Doomsday Asteroid Apophis Passes By; Found To Be Larger And Less Reflective Than Thought

It's no cause for worry today, but the asteroid Apophis actually has a tiny chance of colliding with Earth. The possible-doomsday asteroid will be whizzing past Earth at a distance that could set it up for a collision with our planet in the future. The bad news? It looks like the asteroid, named after the Egyptian demon of darkness and destruction, is bigger than previously thought. 

ESA's Herschel space observatory took the advantage of the Apophis' current proximity to further study it in detail and found it to not only be larger than previously thought, but also less reflective. 

"The 20% increase in diameter, from 270 to 325 m, translates into a 75% increase in our estimates of the asteroid's volume or mass," says Thomas Müller from Max Planck Institute for Extraterrestrial Physics in Garching, Germany, who is leading the analysis of the new data. 

The asteroid Apophis (also known as asteroid 99942) previously had an albedo, or reflectivity, level of 0.33, meaning 33 percent of sunlight striking the asteroid is reflected. The new data from the Herschel space observatory suggest that the Apophis' albedo level is 0.23, meaning the asteroid will get hotter. 

So what does this translate to? A whole lot of number re-crunching for physicists. 

Apophis was discovered in 2004, when it was revealed that Apophis had a chance of striking the Earth when it comes even closer in April 2029. While there's a far greater shot of it missing our planet by a cosmic hair, the 2029 pass could raise the threat level for when Apophis comes back around in 2036. 

In 2029, it will pass so close to us that Earth's gravity will change its orbit," Professor Alan Fitzsimmons, an astronomer at Queen's University in Belfast said in a BBC report. 

"Most of the potential orbits it will end up on will mean we are safe for the next 100 years. But there is a small region of space - something we call a keyhole - and if it passes through that keyhole in 2029, it will come back and hit us on 13 April in 2036."

The decreased reflectivity also means long-term changes in the asteroid's orbit due to the Yarkovsky effect, which is the force acting on a rotating body in space caused by thermal photons. 

None of this is any reason for alarm. The potential impacts are at least 16 years away and the odds of it happening are minuscule. If it does hit, astro-guru Neil deGrasse Tyson states that it will hit off the Pacific cost of Santa Monica and create a ripple of tidal waves - so in any case, just relocate if things look grim next decade.