Another asteroid has been detected barreling through space on a rendezvous with Earth. The asteroid, 2011 AG5 may pass so close to our planet it could skim Earth's atmosphere—even impact with an explosive force equal to an atomic blast. Current calculations of the asteroid's trajectory show it arriving on February 5, 2040.
Astronomers, however, say the chances of the 460 feet wide space rock hitting are only about one in 625.
The United Nations Action Team 14 during discussions about the newly discovered asteroid and its potential threat say that it cannot be labelled a high threat yet because one or two full orbits are needed to accurately calculate its orbital path and whether or not it will hit Earth.
'Keyhole' key to potential impact
Detlef Koschny of the European Space Agency’s Solar System Missions Division in Noordwijk, The Netherlands, explained to SPACE.com that "2011 AG5 is the object which currently has the highest chance of impacting the Earth…in 2040. However, we have only observed it for about half an orbit, thus the confidence in these calculations is still not very high."
Crucial to the orbital math of the asteroid's path is the so-called "keyhole"—a narrow window that a NEO must pass through before it can be declared as an imminent danger to Earth.
NASA's Jet Propulsion Laboratory in Pasadena, California believes 2011 AG5's keyhole is about 62 miles across. If the asteroid passes through that keyhole it will probably hit Earth in 2040, the space agency says.
Since the inception of NASA's Near-Earth Object Observations (NEO) Program tracking objects in space that may be hazardous to life on Earth has become much more refined. Scientists began taking asteroid impacts much more seriously when it was discovered that dinosaurs were wiped out by a gargantuan impact near the Yucatan some 65 million years in the past.
Asteroids and comets pose a danger as some have caused mass extinctions or caused massive devastation to whole continents. Depending on its size, mass and velocity, an asteroid impact could destroy a city, part or all of a continent, or theoretically the entire world.
It's now believed a planetoid impact with Earth about 3 billion years ago created the Moon and destroyed all existing life on Earth, effectively sterilizing the planet. After the slate was wiped clean the process of life had to begin all over again.
While the NEO Program is a good start, the Russians are calling for a unified asteroid deflection program that's internationally funded and equipped. They believe that someday such a defense network may mean the difference between the survival of the human race or its ultimate extinction.
Russian scientists point to the famous Tunguska incident that destroyed a huge region of the Siberian forest in 1908. Evidence suggests that a cometary mass exploded in the atmosphere with a force equal or greater than the atomic bomb detonated over Hiroshima, Japan. Another impact like Tunguska could occur over a city annihilating it and possibly killing millions. People would be vaporized. The kinetic force would be terrifyingly huge.
Incinerating shock waves from the impact would ignite firestorms and destroy buildings as far as one hundred miles away. Winds would approach speeds of hundreds of miles per hour.
Three other NEOs threaten Earth
Three other asteroids potentially threaten Earth. The first NEO that NASA's JPL is watching closely is 2002 NT7. It is calculated to make a very close pass on February 1, 2019. Because of its size, about 1.5 miles wide, it's been dubbed a "continent killer" because its mass and speed are enough to vaporize most of a continent. Thankfully, the probability that it will hit Earth is diminishing. Although it might still impact if there are perturbations in its orbit, it's much less likely than the initial calculations back in 2002 suggested.
A second NEO, the well-known, much discussed Apophis, has been dismissed by NASA as a threat. The Russians, however, are still convinced that it may impact in 2036 seven years after making a very close pass to Earth in 2029.
Russian scientists warn that Apophis could cause the biggest disaster in history creating supersonic tsunamis if it impacted the ocean or wiping out several countries if it impacted over land.
Finally, the third NEO, 1999 RQ36 may be the most worrisome threat, at least Spanish astronomers think so. Maria Eugenia Sansaturio, and astronomers from the Universidad de Valladolid in Spain, believe asteroid 1999 RQ36 has two opportunities to hit Earth during the year 2082. The asteroid is about the same size as Apophis.
With all the talk of asteroids, destruction, extinction and international programs to deflect asteroids from Earth collisions, Anatoly Perminov, the head of the Russian Federal Space Agency Roscosmos, was recently asked if all of those things just smack of science fiction.
Perminov's grim answer: “People’s lives are at stake. We should pay several hundred million dollars and build a system that would allow us to prevent a collision, rather than sit and wait for it to happen and kill hundreds of thousands of people.”