CLOSE CALL: 2015 TB145: Huge Halloween asteroid discovered three weeks before flyby of Earth.

A large asteroid is set to pass Earth on Halloween, surprising astronomers who only discovered it two weeks ago. The asteroid, which measures up to 2,000ft in diameter, will flyby Earth at a distance of around 310,000 miles, or 1.3 lunar distances – the largest object to come so close to our planet in recent years.

Despite its size, the asteroid – called 2015 TB145 – was found just three weeks before its closest approach by astronomers using the Pan-STARRS I telescope in Hawaii. Nasa said it is the biggest asteroid to come this close to Earth until 2027.

“The asteroid is on an extremely eccentric and a high inclination orbit,” the space agency said in a statement, possibly explaining why it avoided detection until two weeks ago. “This is the closest approach by a known object this large until 1999 AN10 approaches within one lunar distance in August 2027. The last approach closer than this by an object with H < 20 was by 2004 XP14 in July 2006 at 1.1 lunar distances." . . . The asteroid's flyby comes as prominent scientists call for more research into asteroid-tracking technology to protect the planet from unknown space rocks. It is currently estimated we have detected around 1% of asteroids bigger than 40m that could pose a risk to Earth. Asteroid Day, launched earlier this year, outlined the goal of rapidly increasing asteroid detection over the next 10 years. Organisers said they want to find 100,000 asteroids every year – at present we have found around 10,000 in total.

If we develop our technology properly, those asteroids won’t be threats, but opportunities. Here’s my InstaVision interview with Planetary Resources’ Chris Lewicki on that.