Will We Survive the Asteroid Encounter of 2029?
In the 1998 movie Armageddon, NASA discovers a Texas-sized asteroid that will hit the earth in 18 days. The President asks: “What kind of damage are we…”. The reply: “Damage? Total, sir. It’s what we call a global killer. The end of mankind. Doesn’t matter where it hits. Nothing would survive, not even bacteria.”
The agency recruits a misfit team of deep core drillers led by Bruce Willis to destroy the asteroid and save the planet. They agree under the condition that they will never have to pay taxes again. They fly a nuclear weapon to the asteroid and blow it to smithereens. Although they were successful in the movie, scientists believe that using a nuclear weapon to divert or destroy an asteroid would not work. In the movie it did work, because after all, it’s a movie,
Asteroids, meteors and comets
An asteroid is a body of rock that orbits the Sun. Within and nearby our solar system, more than 10 trillion asteroids and comets orbit in the cold silence of space. Most asteroids in our solar system are found in the main asteroid belt, a region between Mars and Jupiter. Others orbit the Sun in a path that takes them near Earth.
A meteor is a small piece of an asteroid that burns up upon entering Earth’s atmosphere. The American Meteor Society has catalogued 100 recurring meteor showers. When you see a meteor, it’s already in our atmosphere.
A comet differs from an asteroid in that rather than rock, it is made of dust and ice. Like an asteroid, a comet orbits the Sun. The most well known is Halley’s comet, which orbits the Sun once every 75 years. As a comet approaches the Sun, the ice and dust begin to vaporize and become the comet’s tail. You can see a comet even when it is very far from Earth.
Significant Collisions with the Earth
Three noteworthy asteroid collisions have occurred in the last 110 years: in Tunguska, Russia in 1908; in the Curuça River, Brazil in 1930; and in Chelyabinsk, Russia in 2013.
The Tunguska event leveled an area of 770 square miles, flattened forests and killed reindeer but caused no human casualties. In 1930, inhabitants along the Curuça River in Western Brazil near Peru reported seeing “a blood-red sky and a rain of red dust followed by an eerie whistling sound and fireballs in the sky.” When the asteroid hit the earth, the energy released in this explosion was only 1/10 as powerful as the Tunguska explosion. Yet it was 50 times more powerful than the Hiroshima bomb.
In 2013, a 65-foot-wide meteor exploded 14 miles above the Russian city of Chelyabinsk. Traveling at 11 miles per second, it damaged thousands of buildings. More than 1,500 people were hospitalized due to injuries from the debris caused by the shockwave. Scientists predict that a similar collision will occur every 60 years.
The Day the Dinosaurs Became Extinct
The best understood worldwide extinction event in history occurred 65 million years ago near the Mexican town of Chicxuluv in the Yucatan Peninsula. The crater was discovered in the late 1970s by geophysicists searching for petroleum in the Yucatán. In 1990, they found a gravity anomaly and tektites (gravel-size rocks resulting from asteroid impacts), suggesting it was an impact feature.
A 300-foot-long asteroid weighing 2 trillion metric tons crashed into the Gulf of Mexico 65 million years ago. It ended the age of dinosaurs and caused the extinction of nearly every species on the planet. Using the fossil and geologic records, scientists have constructed a detailed narrative of what occurred over the few months following the collision.
Scientists calculated that as the asteroid neared our planet, the Earth’s gravity accelerated it to a velocity of 44,000 miles/hour. As the asteroid entered the atmosphere at a shallow angle, it skimmed Earth’s surface and created a plasma (a superhot gas) wave in its wake. It then became a fireball as it passed through the atmosphere, its surface glowing with a light 20 times brighter than the surface of the sun. The energy of the collision with the Earth was 1 billion times greater than that of the Hiroshima atom bomb.
Scientists believe that the light it emitted caused the flesh of dinosaurs to become transparent and burn their shadows into the ground. This intense light boiled the moisture from all living things. It vaporized the Gulf of Mexico in an instant and disintegrated upon contact with the seabed. This caused a magnitude 11 earthquake. the result was a tsunami that traveled thousands of miles to the north, reaching the Pacific Northwest 16 minutes after the impact.
A super-hot ejecta cloud, consisting of particles from the collision that were vaporized by the impact, travelled around the globe, killing all life on the ground. Some species did survive. Fish and crocodiles took refuge underwater; small mammals, snakes, insects, arachnids, and lizards moved underground; and birds flew or swam away from the disaster zone. However, the dinosaurs who ruled the earth became extinct. Three years passed before the atmospheric dust from the collision dispersed enough to enable sunlight to reach the surface.
Apophis Will Pay Us a Visit in 2029
Apophis is named after the Egyptian god of chaos. Taller than the Eiffel tower, the asteroid will pass the Earth in 2029 at a distance of only 19,000 miles.
NASA has classified this asteroid as a potentially hazardous object. It will pass us in an orbit much closer to earth than our GPS satellites. By a quirk of fate, it will fly by again on Friday, April 13th in 2037.
A collision with the Earth by an object of this size would release the energy of 1000 atom bombs of the size dropped on Hiroshima, and depending upon where it hit, could cause massive destruction. Fortunately, astronomers have calculated that Apophis is unlikely to impact the Earth.
Can We Protect Ourselves from Asteroid Encounters?
The Gravity Tug: One approach, as yet untried, is to put a massive rocket close to the asteroid. If its mass is sufficient, the rocket’s gravity would attract the asteroid. The rocket could then tow the asteroid to a safer orbit. While theoretically possible, we have not yet been forced to try this method.
The Double Asteroid Redirection Test: DART is a Space X probe designed to collide with an asteroid to change its trajectory. Its first target is a pair of asteroids named Didymus. The larger is approximately 780 meters (2559 feet) in diameter, the size of a small mountain. Its moon, Dimorphous, is the size of the Great Pyramid of Giza. Their large mass makes them dangerous to us. DART should arrive at the double asteroid by either September or October 2022. The hope is that it will crash into Dimorphous and alter its orbit.
This asteroid pair does not threaten us. From this research, scientists will learn whether it would be possible to alter the solar orbit of a hazardous asteroid to deflect it from crashing into the Earth.
Our Vulnerable Future
Asteroid threats remind me of our fragility as a species. This morning I read an article about the fires raging on every continent. It contained a photograph of the Earth taken from space. From that vantage point, our planet looks as though it is recovering from an asteroid impact. If we are not mindful, climate change may do the work of an asteroid. We won’t need an encounter.
