe.
This explosion scattered the Universe into tiny bits. These bits then with the passage of time formed the planets and the stars. The energy from the Big Bang caused an immense rise in temperature of the bits that were formed after the explosion. The expansion proceeded and the temperature steadily dropped until a point was reached when atoms could form. The left over energy continued to cool as the Universe expanded and today it forms the cosmic microwave background radiation.
The current hypothesis is that the solar system formed some 4.6 billion years ago after the gravitational collapse of a gaseous cloud. This gave birth to the nine planets and our only star that is the Sun.
Formation of Planets and Asteroids
After the collapse of the gaseous cloud the solid material cooled down after millions of years and formed planets. But still some particles after the explosion could not form planets as they were too small. These rocks are called the asteroids.
Asteroid Belt
The main asteroid belt occupies an orbit between the Mars and Jupiter. Jupiter has a high gravitational force and it prevents these asteroids from reaching Earth. But when two asteroids collide with one another in space they change their orbits and many of them come hurling towards Earth. These asteroids are termed as ‘Near-Earth Asteroids’. When Asteroids enter the Earth’s atmosphere they are called as Meteors.
Danger to Earth
These ‘Near-Earth Asteroids’ possess a grave danger to the human civilization. We have evidence of asteroid strike on Earth and on the Moon. Earth is protected from these asteroids because it has a dense atmosphere and anything that tries to enter the Earth from space is roasted because of the atmosphere and the gravitational field.
But what if they enter?
Asteroids are traveling at an average speed of 25km/Second. The speed of an asteroid tells us exactly about how big the impact would be if it were to hit Earth. If an asteroid gets closer to the sun, its speed increases due to a slingshot effect from the intense gravity of the sun. This makes the asteroids reach earth at a speed that is fifty times the speed of a jetliner.
If you consider the solar system as a shooting range then we can say that there are bullets that are coming from Space at speeds of 25km/second and our planet is in between these bullets going at a rate of 20km/second.
History of Asteroid Collision with Earth
Earth is not as luck to have avoided all these bullets from the day of its formation. There have been several hits and one of them claimed the entire Dinosaur civilization from our planet some 65 million years ago.
According to the assertion put forward by Australian Engineer Michael Paine, during the last 10,000 years Earth was hit about 350 times by an Asteroid as large as the rock that wasted 2,000 square kilometers of Siberian forest in 1908.
Let’s jump back in time to learn about some more asteroid collisions:
• 65 Million Years Ago:
A 10-Kilometer asteroid strikes north of the Yucatan Peninsula, causes a global firestorm and then a cold snap and finally global warming that extinguishes Dinosaurs and 70% of the life on the planet.
• 3.3 Million Years Ago:
An impact in Argentina precedes numerous extinctions and a global cooling trend.
• 50,000 Years Ago:
An iron meteorite a few dozen meters across gouges the 1.2 kilometer Barringer Meteorite Crater in Arizona.
• Year 1490:
About 10,000 people die in China when an Asteroid breaks overhead and all small particles rained down earth.
• Year 1908:
As asteroid estimated as 50-meters across explodes above Tunguska, Siberia blowing down trees across 2,000 square kilometers and killing some wild life.
Some Close Misses:
It is not like every asteroid that comes our way will hit us. Many of them miss us like a bullet grazing our skin. Some of these close encounters are:
• Year 1937:
An asteroid named Asteroid Hermes about a kilometer in diameter misses Earth by 600,000 miles. If it had hit millions of humans must have died instantly and millions later.
• Year 1998:
Astronomers announce that an asteroid may be on a collision course for Earth. The warning is withdrawn after further observations.
• 18th March 2004:
The closest asteroid ever recorded to pass by the earth. It was discovered by NASA. The asteroid named Asteroid 2004 FH was only 30-meters across and it passed by the Earth at a distance of only 43,000 km. That is where the weather satellites are orbiting. It was so close to Earth that people in Europe and Asia could have seen it just with binoculars.
Future Dangers
They are every where in the solar system and can easily destroy our planet. An Asteroid named Asteroid 2002 NT7 was initially predicted to have a collision with Earth on February 1, 2019. This asteroid is like a space bomb that is 1.2-miles wide and is on a near collision course for Earth and will pass our planet if we are lucky on February 1, 2019. But still if anything comes in the way of the Asteroid and it changes it’s path and comes straight into Earth then we are at risk.
How to protect Earth from Possible Asteroid Collisions
Many Scientists are thinking about mechanisms that can divert these asteroids or destroy them before they destroy us. These include:
• Destroying Asteroids with a Bomb:
This is the way the sci-fi movies do it. But the process is not as easy as it looks in the movies. The reason is that asteroids can be destroyed by a nuclear bomb. But still the tiny fragments will remain on the course of Earth and now they will be radioactive.
• Making a space Tug-boat:
This is a brilliant idea that is to develop a space tug-boat that can dock itself to an incoming asteroid and take it away from the earth that is change its orbit.
• Using Solar Energy to Destroy Asteroids:
If we are able to develop and launch a solar reflector that is about half a mile in diameter and can focus the rays of the sun on the asteroid so that the emission of gases from the asteroid on heating can act as a small engine to propel the asteroid to some other orbit then we can surely save our planet.
All these ways that I discussed above are in development stage. If I talk frankly then we are in a great danger and no space agencies are thinking about these dangers. Maybe only future will tell how are we going to protect ourselves from a danger as big as this?
For now I leave you with a question. Are the space agencies capable in protecting us from an asteroid collision that can wipe out the entire human civilization from our planet or we should pray to get to make Earth a bit luckier...?
