Just outside of Mars’ orbit – the circle it travels around the sun – is an extremely wide belt of asteroids floating in space. Sometimes, these asteroids may brake out of their orbit, and be attracted to the sun. This turns the asteroid into its own mini planet, creating its own orbit around our star. Unlike our planets, though, the size of an asteroid, and the magnetic forces of the otehr planets in our solar system, cause the orbit to be an ever changing elliptical. This is what puts planets and stars at risk, the star’s gravitational force pulls on the asteroid, yet the asteroid can’t get out of the way of pre-existing planets. Should we be afraid?
The answer is no. Presently, according to NASA, Apophis has a 1 in 45,000 chance of interacting with the Earth’s orbit. The reason astronomers are concerned are two fold.
First, there is a window of error in any calculation of an asteroids orbit. As that orbit is in a constant state of metamorphosis, being affected by the many magnetic fields in space, there is an area for a margin of error. If the error is off in the case of Apophis, it will move the asteroid that much closer to impacting Earth.
Secondly, it is believed there are roughly 1,100 asteroids orbiting in our solar system that come “near” Earth’s orbit. Sadly, we’ve only identified about 650 of them.
What can we do to not be afraid of every shadow in the sky?
Support the B612 Foundation. This foundation has met with both the US government and the United Nation. Its goal is to have a plan of action for changing the orbit of any NEO (near Earth Orbit) asteroid, in place by 2015. Currently its favoring a plan that will fasten a nuclear plasma engine to the asteroid surface, thus propelling it out of Earth’s orbit. B612 met with Congress on November 8th and proposed its plan.
A further step in B612’s plan is to launch a type of tracking device onto Asteroid Apophis before it’s first pass through our Earth orbit on April 13, 2029, to better track what it’s return trajectory will be on April 13, 2036.
Also according ti the B612 foundation, Apophis “based on current data [is] approximately 320 – 400 meter’s in diameter. It is projected to pass about 7000 m inside Earth’s orbit (in 2029)…will be an extremely visible object to naked eye observers in both Africa and Europe early on the evening of April 13, 2029.” Extra concern is expressed due to the fact that because the asteroid passes so close to earth the first time “the orbit of the asteroid will be substantially altered,” leaving the return orbit in 2036 to be left up to best probabilities. (1)
So, no, there is no need to stress yet. But I would strongly suggest you write your local congressmen to encourage them to listen to the suggestions made by the B612 Foundation – which incidentally, is a conglomeration of former Astronauts and Cosmonauts.
(1) Letter from Russell Schweickart, CEO of the B612 Foundation to Mr. Michael Griffin, an administrator for NASA on June 6, 2005 http://www.b612foundation.org/