Drawing in a deep breath, Pam released it slowly and said, “Let me see if I’ve got this. Sixteen months ago, LaSagra in southern Spain, determined that 2007 AG5, an M-class approximately 45 meters in diameter, will pass within about 3.5 Earth radii of the Earth’s surface inside the geosynchronous satellite ring. Seventeen hours ago, you, Dr. Mehta . . .” Pam nodded toward the astrophysicist on the other side of her desk. “. . . discovered that 2007 AG5 was hiding another asteroid. A larger asteroid. An asteroid over a kilometer in diameter, masked by the metal content of AG5, including, but not limited to, the brightness of reflected light from its polished surface. You determined the existence of this second asteroid mathematically while killing time waiting for Vesta data to run rather than by actually finding another bright spot in the sky.”

Dr. Mehta’s brows rose, but before she could speak, Pam raised a hand.

“My apologies; that was uncalled for.” Blaming the messenger was not the response of a person with her training and experience. “I’m not doubting your math. I’d like to, given that we apparently have twenty-one months before impact, but I’m not.” At least not right now. It seemed a safe assumption that after discovering an NEO on its way to becoming slightly more than near, everyone would check and then recheck the math. “How long before the trajectories of the two asteroids diverge to the point where there’ll be too many sightings of the second for us to keep . . .” She glanced down at the screen of her tablet, frowned, and looked up. “Seriously, Dr. Grayson? The Armageddon Asteroid? You’re naming a large chunk of rock that will destroy a significant proportion of life on this planet unless we pull off the Hail Mary Pass to end all Hail Mary Passes after a Michael Bay movie?”

“Subsurface nuclear explosives are one of the listed diversion options,” Dr. Grayson pointed out. He covered a yawn with the back of his hand. “Sorry, I can’t sleep on planes. And technically, subsurface nukes are possible. Sort of.”

“Maybe Bruce Willis can save us,” Dr. Mehta offered, rolling her eyes.

“Let’s not rule it out. All right . . .” Pam rewound the conversation back to before the distraction of a scientifically ludicrous movie. “. . . how long before there’s too many sightings worldwide for us to keep this secret? And when I say secret, I mean out of the media, off the blog-sphere, public panic delayed?”

“Given the way the budgets have been cut for the big scopes and that amateurs tend to ignore asteroids once they’ve been listed . . .” Dr. Mehta tucked a strand of short dark hair behind her ear and shrugged. “. . . with luck, six months.”