A 100ft-wide asteroid, first spotted when it flew by Earth two years ago, is set to make its return on March 8th.
Nasa’s initial estimate showed the whale-sized space rock may skim past Earth at just 11,000 miles (17,000 km), which is around 21 times closer to Earth than the moon – but Nasa admitted this estimate may be widely inaccurate, and the asteroid may also pass Earth as far out as 9 million miles (14 million km).
Now a new prediction for 2013 TX68 is that it will fly by roughly 3 million miles (5 million kilometers) from our planet.
‘Additional observations of asteroid 2013 TX68 have been obtained, refining its orbital path and moving the date of the asteroid’s Earth flyby from March 5 to March 8,’ Nasa said.
The observations, from archived images provided by the Nasa-funded Pan-STARRS asteroid survey, enabled scientists at Nasa’s Center for Near-Earth Object Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, California, to refine their earlier flyby and distance predictions, reconfirming that the asteroid poses no threat to Earth.
‘We already knew this asteroid, 2013 TX68, would safely fly past Earth in early March, but this additional data allow us to get a better handle on its orbital path,’ said Paul Chodas, manager of CNEOS. ‘
The data indicate that this small asteroid will probably pass much farther away from Earth than previously thought.’
CNEOS’s new prediction for 2013 TX68 is that it will fly by roughly 3 million miles (5 million kilometers) from our planet.
There is still a chance that it could pass closer, but certainly no closer than 15,000 miles (24,000 kilometers) above Earth’s surface.
The new observations also better constrain the path of 2013 TX68 in future years; CNEOS has determined that 2013 TX68 cannot impact Earth over the next century.
‘There is no concern whatsoever regarding this asteroid – unless you were interested in seeing it with a telescope,’ said Chodas.
‘Prospects for observing this asteroid, which were not very good to begin with, are now even worse because the asteroid is likely to be farther away, and therefore dimmer than previously believed.’
Orbit calculations of asteroids are constantly updated based on observations reported to the Minor Planet Center.
This results in projections of minimum, maximum and nominal distances from Earth, which can sometimes have a wide disparity due to limited data.
Over time, with additional observations added to the equation, scientists are able to refine and narrow the orbit uncertainties.
Scientists have also identified an extremely remote chance that this small asteroid could impact on September 28, 2017, with odds of no more than 1-in-250-million.
‘The possibilities of collision on any of the three future flyby dates are far too small to be of any real concern,’ said Paul Chodas, manager of CNEOS.
‘I fully expect any future observations to reduce the probability even more.’
Asteroid 2013 TX68 is estimated to be about 100ft (30 meters) in diameter.
By comparison, the asteroid that broke up in the atmosphere over Chelyabinsk, Russia, three years ago was approximately 65 feet (20 meters) wide.
If an asteroid the size of 2013 TX68 were to enter Earth’s atmosphere, it would likely produce an air burst with about twice the energy of the Chelyabinsk event.
The asteroid was discovered by the Nasa-funded Catalina Sky Survey on October 6, 2013, as it approached Earth on the night-time side.
After three days of tracking, the asteroid passed into the daytime sky and could no longer be seen.
Because it was not tracked for very long, scientists cannot predict its precise orbit around the sun, but they do know that it cannot impact Earth during its flyby next month.
‘This asteroid’s orbit is quite uncertain, and it will be hard to predict where to look for it,’ said Chodas.
‘There is a chance that the asteroid will be picked up by our asteroid search telescopes when it safely flies past us next month, providing us with data to more precisely define its orbit around the sun.’
In September, Paul Chodas, manager of Nasa’s Near-Earth Object office at the Jet Propulsion Laboratory in Pasadena, said: ‘There is no existing evidence that an asteroid or any other celestial object is on a trajectory that will impact Earth.
‘In fact, not a single one of the known objects has any credible chance of hitting our planet over the next century.
Nasa tracks around 12,992 near-Earth objects which have been discovered orbiting within our solar system close to our own orbit.
It estimates around 1,607 are classified as Potentially Hazardous Asteroids.