Will near-Earth asteroid Apophis strike us in 2068?
Despite widespread affirmative reports, the collision threat is likely negligible.
Many observations, over long timescales, are required to precisely reveal an asteroid’s trajectory.
Close gravitational encounters will also induce significant orbital changes.
Finally, solar heating will lead to volatile offgassing, accelerating asteroids with shape irregularities and rotational motions.
Discovered in 2004, Apophis presently orbits the Sun every 323 days.
Initial measurements indicated Apophis had a 1-in-37 chance of impacting Earth in 2029.
That’s untrue; Apophis will miss Earth by 47,000 km (29,000 miles), with gravity drastically altering its orbit thereafter.
Newly acquired Subaru telescope observations of Apophis revealed a surprise: the Yarkovsky effect.
Sunlight heated the rotating, irregular asteroid, causing unexpected accelerations.
Prior odds of a 2068 collision were estimated at 1-in-150,000; new odds will require a reanalysis.
New satellite megaconstellations complicate ground-based observations near dusk and dawn: the most critical asteroid-tracking window.
Hypothetically, a collision would release ~1200 Megatons of TNT of energy: enough to create a ~5 km (3 mile) crater.
However, with just 0.001% the mass of the legendary dinosaur-killing asteroid, it poses no extinction threat.
Possible mitigations include a future deflection mission: potentially in 2029 or 2036.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.