This Asteroid Day, let’s not forget Earth’s greatest future threat

29 Jun 2017

Image: muratart/Shutterstock

30 June marks Asteroid Day, as astronomers highlight humanity’s fragility in the universe.

While people associate asteroids with wiping out the dinosaurs, other incidents – such as the one that occurred in Tunguska, Russia in 1908 – are arguably less well known.

Even as recently as April, asteroid 2014 JO25 whizzed past Earth at its closest approach for 400 years, while in September last year, two other asteroids were only spotted soon before their own near misses.

Despite being vastly different in scale, all asteroid collisions with Earth show that without proper identification and discovery in deep space, those of a certain yield will be found far too late.

Established in 2014 with the help of Queen guitarist and astrophysicist Dr Brian May, Asteroid Day is now a major event on the global sci-tech calendar, as astronomers highlight the clear and present danger brought by their presence near Earth.

The date of 30 June was not chosen at random, but rather to mark the anniversary of the Tunguska event, which saw an asteroid explode over rural Russia with the power of a 30-megaton blast.

Central to Asteroid Day’s objective is the 100X Declaration, which calls for a 100-fold increase in the detection and monitoring of asteroids.

With support from the UN and thousands of astronomers, the day will mark a number of live events streamed online, including a 24-hour broadcast from Luxembourg, a country with a keen interest in tracking and even mining asteroids in the future.

On the subject of future species-ending asteroids, humankind’s biggest fright in decades occurred back in 2004 with the discovery of Apophis.

Named after the Egyptian god of chaos, Apophis was identified as the asteroid most in danger of striking Earth. Despite an expected safe passage during its next flyby in 2029, a future collision cannot be ruled out.

The hunt continues

It isn’t all doom and gloom, however. Speaking to Astro Watch, former NASA researcher Alan Harris assured people that, so far, no near-Earth objects (NEOs) have been confirmed to be on a collision course with our planet.

“At present, none of the known asteroids have a probability of impact that exceeds the random chance of an undiscovered asteroid of the same size hitting the Earth sometime between now and the possible impact date of the imperfectly known object,” he said.

Current estimates put the number of discovered NEOs at 16,000, 12,000 of which are more than 50 metres in size, big enough to enter Earth’s atmosphere without totally disintegrating.

NASA’s current manager of the Center for NEO Studies, Paul Chodas, is one of those tasked with finding the much, much larger ones, approximately 1km in size.

Speaking with Newsweek, he said that his centre’s remit is to find 90pc of NEOs 140 metres in size or larger. So far, it has only managed to find one-third of these.

It’s safe to say that the hunt for all of space’s civilisation-ending NEOs will continue for some time.

Meanwhile, young, Irish space enthusiasts will get a chance to mark Asteroid Day with a series of free events being held at NUI Galway, including the opportunity to build their own rockets and model asteroids out of clay.

Colm Gorey was a senior journalist with Silicon Republic