I have read a lot and watched some you-tube videos (some by marginally lunatic fringe Christians - not necessarily invalidating) searching for asteroid September 2015 or comet September 2015.
There is some Biblical evidence that, if one doesn't spiritualize / make literally invalid by symbolic exercise, that at the time of the End Of The Age there will be a uniquely severe, single great Earthquake (Isaiah 29:6, Zecharia 4:7, Haggia 2:6, Revelation 6:12, Revelation 16:18) and destructive objects described as hail, mountains falling from the sky, stars falling onto Earth. I note that ancients would not recognize the vastness of outer space and meteroids, asteroids, comets, planets being what we know them as.
There is also the exact symbol of "Then the second angel blew his trumpet, and a great mountain of fire was thrown into the sea. One-third of the water in the sea became blood, one-third of all things living in the sea died, and one-third of all the ships on the sea were destroyed." (Revelation 8:8,9).
That being introduced, is there any secular, scientific, visible evidence that there just might be a 2 mile MOL wide asteroid / comet heading into collision with Earth? I note that the 3 body problem in astronomy makes determining the trajectory of objects in space under the influence of numerous gravity emitters difficult. It takes super-computing to calculate the motion of a 3rd body in an iterative manner. Also, this object has supposedly been tracked for a long time. A planet sized object might be tracked years in advance, but tracking a several mile wide object? And for years?
A seriously sober mystic claims that he was told by God about such an object over flying, smashing part of Puerto Rico and splashing into the Caribbean causing an epic earthquake and a tsunami that could over flow half of Florida under water. This tsunami would travel throughout the Gulf of Mexico and up the Atlantic coast of North America doing catastrophic damage worse than the Indian Ocean or Japanese tsunami of recent history. Another you-tuber claims she has a secular, secret source identifying a comet striking into the Atlantic off Venezuela or Brazil.
I do not believe that the WTBTS has any ability to investigate such an event. The WTBTS would have to invalidate hundreds of pages of figurative explanations of the seven seals, seven trumpets, mountains of fire falling into the sea. The WTBTS wants an absolute monopoly on Biblical topics and they have disqualified anyone else from being prophet teachers or prophets of any degree. The WTBTS has a complete failure / poor record with prophecy, even the return of the League of Nations / UN was in newspapers before they claimed to have deciphered prophecy. Thus, liars and bigots and cultic editors need not stand up and bark.
Large objects have crashed down onto the Earth. There is a large crater in Arizona called Canyon Diablo Crater or Barringer Crater. It is about 1,200 m (3,900 ft) in diameter, some 170 m deep (570 ft), and is surrounded by a rim that rises 45 m (148 ft) above the surrounding plains. The meteor was only about 160 feet wide. Also the Chelyabinsk meteor was 60 feet wide and exploded 97000 feet up. I know nothing about the supposed dinosaur killer.
Well? Anyone got anything of substance?