NEO 2015 TB145: 5 Facts About "Halloween Asteroid

[Astronuc]

Five Things to Know About the 'Halloween Asteroid'
https://gma.yahoo.com/5-things-know-halloween-asteroid-002900478--abc-news-Halloween.html

This asteroid was only discovered days ago. Coming within 1.3 lunar distances -- or ~310,000 miles (49000 km) -- the asteroid, called 2015 TB145 (width ~ 400 m), will brush past Earth but presents no threat to humans. NASA said this asteroid is incredibly fast and predicts it will zoom past Earth at 78,000 miles per hour (125500 kmph).

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2015 TB145;orb=1

The next close encounter of an object that size is expected to happen in in August 2027. That asteroid -- 1999 AN10 -- is estimated to be ~800 m and will brush by our planet at a distance of about 238,000 miles, according to NASA.

Back in January 2015, NASA cited the following:

An asteroid, designated 2004 BL86, will safely pass about three times the distance of Earth to the moon on January 26. From its reflected brightness, astronomers estimate that the asteroid is about a third of a mile (0.5 kilometers) in size. The flyby of 2004 BL86 will be the closest by any known space rock this large until asteroid 1999 AN10 flies past Earth in 2027.

At the time of its closest approach on January 26, the asteroid will be approximately 745,000 miles (1.2 million kilometers) from Earth.

But now we have a closer encounter with 2015 TB145.

Some background:
https://en.wikipedia.org/wiki/(137108)_1999_AN10 - one of many Apollo asteroids
https://en.wikipedia.org/wiki/List_of_Apollo_asteroids

As of 1 August 2015 NASA had listed a cumulative total of 1,605 discovered potentially hazardous asteroids (PHAs). Among these, there are 154 PHAs believed to be larger than one kilometer in diameter.
https://en.wikipedia.org/wiki/Potentially_hazardous_object

But not to worry, they've always been there.

 

[mfb]

An impact of a 400 m asteroid is sufficient to devastate a larger region (energy of several thousand megatons TNT equivalent, >100 times the Tsar Bomba), and 20 days is a really short warning time - probably not enough for evacuations, especially as a precise orbit determination needs some time. Another good reason to improve the systematic searches for those asteroids.

Here is a calculator for impact effects

 

[Astronuc]

Asteroid 2015 TB145 will pass safely by Earth at a range of about 300,000 miles (480,000 kilometers), about 1.3 times the distance between the Earth and the moon. Radar observations of the asteroid have shown it to be larger than expected - it's 1,968.5 feet (600 meters) wide - and rotating once every five hours. The asteroid is speeding through space at 78,293 mph (126,000 km/h) and has shown some signs suggesting it may be a comet.

http://news.yahoo.com/boo-halloween-asteroid-looks-just-creepy-skull-113709066.html